/*-------------------------------------------------------------------------

 *

 * inherit.c

 *    Routines to process child relations in inheritance trees

 *

 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group

 * Portions Copyright (c) 1994, Regents of the University of California

 *

 *

 * IDENTIFICATION

 *    src/backend/optimizer/util/inherit.c

 *

 *-------------------------------------------------------------------------

 */

#include "postgres.h"

#include "access/sysattr.h"

#include "access/table.h"

#include "catalog/partition.h"

#include "catalog/pg_inherits.h"

#include "catalog/pg_type.h"

#include "miscadmin.h"

#include "nodes/makefuncs.h"

#include "optimizer/appendinfo.h"

#include "optimizer/inherit.h"

#include "optimizer/optimizer.h"

#include "optimizer/pathnode.h"

#include "optimizer/plancat.h"

#include "optimizer/planmain.h"

#include "optimizer/planner.h"

#include "optimizer/prep.h"

#include "optimizer/restrictinfo.h"

#include "parser/parsetree.h"

#include "parser/parse_relation.h"

#include "partitioning/partdesc.h"

#include "partitioning/partprune.h"

#include "utils/rel.h"

static void expand_partitioned_rtentry(PlannerInfo *root, RelOptInfo *relinfo,

                     RangeTblEntry *parentrte,

                     Index parentRTindex, Relation parentrel,

                     Bitmapset *parent_updatedCols,

                     PlanRowMark *top_parentrc, LOCKMODE lockmode);

static void expand_single_inheritance_child(PlannerInfo *root,

                      RangeTblEntry *parentrte,

                      Index parentRTindex, Relation parentrel,

                      PlanRowMark *top_parentrc, Relation childrel,

                      RangeTblEntry **childrte_p,

                      Index *childRTindex_p);

static Bitmapset *translate_col_privs(const Bitmapset *parent_privs,

                    List *translated_vars);

static Bitmapset *translate_col_privs_multilevel(PlannerInfo *root,

                         RelOptInfo *rel,

                         RelOptInfo *parent_rel,

                         Bitmapset *parent_cols);

static void expand_appendrel_subquery(PlannerInfo *root, RelOptInfo *rel,

                    RangeTblEntry *rte, Index rti);

/*

 * expand_inherited_rtentry

 *    Expand a rangetable entry that has the "inh" bit set.

 *

 * "inh" is only allowed in two cases: RELATION and SUBQUERY RTEs.

 *

 * "inh" on a plain RELATION RTE means that it is a partitioned table or the

 * parent of a traditional-inheritance set.  In this case we must add entries

 * for all the interesting child tables to the query's rangetable, and build

 * additional planner data structures for them, including RelOptInfos,

 * AppendRelInfos, and possibly PlanRowMarks.

 *

 * Note that the original RTE is considered to represent the whole inheritance

 * set.  In the case of traditional inheritance, the first of the generated

 * RTEs is an RTE for the same table, but with inh = false, to represent the

 * parent table in its role as a simple member of the inheritance set.  For

 * partitioning, we don't need a second RTE because the partitioned table

 * itself has no data and need not be scanned.

 *

 * "inh" on a SUBQUERY RTE means that it's the parent of a UNION ALL group,

 * which is treated as an appendrel similarly to inheritance cases; however,

 * we already made RTEs and AppendRelInfos for the subqueries.  We only need

 * to build RelOptInfos for them, which is done by expand_appendrel_subquery.

 */

void

expand_inherited_rtentry(PlannerInfo *root, RelOptInfo *rel,

             RangeTblEntry *rte, Index rti)

{

  Oid     parentOID;

  Relation  oldrelation;

  LOCKMODE  lockmode;

  PlanRowMark *oldrc;

  bool    old_isParent = false;

  int     old_allMarkTypes = 0;

  Assert(rte->inh);     /* else caller error */

  if (rte->rtekind == RTE_SUBQUERY)

  {

    expand_appendrel_subquery(root, rel, rte, rti);

    return;

  }

  Assert(rte->rtekind == RTE_RELATION);

  parentOID = rte->relid;

  /*

   * We used to check has_subclass() here, but there's no longer any need

   * to, because subquery_planner already did.

