LCOV - code coverage report
Current view: top level - pebble - options.go (source / functions) Hit Total Coverage
Test: 2023-12-19 08:16Z 5c5ad7ed - tests only.lcov Lines: 645 733 88.0 %
Date: 2023-12-19 08:16:27 Functions: 0 0 -

          Line data    Source code
       1             : // Copyright 2011 The LevelDB-Go and Pebble Authors. All rights reserved. Use
       2             : // of this source code is governed by a BSD-style license that can be found in
       3             : // the LICENSE file.
       4             : 
       5             : package pebble
       6             : 
       7             : import (
       8             :         "bytes"
       9             :         "fmt"
      10             :         "io"
      11             :         "runtime"
      12             :         "strconv"
      13             :         "strings"
      14             :         "time"
      15             :         "unicode"
      16             : 
      17             :         "github.com/cockroachdb/errors"
      18             :         "github.com/cockroachdb/pebble/internal/base"
      19             :         "github.com/cockroachdb/pebble/internal/cache"
      20             :         "github.com/cockroachdb/pebble/internal/humanize"
      21             :         "github.com/cockroachdb/pebble/internal/keyspan"
      22             :         "github.com/cockroachdb/pebble/internal/manifest"
      23             :         "github.com/cockroachdb/pebble/objstorage/remote"
      24             :         "github.com/cockroachdb/pebble/rangekey"
      25             :         "github.com/cockroachdb/pebble/sstable"
      26             :         "github.com/cockroachdb/pebble/vfs"
      27             : )
      28             : 
      29             : const (
      30             :         cacheDefaultSize       = 8 << 20 // 8 MB
      31             :         defaultLevelMultiplier = 10
      32             : )
      33             : 
      34             : // Compression exports the base.Compression type.
      35             : type Compression = sstable.Compression
      36             : 
      37             : // Exported Compression constants.
      38             : const (
      39             :         DefaultCompression = sstable.DefaultCompression
      40             :         NoCompression      = sstable.NoCompression
      41             :         SnappyCompression  = sstable.SnappyCompression
      42             :         ZstdCompression    = sstable.ZstdCompression
      43             : )
      44             : 
      45             : // FilterType exports the base.FilterType type.
      46             : type FilterType = base.FilterType
      47             : 
      48             : // Exported TableFilter constants.
      49             : const (
      50             :         TableFilter = base.TableFilter
      51             : )
      52             : 
      53             : // FilterWriter exports the base.FilterWriter type.
      54             : type FilterWriter = base.FilterWriter
      55             : 
      56             : // FilterPolicy exports the base.FilterPolicy type.
      57             : type FilterPolicy = base.FilterPolicy
      58             : 
      59             : // TablePropertyCollector exports the sstable.TablePropertyCollector type.
      60             : type TablePropertyCollector = sstable.TablePropertyCollector
      61             : 
      62             : // BlockPropertyCollector exports the sstable.BlockPropertyCollector type.
      63             : type BlockPropertyCollector = sstable.BlockPropertyCollector
      64             : 
      65             : // BlockPropertyFilter exports the sstable.BlockPropertyFilter type.
      66             : type BlockPropertyFilter = base.BlockPropertyFilter
      67             : 
      68             : // ShortAttributeExtractor exports the base.ShortAttributeExtractor type.
      69             : type ShortAttributeExtractor = base.ShortAttributeExtractor
      70             : 
      71             : // UserKeyPrefixBound exports the sstable.UserKeyPrefixBound type.
      72             : type UserKeyPrefixBound = sstable.UserKeyPrefixBound
      73             : 
      74             : // IterKeyType configures which types of keys an iterator should surface.
      75             : type IterKeyType int8
      76             : 
      77             : const (
      78             :         // IterKeyTypePointsOnly configures an iterator to iterate over point keys
      79             :         // only.
      80             :         IterKeyTypePointsOnly IterKeyType = iota
      81             :         // IterKeyTypeRangesOnly configures an iterator to iterate over range keys
      82             :         // only.
      83             :         IterKeyTypeRangesOnly
      84             :         // IterKeyTypePointsAndRanges configures an iterator iterate over both point
      85             :         // keys and range keys simultaneously.
      86             :         IterKeyTypePointsAndRanges
      87             : )
      88             : 
      89             : // String implements fmt.Stringer.
      90           1 : func (t IterKeyType) String() string {
      91           1 :         switch t {
      92           1 :         case IterKeyTypePointsOnly:
      93           1 :                 return "points-only"
      94           1 :         case IterKeyTypeRangesOnly:
      95           1 :                 return "ranges-only"
      96           1 :         case IterKeyTypePointsAndRanges:
      97           1 :                 return "points-and-ranges"
      98           0 :         default:
      99           0 :                 panic(fmt.Sprintf("unknown key type %d", t))
     100             :         }
     101             : }
     102             : 
     103             : // IterOptions hold the optional per-query parameters for NewIter.
     104             : //
     105             : // Like Options, a nil *IterOptions is valid and means to use the default
     106             : // values.
     107             : type IterOptions struct {
     108             :         // LowerBound specifies the smallest key (inclusive) that the iterator will
     109             :         // return during iteration. If the iterator is seeked or iterated past this
     110             :         // boundary the iterator will return Valid()==false. Setting LowerBound
     111             :         // effectively truncates the key space visible to the iterator.
     112             :         LowerBound []byte
     113             :         // UpperBound specifies the largest key (exclusive) that the iterator will
     114             :         // return during iteration. If the iterator is seeked or iterated past this
     115             :         // boundary the iterator will return Valid()==false. Setting UpperBound
     116             :         // effectively truncates the key space visible to the iterator.
     117             :         UpperBound []byte
     118             :         // TableFilter can be used to filter the tables that are scanned during
     119             :         // iteration based on the user properties. Return true to scan the table and
     120             :         // false to skip scanning. This function must be thread-safe since the same
     121             :         // function can be used by multiple iterators, if the iterator is cloned.
     122             :         TableFilter func(userProps map[string]string) bool
     123             :         // SkipPoint may be used to skip over point keys that don't match an
     124             :         // arbitrary predicate during iteration. If set, the Iterator invokes
     125             :         // SkipPoint for keys encountered. If SkipPoint returns true, the iterator
     126             :         // will skip the key without yielding it to the iterator operation in
     127             :         // progress.
     128             :         //
     129             :         // SkipPoint must be a pure function and always return the same result when
     130             :         // provided the same arguments. The iterator may call SkipPoint multiple
     131             :         // times for the same user key.
     132             :         SkipPoint func(userKey []byte) bool
     133             :         // PointKeyFilters can be used to avoid scanning tables and blocks in tables
     134             :         // when iterating over point keys. This slice represents an intersection
     135             :         // across all filters, i.e., all filters must indicate that the block is
     136             :         // relevant.
     137             :         //
     138             :         // Performance note: When len(PointKeyFilters) > 0, the caller should ensure
     139             :         // that cap(PointKeyFilters) is at least len(PointKeyFilters)+1. This helps
     140             :         // avoid allocations in Pebble internal code that mutates the slice.
     141             :         PointKeyFilters []BlockPropertyFilter
     142             :         // RangeKeyFilters can be usefd to avoid scanning tables and blocks in tables
     143             :         // when iterating over range keys. The same requirements that apply to
     144             :         // PointKeyFilters apply here too.
     145             :         RangeKeyFilters []BlockPropertyFilter
     146             :         // KeyTypes configures which types of keys to iterate over: point keys,
     147             :         // range keys, or both.
     148             :         KeyTypes IterKeyType
     149             :         // RangeKeyMasking can be used to enable automatic masking of point keys by
     150             :         // range keys. Range key masking is only supported during combined range key
     151             :         // and point key iteration mode (IterKeyTypePointsAndRanges).
     152             :         RangeKeyMasking RangeKeyMasking
     153             : 
     154             :         // OnlyReadGuaranteedDurable is an advanced option that is only supported by
     155             :         // the Reader implemented by DB. When set to true, only the guaranteed to be
     156             :         // durable state is visible in the iterator.
     157             :         // - This definition is made under the assumption that the FS implementation
     158             :         //   is providing a durability guarantee when data is synced.
     159             :         // - The visible state represents a consistent point in the history of the
     160             :         //   DB.
     161             :         // - The implementation is free to choose a conservative definition of what
     162             :         //   is guaranteed durable. For simplicity, the current implementation
     163             :         //   ignores memtables. A more sophisticated implementation could track the
     164             :         //   highest seqnum that is synced to the WAL and published and use that as
     165             :         //   the visible seqnum for an iterator. Note that the latter approach is
     166             :         //   not strictly better than the former since we can have DBs that are (a)
     167             :         //   synced more rarely than memtable flushes, (b) have no WAL. (a) is
     168             :         //   likely to be true in a future CockroachDB context where the DB
     169             :         //   containing the state machine may be rarely synced.
     170             :         // NB: this current implementation relies on the fact that memtables are
     171             :         // flushed in seqnum order, and any ingested sstables that happen to have a
     172             :         // lower seqnum than a non-flushed memtable don't have any overlapping keys.
     173             :         // This is the fundamental level invariant used in other code too, like when
     174             :         // merging iterators.
     175             :         //
     176             :         // Semantically, using this option provides the caller a "snapshot" as of
     177             :         // the time the most recent memtable was flushed. An alternate interface
     178             :         // would be to add a NewSnapshot variant. Creating a snapshot is heavier
     179             :         // weight than creating an iterator, so we have opted to support this
     180             :         // iterator option.
     181             :         OnlyReadGuaranteedDurable bool
     182             :         // UseL6Filters allows the caller to opt into reading filter blocks for L6
     183             :         // sstables. Helpful if a lot of SeekPrefixGEs are expected in quick
     184             :         // succession, that are also likely to not yield a single key. Filter blocks in
     185             :         // L6 can be relatively large, often larger than data blocks, so the benefit of
     186             :         // loading them in the cache is minimized if the probability of the key
     187             :         // existing is not low or if we just expect a one-time Seek (where loading the
     188             :         // data block directly is better).
     189             :         UseL6Filters bool
     190             :         // CategoryAndQoS is used for categorized iterator stats. This should not be
     191             :         // changed by calling SetOptions.
     192             :         sstable.CategoryAndQoS
     193             : 
     194             :         // Internal options.
     195             : 
     196             :         logger Logger
     197             :         // Level corresponding to this file. Only passed in if constructed by a
     198             :         // levelIter.
     199             :         level manifest.Level
     200             :         // disableLazyCombinedIteration is an internal testing option.
     201             :         disableLazyCombinedIteration bool
     202             :         // snapshotForHideObsoletePoints is specified for/by levelIter when opening
     203             :         // files and is used to decide whether to hide obsolete points. A value of 0
     204             :         // implies obsolete points should not be hidden.
     205             :         snapshotForHideObsoletePoints uint64
     206             : 
     207             :         // NB: If adding new Options, you must account for them in iterator
     208             :         // construction and Iterator.SetOptions.
     209             : }
     210             : 
     211             : // GetLowerBound returns the LowerBound or nil if the receiver is nil.
     212           1 : func (o *IterOptions) GetLowerBound() []byte {
     213           1 :         if o == nil {
     214           1 :                 return nil
     215           1 :         }
     216           1 :         return o.LowerBound
     217             : }
     218             : 
     219             : // GetUpperBound returns the UpperBound or nil if the receiver is nil.
     220           1 : func (o *IterOptions) GetUpperBound() []byte {
     221           1 :         if o == nil {
     222           1 :                 return nil
     223           1 :         }
     224           1 :         return o.UpperBound
     225             : }
     226             : 
     227           1 : func (o *IterOptions) pointKeys() bool {
     228           1 :         if o == nil {
     229           0 :                 return true
     230           0 :         }
     231           1 :         return o.KeyTypes == IterKeyTypePointsOnly || o.KeyTypes == IterKeyTypePointsAndRanges
     232             : }
     233             : 
     234           1 : func (o *IterOptions) rangeKeys() bool {
     235           1 :         if o == nil {
     236           0 :                 return false
     237           0 :         }
     238           1 :         return o.KeyTypes == IterKeyTypeRangesOnly || o.KeyTypes == IterKeyTypePointsAndRanges
     239             : }
     240             : 
     241           1 : func (o *IterOptions) getLogger() Logger {
     242           1 :         if o == nil || o.logger == nil {
     243           1 :                 return DefaultLogger
     244           1 :         }
     245           1 :         return o.logger
     246             : }
     247             : 
     248             : // SpanIterOptions creates a SpanIterOptions from this IterOptions.
