/src/postgres/src/backend/utils/cache/lsyscache.c

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/*-------------------------------------------------------------------------
 *
 * lsyscache.c
 *    Convenience routines for common queries in the system catalog cache.
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *    src/backend/utils/cache/lsyscache.c
 *
 * NOTES
 *    Eventually, the index information should go through here, too.
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/hash.h"
#include "access/htup_details.h"
#include "bootstrap/bootstrap.h"
#include "catalog/namespace.h"
#include "catalog/pg_am.h"
#include "catalog/pg_amop.h"
#include "catalog/pg_amproc.h"
#include "catalog/pg_cast.h"
#include "catalog/pg_class.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_index.h"
#include "catalog/pg_language.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_opfamily.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_publication.h"
#include "catalog/pg_range.h"
#include "catalog/pg_statistic.h"
#include "catalog/pg_subscription.h"
#include "catalog/pg_transform.h"
#include "catalog/pg_type.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/catcache.h"
#include "utils/datum.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "utils/typcache.h"

/* Hook for plugins to get control in get_attavgwidth() */
get_attavgwidth_hook_type get_attavgwidth_hook = NULL;


/*        ---------- AMOP CACHES ----------            */

/*
 * op_in_opfamily
 *
 *    Return t iff operator 'opno' is in operator family 'opfamily'.
 *
 * This function only considers search operators, not ordering operators.
 */
bool
op_in_opfamily(Oid opno, Oid opfamily)
{
  return SearchSysCacheExists3(AMOPOPID,
                 ObjectIdGetDatum(opno),
                 CharGetDatum(AMOP_SEARCH),
                 ObjectIdGetDatum(opfamily));
}

/*
 * get_op_opfamily_strategy
 *
 *    Get the operator's strategy number within the specified opfamily,
 *    or 0 if it's not a member of the opfamily.
 *
 * This function only considers search operators, not ordering operators.
 */
int
get_op_opfamily_strategy(Oid opno, Oid opfamily)
{
  HeapTuple tp;
  Form_pg_amop amop_tup;
  int     result;

  tp = SearchSysCache3(AMOPOPID,
             ObjectIdGetDatum(opno),
             CharGetDatum(AMOP_SEARCH),
             ObjectIdGetDatum(opfamily));
  if (!HeapTupleIsValid(tp))
    return 0;
  amop_tup = (Form_pg_amop) GETSTRUCT(tp);
  result = amop_tup->amopstrategy;
  ReleaseSysCache(tp);
  return result;
}

/*
 * get_op_opfamily_sortfamily
 *
 *    If the operator is an ordering operator within the specified opfamily,
 *    return its amopsortfamily OID; else return InvalidOid.
 */
Oid
get_op_opfamily_sortfamily(Oid opno, Oid opfamily)
{
  HeapTuple tp;
  Form_pg_amop amop_tup;
  Oid     result;

  tp = SearchSysCache3(AMOPOPID,
             ObjectIdGetDatum(opno),
             CharGetDatum(AMOP_ORDER),
             ObjectIdGetDatum(opfamily));
  if (!HeapTupleIsValid(tp))
    return InvalidOid;
  amop_tup = (Form_pg_amop) GETSTRUCT(tp);
  result = amop_tup->amopsortfamily;
  ReleaseSysCache(tp);
  return result;
}

/*
 * get_op_opfamily_properties
 *
 *    Get the operator's strategy number and declared input data types
 *    within the specified opfamily.
 *
 * Caller should already have verified that opno is a member of opfamily,
 * therefore we raise an error if the tuple is not found.
 */
void
get_op_opfamily_properties(Oid opno, Oid opfamily, bool ordering_op,
               int *strategy,
               Oid *lefttype,
               Oid *righttype)
{
  HeapTuple tp;
  Form_pg_amop amop_tup;

  tp = SearchSysCache3(AMOPOPID,
             ObjectIdGetDatum(opno),
             CharGetDatum(ordering_op ? AMOP_ORDER : AMOP_SEARCH),
             ObjectIdGetDatum(opfamily));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "operator %u is not a member of opfamily %u",
       opno, opfamily);
  amop_tup = (Form_pg_amop) GETSTRUCT(tp);
  *strategy = amop_tup->amopstrategy;
  *lefttype = amop_tup->amoplefttype;
  *righttype = amop_tup->amoprighttype;
  ReleaseSysCache(tp);
}

/*
 * get_opfamily_member
 *    Get the OID of the operator that implements the specified strategy
 *    with the specified datatypes for the specified opfamily.
 *
 * Returns InvalidOid if there is no pg_amop entry for the given keys.
 */
Oid
get_opfamily_member(Oid opfamily, Oid lefttype, Oid righttype,
          int16 strategy)
{
  HeapTuple tp;
  Form_pg_amop amop_tup;
  Oid     result;

  tp = SearchSysCache4(AMOPSTRATEGY,
             ObjectIdGetDatum(opfamily),
             ObjectIdGetDatum(lefttype),
             ObjectIdGetDatum(righttype),
             Int16GetDatum(strategy));
  if (!HeapTupleIsValid(tp))
    return InvalidOid;
  amop_tup = (Form_pg_amop) GETSTRUCT(tp);
  result = amop_tup->amopopr;
  ReleaseSysCache(tp);
  return result;
}

/*
 * get_opfamily_member_for_cmptype
 *    Get the OID of the operator that implements the specified comparison
 *    type with the specified datatypes for the specified opfamily.
 *
 * Returns InvalidOid if there is no mapping for the comparison type or no
 * pg_amop entry for the given keys.
 */
Oid
get_opfamily_member_for_cmptype(Oid opfamily, Oid lefttype, Oid righttype,
                CompareType cmptype)
{
  Oid     opmethod;
  StrategyNumber strategy;

  opmethod = get_opfamily_method(opfamily);
  strategy = IndexAmTranslateCompareType(cmptype, opmethod, opfamily, true);
  if (!strategy)
    return InvalidOid;
  return get_opfamily_member(opfamily, lefttype, righttype, strategy);
}