   */

  /*

   * The rewriter should already have obtained an appropriate lock on each

   * relation named in the query, so we can open the parent relation without

   * locking it.  However, for each child relation we add to the query, we

   * must obtain an appropriate lock, because this will be the first use of

   * those relations in the parse/rewrite/plan pipeline.  Child rels should

   * use the same lockmode as their parent.

   */

  oldrelation = table_open(parentOID, NoLock);

  lockmode = rte->rellockmode;

  /*

   * If parent relation is selected FOR UPDATE/SHARE, we need to mark its

   * PlanRowMark as isParent = true, and generate a new PlanRowMark for each

   * child.

   */

  oldrc = get_plan_rowmark(root->rowMarks, rti);

  if (oldrc)

  {

    old_isParent = oldrc->isParent;

    oldrc->isParent = true;

    /* Save initial value of allMarkTypes before children add to it */

    old_allMarkTypes = oldrc->allMarkTypes;

  }

  /* Scan the inheritance set and expand it */

  if (oldrelation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)

  {

    RTEPermissionInfo *perminfo;

    perminfo = getRTEPermissionInfo(root->parse->rteperminfos, rte);

    /*

     * Partitioned table, so set up for partitioning.

     */

    Assert(rte->relkind == RELKIND_PARTITIONED_TABLE);

    /*

     * Recursively expand and lock the partitions.  While at it, also

     * extract the partition key columns of all the partitioned tables.

     */

    expand_partitioned_rtentry(root, rel, rte, rti,

                   oldrelation,

                   perminfo->updatedCols,

                   oldrc, lockmode);

  }

  else

  {

    /*

     * Ordinary table, so process traditional-inheritance children.  (Note

     * that partitioned tables are not allowed to have inheritance

     * children, so it's not possible for both cases to apply.)

     */

    List     *inhOIDs;

    ListCell   *l;

    /* Scan for all members of inheritance set, acquire needed locks */

    inhOIDs = find_all_inheritors(parentOID, lockmode, NULL);

    /*

     * We used to special-case the situation where the table no longer has

     * any children, by clearing rte->inh and exiting.  That no longer

     * works, because this function doesn't get run until after decisions

     * have been made that depend on rte->inh.  We have to treat such

     * situations as normal inheritance.  The table itself should always

     * have been found, though.

     */

    Assert(inhOIDs != NIL);

    Assert(linitial_oid(inhOIDs) == parentOID);

    /* Expand simple_rel_array and friends to hold child objects. */

    expand_planner_arrays(root, list_length(inhOIDs));

    /*

     * Expand inheritance children in the order the OIDs were returned by

     * find_all_inheritors.

     */

    foreach(l, inhOIDs)

    {

      Oid     childOID = lfirst_oid(l);

      Relation  newrelation;

      RangeTblEntry *childrte;

      Index   childRTindex;

      /* Open rel if needed; we already have required locks */

      if (childOID != parentOID)

        newrelation = table_open(childOID, NoLock);

      else

        newrelation = oldrelation;

      /*

       * It is possible that the parent table has children that are temp

       * tables of other backends.  We cannot safely access such tables

       * (because of buffering issues), and the best thing to do seems

       * to be to silently ignore them.

       */

      if (childOID != parentOID && RELATION_IS_OTHER_TEMP(newrelation))

      {

        table_close(newrelation, lockmode);

        continue;

      }

      /* Create RTE and AppendRelInfo, plus PlanRowMark if needed. */

      expand_single_inheritance_child(root, rte, rti, oldrelation,

                      oldrc, newrelation,

                      &childrte, &childRTindex);

      /* Create the otherrel RelOptInfo too. */

      (void) build_simple_rel(root, childRTindex, rel);

      /* Close child relations, but keep locks */

      if (childOID != parentOID)

        table_close(newrelation, NoLock);

    }

  }

  /*

   * Some children might require different mark types, which would've been

   * reported into oldrc.  If so, add relevant entries to the top-level

   * targetlist and update parent rel's reltarget.  This should match what

   * preprocess_targetlist() would have added if the mark types had been

   * requested originally.

   *

   * (Someday it might be useful to fold these resjunk columns into the

   * row-identity-column management used for UPDATE/DELETE.  Today is not

   * that day, however.)