     249           1 : func (o *IterOptions) SpanIterOptions() keyspan.SpanIterOptions {
     250           1 :         if o == nil {
     251           0 :                 return keyspan.SpanIterOptions{}
     252           0 :         }
     253           1 :         return keyspan.SpanIterOptions{
     254           1 :                 RangeKeyFilters: o.RangeKeyFilters,
     255           1 :         }
     256             : }
     257             : 
     258             : // scanInternalOptions is similar to IterOptions, meant for use with
     259             : // scanInternalIterator.
     260             : type scanInternalOptions struct {
     261             :         sstable.CategoryAndQoS
     262             :         IterOptions
     263             : 
     264             :         visitPointKey   func(key *InternalKey, value LazyValue, iterInfo IteratorLevel) error
     265             :         visitRangeDel   func(start, end []byte, seqNum uint64) error
     266             :         visitRangeKey   func(start, end []byte, keys []rangekey.Key) error
     267             :         visitSharedFile func(sst *SharedSSTMeta) error
     268             : 
     269             :         // skipSharedLevels skips levels that are shareable (level >=
     270             :         // sharedLevelStart).
     271             :         skipSharedLevels bool
     272             : 
     273             :         // includeObsoleteKeys specifies whether keys shadowed by newer internal keys
     274             :         // are exposed. If false, only one internal key per user key is exposed.
     275             :         includeObsoleteKeys bool
     276             : 
     277             :         // rateLimitFunc is used to limit the amount of bytes read per second.
     278             :         rateLimitFunc func(key *InternalKey, value LazyValue) error
     279             : }
     280             : 
     281             : // RangeKeyMasking configures automatic hiding of point keys by range keys. A
     282             : // non-nil Suffix enables range-key masking. When enabled, range keys with
     283             : // suffixes ≥ Suffix behave as masks. All point keys that are contained within a
     284             : // masking range key's bounds and have suffixes greater than the range key's
     285             : // suffix are automatically skipped.
     286             : //
     287             : // Specifically, when configured with a RangeKeyMasking.Suffix _s_, and there
     288             : // exists a range key with suffix _r_ covering a point key with suffix _p_, and
     289             : //
     290             : //      _s_ ≤ _r_ < _p_
     291             : //
     292             : // then the point key is elided.
     293             : //
     294             : // Range-key masking may only be used when iterating over both point keys and
     295             : // range keys with IterKeyTypePointsAndRanges.
     296             : type RangeKeyMasking struct {
     297             :         // Suffix configures which range keys may mask point keys. Only range keys
     298             :         // that are defined at suffixes greater than or equal to Suffix will mask
     299             :         // point keys.
     300             :         Suffix []byte
     301             :         // Filter is an optional field that may be used to improve performance of
     302             :         // range-key masking through a block-property filter defined over key
     303             :         // suffixes. If non-nil, Filter is called by Pebble to construct a
     304             :         // block-property filter mask at iterator creation. The filter is used to
     305             :         // skip whole point-key blocks containing point keys with suffixes greater
     306             :         // than a covering range-key's suffix.
     307             :         //
     308             :         // To use this functionality, the caller must create and configure (through
     309             :         // Options.BlockPropertyCollectors) a block-property collector that records
     310             :         // the maxmimum suffix contained within a block. The caller then must write
     311             :         // and provide a BlockPropertyFilterMask implementation on that same
     312             :         // property. See the BlockPropertyFilterMask type for more information.
     313             :         Filter func() BlockPropertyFilterMask
     314             : }
     315             : 
     316             : // BlockPropertyFilterMask extends the BlockPropertyFilter interface for use
     317             : // with range-key masking. Unlike an ordinary block property filter, a
     318             : // BlockPropertyFilterMask's filtering criteria is allowed to change when Pebble
     319             : // invokes its SetSuffix method.
     320             : //
     321             : // When a Pebble iterator steps into a range key's bounds and the range key has
     322             : // a suffix greater than or equal to RangeKeyMasking.Suffix, the range key acts
     323             : // as a mask. The masking range key hides all point keys that fall within the
     324             : // range key's bounds and have suffixes > the range key's suffix. Without a
     325             : // filter mask configured, Pebble performs this hiding by stepping through point
     326             : // keys and comparing suffixes. If large numbers of point keys are masked, this
     327             : // requires Pebble to load, iterate through and discard a large number of
     328             : // sstable blocks containing masked point keys.
     329             : //
     330             : // If a block-property collector and a filter mask are configured, Pebble may
     331             : // skip loading some point-key blocks altogether. If a block's keys are known to
     332             : // all fall within the bounds of the masking range key and the block was
     333             : // annotated by a block-property collector with the maximal suffix, Pebble can
     334             : // ask the filter mask to compare the property to the current masking range
     335             : // key's suffix. If the mask reports no intersection, the block may be skipped.
     336             : //
     337             : // If unsuffixed and suffixed keys are written to the database, care must be
     338             : // taken to avoid unintentionally masking un-suffixed keys located in the same
     339             : // block as suffixed keys. One solution is to interpret unsuffixed keys as
     340             : // containing the maximal suffix value, ensuring that blocks containing
     341             : // unsuffixed keys are always loaded.
     342             : type BlockPropertyFilterMask interface {
     343             :         BlockPropertyFilter
     344             : 
     345             :         // SetSuffix configures the mask with the suffix of a range key. The filter
     346             :         // should return false from Intersects whenever it's provided with a
     347             :         // property encoding a block's minimum suffix that's greater (according to
     348             :         // Compare) than the provided suffix.
     349             :         SetSuffix(suffix []byte) error
     350             : }
     351             : 
     352             : // WriteOptions hold the optional per-query parameters for Set and Delete
     353             : // operations.
     354             : //
     355             : // Like Options, a nil *WriteOptions is valid and means to use the default
     356             : // values.
     357             : type WriteOptions struct {
     358             :         // Sync is whether to sync writes through the OS buffer cache and down onto
     359             :         // the actual disk, if applicable. Setting Sync is required for durability of
     360             :         // individual write operations but can result in slower writes.
     361             :         //
     362             :         // If false, and the process or machine crashes, then a recent write may be
     363             :         // lost. This is due to the recently written data being buffered inside the
     364             :         // process running Pebble. This differs from the semantics of a write system
     365             :         // call in which the data is buffered in the OS buffer cache and would thus
     366             :         // survive a process crash.
     367             :         //
     368             :         // The default value is true.
     369             :         Sync bool
     370             : }
     371             : 
     372             : // Sync specifies the default write options for writes which synchronize to
     373             : // disk.
     374             : var Sync = &WriteOptions{Sync: true}
     375             : 
     376             : // NoSync specifies the default write options for writes which do not
     377             : // synchronize to disk.
     378             : var NoSync = &WriteOptions{Sync: false}
     379             : 
     380             : // GetSync returns the Sync value or true if the receiver is nil.
     381           1 : func (o *WriteOptions) GetSync() bool {
     382           1 :         return o == nil || o.Sync
     383           1 : }
     384             : 
     385             : // LevelOptions holds the optional per-level parameters.
     386             : type LevelOptions struct {
     387             :         // BlockRestartInterval is the number of keys between restart points
     388             :         // for delta encoding of keys.
     389             :         //
     390             :         // The default value is 16.
     391             :         BlockRestartInterval int
     392             : 
     393             :         // BlockSize is the target uncompressed size in bytes of each table block.
     394             :         //
     395             :         // The default value is 4096.
     396             :         BlockSize int
     397             : 
     398             :         // BlockSizeThreshold finishes a block if the block size is larger than the
     399             :         // specified percentage of the target block size and adding the next entry
     400             :         // would cause the block to be larger than the target block size.
     401             :         //
     402             :         // The default value is 90
     403             :         BlockSizeThreshold int
     404             : 
     405             :         // Compression defines the per-block compression to use.
     406             :         //
     407             :         // The default value (DefaultCompression) uses snappy compression.
     408             :         Compression Compression
     409             : 
     410             :         // FilterPolicy defines a filter algorithm (such as a Bloom filter) that can
     411             :         // reduce disk reads for Get calls.
     412             :         //
     413             :         // One such implementation is bloom.FilterPolicy(10) from the pebble/bloom
     414             :         // package.
     415             :         //
     416             :         // The default value means to use no filter.
     417             :         FilterPolicy FilterPolicy
     418             : 
     419             :         // FilterType defines whether an existing filter policy is applied at a
     420             :         // block-level or table-level. Block-level filters use less memory to create,
     421             :         // but are slower to access as a check for the key in the index must first be
     422             :         // performed to locate the filter block. A table-level filter will require
     423             :         // memory proportional to the number of keys in an sstable to create, but
     424             :         // avoids the index lookup when determining if a key is present. Table-level
     425             :         // filters should be preferred except under constrained memory situations.
     426             :         FilterType FilterType
     427             : 
     428             :         // IndexBlockSize is the target uncompressed size in bytes of each index
     429             :         // block. When the index block size is larger than this target, two-level
     430             :         // indexes are automatically enabled. Setting this option to a large value
     431             :         // (such as math.MaxInt32) disables the automatic creation of two-level
     432             :         // indexes.
     433             :         //
     434             :         // The default value is the value of BlockSize.
     435             :         IndexBlockSize int
     436             : 
     437             :         // The target file size for the level.
     438             :         TargetFileSize int64
     439             : }
     440             : 
     441             : // EnsureDefaults ensures that the default values for all of the options have
     442             : // been initialized. It is valid to call EnsureDefaults on a nil receiver. A
     443             : // non-nil result will always be returned.
     444           1 : func (o *LevelOptions) EnsureDefaults() *LevelOptions {
     445           1 :         if o == nil {
     446           0 :                 o = &LevelOptions{}
     447           0 :         }
     448           1 :         if o.BlockRestartInterval <= 0 {
     449           1 :                 o.BlockRestartInterval = base.DefaultBlockRestartInterval
     450           1 :         }
     451           1 :         if o.BlockSize <= 0 {
     452           1 :                 o.BlockSize = base.DefaultBlockSize
     453           1 :         } else if o.BlockSize > sstable.MaximumBlockSize {
     454           0 :                 panic(errors.Errorf("BlockSize %d exceeds MaximumBlockSize", o.BlockSize))
     455             :         }
     456           1 :         if o.BlockSizeThreshold <= 0 {
     457           1 :                 o.BlockSizeThreshold = base.DefaultBlockSizeThreshold
     458           1 :         }
     459           1 :         if o.Compression <= DefaultCompression || o.Compression >= sstable.NCompression {
     460           1 :                 o.Compression = SnappyCompression
     461           1 :         }
     462           1 :         if o.IndexBlockSize <= 0 {
     463           1 :                 o.IndexBlockSize = o.BlockSize
     464           1 :         }
     465           1 :         if o.TargetFileSize <= 0 {
     466           1 :                 o.TargetFileSize = 2 << 20 // 2 MB
     467           1 :         }
     468           1 :         return o
     469             : }
     470             : 
     471             : // Options holds the optional parameters for configuring pebble. These options
     472             : // apply to the DB at large; per-query options are defined by the IterOptions
     473             : // and WriteOptions types.
     474             : type Options struct {
     475             :         // Sync sstables periodically in order to smooth out writes to disk. This
     476             :         // option does not provide any persistency guarantee, but is used to avoid
     477             :         // latency spikes if the OS automatically decides to write out a large chunk
     478             :         // of dirty filesystem buffers. This option only controls SSTable syncs; WAL
     479             :         // syncs are controlled by WALBytesPerSync.
     480             :         //
     481             :         // The default value is 512KB.
     482             :         BytesPerSync int
     483             : 
     484             :         // Cache is used to cache uncompressed blocks from sstables.
     485             :         //
     486             :         // The default cache size is 8 MB.
     487             :         Cache *cache.Cache
     488             : 
     489             :         // Cleaner cleans obsolete files.
     490             :         //
     491             :         // The default cleaner uses the DeleteCleaner.
     492             :         Cleaner Cleaner
     493             : 
     494             :         // Comparer defines a total ordering over the space of []byte keys: a 'less
     495             :         // than' relationship. The same comparison algorithm must be used for reads
     496             :         // and writes over the lifetime of the DB.
     497             :         //
     498             :         // The default value uses the same ordering as bytes.Compare.
     499             :         Comparer *Comparer
     500             : 
     501             :         // DebugCheck is invoked, if non-nil, whenever a new version is being
     502             :         // installed. Typically, this is set to pebble.DebugCheckLevels in tests
     503             :         // or tools only, to check invariants over all the data in the database.