/*
 * get_opmethod_canorder
 *    Return amcanorder field for given index AM.
 *
 * To speed things up in the common cases, we're hardcoding the results from
 * the built-in index types.  Note that we also need to hardcode the negative
 * results from the built-in non-btree index types, since you'll usually get a
 * few hits for those as well.  It would be nice to organize and cache this a
 * bit differently to avoid the hardcoding.
 */
static bool
get_opmethod_canorder(Oid amoid)
{
  switch (amoid)
  {
    case BTREE_AM_OID:
      return true;
    case HASH_AM_OID:
    case GIST_AM_OID:
    case GIN_AM_OID:
    case SPGIST_AM_OID:
    case BRIN_AM_OID:
      return false;
    default:
      {
        bool    result;
        IndexAmRoutine *amroutine = GetIndexAmRoutineByAmId(amoid, false);

        result = amroutine->amcanorder;
        pfree(amroutine);
        return result;
      }
  }
}

/*
 * get_ordering_op_properties
 *    Given the OID of an ordering operator (a "<" or ">" operator),
 *    determine its opfamily, its declared input datatype, and its
 *    comparison type.
 *
 * Returns true if successful, false if no matching pg_amop entry exists.
 * (This indicates that the operator is not a valid ordering operator.)
 *
 * Note: the operator could be registered in multiple families, for example
 * if someone were to build a "reverse sort" opfamily.  This would result in
 * uncertainty as to whether "ORDER BY USING op" would default to NULLS FIRST
 * or NULLS LAST, as well as inefficient planning due to failure to match up
 * pathkeys that should be the same.  So we want a determinate result here.
 * Because of the way the syscache search works, we'll use the interpretation
 * associated with the opfamily with smallest OID, which is probably
 * determinate enough.  Since there is no longer any particularly good reason
 * to build reverse-sort opfamilies, it doesn't seem worth expending any
 * additional effort on ensuring consistency.
 */
bool
get_ordering_op_properties(Oid opno,
               Oid *opfamily, Oid *opcintype, CompareType *cmptype)
{
  bool    result = false;
  CatCList   *catlist;
  int     i;

  /* ensure outputs are initialized on failure */
  *opfamily = InvalidOid;
  *opcintype = InvalidOid;
  *cmptype = COMPARE_INVALID;

  /*
   * Search pg_amop to see if the target operator is registered as the "<"
   * or ">" operator of any btree opfamily.
   */
  catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));

  for (i = 0; i < catlist->n_members; i++)
  {
    HeapTuple tuple = &catlist->members[i]->tuple;
    Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
    CompareType am_cmptype;

    /* must be ordering index */
    if (!get_opmethod_canorder(aform->amopmethod))
      continue;

    am_cmptype = IndexAmTranslateStrategy(aform->amopstrategy,
                        aform->amopmethod,
                        aform->amopfamily,
                        true);

    if (am_cmptype == COMPARE_LT || am_cmptype == COMPARE_GT)
    {
      /* Found it ... should have consistent input types */
      if (aform->amoplefttype == aform->amoprighttype)
      {
        /* Found a suitable opfamily, return info */
        *opfamily = aform->amopfamily;
        *opcintype = aform->amoplefttype;
        *cmptype = am_cmptype;
        result = true;
        break;
      }
    }
  }

  ReleaseSysCacheList(catlist);

  return result;
}

/*
 * get_equality_op_for_ordering_op
 *    Get the OID of the datatype-specific equality operator
 *    associated with an ordering operator (a "<" or ">" operator).
 *
 * If "reverse" isn't NULL, also set *reverse to false if the operator is "<",
 * true if it's ">"
 *
 * Returns InvalidOid if no matching equality operator can be found.
 * (This indicates that the operator is not a valid ordering operator.)
 */
Oid
get_equality_op_for_ordering_op(Oid opno, bool *reverse)
{
  Oid     result = InvalidOid;
  Oid     opfamily;
  Oid     opcintype;
  CompareType cmptype;

  /* Find the operator in pg_amop */
  if (get_ordering_op_properties(opno,
                   &opfamily, &opcintype, &cmptype))
  {
    /* Found a suitable opfamily, get matching equality operator */
    result = get_opfamily_member_for_cmptype(opfamily,
                         opcintype,
                         opcintype,
                         COMPARE_EQ);
    if (reverse)
      *reverse = (cmptype == COMPARE_GT);
  }

  return result;
}

/*
 * get_ordering_op_for_equality_op
 *    Get the OID of a datatype-specific "less than" ordering operator
 *    associated with an equality operator.  (If there are multiple
 *    possibilities, assume any one will do.)
 *
 * This function is used when we have to sort data before unique-ifying,
 * and don't much care which sorting op is used as long as it's compatible
 * with the intended equality operator.  Since we need a sorting operator,
 * it should be single-data-type even if the given operator is cross-type.
 * The caller specifies whether to find an op for the LHS or RHS data type.
 *
 * Returns InvalidOid if no matching ordering operator can be found.
 */
Oid
get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type)
{
  Oid     result = InvalidOid;
  CatCList   *catlist;
  int     i;

  /*
   * Search pg_amop to see if the target operator is registered as the "="
   * operator of any btree opfamily.
   */
  catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));

  for (i = 0; i < catlist->n_members; i++)
  {
    HeapTuple tuple = &catlist->members[i]->tuple;
    Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
    CompareType cmptype;

    /* must be ordering index */
    if (!get_opmethod_canorder(aform->amopmethod))
      continue;

    cmptype = IndexAmTranslateStrategy(aform->amopstrategy,
                       aform->amopmethod,
                       aform->amopfamily,
                       true);
    if (cmptype == COMPARE_EQ)
    {
      /* Found a suitable opfamily, get matching ordering operator */
      Oid     typid;

      typid = use_lhs_type ? aform->amoplefttype : aform->amoprighttype;
      result = get_opfamily_member_for_cmptype(aform->amopfamily,
                           typid, typid,
                           COMPARE_LT);
      if (OidIsValid(result))
        break;
      /* failure probably shouldn't happen, but keep looking if so */
    }
  }