   */

  if (oldrc)

  {

    int     new_allMarkTypes = oldrc->allMarkTypes;

    Var      *var;

    TargetEntry *tle;

    char    resname[32];

    List     *newvars = NIL;

    /* Add TID junk Var if needed, unless we had it already */

    if (new_allMarkTypes & ~(1 << ROW_MARK_COPY) &&

      !(old_allMarkTypes & ~(1 << ROW_MARK_COPY)))

    {

      /* Need to fetch TID */

      var = makeVar(oldrc->rti,

              SelfItemPointerAttributeNumber,

              TIDOID,

              -1,

              InvalidOid,

              0);

      snprintf(resname, sizeof(resname), "ctid%u", oldrc->rowmarkId);

      tle = makeTargetEntry((Expr *) var,

                  list_length(root->processed_tlist) + 1,

                  pstrdup(resname),

                  true);

      root->processed_tlist = lappend(root->processed_tlist, tle);

      newvars = lappend(newvars, var);

    }

    /* Add whole-row junk Var if needed, unless we had it already */

    if ((new_allMarkTypes & (1 << ROW_MARK_COPY)) &&

      !(old_allMarkTypes & (1 << ROW_MARK_COPY)))

    {

      var = makeWholeRowVar(planner_rt_fetch(oldrc->rti, root),

                  oldrc->rti,

                  0,

                  false);

      snprintf(resname, sizeof(resname), "wholerow%u", oldrc->rowmarkId);

      tle = makeTargetEntry((Expr *) var,

                  list_length(root->processed_tlist) + 1,

                  pstrdup(resname),

                  true);

      root->processed_tlist = lappend(root->processed_tlist, tle);

      newvars = lappend(newvars, var);

    }

    /* Add tableoid junk Var, unless we had it already */

    if (!old_isParent)

    {

      var = makeVar(oldrc->rti,

              TableOidAttributeNumber,

              OIDOID,

              -1,

              InvalidOid,

              0);

      snprintf(resname, sizeof(resname), "tableoid%u", oldrc->rowmarkId);

      tle = makeTargetEntry((Expr *) var,

                  list_length(root->processed_tlist) + 1,

                  pstrdup(resname),

                  true);

      root->processed_tlist = lappend(root->processed_tlist, tle);

      newvars = lappend(newvars, var);

    }

    /*

     * Add the newly added Vars to parent's reltarget.  We needn't worry

     * about the children's reltargets, they'll be made later.

     */

    add_vars_to_targetlist(root, newvars, bms_make_singleton(0));

  }

  table_close(oldrelation, NoLock);

}

/*

 * expand_partitioned_rtentry

 *    Recursively expand an RTE for a partitioned table.

 */

static void

expand_partitioned_rtentry(PlannerInfo *root, RelOptInfo *relinfo,

               RangeTblEntry *parentrte,

               Index parentRTindex, Relation parentrel,

               Bitmapset *parent_updatedCols,

               PlanRowMark *top_parentrc, LOCKMODE lockmode)

{

  PartitionDesc partdesc;

  int     num_live_parts;

  int     i;

  check_stack_depth();

  Assert(parentrte->inh);

  partdesc = PartitionDirectoryLookup(root->glob->partition_directory,

                    parentrel);

  /* A partitioned table should always have a partition descriptor. */

  Assert(partdesc);

  /*

   * Note down whether any partition key cols are being updated. Though it's

   * the root partitioned table's updatedCols we are interested in,

   * parent_updatedCols provided by the caller contains the root partrel's

   * updatedCols translated to match the attribute ordering of parentrel.

   */

  if (!root->partColsUpdated)

    root->partColsUpdated =

      has_partition_attrs(parentrel, parent_updatedCols, NULL);

  /* Nothing further to do here if there are no partitions. */

  if (partdesc->nparts == 0)

    return;

  /*

   * Perform partition pruning using restriction clauses assigned to parent

   * relation.  live_parts will contain PartitionDesc indexes of partitions

   * that survive pruning.  Below, we will initialize child objects for the

   * surviving partitions.