     504             :         DebugCheck func(*DB) error
     505             : 
     506             :         // Disable the write-ahead log (WAL). Disabling the write-ahead log prohibits
     507             :         // crash recovery, but can improve performance if crash recovery is not
     508             :         // needed (e.g. when only temporary state is being stored in the database).
     509             :         //
     510             :         // TODO(peter): untested
     511             :         DisableWAL bool
     512             : 
     513             :         // ErrorIfExists causes an error on Open if the database already exists.
     514             :         // The error can be checked with errors.Is(err, ErrDBAlreadyExists).
     515             :         //
     516             :         // The default value is false.
     517             :         ErrorIfExists bool
     518             : 
     519             :         // ErrorIfNotExists causes an error on Open if the database does not already
     520             :         // exist. The error can be checked with errors.Is(err, ErrDBDoesNotExist).
     521             :         //
     522             :         // The default value is false which will cause a database to be created if it
     523             :         // does not already exist.
     524             :         ErrorIfNotExists bool
     525             : 
     526             :         // ErrorIfNotPristine causes an error on Open if the database already exists
     527             :         // and any operations have been performed on the database. The error can be
     528             :         // checked with errors.Is(err, ErrDBNotPristine).
     529             :         //
     530             :         // Note that a database that contained keys that were all subsequently deleted
     531             :         // may or may not trigger the error. Currently, we check if there are any live
     532             :         // SSTs or log records to replay.
     533             :         ErrorIfNotPristine bool
     534             : 
     535             :         // EventListener provides hooks to listening to significant DB events such as
     536             :         // flushes, compactions, and table deletion.
     537             :         EventListener *EventListener
     538             : 
     539             :         // Experimental contains experimental options which are off by default.
     540             :         // These options are temporary and will eventually either be deleted, moved
     541             :         // out of the experimental group, or made the non-adjustable default. These
     542             :         // options may change at any time, so do not rely on them.
     543             :         Experimental struct {
     544             :                 // The threshold of L0 read-amplification at which compaction concurrency
     545             :                 // is enabled (if CompactionDebtConcurrency was not already exceeded).
     546             :                 // Every multiple of this value enables another concurrent
     547             :                 // compaction up to MaxConcurrentCompactions.
     548             :                 L0CompactionConcurrency int
     549             : 
     550             :                 // CompactionDebtConcurrency controls the threshold of compaction debt
     551             :                 // at which additional compaction concurrency slots are added. For every
     552             :                 // multiple of this value in compaction debt bytes, an additional
     553             :                 // concurrent compaction is added. This works "on top" of
     554             :                 // L0CompactionConcurrency, so the higher of the count of compaction
     555             :                 // concurrency slots as determined by the two options is chosen.
     556             :                 CompactionDebtConcurrency uint64
     557             : 
     558             :                 // IngestSplit, if it returns true, allows for ingest-time splitting of
     559             :                 // existing sstables into two virtual sstables to allow ingestion sstables to
     560             :                 // slot into a lower level than they otherwise would have.
     561             :                 IngestSplit func() bool
     562             : 
     563             :                 // ReadCompactionRate controls the frequency of read triggered
     564             :                 // compactions by adjusting `AllowedSeeks` in manifest.FileMetadata:
     565             :                 //
     566             :                 // AllowedSeeks = FileSize / ReadCompactionRate
     567             :                 //
     568             :                 // From LevelDB:
     569             :                 // ```
     570             :                 // We arrange to automatically compact this file after
     571             :                 // a certain number of seeks. Let's assume:
     572             :                 //   (1) One seek costs 10ms
     573             :                 //   (2) Writing or reading 1MB costs 10ms (100MB/s)
     574             :                 //   (3) A compaction of 1MB does 25MB of IO:
     575             :                 //         1MB read from this level
     576             :                 //         10-12MB read from next level (boundaries may be misaligned)
     577             :                 //         10-12MB written to next level
     578             :                 // This implies that 25 seeks cost the same as the compaction
     579             :                 // of 1MB of data.  I.e., one seek costs approximately the
     580             :                 // same as the compaction of 40KB of data.  We are a little
     581             :                 // conservative and allow approximately one seek for every 16KB
     582             :                 // of data before triggering a compaction.
     583             :                 // ```
     584             :                 ReadCompactionRate int64
     585             : 
     586             :                 // ReadSamplingMultiplier is a multiplier for the readSamplingPeriod in
     587             :                 // iterator.maybeSampleRead() to control the frequency of read sampling
     588             :                 // to trigger a read triggered compaction. A value of -1 prevents sampling
     589             :                 // and disables read triggered compactions. The default is 1 << 4. which
     590             :                 // gets multiplied with a constant of 1 << 16 to yield 1 << 20 (1MB).
     591             :                 ReadSamplingMultiplier int64
     592             : 
     593             :                 // TableCacheShards is the number of shards per table cache.
     594             :                 // Reducing the value can reduce the number of idle goroutines per DB
     595             :                 // instance which can be useful in scenarios with a lot of DB instances
     596             :                 // and a large number of CPUs, but doing so can lead to higher contention
     597             :                 // in the table cache and reduced performance.
     598             :                 //
     599             :                 // The default value is the number of logical CPUs, which can be
     600             :                 // limited by runtime.GOMAXPROCS.
     601             :                 TableCacheShards int
     602             : 
     603             :                 // KeyValidationFunc is a function to validate a user key in an SSTable.
     604             :                 //
     605             :                 // Currently, this function is used to validate the smallest and largest
     606             :                 // keys in an SSTable undergoing compaction. In this case, returning an
     607             :                 // error from the validation function will result in a panic at runtime,
     608             :                 // given that there is rarely any way of recovering from malformed keys
     609             :                 // present in compacted files. By default, validation is not performed.
     610             :                 //
     611             :                 // Additional use-cases may be added in the future.
     612             :                 //
     613             :                 // NOTE: callers should take care to not mutate the key being validated.
     614             :                 KeyValidationFunc func(userKey []byte) error
     615             : 
     616             :                 // ValidateOnIngest schedules validation of sstables after they have
     617             :                 // been ingested.
     618             :                 //
     619             :                 // By default, this value is false.
     620             :                 ValidateOnIngest bool
     621             : 
     622             :                 // LevelMultiplier configures the size multiplier used to determine the
     623             :                 // desired size of each level of the LSM. Defaults to 10.
     624             :                 LevelMultiplier int
     625             : 
     626             :                 // MultiLevelCompactionHeuristic determines whether to add an additional
     627             :                 // level to a conventional two level compaction. If nil, a multilevel
     628             :                 // compaction will never get triggered.
     629             :                 MultiLevelCompactionHeuristic MultiLevelHeuristic
     630             : 
     631             :                 // MaxWriterConcurrency is used to indicate the maximum number of
     632             :                 // compression workers the compression queue is allowed to use. If
     633             :                 // MaxWriterConcurrency > 0, then the Writer will use parallelism, to
     634             :                 // compress and write blocks to disk. Otherwise, the writer will
     635             :                 // compress and write blocks to disk synchronously.
     636             :                 MaxWriterConcurrency int
     637             : 
     638             :                 // ForceWriterParallelism is used to force parallelism in the sstable
     639             :                 // Writer for the metamorphic tests. Even with the MaxWriterConcurrency
     640             :                 // option set, we only enable parallelism in the sstable Writer if there
     641             :                 // is enough CPU available, and this option bypasses that.
     642             :                 ForceWriterParallelism bool
     643             : 
     644             :                 // CPUWorkPermissionGranter should be set if Pebble should be given the
     645             :                 // ability to optionally schedule additional CPU. See the documentation
     646             :                 // for CPUWorkPermissionGranter for more details.
     647             :                 CPUWorkPermissionGranter CPUWorkPermissionGranter
     648             : 
     649             :                 // EnableValueBlocks is used to decide whether to enable writing
     650             :                 // TableFormatPebblev3 sstables. This setting is only respected by a
     651             :                 // specific subset of format major versions: FormatSSTableValueBlocks,
     652             :                 // FormatFlushableIngest and FormatPrePebblev1MarkedCompacted. In lower
     653             :                 // format major versions, value blocks are never enabled. In higher
     654             :                 // format major versions, value blocks are always enabled.
     655             :                 EnableValueBlocks func() bool
     656             : 
     657             :                 // ShortAttributeExtractor is used iff EnableValueBlocks() returns true
     658             :                 // (else ignored). If non-nil, a ShortAttribute can be extracted from the
     659             :                 // value and stored with the key, when the value is stored elsewhere.
     660             :                 ShortAttributeExtractor ShortAttributeExtractor
     661             : 
     662             :                 // RequiredInPlaceValueBound specifies an optional span of user key
     663             :                 // prefixes that are not-MVCC, but have a suffix. For these the values
     664             :                 // must be stored with the key, since the concept of "older versions" is
     665             :                 // not defined. It is also useful for statically known exclusions to value
     666             :                 // separation. In CockroachDB, this will be used for the lock table key
     667             :                 // space that has non-empty suffixes, but those locks don't represent
     668             :                 // actual MVCC versions (the suffix ordering is arbitrary). We will also
     669             :                 // need to add support for dynamically configured exclusions (we want the
     670             :                 // default to be to allow Pebble to decide whether to separate the value
     671             :                 // or not, hence this is structured as exclusions), for example, for users
     672             :                 // of CockroachDB to dynamically exclude certain tables.
     673             :                 //
     674             :                 // Any change in exclusion behavior takes effect only on future written
     675             :                 // sstables, and does not start rewriting existing sstables.
     676             :                 //
     677             :                 // Even ignoring changes in this setting, exclusions are interpreted as a
     678             :                 // guidance by Pebble, and not necessarily honored. Specifically, user
     679             :                 // keys with multiple Pebble-versions *may* have the older versions stored
     680             :                 // in value blocks.
     681             :                 RequiredInPlaceValueBound UserKeyPrefixBound
     682             : 
     683             :                 // DisableIngestAsFlushable disables lazy ingestion of sstables through
     684             :                 // a WAL write and memtable rotation. Only effectual if the the format
     685             :                 // major version is at least `FormatFlushableIngest`.
     686             :                 DisableIngestAsFlushable func() bool
     687             : 
     688             :                 // RemoteStorage enables use of remote storage (e.g. S3) for storing
     689             :                 // sstables. Setting this option enables use of CreateOnShared option and
     690             :                 // allows ingestion of external files.
     691             :                 RemoteStorage remote.StorageFactory
     692             : 
     693             :                 // If CreateOnShared is non-zero, new sstables are created on remote storage
     694             :                 // (using CreateOnSharedLocator and with the appropriate
     695             :                 // CreateOnSharedStrategy). These sstables can be shared between different
     696             :                 // Pebble instances; the lifecycle of such objects is managed by the
     697             :                 // remote.Storage constructed by options.RemoteStorage.
     698             :                 //
     699             :                 // Can only be used when RemoteStorage is set (and recognizes
     700             :                 // CreateOnSharedLocator).
     701             :                 CreateOnShared        remote.CreateOnSharedStrategy
     702             :                 CreateOnSharedLocator remote.Locator
     703             : 
     704             :                 // CacheSizeBytesBytes is the size of the on-disk block cache for objects
     705             :                 // on shared storage in bytes. If it is 0, no cache is used.
     706             :                 SecondaryCacheSizeBytes int64
     707             : 
     708             :                 // IneffectualPointDeleteCallback is called in compactions/flushes if any
     709             :                 // single delete is being elided without deleting a point set/merge.
     710             :                 IneffectualSingleDeleteCallback func(userKey []byte)
     711             : 
     712             :                 // SingleDeleteInvariantViolationCallback is called in compactions/flushes if any
     713             :                 // single delete has consumed a Set/Merge, and there is another immediately older
     714             :                 // Set/SetWithDelete/Merge. The user of Pebble has violated the invariant under
     715             :                 // which SingleDelete can be used correctly.
     716             :                 //
     717             :                 // Consider the sequence SingleDelete#3, Set#2, Set#1. There are three
     718             :                 // ways some of these keys can first meet in a compaction.
     719             :                 //
     720             :                 // - All 3 keys in the same compaction: this callback will detect the
     721             :                 //   violation.
     722             :                 //
     723             :                 // - SingleDelete#3, Set#2 meet in a compaction first: Both keys will
     724             :                 //   disappear. The violation will not be detected, and the DB will have
     725             :                 //   Set#1 which is likely incorrect (from the user's perspective).