  ReleaseSysCacheList(catlist);

  return result;
}

/*
 * get_mergejoin_opfamilies
 *    Given a putatively mergejoinable operator, return a list of the OIDs
 *    of the amcanorder opfamilies in which it represents equality.
 *
 * It is possible (though at present unusual) for an operator to be equality
 * in more than one opfamily, hence the result is a list.  This also lets us
 * return NIL if the operator is not found in any opfamilies.
 *
 * The planner currently uses simple equal() tests to compare the lists
 * returned by this function, which makes the list order relevant, though
 * strictly speaking it should not be.  Because of the way syscache list
 * searches are handled, in normal operation the result will be sorted by OID
 * so everything works fine.  If running with system index usage disabled,
 * the result ordering is unspecified and hence the planner might fail to
 * recognize optimization opportunities ... but that's hardly a scenario in
 * which performance is good anyway, so there's no point in expending code
 * or cycles here to guarantee the ordering in that case.
 */
List *
get_mergejoin_opfamilies(Oid opno)
{
  List     *result = NIL;
  CatCList   *catlist;
  int     i;

  /*
   * Search pg_amop to see if the target operator is registered as the "="
   * operator of any opfamily of an ordering index type.
   */
  catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));

  for (i = 0; i < catlist->n_members; i++)
  {
    HeapTuple tuple = &catlist->members[i]->tuple;
    Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);

    /* must be ordering index equality */
    if (get_opmethod_canorder(aform->amopmethod) &&
      IndexAmTranslateStrategy(aform->amopstrategy,
                   aform->amopmethod,
                   aform->amopfamily,
                   true) == COMPARE_EQ)
      result = lappend_oid(result, aform->amopfamily);
  }

  ReleaseSysCacheList(catlist);

  return result;
}

/*
 * get_compatible_hash_operators
 *    Get the OID(s) of hash equality operator(s) compatible with the given
 *    operator, but operating on its LHS and/or RHS datatype.
 *
 * An operator for the LHS type is sought and returned into *lhs_opno if
 * lhs_opno isn't NULL.  Similarly, an operator for the RHS type is sought
 * and returned into *rhs_opno if rhs_opno isn't NULL.
 *
 * If the given operator is not cross-type, the results should be the same
 * operator, but in cross-type situations they will be different.
 *
 * Returns true if able to find the requested operator(s), false if not.
 * (This indicates that the operator should not have been marked oprcanhash.)
 */
bool
get_compatible_hash_operators(Oid opno,
                Oid *lhs_opno, Oid *rhs_opno)
{
  bool    result = false;
  CatCList   *catlist;
  int     i;

  /* Ensure output args are initialized on failure */
  if (lhs_opno)
    *lhs_opno = InvalidOid;
  if (rhs_opno)
    *rhs_opno = InvalidOid;

  /*
   * Search pg_amop to see if the target operator is registered as the "="
   * operator of any hash opfamily.  If the operator is registered in
   * multiple opfamilies, assume we can use any one.
   */
  catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));

  for (i = 0; i < catlist->n_members; i++)
  {
    HeapTuple tuple = &catlist->members[i]->tuple;
    Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);

    if (aform->amopmethod == HASH_AM_OID &&
      aform->amopstrategy == HTEqualStrategyNumber)
    {
      /* No extra lookup needed if given operator is single-type */
      if (aform->amoplefttype == aform->amoprighttype)
      {
        if (lhs_opno)
          *lhs_opno = opno;
        if (rhs_opno)
          *rhs_opno = opno;
        result = true;
        break;
      }

      /*
       * Get the matching single-type operator(s).  Failure probably
       * shouldn't happen --- it implies a bogus opfamily --- but
       * continue looking if so.
       */
      if (lhs_opno)
      {
        *lhs_opno = get_opfamily_member(aform->amopfamily,
                        aform->amoplefttype,
                        aform->amoplefttype,
                        HTEqualStrategyNumber);
        if (!OidIsValid(*lhs_opno))
          continue;
        /* Matching LHS found, done if caller doesn't want RHS */
        if (!rhs_opno)
        {
          result = true;
          break;
        }
      }
      if (rhs_opno)
      {
        *rhs_opno = get_opfamily_member(aform->amopfamily,
                        aform->amoprighttype,
                        aform->amoprighttype,
                        HTEqualStrategyNumber);
        if (!OidIsValid(*rhs_opno))
        {
          /* Forget any LHS operator from this opfamily */
          if (lhs_opno)
            *lhs_opno = InvalidOid;
          continue;
        }
        /* Matching RHS found, so done */
        result = true;
        break;
      }
    }
  }

  ReleaseSysCacheList(catlist);

  return result;
}

/*
 * get_op_hash_functions
 *    Get the OID(s) of the standard hash support function(s) compatible with
 *    the given operator, operating on its LHS and/or RHS datatype as required.
 *
 * A function for the LHS type is sought and returned into *lhs_procno if
 * lhs_procno isn't NULL.  Similarly, a function for the RHS type is sought
 * and returned into *rhs_procno if rhs_procno isn't NULL.
 *
 * If the given operator is not cross-type, the results should be the same
 * function, but in cross-type situations they will be different.
 *
 * Returns true if able to find the requested function(s), false if not.
 * (This indicates that the operator should not have been marked oprcanhash.)
 */
bool
get_op_hash_functions(Oid opno,
            RegProcedure *lhs_procno, RegProcedure *rhs_procno)
{
  bool    result = false;
  CatCList   *catlist;
  int     i;

  /* Ensure output args are initialized on failure */
  if (lhs_procno)
    *lhs_procno = InvalidOid;
  if (rhs_procno)
    *rhs_procno = InvalidOid;