   */

  relinfo->live_parts = prune_append_rel_partitions(relinfo);

  /* Expand simple_rel_array and friends to hold child objects. */

  num_live_parts = bms_num_members(relinfo->live_parts);

  if (num_live_parts > 0)

    expand_planner_arrays(root, num_live_parts);

  /*

   * We also store partition RelOptInfo pointers in the parent relation.

   * Since we're palloc0'ing, slots corresponding to pruned partitions will

   * contain NULL.

   */

  Assert(relinfo->part_rels == NULL);

  relinfo->part_rels = (RelOptInfo **)

    palloc0(relinfo->nparts * sizeof(RelOptInfo *));

  /*

   * Create a child RTE for each live partition.  Note that unlike

   * traditional inheritance, we don't need a child RTE for the partitioned

   * table itself, because it's not going to be scanned.

   */

  i = -1;

  while ((i = bms_next_member(relinfo->live_parts, i)) >= 0)

  {

    Oid     childOID = partdesc->oids[i];

    Relation  childrel;

    RangeTblEntry *childrte;

    Index   childRTindex;

    RelOptInfo *childrelinfo;

    /*

     * Open rel, acquiring required locks.  If a partition was recently

     * detached and subsequently dropped, then opening it will fail.  In

     * this case, behave as though the partition had been pruned.

     */

    childrel = try_table_open(childOID, lockmode);

    if (childrel == NULL)

    {

      relinfo->live_parts = bms_del_member(relinfo->live_parts, i);

      continue;

    }

    /*

     * Temporary partitions belonging to other sessions should have been

     * disallowed at definition, but for paranoia's sake, let's double

     * check.

     */

    if (RELATION_IS_OTHER_TEMP(childrel))

      elog(ERROR, "temporary relation from another session found as partition");

    /* Create RTE and AppendRelInfo, plus PlanRowMark if needed. */

    expand_single_inheritance_child(root, parentrte, parentRTindex,

                    parentrel, top_parentrc, childrel,

                    &childrte, &childRTindex);

    /* Create the otherrel RelOptInfo too. */

    childrelinfo = build_simple_rel(root, childRTindex, relinfo);

    relinfo->part_rels[i] = childrelinfo;

    relinfo->all_partrels = bms_add_members(relinfo->all_partrels,

                        childrelinfo->relids);

    /* If this child is itself partitioned, recurse */

    if (childrel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)

    {

      AppendRelInfo *appinfo = root->append_rel_array[childRTindex];

      Bitmapset  *child_updatedCols;

      child_updatedCols = translate_col_privs(parent_updatedCols,

                          appinfo->translated_vars);

      expand_partitioned_rtentry(root, childrelinfo,

                     childrte, childRTindex,

                     childrel,

                     child_updatedCols,

                     top_parentrc, lockmode);

    }

    /* Close child relation, but keep locks */

    table_close(childrel, NoLock);

  }

}

/*

 * expand_single_inheritance_child

 *    Build a RangeTblEntry and an AppendRelInfo, plus maybe a PlanRowMark.

 *

 * We now expand the partition hierarchy level by level, creating a

 * corresponding hierarchy of AppendRelInfos and RelOptInfos, where each

 * partitioned descendant acts as a parent of its immediate partitions.

 * (This is a difference from what older versions of PostgreSQL did and what

 * is still done in the case of table inheritance for unpartitioned tables,

 * where the hierarchy is flattened during RTE expansion.)

 *

 * PlanRowMarks still carry the top-parent's RTI, and the top-parent's

 * allMarkTypes field still accumulates values from all descendents.

 *

 * "parentrte" and "parentRTindex" are immediate parent's RTE and

 * RTI. "top_parentrc" is top parent's PlanRowMark.

 *

 * The child RangeTblEntry and its RTI are returned in "childrte_p" and

 * "childRTindex_p" resp.