     726             :                 //
     727             :                 // - Set#2, Set#1 meet in a compaction first: The output will be Set#2,
     728             :                 //   which will later be consumed by SingleDelete#3. The violation will
     729             :                 //   not be detected and the DB will be correct.
     730             :                 SingleDeleteInvariantViolationCallback func(userKey []byte)
     731             :         }
     732             : 
     733             :         // Filters is a map from filter policy name to filter policy. It is used for
     734             :         // debugging tools which may be used on multiple databases configured with
     735             :         // different filter policies. It is not necessary to populate this filters
     736             :         // map during normal usage of a DB.
     737             :         Filters map[string]FilterPolicy
     738             : 
     739             :         // FlushDelayDeleteRange configures how long the database should wait before
     740             :         // forcing a flush of a memtable that contains a range deletion. Disk space
     741             :         // cannot be reclaimed until the range deletion is flushed. No automatic
     742             :         // flush occurs if zero.
     743             :         FlushDelayDeleteRange time.Duration
     744             : 
     745             :         // FlushDelayRangeKey configures how long the database should wait before
     746             :         // forcing a flush of a memtable that contains a range key. Range keys in
     747             :         // the memtable prevent lazy combined iteration, so it's desirable to flush
     748             :         // range keys promptly. No automatic flush occurs if zero.
     749             :         FlushDelayRangeKey time.Duration
     750             : 
     751             :         // FlushSplitBytes denotes the target number of bytes per sublevel in
     752             :         // each flush split interval (i.e. range between two flush split keys)
     753             :         // in L0 sstables. When set to zero, only a single sstable is generated
     754             :         // by each flush. When set to a non-zero value, flushes are split at
     755             :         // points to meet L0's TargetFileSize, any grandparent-related overlap
     756             :         // options, and at boundary keys of L0 flush split intervals (which are
     757             :         // targeted to contain around FlushSplitBytes bytes in each sublevel
     758             :         // between pairs of boundary keys). Splitting sstables during flush
     759             :         // allows increased compaction flexibility and concurrency when those
     760             :         // tables are compacted to lower levels.
     761             :         FlushSplitBytes int64
     762             : 
     763             :         // FormatMajorVersion sets the format of on-disk files. It is
     764             :         // recommended to set the format major version to an explicit
     765             :         // version, as the default may change over time.
     766             :         //
     767             :         // At Open if the existing database is formatted using a later
     768             :         // format major version that is known to this version of Pebble,
     769             :         // Pebble will continue to use the later format major version. If
     770             :         // the existing database's version is unknown, the caller may use
     771             :         // FormatMostCompatible and will be able to open the database
     772             :         // regardless of its actual version.
     773             :         //
     774             :         // If the existing database is formatted using a format major
     775             :         // version earlier than the one specified, Open will automatically
     776             :         // ratchet the database to the specified format major version.
     777             :         FormatMajorVersion FormatMajorVersion
     778             : 
     779             :         // FS provides the interface for persistent file storage.
     780             :         //
     781             :         // The default value uses the underlying operating system's file system.
     782             :         FS vfs.FS
     783             : 
     784             :         // Lock, if set, must be a database lock acquired through LockDirectory for
     785             :         // the same directory passed to Open. If provided, Open will skip locking
     786             :         // the directory. Closing the database will not release the lock, and it's
     787             :         // the responsibility of the caller to release the lock after closing the
     788             :         // database.
     789             :         //
     790             :         // Open will enforce that the Lock passed locks the same directory passed to
     791             :         // Open. Concurrent calls to Open using the same Lock are detected and
     792             :         // prohibited.
     793             :         Lock *Lock
     794             : 
     795             :         // The count of L0 files necessary to trigger an L0 compaction.
     796             :         L0CompactionFileThreshold int
     797             : 
     798             :         // The amount of L0 read-amplification necessary to trigger an L0 compaction.
     799             :         L0CompactionThreshold int
     800             : 
     801             :         // Hard limit on L0 read-amplification, computed as the number of L0
     802             :         // sublevels. Writes are stopped when this threshold is reached.
     803             :         L0StopWritesThreshold int
     804             : 
     805             :         // The maximum number of bytes for LBase. The base level is the level which
     806             :         // L0 is compacted into. The base level is determined dynamically based on
     807             :         // the existing data in the LSM. The maximum number of bytes for other levels
     808             :         // is computed dynamically based on the base level's maximum size. When the
     809             :         // maximum number of bytes for a level is exceeded, compaction is requested.
     810             :         LBaseMaxBytes int64
     811             : 
     812             :         // Per-level options. Options for at least one level must be specified. The
     813             :         // options for the last level are used for all subsequent levels.
     814             :         Levels []LevelOptions
     815             : 
     816             :         // LoggerAndTracer will be used, if non-nil, else Logger will be used and
     817             :         // tracing will be a noop.
     818             : 
     819             :         // Logger used to write log messages.
     820             :         //
     821             :         // The default logger uses the Go standard library log package.
     822             :         Logger Logger
     823             :         // LoggerAndTracer is used for writing log messages and traces.
     824             :         LoggerAndTracer LoggerAndTracer
     825             : 
     826             :         // MaxManifestFileSize is the maximum size the MANIFEST file is allowed to
     827             :         // become. When the MANIFEST exceeds this size it is rolled over and a new
     828             :         // MANIFEST is created.
     829             :         MaxManifestFileSize int64
     830             : 
     831             :         // MaxOpenFiles is a soft limit on the number of open files that can be
     832             :         // used by the DB.
     833             :         //
     834             :         // The default value is 1000.
     835             :         MaxOpenFiles int
     836             : 
     837             :         // The size of a MemTable in steady state. The actual MemTable size starts at
     838             :         // min(256KB, MemTableSize) and doubles for each subsequent MemTable up to
     839             :         // MemTableSize. This reduces the memory pressure caused by MemTables for
     840             :         // short lived (test) DB instances. Note that more than one MemTable can be
     841             :         // in existence since flushing a MemTable involves creating a new one and
     842             :         // writing the contents of the old one in the
     843             :         // background. MemTableStopWritesThreshold places a hard limit on the size of
     844             :         // the queued MemTables.
     845             :         //
     846             :         // The default value is 4MB.
     847             :         MemTableSize uint64
     848             : 
     849             :         // Hard limit on the number of queued of MemTables. Writes are stopped when
     850             :         // the sum of the queued memtable sizes exceeds:
     851             :         //   MemTableStopWritesThreshold * MemTableSize.
     852             :         //
     853             :         // This value should be at least 2 or writes will stop whenever a MemTable is
     854             :         // being flushed.
     855             :         //
     856             :         // The default value is 2.
     857             :         MemTableStopWritesThreshold int
     858             : 
     859             :         // Merger defines the associative merge operation to use for merging values
     860             :         // written with {Batch,DB}.Merge.
     861             :         //
     862             :         // The default merger concatenates values.
     863             :         Merger *Merger
     864             : 
     865             :         // MaxConcurrentCompactions specifies the maximum number of concurrent
     866             :         // compactions. The default is 1. Concurrent compactions are performed
     867             :         // - when L0 read-amplification passes the L0CompactionConcurrency threshold
     868             :         // - for automatic background compactions
     869             :         // - when a manual compaction for a level is split and parallelized
     870             :         // MaxConcurrentCompactions must be greater than 0.
     871             :         MaxConcurrentCompactions func() int
     872             : 
     873             :         // DisableAutomaticCompactions dictates whether automatic compactions are
     874             :         // scheduled or not. The default is false (enabled). This option is only used
     875             :         // externally when running a manual compaction, and internally for tests.
     876             :         DisableAutomaticCompactions bool
     877             : 
     878             :         // NoSyncOnClose decides whether the Pebble instance will enforce a
     879             :         // close-time synchronization (e.g., fdatasync() or sync_file_range())
     880             :         // on files it writes to. Setting this to true removes the guarantee for a
     881             :         // sync on close. Some implementations can still issue a non-blocking sync.
     882             :         NoSyncOnClose bool
     883             : 
     884             :         // NumPrevManifest is the number of non-current or older manifests which
     885             :         // we want to keep around for debugging purposes. By default, we're going
     886             :         // to keep one older manifest.
     887             :         NumPrevManifest int
     888             : 
     889             :         // ReadOnly indicates that the DB should be opened in read-only mode. Writes
     890             :         // to the DB will return an error, background compactions are disabled, and
     891             :         // the flush that normally occurs after replaying the WAL at startup is
     892             :         // disabled.
     893             :         ReadOnly bool
     894             : 
     895             :         // TableCache is an initialized TableCache which should be set as an
     896             :         // option if the DB needs to be initialized with a pre-existing table cache.
     897             :         // If TableCache is nil, then a table cache which is unique to the DB instance
     898             :         // is created. TableCache can be shared between db instances by setting it here.
     899             :         // The TableCache set here must use the same underlying cache as Options.Cache
     900             :         // and pebble will panic otherwise.
     901             :         TableCache *TableCache
     902             : 
     903             :         // TablePropertyCollectors is a list of TablePropertyCollector creation
     904             :         // functions. A new TablePropertyCollector is created for each sstable built
     905             :         // and lives for the lifetime of the table.
     906             :         TablePropertyCollectors []func() TablePropertyCollector
     907             : 
     908             :         // BlockPropertyCollectors is a list of BlockPropertyCollector creation
     909             :         // functions. A new BlockPropertyCollector is created for each sstable
     910             :         // built and lives for the lifetime of writing that table.
     911             :         BlockPropertyCollectors []func() BlockPropertyCollector
     912             : 
     913             :         // WALBytesPerSync sets the number of bytes to write to a WAL before calling
     914             :         // Sync on it in the background. Just like with BytesPerSync above, this
     915             :         // helps smooth out disk write latencies, and avoids cases where the OS
     916             :         // writes a lot of buffered data to disk at once. However, this is less
     917             :         // necessary with WALs, as many write operations already pass in
     918             :         // Sync = true.
     919             :         //
     920             :         // The default value is 0, i.e. no background syncing. This matches the
     921             :         // default behaviour in RocksDB.
     922             :         WALBytesPerSync int
     923             : 
     924             :         // WALDir specifies the directory to store write-ahead logs (WALs) in. If
     925             :         // empty (the default), WALs will be stored in the same directory as sstables
     926             :         // (i.e. the directory passed to pebble.Open).
     927             :         WALDir string
     928             : 
     929             :         // WALMinSyncInterval is the minimum duration between syncs of the WAL. If
     930             :         // WAL syncs are requested faster than this interval, they will be
     931             :         // artificially delayed. Introducing a small artificial delay (500us) between
     932             :         // WAL syncs can allow more operations to arrive and reduce IO operations
     933             :         // while having a minimal impact on throughput. This option is supplied as a
     934             :         // closure in order to allow the value to be changed dynamically. The default
     935             :         // value is 0.
     936             :         //
     937             :         // TODO(peter): rather than a closure, should there be another mechanism for
     938             :         // changing options dynamically?
     939             :         WALMinSyncInterval func() time.Duration
     940             : 
     941             :         // TargetByteDeletionRate is the rate (in bytes per second) at which sstable file
     942             :         // deletions are limited to (under normal circumstances).
     943             :         //
     944             :         // Deletion pacing is used to slow down deletions when compactions finish up
     945             :         // or readers close and newly-obsolete files need cleaning up. Deleting lots
     946             :         // of files at once can cause disk latency to go up on some SSDs, which this
     947             :         // functionality guards against.
     948             :         //
     949             :         // This value is only a best-effort target; the effective rate can be
     950             :         // higher if deletions are falling behind or disk space is running low.
     951             :         //
     952             :         // Setting this to 0 disables deletion pacing, which is also the default.
     953             :         TargetByteDeletionRate int
     954             : 
     955             :         // private options are only used by internal tests or are used internally
     956             :         // for facilitating upgrade paths of unconfigurable functionality.
     957             :         private struct {
     958             :                 // strictWALTail configures whether or not a database's WALs created
     959             :                 // prior to the most recent one should be interpreted strictly,
     960             :                 // requiring a clean EOF. RocksDB 6.2.1 and the version of Pebble
     961             :                 // included in CockroachDB 20.1 do not guarantee that closed WALs end
     962             :                 // cleanly. If this option is set within an OPTIONS file, Pebble
     963             :                 // interprets previous WALs strictly, requiring a clean EOF.
     964             :                 // Otherwise, it interprets them permissively in the same manner as
     965             :                 // RocksDB 6.2.1.
     966             :                 strictWALTail bool
     967             : 
     968             :                 // disableDeleteOnlyCompactions prevents the scheduling of delete-only
     969             :                 // compactions that drop sstables wholy covered by range tombstones or
     970             :                 // range key tombstones.