  /*
   * Search pg_amop to see if the target operator is registered as the "="
   * operator of any hash opfamily.  If the operator is registered in
   * multiple opfamilies, assume we can use any one.
   */
  catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));

  for (i = 0; i < catlist->n_members; i++)
  {
    HeapTuple tuple = &catlist->members[i]->tuple;
    Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);

    if (aform->amopmethod == HASH_AM_OID &&
      aform->amopstrategy == HTEqualStrategyNumber)
    {
      /*
       * Get the matching support function(s).  Failure probably
       * shouldn't happen --- it implies a bogus opfamily --- but
       * continue looking if so.
       */
      if (lhs_procno)
      {
        *lhs_procno = get_opfamily_proc(aform->amopfamily,
                        aform->amoplefttype,
                        aform->amoplefttype,
                        HASHSTANDARD_PROC);
        if (!OidIsValid(*lhs_procno))
          continue;
        /* Matching LHS found, done if caller doesn't want RHS */
        if (!rhs_procno)
        {
          result = true;
          break;
        }
        /* Only one lookup needed if given operator is single-type */
        if (aform->amoplefttype == aform->amoprighttype)
        {
          *rhs_procno = *lhs_procno;
          result = true;
          break;
        }
      }
      if (rhs_procno)
      {
        *rhs_procno = get_opfamily_proc(aform->amopfamily,
                        aform->amoprighttype,
                        aform->amoprighttype,
                        HASHSTANDARD_PROC);
        if (!OidIsValid(*rhs_procno))
        {
          /* Forget any LHS function from this opfamily */
          if (lhs_procno)
            *lhs_procno = InvalidOid;
          continue;
        }
        /* Matching RHS found, so done */
        result = true;
        break;
      }
    }
  }

  ReleaseSysCacheList(catlist);

  return result;
}

/*
 * get_op_index_interpretation
 *    Given an operator's OID, find out which amcanorder opfamilies it belongs to,
 *    and what properties it has within each one.  The results are returned
 *    as a palloc'd list of OpIndexInterpretation structs.
 *
 * In addition to the normal btree operators, we consider a <> operator to be
 * a "member" of an opfamily if its negator is an equality operator of the
 * opfamily.  COMPARE_NE is returned as the strategy number for this case.
 */
List *
get_op_index_interpretation(Oid opno)
{
  List     *result = NIL;
  OpIndexInterpretation *thisresult;
  CatCList   *catlist;
  int     i;

  /*
   * Find all the pg_amop entries containing the operator.
   */
  catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));

  for (i = 0; i < catlist->n_members; i++)
  {
    HeapTuple op_tuple = &catlist->members[i]->tuple;
    Form_pg_amop op_form = (Form_pg_amop) GETSTRUCT(op_tuple);
    CompareType cmptype;

    /* must be ordering index */
    if (!get_opmethod_canorder(op_form->amopmethod))
      continue;

    /* Get the operator's comparision type */
    cmptype = IndexAmTranslateStrategy(op_form->amopstrategy,
                       op_form->amopmethod,
                       op_form->amopfamily,
                       true);

    /* should not happen */
    if (cmptype == COMPARE_INVALID)
      continue;

    thisresult = (OpIndexInterpretation *)
      palloc(sizeof(OpIndexInterpretation));
    thisresult->opfamily_id = op_form->amopfamily;
    thisresult->cmptype = cmptype;
    thisresult->oplefttype = op_form->amoplefttype;
    thisresult->oprighttype = op_form->amoprighttype;
    result = lappend(result, thisresult);
  }

  ReleaseSysCacheList(catlist);

  /*
   * If we didn't find any btree opfamily containing the operator, perhaps
   * it is a <> operator.  See if it has a negator that is in an opfamily.
   */
  if (result == NIL)
  {
    Oid     op_negator = get_negator(opno);

    if (OidIsValid(op_negator))
    {
      catlist = SearchSysCacheList1(AMOPOPID,
                      ObjectIdGetDatum(op_negator));

      for (i = 0; i < catlist->n_members; i++)
      {
        HeapTuple op_tuple = &catlist->members[i]->tuple;
        Form_pg_amop op_form = (Form_pg_amop) GETSTRUCT(op_tuple);
        IndexAmRoutine *amroutine = GetIndexAmRoutineByAmId(op_form->amopmethod, false);
        CompareType cmptype;

        /* must be ordering index */
        if (!amroutine->amcanorder)
          continue;

        /* Get the operator's comparision type */
        cmptype = IndexAmTranslateStrategy(op_form->amopstrategy,
                           op_form->amopmethod,
                           op_form->amopfamily,
                           true);

        /* Only consider negators that are = */
        if (cmptype != COMPARE_EQ)
          continue;

        /* OK, report it as COMPARE_NE */
        thisresult = (OpIndexInterpretation *)
          palloc(sizeof(OpIndexInterpretation));
        thisresult->opfamily_id = op_form->amopfamily;
        thisresult->cmptype = COMPARE_NE;
        thisresult->oplefttype = op_form->amoplefttype;
        thisresult->oprighttype = op_form->amoprighttype;
        result = lappend(result, thisresult);
      }

      ReleaseSysCacheList(catlist);
    }
  }

  return result;
}

/*
 * equality_ops_are_compatible
 *    Return true if the two given equality operators have compatible
 *    semantics.
 *
 * This is trivially true if they are the same operator.  Otherwise,
 * Otherwise, we look to see if they both belong to an opfamily that
 * guarantees compatible semantics for equality.  Either finding allows us to
 * assume that they have compatible notions of equality.  (The reason we need
 * to do these pushups is that one might be a cross-type operator; for
 * instance int24eq vs int4eq.)
 */
bool
equality_ops_are_compatible(Oid opno1, Oid opno2)
{
  bool    result;
  CatCList   *catlist;
  int     i;

  /* Easy if they're the same operator */
  if (opno1 == opno2)
    return true;

  /*
   * We search through all the pg_amop entries for opno1.
   */
  catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno1));

  result = false;
  for (i = 0; i < catlist->n_members; i++)
  {
    HeapTuple op_tuple = &catlist->members[i]->tuple;
    Form_pg_amop op_form = (Form_pg_amop) GETSTRUCT(op_tuple);