 */

static void

expand_single_inheritance_child(PlannerInfo *root, RangeTblEntry *parentrte,

                Index parentRTindex, Relation parentrel,

                PlanRowMark *top_parentrc, Relation childrel,

                RangeTblEntry **childrte_p,

                Index *childRTindex_p)

{

  Query    *parse = root->parse;

  Oid     parentOID = RelationGetRelid(parentrel);

  Oid     childOID = RelationGetRelid(childrel);

  RangeTblEntry *childrte;

  Index   childRTindex;

  AppendRelInfo *appinfo;

  TupleDesc child_tupdesc;

  List     *parent_colnames;

  List     *child_colnames;

  /*

   * Build an RTE for the child, and attach to query's rangetable list. We

   * copy most scalar fields of the parent's RTE, but replace relation OID,

   * relkind, and inh for the child.  Set the child's securityQuals to

   * empty, because we only want to apply the parent's RLS conditions

   * regardless of what RLS properties individual children may have. (This

   * is an intentional choice to make inherited RLS work like regular

   * permissions checks.) The parent securityQuals will be propagated to

   * children along with other base restriction clauses, so we don't need to

   * do it here.  Other infrastructure of the parent RTE has to be

   * translated to match the child table's column ordering, which we do

   * below, so a "flat" copy is sufficient to start with.

   */

  childrte = makeNode(RangeTblEntry);

  memcpy(childrte, parentrte, sizeof(RangeTblEntry));

  Assert(parentrte->rtekind == RTE_RELATION); /* else this is dubious */

  childrte->relid = childOID;

  childrte->relkind = childrel->rd_rel->relkind;

  /* A partitioned child will need to be expanded further. */

  if (childrte->relkind == RELKIND_PARTITIONED_TABLE)

  {

    Assert(childOID != parentOID);

    childrte->inh = true;

  }

  else

    childrte->inh = false;

  childrte->securityQuals = NIL;

  /* No permission checking for child RTEs. */

  childrte->perminfoindex = 0;

  /* Link not-yet-fully-filled child RTE into data structures */

  parse->rtable = lappend(parse->rtable, childrte);

  childRTindex = list_length(parse->rtable);

  *childrte_p = childrte;

  *childRTindex_p = childRTindex;

  /*

   * Retrieve column not-null constraint information for the child relation

   * if its relation OID is different from the parent's.

   */

  if (childOID != parentOID)

    get_relation_notnullatts(root, childrel);

  /*

   * Build an AppendRelInfo struct for each parent/child pair.

   */

  appinfo = make_append_rel_info(parentrel, childrel,

                   parentRTindex, childRTindex);

  root->append_rel_list = lappend(root->append_rel_list, appinfo);

  /* tablesample is probably null, but copy it */

  childrte->tablesample = copyObject(parentrte->tablesample);

  /*

   * Construct an alias clause for the child, which we can also use as eref.

   * This is important so that EXPLAIN will print the right column aliases

   * for child-table columns.  (Since ruleutils.c doesn't have any easy way

   * to reassociate parent and child columns, we must get the child column

   * aliases right to start with.  Note that setting childrte->alias forces

   * ruleutils.c to use these column names, which it otherwise would not.)

   */

  child_tupdesc = RelationGetDescr(childrel);

  parent_colnames = parentrte->eref->colnames;

  child_colnames = NIL;

  for (int cattno = 0; cattno < child_tupdesc->natts; cattno++)

  {

    Form_pg_attribute att = TupleDescAttr(child_tupdesc, cattno);

    const char *attname;

    if (att->attisdropped)

    {

      /* Always insert an empty string for a dropped column */

      attname = "";

    }

    else if (appinfo->parent_colnos[cattno] > 0 &&

         appinfo->parent_colnos[cattno] <= list_length(parent_colnames))

    {

      /* Duplicate the query-assigned name for the parent column */

      attname = strVal(list_nth(parent_colnames,

                    appinfo->parent_colnos[cattno] - 1));

    }

    else

    {

      /* New column, just use its real name */

      attname = NameStr(att->attname);

    }

    child_colnames = lappend(child_colnames, makeString(pstrdup(attname)));

  }

  /*

   * We just duplicate the parent's table alias name for each child.  If the

   * plan gets printed, ruleutils.c has to sort out unique table aliases to

   * use, which it can handle.

   */

  childrte->alias = childrte->eref = makeAlias(parentrte->eref->aliasname,

                         child_colnames);

  /*

   * Store the RTE and appinfo in the respective PlannerInfo arrays, which

   * the caller must already have allocated space for.