     971             :                 disableDeleteOnlyCompactions bool
     972             : 
     973             :                 // disableElisionOnlyCompactions prevents the scheduling of elision-only
     974             :                 // compactions that rewrite sstables in place in order to elide obsolete
     975             :                 // keys.
     976             :                 disableElisionOnlyCompactions bool
     977             : 
     978             :                 // disableLazyCombinedIteration is a private option used by the
     979             :                 // metamorphic tests to test equivalence between lazy-combined iteration
     980             :                 // and constructing the range-key iterator upfront. It's a private
     981             :                 // option to avoid littering the public interface with options that we
     982             :                 // do not want to allow users to actually configure.
     983             :                 disableLazyCombinedIteration bool
     984             : 
     985             :                 // A private option to disable stats collection.
     986             :                 disableTableStats bool
     987             : 
     988             :                 // testingAlwaysWaitForCleanup is set by some tests to force waiting for
     989             :                 // obsolete file deletion (to make events deterministic).
     990             :                 testingAlwaysWaitForCleanup bool
     991             : 
     992             :                 // fsCloser holds a closer that should be invoked after a DB using these
     993             :                 // Options is closed. This is used to automatically stop the
     994             :                 // long-running goroutine associated with the disk-health-checking FS.
     995             :                 // See the initialization of FS in EnsureDefaults. Note that care has
     996             :                 // been taken to ensure that it is still safe to continue using the FS
     997             :                 // after this closer has been invoked. However, if write operations
     998             :                 // against the FS are made after the DB is closed, the FS may leak a
     999             :                 // goroutine indefinitely.
    1000             :                 fsCloser io.Closer
    1001             : 
    1002             :                 // efosAlwaysCreatesIterators is set by some tests to force
    1003             :                 // EventuallyFileOnlySnapshots to always create iterators, even after a
    1004             :                 // conflicting excise.
    1005             :                 efosAlwaysCreatesIterators bool
    1006             :         }
    1007             : }
    1008             : 
    1009             : // DebugCheckLevels calls CheckLevels on the provided database.
    1010             : // It may be set in the DebugCheck field of Options to check
    1011             : // level invariants whenever a new version is installed.
    1012           1 : func DebugCheckLevels(db *DB) error {
    1013           1 :         return db.CheckLevels(nil)
    1014           1 : }
    1015             : 
    1016             : // EnsureDefaults ensures that the default values for all options are set if a
    1017             : // valid value was not already specified. Returns the new options.
    1018           1 : func (o *Options) EnsureDefaults() *Options {
    1019           1 :         if o == nil {
    1020           1 :                 o = &Options{}
    1021           1 :         }
    1022           1 :         if o.BytesPerSync <= 0 {
    1023           1 :                 o.BytesPerSync = 512 << 10 // 512 KB
    1024           1 :         }
    1025           1 :         if o.Cleaner == nil {
    1026           1 :                 o.Cleaner = DeleteCleaner{}
    1027           1 :         }
    1028           1 :         if o.Comparer == nil {
    1029           1 :                 o.Comparer = DefaultComparer
    1030           1 :         }
    1031           1 :         if o.Experimental.DisableIngestAsFlushable == nil {
    1032           1 :                 o.Experimental.DisableIngestAsFlushable = func() bool { return false }
    1033             :         }
    1034           1 :         if o.Experimental.L0CompactionConcurrency <= 0 {
    1035           1 :                 o.Experimental.L0CompactionConcurrency = 10
    1036           1 :         }
    1037           1 :         if o.Experimental.CompactionDebtConcurrency <= 0 {
    1038           1 :                 o.Experimental.CompactionDebtConcurrency = 1 << 30 // 1 GB
    1039           1 :         }
    1040           1 :         if o.Experimental.KeyValidationFunc == nil {
    1041           1 :                 o.Experimental.KeyValidationFunc = func([]byte) error { return nil }
    1042             :         }
    1043           1 :         if o.L0CompactionThreshold <= 0 {
    1044           1 :                 o.L0CompactionThreshold = 4
    1045           1 :         }
    1046           1 :         if o.L0CompactionFileThreshold <= 0 {
    1047           1 :                 // Some justification for the default of 500:
    1048           1 :                 // Why not smaller?:
    1049           1 :                 // - The default target file size for L0 is 2MB, so 500 files is <= 1GB
    1050           1 :                 //   of data. At observed compaction speeds of > 20MB/s, L0 can be
    1051           1 :                 //   cleared of all files in < 1min, so this backlog is not huge.
    1052           1 :                 // - 500 files is low overhead for instantiating L0 sublevels from
    1053           1 :                 //   scratch.
    1054           1 :                 // - Lower values were observed to cause excessive and inefficient
    1055           1 :                 //   compactions out of L0 in a TPCC import benchmark.
    1056           1 :                 // Why not larger?:
    1057           1 :                 // - More than 1min to compact everything out of L0.
    1058           1 :                 // - CockroachDB's admission control system uses a threshold of 1000
    1059           1 :                 //   files to start throttling writes to Pebble. Using 500 here gives
    1060           1 :                 //   us headroom between when Pebble should start compacting L0 and
    1061           1 :                 //   when the admission control threshold is reached.
    1062           1 :                 //
    1063           1 :                 // We can revisit this default in the future based on better
    1064           1 :                 // experimental understanding.
    1065           1 :                 //
    1066           1 :                 // TODO(jackson): Experiment with slightly lower thresholds [or higher
    1067           1 :                 // admission control thresholds] to see whether a higher L0 score at the
    1068           1 :                 // threshold (currently 2.0) is necessary for some workloads to avoid
    1069           1 :                 // starving L0 in favor of lower-level compactions.
    1070           1 :                 o.L0CompactionFileThreshold = 500
    1071           1 :         }
    1072           1 :         if o.L0StopWritesThreshold <= 0 {
    1073           1 :                 o.L0StopWritesThreshold = 12
    1074           1 :         }
    1075           1 :         if o.LBaseMaxBytes <= 0 {
    1076           1 :                 o.LBaseMaxBytes = 64 << 20 // 64 MB
    1077           1 :         }
    1078           1 :         if o.Levels == nil {
    1079           1 :                 o.Levels = make([]LevelOptions, 1)
    1080           1 :                 for i := range o.Levels {
    1081           1 :                         if i > 0 {
    1082           0 :                                 l := &o.Levels[i]
    1083           0 :                                 if l.TargetFileSize <= 0 {
    1084           0 :                                         l.TargetFileSize = o.Levels[i-1].TargetFileSize * 2
    1085           0 :                                 }
    1086             :                         }
    1087           1 :                         o.Levels[i].EnsureDefaults()
    1088             :                 }
    1089           1 :         } else {
    1090           1 :                 for i := range o.Levels {
    1091           1 :                         o.Levels[i].EnsureDefaults()
    1092           1 :                 }
    1093             :         }
    1094           1 :         if o.Logger == nil {
    1095           1 :                 o.Logger = DefaultLogger
    1096           1 :         }
    1097           1 :         if o.EventListener == nil {
    1098           1 :                 o.EventListener = &EventListener{}
    1099           1 :         }
    1100           1 :         o.EventListener.EnsureDefaults(o.Logger)
    1101           1 :         if o.MaxManifestFileSize == 0 {
    1102           1 :                 o.MaxManifestFileSize = 128 << 20 // 128 MB
    1103           1 :         }
    1104           1 :         if o.MaxOpenFiles == 0 {
    1105           1 :                 o.MaxOpenFiles = 1000
    1106           1 :         }
    1107           1 :         if o.MemTableSize <= 0 {
    1108           1 :                 o.MemTableSize = 4 << 20 // 4 MB
    1109           1 :         }
    1110           1 :         if o.MemTableStopWritesThreshold <= 0 {
    1111           1 :                 o.MemTableStopWritesThreshold = 2
    1112           1 :         }
    1113           1 :         if o.Merger == nil {
    1114           1 :                 o.Merger = DefaultMerger
    1115           1 :         }
    1116           1 :         o.private.strictWALTail = true
    1117           1 :         if o.MaxConcurrentCompactions == nil {
    1118           1 :                 o.MaxConcurrentCompactions = func() int { return 1 }
    1119             :         }
    1120           1 :         if o.NumPrevManifest <= 0 {
    1121           1 :                 o.NumPrevManifest = 1
    1122           1 :         }
    1123             : 
    1124           1 :         if o.FormatMajorVersion == FormatDefault {
    1125           1 :                 o.FormatMajorVersion = FormatMinSupported
    1126           1 :         }
    1127             : 
    1128           1 :         if o.FS == nil {
    1129           1 :                 o.WithFSDefaults()
    1130           1 :         }
    1131           1 :         if o.FlushSplitBytes <= 0 {
    1132           1 :                 o.FlushSplitBytes = 2 * o.Levels[0].TargetFileSize
    1133           1 :         }
    1134           1 :         if o.Experimental.LevelMultiplier <= 0 {
    1135           1 :                 o.Experimental.LevelMultiplier = defaultLevelMultiplier
    1136           1 :         }
    1137           1 :         if o.Experimental.ReadCompactionRate == 0 {
    1138           1 :                 o.Experimental.ReadCompactionRate = 16000
    1139           1 :         }
    1140           1 :         if o.Experimental.ReadSamplingMultiplier == 0 {
    1141           1 :                 o.Experimental.ReadSamplingMultiplier = 1 << 4
    1142           1 :         }
    1143           1 :         if o.Experimental.TableCacheShards <= 0 {
    1144           1 :                 o.Experimental.TableCacheShards = runtime.GOMAXPROCS(0)
    1145           1 :         }
    1146           1 :         if o.Experimental.CPUWorkPermissionGranter == nil {
    1147           1 :                 o.Experimental.CPUWorkPermissionGranter = defaultCPUWorkGranter{}
    1148           1 :         }
    1149           1 :         if o.Experimental.MultiLevelCompactionHeuristic == nil {
    1150           1 :                 o.Experimental.MultiLevelCompactionHeuristic = WriteAmpHeuristic{}
    1151           1 :         }
    1152             : 
    1153           1 :         o.initMaps()
    1154           1 :         return o
    1155             : }
    1156             : 
    1157             : // WithFSDefaults configures the Options to wrap the configured filesystem with
    1158             : // the default virtual file system middleware, like disk-health checking.
    1159           1 : func (o *Options) WithFSDefaults() *Options {
    1160           1 :         if o.FS == nil {
    1161           1 :                 o.FS = vfs.Default
    1162           1 :         }
    1163           1 :         o.FS, o.private.fsCloser = vfs.WithDiskHealthChecks(o.FS, 5*time.Second,
    1164           1 :                 func(info vfs.DiskSlowInfo) {
    1165           0 :                         o.EventListener.DiskSlow(info)
    1166           0 :                 })
    1167           1 :         return o
    1168             : }
    1169             : 
    1170             : // AddEventListener adds the provided event listener to the Options, in addition
    1171             : // to any existing event listener.
    1172           1 : func (o *Options) AddEventListener(l EventListener) {
    1173           1 :         if o.EventListener != nil {
    1174           1 :                 l = TeeEventListener(l, *o.EventListener)
    1175           1 :         }
    1176           1 :         o.EventListener = &l
    1177             : }
    1178             : 
    1179             : // TestingAlwaysCreateEFOSIterators is used to toggle a private option for
    1180             : // having EventuallyFileOnlySnapshots always create iterators. Meant to only
    1181             : // be used in tests.
    1182           1 : func (o *Options) TestingAlwaysCreateEFOSIterators(value bool) {
    1183           1 :         o.private.efosAlwaysCreatesIterators = value
    1184           1 : }
    1185             : 
    1186           1 : func (o *Options) equal() Equal {
    1187           1 :         if o.Comparer.Equal == nil {
    1188           1 :                 return bytes.Equal
    1189           1 :         }
    1190           1 :         return o.Comparer.Equal
    1191             : }
    1192             : 
    1193             : // initMaps initializes the Comparers, Filters, and Mergers maps.
    1194           1 : func (o *Options) initMaps() {
    1195           1 :         for i := range o.Levels {
    1196           1 :                 l := &o.Levels[i]
    1197           1 :                 if l.FilterPolicy != nil {
    1198           1 :                         if o.Filters == nil {
    1199           1 :                                 o.Filters = make(map[string]FilterPolicy)
    1200           1 :                         }
    1201           1 :                         name := l.FilterPolicy.Name()
    1202           1 :                         if _, ok := o.Filters[name]; !ok {
    1203           1 :                                 o.Filters[name] = l.FilterPolicy
    1204           1 :                         }
    1205             :                 }
    1206             :         }
    1207             : }
    1208             : 
    1209             : // Level returns the LevelOptions for the specified level.