    /*
     * op_in_opfamily() is cheaper than GetIndexAmRoutineByAmId(), so
     * check it first
     */
    if (op_in_opfamily(opno2, op_form->amopfamily))
    {
      IndexAmRoutine *amroutine = GetIndexAmRoutineByAmId(op_form->amopmethod, false);

      if (amroutine->amconsistentequality)
      {
        result = true;
        break;
      }
    }
  }

  ReleaseSysCacheList(catlist);

  return result;
}

/*
 * comparison_ops_are_compatible
 *    Return true if the two given comparison operators have compatible
 *    semantics.
 *
 * This is trivially true if they are the same operator.  Otherwise, we look
 * to see if they both belong to an opfamily that guarantees compatible
 * semantics for ordering.  (For example, for btree, '<' and '>=' ops match if
 * they belong to the same family.)
 *
 * (This is identical to equality_ops_are_compatible(), except that we check
 * amconsistentordering instead of amconsistentequality.)
 */
bool
comparison_ops_are_compatible(Oid opno1, Oid opno2)
{
  bool    result;
  CatCList   *catlist;
  int     i;

  /* Easy if they're the same operator */
  if (opno1 == opno2)
    return true;

  /*
   * We search through all the pg_amop entries for opno1.
   */
  catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno1));

  result = false;
  for (i = 0; i < catlist->n_members; i++)
  {
    HeapTuple op_tuple = &catlist->members[i]->tuple;
    Form_pg_amop op_form = (Form_pg_amop) GETSTRUCT(op_tuple);

    /*
     * op_in_opfamily() is cheaper than GetIndexAmRoutineByAmId(), so
     * check it first
     */
    if (op_in_opfamily(opno2, op_form->amopfamily))
    {
      IndexAmRoutine *amroutine = GetIndexAmRoutineByAmId(op_form->amopmethod, false);

      if (amroutine->amconsistentordering)
      {
        result = true;
        break;
      }
    }
  }

  ReleaseSysCacheList(catlist);

  return result;
}


/*        ---------- AMPROC CACHES ----------            */

/*
 * get_opfamily_proc
 *    Get the OID of the specified support function
 *    for the specified opfamily and datatypes.
 *
 * Returns InvalidOid if there is no pg_amproc entry for the given keys.
 */
Oid
get_opfamily_proc(Oid opfamily, Oid lefttype, Oid righttype, int16 procnum)
{
  HeapTuple tp;
  Form_pg_amproc amproc_tup;
  RegProcedure result;

  tp = SearchSysCache4(AMPROCNUM,
             ObjectIdGetDatum(opfamily),
             ObjectIdGetDatum(lefttype),
             ObjectIdGetDatum(righttype),
             Int16GetDatum(procnum));
  if (!HeapTupleIsValid(tp))
    return InvalidOid;
  amproc_tup = (Form_pg_amproc) GETSTRUCT(tp);
  result = amproc_tup->amproc;
  ReleaseSysCache(tp);
  return result;
}


/*        ---------- ATTRIBUTE CACHES ----------           */

/*
 * get_attname
 *    Given the relation id and the attribute number, return the "attname"
 *    field from the attribute relation as a palloc'ed string.
 *
 * If no such attribute exists and missing_ok is true, NULL is returned;
 * otherwise a not-intended-for-user-consumption error is thrown.
 */
char *
get_attname(Oid relid, AttrNumber attnum, bool missing_ok)
{
  HeapTuple tp;

  tp = SearchSysCache2(ATTNUM,
             ObjectIdGetDatum(relid), Int16GetDatum(attnum));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_attribute att_tup = (Form_pg_attribute) GETSTRUCT(tp);
    char     *result;

    result = pstrdup(NameStr(att_tup->attname));
    ReleaseSysCache(tp);
    return result;
  }

  if (!missing_ok)
    elog(ERROR, "cache lookup failed for attribute %d of relation %u",
       attnum, relid);
  return NULL;
}

/*
 * get_attnum
 *
 *    Given the relation id and the attribute name,
 *    return the "attnum" field from the attribute relation.
 *
 *    Returns InvalidAttrNumber if the attr doesn't exist (or is dropped).
 */
AttrNumber
get_attnum(Oid relid, const char *attname)
{
  HeapTuple tp;

  tp = SearchSysCacheAttName(relid, attname);
  if (HeapTupleIsValid(tp))
  {
    Form_pg_attribute att_tup = (Form_pg_attribute) GETSTRUCT(tp);
    AttrNumber  result;

    result = att_tup->attnum;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidAttrNumber;
}

/*
 * get_attgenerated
 *
 *    Given the relation id and the attribute number,
 *    return the "attgenerated" field from the attribute relation.
 *
 *    Errors if not found.
 *
 *    Since not generated is represented by '\0', this can also be used as a
 *    Boolean test.
 */
char
get_attgenerated(Oid relid, AttrNumber attnum)
{
  HeapTuple tp;
  Form_pg_attribute att_tup;
  char    result;

  tp = SearchSysCache2(ATTNUM,
             ObjectIdGetDatum(relid),
             Int16GetDatum(attnum));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for attribute %d of relation %u",
       attnum, relid);
  att_tup = (Form_pg_attribute) GETSTRUCT(tp);
  result = att_tup->attgenerated;
  ReleaseSysCache(tp);
  return result;
}