   */

  Assert(childRTindex < root->simple_rel_array_size);

  Assert(root->simple_rte_array[childRTindex] == NULL);

  root->simple_rte_array[childRTindex] = childrte;

  Assert(root->append_rel_array[childRTindex] == NULL);

  root->append_rel_array[childRTindex] = appinfo;

  /*

   * Build a PlanRowMark if parent is marked FOR UPDATE/SHARE.

   */

  if (top_parentrc)

  {

    PlanRowMark *childrc = makeNode(PlanRowMark);

    childrc->rti = childRTindex;

    childrc->prti = top_parentrc->rti;

    childrc->rowmarkId = top_parentrc->rowmarkId;

    /* Reselect rowmark type, because relkind might not match parent */

    childrc->markType = select_rowmark_type(childrte,

                        top_parentrc->strength);

    childrc->allMarkTypes = (1 << childrc->markType);

    childrc->strength = top_parentrc->strength;

    childrc->waitPolicy = top_parentrc->waitPolicy;

    /*

     * We mark RowMarks for partitioned child tables as parent RowMarks so

     * that the executor ignores them (except their existence means that

     * the child tables will be locked using the appropriate mode).

     */

    childrc->isParent = (childrte->relkind == RELKIND_PARTITIONED_TABLE);

    /* Include child's rowmark type in top parent's allMarkTypes */

    top_parentrc->allMarkTypes |= childrc->allMarkTypes;

    root->rowMarks = lappend(root->rowMarks, childrc);

  }

  /*

   * If we are creating a child of the query target relation (only possible

   * in UPDATE/DELETE/MERGE), add it to all_result_relids, as well as

   * leaf_result_relids if appropriate, and make sure that we generate

   * required row-identity data.

   */

  if (bms_is_member(parentRTindex, root->all_result_relids))

  {

    /* OK, record the child as a result rel too. */

    root->all_result_relids = bms_add_member(root->all_result_relids,

                         childRTindex);

    /* Non-leaf partitions don't need any row identity info. */

    if (childrte->relkind != RELKIND_PARTITIONED_TABLE)

    {

      Var      *rrvar;

      root->leaf_result_relids = bms_add_member(root->leaf_result_relids,

                            childRTindex);

      /*

       * If we have any child target relations, assume they all need to

       * generate a junk "tableoid" column.  (If only one child survives

       * pruning, we wouldn't really need this, but it's not worth

       * thrashing about to avoid it.)

       */

      rrvar = makeVar(childRTindex,

              TableOidAttributeNumber,

              OIDOID,

              -1,

              InvalidOid,

              0);

      add_row_identity_var(root, rrvar, childRTindex, "tableoid");

      /* Register any row-identity columns needed by this child. */

      add_row_identity_columns(root, childRTindex,

                   childrte, childrel);

    }

  }

}

/*

 * get_rel_all_updated_cols

 *    Returns the set of columns of a given "simple" relation that are

 *    updated by this query.

 */

Bitmapset *

get_rel_all_updated_cols(PlannerInfo *root, RelOptInfo *rel)

{

  Index   relid;

  RangeTblEntry *rte;

  RTEPermissionInfo *perminfo;

  Bitmapset  *updatedCols,

         *extraUpdatedCols;

  Assert(root->parse->commandType == CMD_UPDATE);

  Assert(IS_SIMPLE_REL(rel));

  /*

   * We obtain updatedCols for the query's result relation.  Then, if

   * necessary, we map it to the column numbers of the relation for which

   * they were requested.

   */

  relid = root->parse->resultRelation;

  rte = planner_rt_fetch(relid, root);

  perminfo = getRTEPermissionInfo(root->parse->rteperminfos, rte);

  updatedCols = perminfo->updatedCols;

  if (rel->relid != relid)

  {

    RelOptInfo *top_parent_rel = find_base_rel(root, relid);

    Assert(IS_OTHER_REL(rel));

    updatedCols = translate_col_privs_multilevel(root, rel, top_parent_rel,

                           updatedCols);

  }

  /*

   * Now we must check to see if there are any generated columns that depend

   * on the updatedCols, and add them to the result.

   */

  extraUpdatedCols = get_dependent_generated_columns(root, rel->relid,

                             updatedCols);

  return bms_union(updatedCols, extraUpdatedCols);

}

/*

 * translate_col_privs

 *    Translate a bitmapset representing per-column privileges from the

 *    parent rel's attribute numbering to the child's.