    1210           1 : func (o *Options) Level(level int) LevelOptions {
    1211           1 :         if level < len(o.Levels) {
    1212           1 :                 return o.Levels[level]
    1213           1 :         }
    1214           1 :         n := len(o.Levels) - 1
    1215           1 :         l := o.Levels[n]
    1216           1 :         for i := n; i < level; i++ {
    1217           1 :                 l.TargetFileSize *= 2
    1218           1 :         }
    1219           1 :         return l
    1220             : }
    1221             : 
    1222             : // Clone creates a shallow-copy of the supplied options.
    1223           1 : func (o *Options) Clone() *Options {
    1224           1 :         n := &Options{}
    1225           1 :         if o != nil {
    1226           1 :                 *n = *o
    1227           1 :         }
    1228           1 :         return n
    1229             : }
    1230             : 
    1231           1 : func filterPolicyName(p FilterPolicy) string {
    1232           1 :         if p == nil {
    1233           1 :                 return "none"
    1234           1 :         }
    1235           1 :         return p.Name()
    1236             : }
    1237             : 
    1238           1 : func (o *Options) String() string {
    1239           1 :         var buf bytes.Buffer
    1240           1 : 
    1241           1 :         cacheSize := int64(cacheDefaultSize)
    1242           1 :         if o.Cache != nil {
    1243           1 :                 cacheSize = o.Cache.MaxSize()
    1244           1 :         }
    1245             : 
    1246           1 :         fmt.Fprintf(&buf, "[Version]\n")
    1247           1 :         fmt.Fprintf(&buf, "  pebble_version=0.1\n")
    1248           1 :         fmt.Fprintf(&buf, "\n")
    1249           1 :         fmt.Fprintf(&buf, "[Options]\n")
    1250           1 :         fmt.Fprintf(&buf, "  bytes_per_sync=%d\n", o.BytesPerSync)
    1251           1 :         fmt.Fprintf(&buf, "  cache_size=%d\n", cacheSize)
    1252           1 :         fmt.Fprintf(&buf, "  cleaner=%s\n", o.Cleaner)
    1253           1 :         fmt.Fprintf(&buf, "  compaction_debt_concurrency=%d\n", o.Experimental.CompactionDebtConcurrency)
    1254           1 :         fmt.Fprintf(&buf, "  comparer=%s\n", o.Comparer.Name)
    1255           1 :         fmt.Fprintf(&buf, "  disable_wal=%t\n", o.DisableWAL)
    1256           1 :         if o.Experimental.DisableIngestAsFlushable != nil && o.Experimental.DisableIngestAsFlushable() {
    1257           1 :                 fmt.Fprintf(&buf, "  disable_ingest_as_flushable=%t\n", true)
    1258           1 :         }
    1259           1 :         fmt.Fprintf(&buf, "  flush_delay_delete_range=%s\n", o.FlushDelayDeleteRange)
    1260           1 :         fmt.Fprintf(&buf, "  flush_delay_range_key=%s\n", o.FlushDelayRangeKey)
    1261           1 :         fmt.Fprintf(&buf, "  flush_split_bytes=%d\n", o.FlushSplitBytes)
    1262           1 :         fmt.Fprintf(&buf, "  format_major_version=%d\n", o.FormatMajorVersion)
    1263           1 :         fmt.Fprintf(&buf, "  l0_compaction_concurrency=%d\n", o.Experimental.L0CompactionConcurrency)
    1264           1 :         fmt.Fprintf(&buf, "  l0_compaction_file_threshold=%d\n", o.L0CompactionFileThreshold)
    1265           1 :         fmt.Fprintf(&buf, "  l0_compaction_threshold=%d\n", o.L0CompactionThreshold)
    1266           1 :         fmt.Fprintf(&buf, "  l0_stop_writes_threshold=%d\n", o.L0StopWritesThreshold)
    1267           1 :         fmt.Fprintf(&buf, "  lbase_max_bytes=%d\n", o.LBaseMaxBytes)
    1268           1 :         if o.Experimental.LevelMultiplier != defaultLevelMultiplier {
    1269           1 :                 fmt.Fprintf(&buf, "  level_multiplier=%d\n", o.Experimental.LevelMultiplier)
    1270           1 :         }
    1271           1 :         fmt.Fprintf(&buf, "  max_concurrent_compactions=%d\n", o.MaxConcurrentCompactions())
    1272           1 :         fmt.Fprintf(&buf, "  max_manifest_file_size=%d\n", o.MaxManifestFileSize)
    1273           1 :         fmt.Fprintf(&buf, "  max_open_files=%d\n", o.MaxOpenFiles)
    1274           1 :         fmt.Fprintf(&buf, "  mem_table_size=%d\n", o.MemTableSize)
    1275           1 :         fmt.Fprintf(&buf, "  mem_table_stop_writes_threshold=%d\n", o.MemTableStopWritesThreshold)
    1276           1 :         fmt.Fprintf(&buf, "  min_deletion_rate=%d\n", o.TargetByteDeletionRate)
    1277           1 :         fmt.Fprintf(&buf, "  merger=%s\n", o.Merger.Name)
    1278           1 :         if o.Experimental.MultiLevelCompactionHeuristic != nil {
    1279           1 :                 fmt.Fprintf(&buf, "  multilevel_compaction_heuristic=%s\n", o.Experimental.MultiLevelCompactionHeuristic.String())
    1280           1 :         }
    1281           1 :         fmt.Fprintf(&buf, "  read_compaction_rate=%d\n", o.Experimental.ReadCompactionRate)
    1282           1 :         fmt.Fprintf(&buf, "  read_sampling_multiplier=%d\n", o.Experimental.ReadSamplingMultiplier)
    1283           1 :         fmt.Fprintf(&buf, "  strict_wal_tail=%t\n", o.private.strictWALTail)
    1284           1 :         fmt.Fprintf(&buf, "  table_cache_shards=%d\n", o.Experimental.TableCacheShards)
    1285           1 :         fmt.Fprintf(&buf, "  table_property_collectors=[")
    1286           1 :         for i := range o.TablePropertyCollectors {
    1287           1 :                 if i > 0 {
    1288           0 :                         fmt.Fprintf(&buf, ",")
    1289           0 :                 }
    1290             :                 // NB: This creates a new TablePropertyCollector, but Options.String() is
    1291             :                 // called rarely so the overhead of doing so is not consequential.
    1292           1 :                 fmt.Fprintf(&buf, "%s", o.TablePropertyCollectors[i]().Name())
    1293             :         }
    1294           1 :         fmt.Fprintf(&buf, "]\n")
    1295           1 :         fmt.Fprintf(&buf, "  validate_on_ingest=%t\n", o.Experimental.ValidateOnIngest)
    1296           1 :         fmt.Fprintf(&buf, "  wal_dir=%s\n", o.WALDir)
    1297           1 :         fmt.Fprintf(&buf, "  wal_bytes_per_sync=%d\n", o.WALBytesPerSync)
    1298           1 :         fmt.Fprintf(&buf, "  max_writer_concurrency=%d\n", o.Experimental.MaxWriterConcurrency)
    1299           1 :         fmt.Fprintf(&buf, "  force_writer_parallelism=%t\n", o.Experimental.ForceWriterParallelism)
    1300           1 :         fmt.Fprintf(&buf, "  secondary_cache_size_bytes=%d\n", o.Experimental.SecondaryCacheSizeBytes)
    1301           1 :         fmt.Fprintf(&buf, "  create_on_shared=%d\n", o.Experimental.CreateOnShared)
    1302           1 : 
    1303           1 :         // Private options.
    1304           1 :         //
    1305           1 :         // These options are only encoded if true, because we do not want them to
    1306           1 :         // appear in production serialized Options files, since they're testing-only
    1307           1 :         // options. They're only serialized when true, which still ensures that the
    1308           1 :         // metamorphic tests may propagate them to subprocesses.
    1309           1 :         if o.private.disableDeleteOnlyCompactions {
    1310           1 :                 fmt.Fprintln(&buf, "  disable_delete_only_compactions=true")
    1311           1 :         }
    1312           1 :         if o.private.disableElisionOnlyCompactions {
    1313           1 :                 fmt.Fprintln(&buf, "  disable_elision_only_compactions=true")
    1314           1 :         }
    1315           1 :         if o.private.disableLazyCombinedIteration {
    1316           1 :                 fmt.Fprintln(&buf, "  disable_lazy_combined_iteration=true")
    1317           1 :         }
    1318             : 
    1319           1 :         for i := range o.Levels {
    1320           1 :                 l := &o.Levels[i]
    1321           1 :                 fmt.Fprintf(&buf, "\n")
    1322           1 :                 fmt.Fprintf(&buf, "[Level \"%d\"]\n", i)
    1323           1 :                 fmt.Fprintf(&buf, "  block_restart_interval=%d\n", l.BlockRestartInterval)
    1324           1 :                 fmt.Fprintf(&buf, "  block_size=%d\n", l.BlockSize)
    1325           1 :                 fmt.Fprintf(&buf, "  block_size_threshold=%d\n", l.BlockSizeThreshold)
    1326           1 :                 fmt.Fprintf(&buf, "  compression=%s\n", l.Compression)
    1327           1 :                 fmt.Fprintf(&buf, "  filter_policy=%s\n", filterPolicyName(l.FilterPolicy))
    1328           1 :                 fmt.Fprintf(&buf, "  filter_type=%s\n", l.FilterType)
    1329           1 :                 fmt.Fprintf(&buf, "  index_block_size=%d\n", l.IndexBlockSize)
    1330           1 :                 fmt.Fprintf(&buf, "  target_file_size=%d\n", l.TargetFileSize)
    1331           1 :         }
    1332             : 
    1333           1 :         return buf.String()
    1334             : }
    1335             : 
    1336           1 : func parseOptions(s string, fn func(section, key, value string) error) error {
    1337           1 :         var section string
    1338           1 :         for _, line := range strings.Split(s, "\n") {
    1339           1 :                 line = strings.TrimSpace(line)
    1340           1 :                 if len(line) == 0 {
    1341           1 :                         // Skip blank lines.
    1342           1 :                         continue
    1343             :                 }
    1344           1 :                 if line[0] == ';' || line[0] == '#' {
    1345           0 :                         // Skip comments.
    1346           0 :                         continue
    1347             :                 }
    1348           1 :                 n := len(line)
    1349           1 :                 if line[0] == '[' && line[n-1] == ']' {
    1350           1 :                         // Parse section.
    1351           1 :                         section = line[1 : n-1]
    1352           1 :                         continue
    1353             :                 }
    1354             : 
    1355           1 :                 pos := strings.Index(line, "=")
    1356           1 :                 if pos < 0 {
    1357           1 :                         const maxLen = 50
    1358           1 :                         if len(line) > maxLen {
    1359           0 :                                 line = line[:maxLen-3] + "..."
    1360           0 :                         }
    1361           1 :                         return base.CorruptionErrorf("invalid key=value syntax: %q", errors.Safe(line))
    1362             :                 }
    1363             : 
    1364           1 :                 key := strings.TrimSpace(line[:pos])
    1365           1 :                 value := strings.TrimSpace(line[pos+1:])
    1366           1 : 
    1367           1 :                 // RocksDB uses a similar (INI-style) syntax for the OPTIONS file, but
    1368           1 :                 // different section names and keys. The "CFOptions ..." paths are the
    1369           1 :                 // RocksDB versions which we map to the Pebble paths.
    1370           1 :                 mappedSection := section
    1371           1 :                 if section == `CFOptions "default"` {
    1372           1 :                         mappedSection = "Options"
    1373           1 :                         switch key {
    1374           1 :                         case "comparator":
    1375           1 :                                 key = "comparer"
    1376           1 :                         case "merge_operator":
    1377           1 :                                 key = "merger"
    1378             :                         }
    1379             :                 }
    1380             : 
    1381           1 :                 if err := fn(mappedSection, key, value); err != nil {
    1382           1 :                         return err
    1383           1 :                 }
    1384             :         }
    1385           1 :         return nil
    1386             : }
    1387             : 
    1388             : // ParseHooks contains callbacks to create options fields which can have
    1389             : // user-defined implementations.