/*
 * get_atttype
 *
 *    Given the relation OID and the attribute number with the relation,
 *    return the attribute type OID.
 */
Oid
get_atttype(Oid relid, AttrNumber attnum)
{
  HeapTuple tp;

  tp = SearchSysCache2(ATTNUM,
             ObjectIdGetDatum(relid),
             Int16GetDatum(attnum));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_attribute att_tup = (Form_pg_attribute) GETSTRUCT(tp);
    Oid     result;

    result = att_tup->atttypid;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * get_atttypetypmodcoll
 *
 *    A three-fer: given the relation id and the attribute number,
 *    fetch atttypid, atttypmod, and attcollation in a single cache lookup.
 *
 * Unlike the otherwise-similar get_atttype, this routine
 * raises an error if it can't obtain the information.
 */
void
get_atttypetypmodcoll(Oid relid, AttrNumber attnum,
            Oid *typid, int32 *typmod, Oid *collid)
{
  HeapTuple tp;
  Form_pg_attribute att_tup;

  tp = SearchSysCache2(ATTNUM,
             ObjectIdGetDatum(relid),
             Int16GetDatum(attnum));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for attribute %d of relation %u",
       attnum, relid);
  att_tup = (Form_pg_attribute) GETSTRUCT(tp);

  *typid = att_tup->atttypid;
  *typmod = att_tup->atttypmod;
  *collid = att_tup->attcollation;
  ReleaseSysCache(tp);
}

/*
 * get_attoptions
 *
 *    Given the relation id and the attribute number,
 *    return the attribute options text[] datum, if any.
 */
Datum
get_attoptions(Oid relid, int16 attnum)
{
  HeapTuple tuple;
  Datum   attopts;
  Datum   result;
  bool    isnull;

  tuple = SearchSysCache2(ATTNUM,
              ObjectIdGetDatum(relid),
              Int16GetDatum(attnum));

  if (!HeapTupleIsValid(tuple))
    elog(ERROR, "cache lookup failed for attribute %d of relation %u",
       attnum, relid);

  attopts = SysCacheGetAttr(ATTNAME, tuple, Anum_pg_attribute_attoptions,
                &isnull);

  if (isnull)
    result = (Datum) 0;
  else
    result = datumCopy(attopts, false, -1); /* text[] */

  ReleaseSysCache(tuple);

  return result;
}

/*        ---------- PG_CAST CACHE ----------          */

/*
 * get_cast_oid - given two type OIDs, look up a cast OID
 *
 * If missing_ok is false, throw an error if the cast is not found.  If
 * true, just return InvalidOid.
 */
Oid
get_cast_oid(Oid sourcetypeid, Oid targettypeid, bool missing_ok)
{
  Oid     oid;

  oid = GetSysCacheOid2(CASTSOURCETARGET, Anum_pg_cast_oid,
              ObjectIdGetDatum(sourcetypeid),
              ObjectIdGetDatum(targettypeid));
  if (!OidIsValid(oid) && !missing_ok)
    ereport(ERROR,
        (errcode(ERRCODE_UNDEFINED_OBJECT),
         errmsg("cast from type %s to type %s does not exist",
            format_type_be(sourcetypeid),
            format_type_be(targettypeid))));
  return oid;
}

/*        ---------- COLLATION CACHE ----------          */

/*
 * get_collation_name
 *    Returns the name of a given pg_collation entry.
 *
 * Returns a palloc'd copy of the string, or NULL if no such collation.
 *
 * NOTE: since collation name is not unique, be wary of code that uses this
 * for anything except preparing error messages.
 */
char *
get_collation_name(Oid colloid)
{
  HeapTuple tp;

  tp = SearchSysCache1(COLLOID, ObjectIdGetDatum(colloid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_collation colltup = (Form_pg_collation) GETSTRUCT(tp);
    char     *result;

    result = pstrdup(NameStr(colltup->collname));
    ReleaseSysCache(tp);
    return result;
  }
  else
    return NULL;
}

bool
get_collation_isdeterministic(Oid colloid)
{
  HeapTuple tp;
  Form_pg_collation colltup;
  bool    result;

  tp = SearchSysCache1(COLLOID, ObjectIdGetDatum(colloid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for collation %u", colloid);
  colltup = (Form_pg_collation) GETSTRUCT(tp);
  result = colltup->collisdeterministic;
  ReleaseSysCache(tp);
  return result;
}

/*        ---------- CONSTRAINT CACHE ----------           */

/*
 * get_constraint_name
 *    Returns the name of a given pg_constraint entry.
 *
 * Returns a palloc'd copy of the string, or NULL if no such constraint.
 *
 * NOTE: since constraint name is not unique, be wary of code that uses this
 * for anything except preparing error messages.
 */
char *
get_constraint_name(Oid conoid)
{
  HeapTuple tp;

  tp = SearchSysCache1(CONSTROID, ObjectIdGetDatum(conoid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_constraint contup = (Form_pg_constraint) GETSTRUCT(tp);
    char     *result;

    result = pstrdup(NameStr(contup->conname));
    ReleaseSysCache(tp);
    return result;
  }
  else
    return NULL;
}

/*
 * get_constraint_index
 *    Given the OID of a unique, primary-key, or exclusion constraint,
 *    return the OID of the underlying index.
 *
 * Returns InvalidOid if the constraint could not be found or is of
 * the wrong type.
 *
 * The intent of this function is to return the index "owned" by the
 * specified constraint.  Therefore we must check contype, since some
 * pg_constraint entries (e.g. for foreign-key constraints) store the
 * OID of an index that is referenced but not owned by the constraint.
 */
Oid
get_constraint_index(Oid conoid)
{
  HeapTuple tp;

  tp = SearchSysCache1(CONSTROID, ObjectIdGetDatum(conoid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_constraint contup = (Form_pg_constraint) GETSTRUCT(tp);
    Oid     result;

    if (contup->contype == CONSTRAINT_UNIQUE ||
      contup->contype == CONSTRAINT_PRIMARY ||
      contup->contype == CONSTRAINT_EXCLUSION)
      result = contup->conindid;
    else
      result = InvalidOid;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * get_constraint_type
 *    Return the pg_constraint.contype value for the given constraint.
 *
 * No frills.
 */
char
get_constraint_type(Oid conoid)
{
  HeapTuple tp;
  char    contype;

  tp = SearchSysCache1(CONSTROID, ObjectIdGetDatum(conoid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for constraint %u", conoid);

  contype = ((Form_pg_constraint) GETSTRUCT(tp))->contype;
  ReleaseSysCache(tp);

  return contype;
}

/*        ---------- LANGUAGE CACHE ----------           */

char *
get_language_name(Oid langoid, bool missing_ok)
{
  HeapTuple tp;

  tp = SearchSysCache1(LANGOID, ObjectIdGetDatum(langoid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_language lantup = (Form_pg_language) GETSTRUCT(tp);
    char     *result;

    result = pstrdup(NameStr(lantup->lanname));
    ReleaseSysCache(tp);
    return result;
  }

  if (!missing_ok)
    elog(ERROR, "cache lookup failed for language %u",
       langoid);
  return NULL;
}