 *

 * The only surprise here is that we don't translate a parent whole-row

 * reference into a child whole-row reference.  That would mean requiring

 * permissions on all child columns, which is overly strict, since the

 * query is really only going to reference the inherited columns.  Instead

 * we set the per-column bits for all inherited columns.

 */

static Bitmapset *

translate_col_privs(const Bitmapset *parent_privs,

          List *translated_vars)

{

  Bitmapset  *child_privs = NULL;

  bool    whole_row;

  int     attno;

  ListCell   *lc;

  /* System attributes have the same numbers in all tables */

  for (attno = FirstLowInvalidHeapAttributeNumber + 1; attno < 0; attno++)

  {

    if (bms_is_member(attno - FirstLowInvalidHeapAttributeNumber,

              parent_privs))

      child_privs = bms_add_member(child_privs,

                     attno - FirstLowInvalidHeapAttributeNumber);

  }

  /* Check if parent has whole-row reference */

  whole_row = bms_is_member(InvalidAttrNumber - FirstLowInvalidHeapAttributeNumber,

                parent_privs);

  /* And now translate the regular user attributes, using the vars list */

  attno = InvalidAttrNumber;

  foreach(lc, translated_vars)

  {

    Var      *var = lfirst_node(Var, lc);

    attno++;

    if (var == NULL)   /* ignore dropped columns */

      continue;

    if (whole_row ||

      bms_is_member(attno - FirstLowInvalidHeapAttributeNumber,

              parent_privs))

      child_privs = bms_add_member(child_privs,

                     var->varattno - FirstLowInvalidHeapAttributeNumber);

  }

  return child_privs;

}

/*

 * translate_col_privs_multilevel

 *    Recursively translates the column numbers contained in 'parent_cols'

 *    to the column numbers of a descendant relation given by 'rel'

 *

 * Note that because this is based on translate_col_privs, it will expand

 * a whole-row reference into all inherited columns.  This is not an issue

 * for current usages, but beware.

 */

static Bitmapset *

translate_col_privs_multilevel(PlannerInfo *root, RelOptInfo *rel,

                 RelOptInfo *parent_rel,

                 Bitmapset *parent_cols)

{

  AppendRelInfo *appinfo;

  /* Fast path for easy case. */

  if (parent_cols == NULL)

    return NULL;

  /* Recurse if immediate parent is not the top parent. */

  if (rel->parent != parent_rel)

  {

    if (rel->parent)

      parent_cols = translate_col_privs_multilevel(root, rel->parent,

                             parent_rel,

                             parent_cols);

    else

      elog(ERROR, "rel with relid %u is not a child rel", rel->relid);

  }

  /* Now translate for this child. */

  Assert(root->append_rel_array != NULL);

  appinfo = root->append_rel_array[rel->relid];

  Assert(appinfo != NULL);

  return translate_col_privs(parent_cols, appinfo->translated_vars);

}

/*

 * expand_appendrel_subquery

 *    Add "other rel" RelOptInfos for the children of an appendrel baserel

 *

 * "rel" is a subquery relation that has the rte->inh flag set, meaning it

 * is a UNION ALL subquery that's been flattened into an appendrel, with

 * child subqueries listed in root->append_rel_list.  We need to build

 * a RelOptInfo for each child relation so that we can plan scans on them.

 */

static void

expand_appendrel_subquery(PlannerInfo *root, RelOptInfo *rel,

              RangeTblEntry *rte, Index rti)

{

  ListCell   *l;

  foreach(l, root->append_rel_list)

  {

    AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);

    Index   childRTindex = appinfo->child_relid;

    RangeTblEntry *childrte;

    RelOptInfo *childrel;

    /* append_rel_list contains all append rels; ignore others */

    if (appinfo->parent_relid != rti)

      continue;

    /* find the child RTE, which should already exist */

    Assert(childRTindex < root->simple_rel_array_size);

    childrte = root->simple_rte_array[childRTindex];

    Assert(childrte != NULL);

    /* Build the child RelOptInfo. */

    childrel = build_simple_rel(root, childRTindex, rel);

    /* Child may itself be an inherited rel, either table or subquery. */

    if (childrte->inh)

      expand_inherited_rtentry(root, childrel, childrte, childRTindex);

  }

}

/*

 * apply_child_basequals

 *    Populate childrel's base restriction quals from parent rel's quals,

 *    translating Vars using appinfo and re-checking for quals which are

 *    constant-TRUE or constant-FALSE when applied to this child relation.