    1390             : type ParseHooks struct {
    1391             :         NewCache        func(size int64) *Cache
    1392             :         NewCleaner      func(name string) (Cleaner, error)
    1393             :         NewComparer     func(name string) (*Comparer, error)
    1394             :         NewFilterPolicy func(name string) (FilterPolicy, error)
    1395             :         NewMerger       func(name string) (*Merger, error)
    1396             :         SkipUnknown     func(name, value string) bool
    1397             : }
    1398             : 
    1399             : // Parse parses the options from the specified string. Note that certain
    1400             : // options cannot be parsed into populated fields. For example, comparer and
    1401             : // merger.
    1402           1 : func (o *Options) Parse(s string, hooks *ParseHooks) error {
    1403           1 :         return parseOptions(s, func(section, key, value string) error {
    1404           1 :                 // WARNING: DO NOT remove entries from the switches below because doing so
    1405           1 :                 // causes a key previously written to the OPTIONS file to be considered unknown,
    1406           1 :                 // a backwards incompatible change. Instead, leave in support for parsing the
    1407           1 :                 // key but simply don't parse the value.
    1408           1 : 
    1409           1 :                 switch {
    1410           1 :                 case section == "Version":
    1411           1 :                         switch key {
    1412           1 :                         case "pebble_version":
    1413           0 :                         default:
    1414           0 :                                 if hooks != nil && hooks.SkipUnknown != nil && hooks.SkipUnknown(section+"."+key, value) {
    1415           0 :                                         return nil
    1416           0 :                                 }
    1417           0 :                                 return errors.Errorf("pebble: unknown option: %s.%s",
    1418           0 :                                         errors.Safe(section), errors.Safe(key))
    1419             :                         }
    1420           1 :                         return nil
    1421             : 
    1422           1 :                 case section == "Options":
    1423           1 :                         var err error
    1424           1 :                         switch key {
    1425           1 :                         case "bytes_per_sync":
    1426           1 :                                 o.BytesPerSync, err = strconv.Atoi(value)
    1427           1 :                         case "cache_size":
    1428           1 :                                 var n int64
    1429           1 :                                 n, err = strconv.ParseInt(value, 10, 64)
    1430           1 :                                 if err == nil && hooks != nil && hooks.NewCache != nil {
    1431           1 :                                         if o.Cache != nil {
    1432           0 :                                                 o.Cache.Unref()
    1433           0 :                                         }
    1434           1 :                                         o.Cache = hooks.NewCache(n)
    1435             :                                 }
    1436             :                                 // We avoid calling cache.New in parsing because it makes it
    1437             :                                 // too easy to leak a cache.
    1438           1 :                         case "cleaner":
    1439           1 :                                 switch value {
    1440           1 :                                 case "archive":
    1441           1 :                                         o.Cleaner = ArchiveCleaner{}
    1442           1 :                                 case "delete":
    1443           1 :                                         o.Cleaner = DeleteCleaner{}
    1444           0 :                                 default:
    1445           0 :                                         if hooks != nil && hooks.NewCleaner != nil {
    1446           0 :                                                 o.Cleaner, err = hooks.NewCleaner(value)
    1447           0 :                                         }
    1448             :                                 }
    1449           1 :                         case "comparer":
    1450           1 :                                 switch value {
    1451           1 :                                 case "leveldb.BytewiseComparator":
    1452           1 :                                         o.Comparer = DefaultComparer
    1453           1 :                                 default:
    1454           1 :                                         if hooks != nil && hooks.NewComparer != nil {
    1455           1 :                                                 o.Comparer, err = hooks.NewComparer(value)
    1456           1 :                                         }
    1457             :                                 }
    1458           1 :                         case "compaction_debt_concurrency":
    1459           1 :                                 o.Experimental.CompactionDebtConcurrency, err = strconv.ParseUint(value, 10, 64)
    1460           0 :                         case "delete_range_flush_delay":
    1461           0 :                                 // NB: This is a deprecated serialization of the
    1462           0 :                                 // `flush_delay_delete_range`.
    1463           0 :                                 o.FlushDelayDeleteRange, err = time.ParseDuration(value)
    1464           1 :                         case "disable_delete_only_compactions":
    1465           1 :                                 o.private.disableDeleteOnlyCompactions, err = strconv.ParseBool(value)
    1466           1 :                         case "disable_elision_only_compactions":
    1467           1 :                                 o.private.disableElisionOnlyCompactions, err = strconv.ParseBool(value)
    1468           1 :                         case "disable_ingest_as_flushable":
    1469           1 :                                 var v bool
    1470           1 :                                 v, err = strconv.ParseBool(value)
    1471           1 :                                 if err == nil {
    1472           1 :                                         o.Experimental.DisableIngestAsFlushable = func() bool { return v }
    1473             :                                 }
    1474           1 :                         case "disable_lazy_combined_iteration":
    1475           1 :                                 o.private.disableLazyCombinedIteration, err = strconv.ParseBool(value)
    1476           1 :                         case "disable_wal":
    1477           1 :                                 o.DisableWAL, err = strconv.ParseBool(value)
    1478           1 :                         case "flush_delay_delete_range":
    1479           1 :                                 o.FlushDelayDeleteRange, err = time.ParseDuration(value)
    1480           1 :                         case "flush_delay_range_key":
    1481           1 :                                 o.FlushDelayRangeKey, err = time.ParseDuration(value)
    1482           1 :                         case "flush_split_bytes":
    1483           1 :                                 o.FlushSplitBytes, err = strconv.ParseInt(value, 10, 64)
    1484           1 :                         case "format_major_version":
    1485           1 :                                 // NB: The version written here may be stale. Open does
    1486           1 :                                 // not use the format major version encoded in the
    1487           1 :                                 // OPTIONS file other than to validate that the encoded
    1488           1 :                                 // version is valid right here.
    1489           1 :                                 var v uint64
    1490           1 :                                 v, err = strconv.ParseUint(value, 10, 64)
    1491           1 :                                 if vers := FormatMajorVersion(v); vers > internalFormatNewest || vers == FormatDefault {
    1492           0 :                                         err = errors.Newf("unsupported format major version %d", o.FormatMajorVersion)
    1493           0 :                                 }
    1494           1 :                                 if err == nil {
    1495           1 :                                         o.FormatMajorVersion = FormatMajorVersion(v)
    1496           1 :                                 }
    1497           1 :                         case "l0_compaction_concurrency":
    1498           1 :                                 o.Experimental.L0CompactionConcurrency, err = strconv.Atoi(value)
    1499           1 :                         case "l0_compaction_file_threshold":
    1500           1 :                                 o.L0CompactionFileThreshold, err = strconv.Atoi(value)
    1501           1 :                         case "l0_compaction_threshold":
    1502           1 :                                 o.L0CompactionThreshold, err = strconv.Atoi(value)
    1503           1 :                         case "l0_stop_writes_threshold":
    1504           1 :                                 o.L0StopWritesThreshold, err = strconv.Atoi(value)
    1505           0 :                         case "l0_sublevel_compactions":
    1506             :                                 // Do nothing; option existed in older versions of pebble.
    1507           1 :                         case "lbase_max_bytes":
    1508           1 :                                 o.LBaseMaxBytes, err = strconv.ParseInt(value, 10, 64)
    1509           1 :                         case "level_multiplier":
    1510           1 :                                 o.Experimental.LevelMultiplier, err = strconv.Atoi(value)
    1511           1 :                         case "max_concurrent_compactions":
    1512           1 :                                 var concurrentCompactions int
    1513           1 :                                 concurrentCompactions, err = strconv.Atoi(value)
    1514           1 :                                 if concurrentCompactions <= 0 {
    1515           0 :                                         err = errors.New("max_concurrent_compactions cannot be <= 0")
    1516           1 :                                 } else {
    1517           1 :                                         o.MaxConcurrentCompactions = func() int { return concurrentCompactions }
    1518             :                                 }
    1519           1 :                         case "max_manifest_file_size":
    1520           1 :                                 o.MaxManifestFileSize, err = strconv.ParseInt(value, 10, 64)
    1521           1 :                         case "max_open_files":
    1522           1 :                                 o.MaxOpenFiles, err = strconv.Atoi(value)
    1523           1 :                         case "mem_table_size":
    1524           1 :                                 o.MemTableSize, err = strconv.ParseUint(value, 10, 64)
    1525           1 :                         case "mem_table_stop_writes_threshold":
    1526           1 :                                 o.MemTableStopWritesThreshold, err = strconv.Atoi(value)
    1527           0 :                         case "min_compaction_rate":
    1528             :                                 // Do nothing; option existed in older versions of pebble, and
    1529             :                                 // may be meaningful again eventually.
    1530           1 :                         case "min_deletion_rate":
    1531           1 :                                 o.TargetByteDeletionRate, err = strconv.Atoi(value)
    1532           0 :                         case "min_flush_rate":
    1533             :                                 // Do nothing; option existed in older versions of pebble, and
    1534             :                                 // may be meaningful again eventually.
    1535           1 :                         case "multilevel_compaction_heuristic":
    1536           1 :                                 switch {
    1537           1 :                                 case value == "none":
    1538           1 :                                         o.Experimental.MultiLevelCompactionHeuristic = NoMultiLevel{}
    1539           1 :                                 case strings.HasPrefix(value, "wamp"):
    1540           1 :                                         fields := strings.FieldsFunc(strings.TrimPrefix(value, "wamp"), func(r rune) bool {
    1541           1 :                                                 return unicode.IsSpace(r) || r == ',' || r == '(' || r == ')'
    1542           1 :                                         })
    1543           1 :                                         if len(fields) != 2 {
    1544           0 :                                                 err = errors.Newf("require 2 arguments")
    1545           0 :                                         }
    1546           1 :                                         var h WriteAmpHeuristic
    1547           1 :                                         if err == nil {
    1548           1 :                                                 h.AddPropensity, err = strconv.ParseFloat(fields[0], 64)
    1549           1 :                                         }
    1550           1 :                                         if err == nil {
    1551           1 :                                                 h.AllowL0, err = strconv.ParseBool(fields[1])
    1552           1 :                                         }
    1553           1 :                                         if err == nil {
    1554           1 :                                                 o.Experimental.MultiLevelCompactionHeuristic = h
    1555           1 :                                         } else {
    1556           0 :                                                 err = errors.Wrapf(err, "unexpected wamp heuristic arguments: %s", value)
    1557           0 :                                         }
    1558           0 :                                 default:
    1559           0 :                                         err = errors.Newf("unrecognized multilevel compaction heuristic: %s", value)
    1560             :                                 }
    1561           0 :                         case "point_tombstone_weight":
    1562             :                                 // Do nothing; deprecated.