/*        ---------- OPCLASS CACHE ----------            */

/*
 * get_opclass_family
 *
 *    Returns the OID of the operator family the opclass belongs to.
 */
Oid
get_opclass_family(Oid opclass)
{
  HeapTuple tp;
  Form_pg_opclass cla_tup;
  Oid     result;

  tp = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclass));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for opclass %u", opclass);
  cla_tup = (Form_pg_opclass) GETSTRUCT(tp);

  result = cla_tup->opcfamily;
  ReleaseSysCache(tp);
  return result;
}

/*
 * get_opclass_input_type
 *
 *    Returns the OID of the datatype the opclass indexes.
 */
Oid
get_opclass_input_type(Oid opclass)
{
  HeapTuple tp;
  Form_pg_opclass cla_tup;
  Oid     result;

  tp = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclass));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for opclass %u", opclass);
  cla_tup = (Form_pg_opclass) GETSTRUCT(tp);

  result = cla_tup->opcintype;
  ReleaseSysCache(tp);
  return result;
}

/*
 * get_opclass_opfamily_and_input_type
 *
 *    Returns the OID of the operator family the opclass belongs to,
 *        the OID of the datatype the opclass indexes
 */
bool
get_opclass_opfamily_and_input_type(Oid opclass, Oid *opfamily, Oid *opcintype)
{
  HeapTuple tp;
  Form_pg_opclass cla_tup;

  tp = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclass));
  if (!HeapTupleIsValid(tp))
    return false;

  cla_tup = (Form_pg_opclass) GETSTRUCT(tp);

  *opfamily = cla_tup->opcfamily;
  *opcintype = cla_tup->opcintype;

  ReleaseSysCache(tp);

  return true;
}

/*
 * get_opclass_method
 *
 *    Returns the OID of the index access method the opclass belongs to.
 */
Oid
get_opclass_method(Oid opclass)
{
  HeapTuple tp;
  Form_pg_opclass cla_tup;
  Oid     result;

  tp = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclass));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for opclass %u", opclass);
  cla_tup = (Form_pg_opclass) GETSTRUCT(tp);

  result = cla_tup->opcmethod;
  ReleaseSysCache(tp);
  return result;
}

/*        ---------- OPFAMILY CACHE ----------           */

/*
 * get_opfamily_method
 *
 *    Returns the OID of the index access method the opfamily is for.
 */
Oid
get_opfamily_method(Oid opfid)
{
  HeapTuple tp;
  Form_pg_opfamily opfform;
  Oid     result;

  tp = SearchSysCache1(OPFAMILYOID, ObjectIdGetDatum(opfid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for operator family %u", opfid);
  opfform = (Form_pg_opfamily) GETSTRUCT(tp);

  result = opfform->opfmethod;
  ReleaseSysCache(tp);
  return result;
}

char *
get_opfamily_name(Oid opfid, bool missing_ok)
{
  HeapTuple tup;
  char     *opfname;
  Form_pg_opfamily opfform;

  tup = SearchSysCache1(OPFAMILYOID, ObjectIdGetDatum(opfid));

  if (!HeapTupleIsValid(tup))
  {
    if (!missing_ok)
      elog(ERROR, "cache lookup failed for operator family %u", opfid);
    return NULL;
  }

  opfform = (Form_pg_opfamily) GETSTRUCT(tup);
  opfname = pstrdup(NameStr(opfform->opfname));

  ReleaseSysCache(tup);

  return opfname;
}

/*        ---------- OPERATOR CACHE ----------           */

/*
 * get_opcode
 *
 *    Returns the regproc id of the routine used to implement an
 *    operator given the operator oid.
 */
RegProcedure
get_opcode(Oid opno)
{
  HeapTuple tp;

  tp = SearchSysCache1(OPEROID, ObjectIdGetDatum(opno));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_operator optup = (Form_pg_operator) GETSTRUCT(tp);
    RegProcedure result;

    result = optup->oprcode;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return (RegProcedure) InvalidOid;
}

/*
 * get_opname
 *    returns the name of the operator with the given opno
 *
 * Note: returns a palloc'd copy of the string, or NULL if no such operator.
 */
char *
get_opname(Oid opno)
{
  HeapTuple tp;

  tp = SearchSysCache1(OPEROID, ObjectIdGetDatum(opno));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_operator optup = (Form_pg_operator) GETSTRUCT(tp);
    char     *result;

    result = pstrdup(NameStr(optup->oprname));
    ReleaseSysCache(tp);
    return result;
  }
  else
    return NULL;
}

/*
 * get_op_rettype
 *    Given operator oid, return the operator's result type.
 */
Oid
get_op_rettype(Oid opno)
{
  HeapTuple tp;

  tp = SearchSysCache1(OPEROID, ObjectIdGetDatum(opno));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_operator optup = (Form_pg_operator) GETSTRUCT(tp);
    Oid     result;

    result = optup->oprresult;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * op_input_types
 *
 *    Returns the left and right input datatypes for an operator
 *    (InvalidOid if not relevant).
 */
void
op_input_types(Oid opno, Oid *lefttype, Oid *righttype)
{
  HeapTuple tp;
  Form_pg_operator optup;

  tp = SearchSysCache1(OPEROID, ObjectIdGetDatum(opno));
  if (!HeapTupleIsValid(tp)) /* shouldn't happen */
    elog(ERROR, "cache lookup failed for operator %u", opno);
  optup = (Form_pg_operator) GETSTRUCT(tp);
  *lefttype = optup->oprleft;
  *righttype = optup->oprright;
  ReleaseSysCache(tp);
}