 *

 * If any of the resulting clauses evaluate to constant false or NULL, we

 * return false and don't apply any quals.  Caller should mark the relation as

 * a dummy rel in this case, since it doesn't need to be scanned.  Constant

 * true quals are ignored.

 */

bool

apply_child_basequals(PlannerInfo *root, RelOptInfo *parentrel,

            RelOptInfo *childrel, RangeTblEntry *childRTE,

            AppendRelInfo *appinfo)

{

  List     *childquals;

  Index   cq_min_security;

  ListCell   *lc;

  /*

   * The child rel's targetlist might contain non-Var expressions, which

   * means that substitution into the quals could produce opportunities for

   * const-simplification, and perhaps even pseudoconstant quals. Therefore,

   * transform each RestrictInfo separately to see if it reduces to a

   * constant or pseudoconstant.  (We must process them separately to keep

   * track of the security level of each qual.)

   */

  childquals = NIL;

  cq_min_security = UINT_MAX;

  foreach(lc, parentrel->baserestrictinfo)

  {

    RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);

    Node     *childqual;

    ListCell   *lc2;

    Assert(IsA(rinfo, RestrictInfo));

    childqual = adjust_appendrel_attrs(root,

                       (Node *) rinfo->clause,

                       1, &appinfo);

    childqual = eval_const_expressions(root, childqual);

    /* check for flat-out constant */

    if (childqual && IsA(childqual, Const))

    {

      if (((Const *) childqual)->constisnull ||

        !DatumGetBool(((Const *) childqual)->constvalue))

      {

        /* Restriction reduces to constant FALSE or NULL */

        return false;

      }

      /* Restriction reduces to constant TRUE, so drop it */

      continue;

    }

    /* might have gotten an AND clause, if so flatten it */

    foreach(lc2, make_ands_implicit((Expr *) childqual))

    {

      Node     *onecq = (Node *) lfirst(lc2);

      bool    pseudoconstant;

      RestrictInfo *childrinfo;

      /* check for pseudoconstant (no Vars or volatile functions) */

      pseudoconstant =

        !contain_vars_of_level(onecq, 0) &&

        !contain_volatile_functions(onecq);

      if (pseudoconstant)

      {

        /* tell createplan.c to check for gating quals */

        root->hasPseudoConstantQuals = true;

      }

      /* reconstitute RestrictInfo with appropriate properties */

      childrinfo = make_restrictinfo(root,

                       (Expr *) onecq,

                       rinfo->is_pushed_down,

                       rinfo->has_clone,

                       rinfo->is_clone,

                       pseudoconstant,

                       rinfo->security_level,

                       NULL, NULL, NULL);

      /* Restriction is proven always false */

      if (restriction_is_always_false(root, childrinfo))

        return false;

      /* Restriction is proven always true, so drop it */

      if (restriction_is_always_true(root, childrinfo))

        continue;

      childquals = lappend(childquals, childrinfo);

      /* track minimum security level among child quals */

      cq_min_security = Min(cq_min_security, rinfo->security_level);

    }

  }

  /*

   * In addition to the quals inherited from the parent, we might have

   * securityQuals associated with this particular child node.  (Currently

   * this can only happen in appendrels originating from UNION ALL;

   * inheritance child tables don't have their own securityQuals, see

   * expand_single_inheritance_child().)  Pull any such securityQuals up

   * into the baserestrictinfo for the child.  This is similar to

   * process_security_barrier_quals() for the parent rel, except that we

   * can't make any general deductions from such quals, since they don't

   * hold for the whole appendrel.

   */

  if (childRTE->securityQuals)

  {

    Index   security_level = 0;

    foreach(lc, childRTE->securityQuals)

    {

      List     *qualset = (List *) lfirst(lc);

      ListCell   *lc2;

      foreach(lc2, qualset)

      {

        Expr     *qual = (Expr *) lfirst(lc2);

        /* not likely that we'd see constants here, so no check */