    1563           1 :                         case "strict_wal_tail":
    1564           1 :                                 o.private.strictWALTail, err = strconv.ParseBool(value)
    1565           1 :                         case "merger":
    1566           1 :                                 switch value {
    1567           0 :                                 case "nullptr":
    1568           0 :                                         o.Merger = nil
    1569           1 :                                 case "pebble.concatenate":
    1570           1 :                                         o.Merger = DefaultMerger
    1571           1 :                                 default:
    1572           1 :                                         if hooks != nil && hooks.NewMerger != nil {
    1573           1 :                                                 o.Merger, err = hooks.NewMerger(value)
    1574           1 :                                         }
    1575             :                                 }
    1576           1 :                         case "read_compaction_rate":
    1577           1 :                                 o.Experimental.ReadCompactionRate, err = strconv.ParseInt(value, 10, 64)
    1578           1 :                         case "read_sampling_multiplier":
    1579           1 :                                 o.Experimental.ReadSamplingMultiplier, err = strconv.ParseInt(value, 10, 64)
    1580           1 :                         case "table_cache_shards":
    1581           1 :                                 o.Experimental.TableCacheShards, err = strconv.Atoi(value)
    1582           0 :                         case "table_format":
    1583           0 :                                 switch value {
    1584           0 :                                 case "leveldb":
    1585           0 :                                 case "rocksdbv2":
    1586           0 :                                 default:
    1587           0 :                                         return errors.Errorf("pebble: unknown table format: %q", errors.Safe(value))
    1588             :                                 }
    1589           1 :                         case "table_property_collectors":
    1590             :                                 // TODO(peter): set o.TablePropertyCollectors
    1591           1 :                         case "validate_on_ingest":
    1592           1 :                                 o.Experimental.ValidateOnIngest, err = strconv.ParseBool(value)
    1593           1 :                         case "wal_dir":
    1594           1 :                                 o.WALDir = value
    1595           1 :                         case "wal_bytes_per_sync":
    1596           1 :                                 o.WALBytesPerSync, err = strconv.Atoi(value)
    1597           1 :                         case "max_writer_concurrency":
    1598           1 :                                 o.Experimental.MaxWriterConcurrency, err = strconv.Atoi(value)
    1599           1 :                         case "force_writer_parallelism":
    1600           1 :                                 o.Experimental.ForceWriterParallelism, err = strconv.ParseBool(value)
    1601           1 :                         case "secondary_cache_size_bytes":
    1602           1 :                                 o.Experimental.SecondaryCacheSizeBytes, err = strconv.ParseInt(value, 10, 64)
    1603           1 :                         case "create_on_shared":
    1604           1 :                                 var createOnSharedInt int64
    1605           1 :                                 createOnSharedInt, err = strconv.ParseInt(value, 10, 64)
    1606           1 :                                 o.Experimental.CreateOnShared = remote.CreateOnSharedStrategy(createOnSharedInt)
    1607           0 :                         default:
    1608           0 :                                 if hooks != nil && hooks.SkipUnknown != nil && hooks.SkipUnknown(section+"."+key, value) {
    1609           0 :                                         return nil
    1610           0 :                                 }
    1611           0 :                                 return errors.Errorf("pebble: unknown option: %s.%s",
    1612           0 :                                         errors.Safe(section), errors.Safe(key))
    1613             :                         }
    1614           1 :                         return err
    1615             : 
    1616           1 :                 case strings.HasPrefix(section, "Level "):
    1617           1 :                         var index int
    1618           1 :                         if n, err := fmt.Sscanf(section, `Level "%d"`, &index); err != nil {
    1619           0 :                                 return err
    1620           1 :                         } else if n != 1 {
    1621           0 :                                 if hooks != nil && hooks.SkipUnknown != nil && hooks.SkipUnknown(section, value) {
    1622           0 :                                         return nil
    1623           0 :                                 }
    1624           0 :                                 return errors.Errorf("pebble: unknown section: %q", errors.Safe(section))
    1625             :                         }
    1626             : 
    1627           1 :                         if len(o.Levels) <= index {
    1628           1 :                                 newLevels := make([]LevelOptions, index+1)
    1629           1 :                                 copy(newLevels, o.Levels)
    1630           1 :                                 o.Levels = newLevels
    1631           1 :                         }
    1632           1 :                         l := &o.Levels[index]
    1633           1 : 
    1634           1 :                         var err error
    1635           1 :                         switch key {
    1636           1 :                         case "block_restart_interval":
    1637           1 :                                 l.BlockRestartInterval, err = strconv.Atoi(value)
    1638           1 :                         case "block_size":
    1639           1 :                                 l.BlockSize, err = strconv.Atoi(value)
    1640           1 :                         case "block_size_threshold":
    1641           1 :                                 l.BlockSizeThreshold, err = strconv.Atoi(value)
    1642           1 :                         case "compression":
    1643           1 :                                 switch value {
    1644           0 :                                 case "Default":
    1645           0 :                                         l.Compression = DefaultCompression
    1646           1 :                                 case "NoCompression":
    1647           1 :                                         l.Compression = NoCompression
    1648           1 :                                 case "Snappy":
    1649           1 :                                         l.Compression = SnappyCompression
    1650           1 :                                 case "ZSTD":
    1651           1 :                                         l.Compression = ZstdCompression
    1652           0 :                                 default:
    1653           0 :                                         return errors.Errorf("pebble: unknown compression: %q", errors.Safe(value))
    1654             :                                 }
    1655           1 :                         case "filter_policy":
    1656           1 :                                 if hooks != nil && hooks.NewFilterPolicy != nil {
    1657           1 :                                         l.FilterPolicy, err = hooks.NewFilterPolicy(value)
    1658           1 :                                 }
    1659           1 :                         case "filter_type":
    1660           1 :                                 switch value {
    1661           1 :                                 case "table":
    1662           1 :                                         l.FilterType = TableFilter
    1663           0 :                                 default:
    1664           0 :                                         return errors.Errorf("pebble: unknown filter type: %q", errors.Safe(value))
    1665             :                                 }
    1666           1 :                         case "index_block_size":
    1667           1 :                                 l.IndexBlockSize, err = strconv.Atoi(value)
    1668           1 :                         case "target_file_size":
    1669           1 :                                 l.TargetFileSize, err = strconv.ParseInt(value, 10, 64)
    1670           0 :                         default:
    1671           0 :                                 if hooks != nil && hooks.SkipUnknown != nil && hooks.SkipUnknown(section+"."+key, value) {
    1672           0 :                                         return nil
    1673           0 :                                 }
    1674           0 :                                 return errors.Errorf("pebble: unknown option: %s.%s", errors.Safe(section), errors.Safe(key))
    1675             :                         }
    1676           1 :                         return err
    1677             :                 }
    1678           1 :                 if hooks != nil && hooks.SkipUnknown != nil && hooks.SkipUnknown(section+"."+key, value) {
    1679           1 :                         return nil
    1680           1 :                 }
    1681           0 :                 return errors.Errorf("pebble: unknown section: %q", errors.Safe(section))
    1682             :         })
    1683             : }
    1684             : 
    1685           1 : func (o *Options) checkOptions(s string) (strictWALTail bool, err error) {
    1686           1 :         // TODO(jackson): Refactor to avoid awkwardness of the strictWALTail return value.
    1687           1 :         return strictWALTail, parseOptions(s, func(section, key, value string) error {
    1688           1 :                 switch section + "." + key {
    1689           1 :                 case "Options.comparer":
    1690           1 :                         if value != o.Comparer.Name {
    1691           1 :                                 return errors.Errorf("pebble: comparer name from file %q != comparer name from options %q",
    1692           1 :                                         errors.Safe(value), errors.Safe(o.Comparer.Name))
    1693           1 :                         }
    1694           1 :                 case "Options.merger":
    1695           1 :                         // RocksDB allows the merge operator to be unspecified, in which case it
    1696           1 :                         // shows up as "nullptr".
    1697           1 :                         if value != "nullptr" && value != o.Merger.Name {
    1698           1 :                                 return errors.Errorf("pebble: merger name from file %q != merger name from options %q",
    1699           1 :                                         errors.Safe(value), errors.Safe(o.Merger.Name))
    1700           1 :                         }
    1701           1 :                 case "Options.strict_wal_tail":
    1702           1 :                         strictWALTail, err = strconv.ParseBool(value)
    1703           1 :                         if err != nil {
    1704           0 :                                 return errors.Errorf("pebble: error parsing strict_wal_tail value %q: %w", value, err)
    1705           0 :                         }
    1706             :                 }
    1707           1 :                 return nil
    1708             :         })
    1709             : }
    1710             : 
    1711             : // Check verifies the options are compatible with the previous options
    1712             : // serialized by Options.String(). For example, the Comparer and Merger must be
    1713             : // the same, or data will not be able to be properly read from the DB.
    1714           1 : func (o *Options) Check(s string) error {
    1715           1 :         _, err := o.checkOptions(s)
    1716           1 :         return err
    1717           1 : }
    1718             : 
    1719             : // Validate verifies that the options are mutually consistent. For example,
    1720             : // L0StopWritesThreshold must be >= L0CompactionThreshold, otherwise a write
    1721             : // stall would persist indefinitely.
    1722           1 : func (o *Options) Validate() error {
    1723           1 :         // Note that we can presume Options.EnsureDefaults has been called, so there
    1724           1 :         // is no need to check for zero values.
    1725           1 : 
    1726           1 :         var buf strings.Builder
    1727           1 :         if o.Experimental.L0CompactionConcurrency < 1 {
    1728           1 :                 fmt.Fprintf(&buf, "L0CompactionConcurrency (%d) must be >= 1\n",
    1729           1 :                         o.Experimental.L0CompactionConcurrency)
    1730           1 :         }
    1731           1 :         if o.L0StopWritesThreshold < o.L0CompactionThreshold {
    1732           1 :                 fmt.Fprintf(&buf, "L0StopWritesThreshold (%d) must be >= L0CompactionThreshold (%d)\n",
    1733           1 :                         o.L0StopWritesThreshold, o.L0CompactionThreshold)
    1734           1 :         }
    1735           1 :         if uint64(o.MemTableSize) >= maxMemTableSize {
    1736           1 :                 fmt.Fprintf(&buf, "MemTableSize (%s) must be < %s\n",
    1737           1 :                         humanize.Bytes.Uint64(uint64(o.MemTableSize)), humanize.Bytes.Uint64(maxMemTableSize))
    1738           1 :         }
    1739           1 :         if o.MemTableStopWritesThreshold < 2 {
    1740           1 :                 fmt.Fprintf(&buf, "MemTableStopWritesThreshold (%d) must be >= 2\n",
    1741           1 :                         o.MemTableStopWritesThreshold)
    1742           1 :         }
    1743           1 :         if o.FormatMajorVersion < FormatMinSupported || o.FormatMajorVersion > internalFormatNewest {
    1744           0 :                 fmt.Fprintf(&buf, "FormatMajorVersion (%d) must be between %d and %d\n",
    1745           0 :                         o.FormatMajorVersion, FormatMinSupported, internalFormatNewest)
    1746           0 :         }
    1747           1 :         if o.TableCache != nil && o.Cache != o.TableCache.cache {
    1748           1 :                 fmt.Fprintf(&buf, "underlying cache in the TableCache and the Cache dont match\n")
    1749           1 :         }
    1750           1 :         if buf.Len() == 0 {
    1751           1 :                 return nil
    1752           1 :         }
    1753           1 :         return errors.New(buf.String())
    1754             : }
    1755             : 
    1756             : // MakeReaderOptions constructs sstable.ReaderOptions from the corresponding
    1757             : // options in the receiver.
    1758           1 : func (o *Options) MakeReaderOptions() sstable.ReaderOptions {
    1759           1 :         var readerOpts sstable.ReaderOptions
    1760           1 :         if o != nil {
    1761           1 :                 readerOpts.Cache = o.Cache
    1762           1 :                 readerOpts.Comparer = o.Comparer
    1763           1 :                 readerOpts.Filters = o.Filters
    1764           1 :                 if o.Merger != nil {
    1765           1 :                         readerOpts.Merge = o.Merger.Merge
    1766           1 :                         readerOpts.MergerName = o.Merger.Name
    1767           1 :                 }
    1768           1 :                 readerOpts.LoggerAndTracer = o.LoggerAndTracer
    1769             :         }
    1770           1 :         return readerOpts
    1771             : }
    1772             : 
    1773             : // MakeWriterOptions constructs sstable.WriterOptions for the specified level
    1774             : // from the corresponding options in the receiver.
    1775           1 : func (o *Options) MakeWriterOptions(level int, format sstable.TableFormat) sstable.WriterOptions {
    1776           1 :         var writerOpts sstable.WriterOptions
    1777           1 :         writerOpts.TableFormat = format
    1778           1 :         if o != nil {
    1779           1 :                 writerOpts.Cache = o.Cache
    1780           1 :                 writerOpts.Comparer = o.Comparer
    1781           1 :                 if o.Merger != nil {
    1782           1 :                         writerOpts.MergerName = o.Merger.Name
    1783           1 :                 }
    1784           1 :                 writerOpts.TablePropertyCollectors = o.TablePropertyCollectors
    1785           1 :                 writerOpts.BlockPropertyCollectors = o.BlockPropertyCollectors
    1786             :         }
    1787           1 :         if format >= sstable.TableFormatPebblev3 {
    1788           1 :                 writerOpts.ShortAttributeExtractor = o.Experimental.ShortAttributeExtractor
    1789           1 :                 writerOpts.RequiredInPlaceValueBound = o.Experimental.RequiredInPlaceValueBound
    1790           1 :                 if format >= sstable.TableFormatPebblev4 && level == numLevels-1 {
    1791           1 :                         writerOpts.WritingToLowestLevel = true
    1792           1 :                 }
    1793             :         }
    1794           1 :         levelOpts := o.Level(level)
    1795           1 :         writerOpts.BlockRestartInterval = levelOpts.BlockRestartInterval
    1796           1 :         writerOpts.BlockSize = levelOpts.BlockSize
    1797           1 :         writerOpts.BlockSizeThreshold = levelOpts.BlockSizeThreshold
    1798           1 :         writerOpts.Compression = levelOpts.Compression
    1799           1 :         writerOpts.FilterPolicy = levelOpts.FilterPolicy
    1800           1 :         writerOpts.FilterType = levelOpts.FilterType
    1801           1 :         writerOpts.IndexBlockSize = levelOpts.IndexBlockSize
    1802           1 :         return writerOpts
    1803             : }

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