/*
 * op_mergejoinable
 *
 * Returns true if the operator is potentially mergejoinable.  (The planner
 * will fail to find any mergejoin plans unless there are suitable btree
 * opfamily entries for this operator and associated sortops.  The pg_operator
 * flag is just a hint to tell the planner whether to bother looking.)
 *
 * In some cases (currently only array_eq and record_eq), mergejoinability
 * depends on the specific input data type the operator is invoked for, so
 * that must be passed as well. We currently assume that only one input's type
 * is needed to check this --- by convention, pass the left input's data type.
 */
bool
op_mergejoinable(Oid opno, Oid inputtype)
{
  bool    result = false;
  HeapTuple tp;
  TypeCacheEntry *typentry;

  /*
   * For array_eq or record_eq, we can sort if the element or field types
   * are all sortable.  We could implement all the checks for that here, but
   * the typcache already does that and caches the results too, so let's
   * rely on the typcache.
   */
  if (opno == ARRAY_EQ_OP)
  {
    typentry = lookup_type_cache(inputtype, TYPECACHE_CMP_PROC);
    if (typentry->cmp_proc == F_BTARRAYCMP)
      result = true;
  }
  else if (opno == RECORD_EQ_OP)
  {
    typentry = lookup_type_cache(inputtype, TYPECACHE_CMP_PROC);
    if (typentry->cmp_proc == F_BTRECORDCMP)
      result = true;
  }
  else
  {
    /* For all other operators, rely on pg_operator.oprcanmerge */
    tp = SearchSysCache1(OPEROID, ObjectIdGetDatum(opno));
    if (HeapTupleIsValid(tp))
    {
      Form_pg_operator optup = (Form_pg_operator) GETSTRUCT(tp);

      result = optup->oprcanmerge;
      ReleaseSysCache(tp);
    }
  }
  return result;
}

/*
 * op_hashjoinable
 *
 * Returns true if the operator is hashjoinable.  (There must be a suitable
 * hash opfamily entry for this operator if it is so marked.)
 *
 * In some cases (currently only array_eq), hashjoinability depends on the
 * specific input data type the operator is invoked for, so that must be
 * passed as well.  We currently assume that only one input's type is needed
 * to check this --- by convention, pass the left input's data type.
 */
bool
op_hashjoinable(Oid opno, Oid inputtype)
{
  bool    result = false;
  HeapTuple tp;
  TypeCacheEntry *typentry;

  /* As in op_mergejoinable, let the typcache handle the hard cases */
  if (opno == ARRAY_EQ_OP)
  {
    typentry = lookup_type_cache(inputtype, TYPECACHE_HASH_PROC);
    if (typentry->hash_proc == F_HASH_ARRAY)
      result = true;
  }
  else if (opno == RECORD_EQ_OP)
  {
    typentry = lookup_type_cache(inputtype, TYPECACHE_HASH_PROC);
    if (typentry->hash_proc == F_HASH_RECORD)
      result = true;
  }
  else
  {
    /* For all other operators, rely on pg_operator.oprcanhash */
    tp = SearchSysCache1(OPEROID, ObjectIdGetDatum(opno));
    if (HeapTupleIsValid(tp))
    {
      Form_pg_operator optup = (Form_pg_operator) GETSTRUCT(tp);

      result = optup->oprcanhash;
      ReleaseSysCache(tp);
    }
  }
  return result;
}

/*
 * op_strict
 *
 * Get the proisstrict flag for the operator's underlying function.
 */
bool
op_strict(Oid opno)
{
  RegProcedure funcid = get_opcode(opno);

  if (funcid == (RegProcedure) InvalidOid)
    elog(ERROR, "operator %u does not exist", opno);

  return func_strict((Oid) funcid);
}

/*
 * op_volatile
 *
 * Get the provolatile flag for the operator's underlying function.
 */
char
op_volatile(Oid opno)
{
  RegProcedure funcid = get_opcode(opno);

  if (funcid == (RegProcedure) InvalidOid)
    elog(ERROR, "operator %u does not exist", opno);

  return func_volatile((Oid) funcid);
}

/*
 * get_commutator
 *
 *    Returns the corresponding commutator of an operator.
 */
Oid
get_commutator(Oid opno)
{
  HeapTuple tp;

  tp = SearchSysCache1(OPEROID, ObjectIdGetDatum(opno));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_operator optup = (Form_pg_operator) GETSTRUCT(tp);
    Oid     result;

    result = optup->oprcom;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * get_negator
 *
 *    Returns the corresponding negator of an operator.
 */
Oid
get_negator(Oid opno)
{
  HeapTuple tp;

  tp = SearchSysCache1(OPEROID, ObjectIdGetDatum(opno));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_operator optup = (Form_pg_operator) GETSTRUCT(tp);
    Oid     result;

    result = optup->oprnegate;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * get_oprrest
 *
 *    Returns procedure id for computing selectivity of an operator.
 */
RegProcedure
get_oprrest(Oid opno)
{
  HeapTuple tp;

  tp = SearchSysCache1(OPEROID, ObjectIdGetDatum(opno));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_operator optup = (Form_pg_operator) GETSTRUCT(tp);
    RegProcedure result;

    result = optup->oprrest;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return (RegProcedure) InvalidOid;
}

/*
 * get_oprjoin
 *
 *    Returns procedure id for computing selectivity of a join.
 */
RegProcedure
get_oprjoin(Oid opno)
{
  HeapTuple tp;

  tp = SearchSysCache1(OPEROID, ObjectIdGetDatum(opno));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_operator optup = (Form_pg_operator) GETSTRUCT(tp);
    RegProcedure result;

    result = optup->oprjoin;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return (RegProcedure) InvalidOid;
}

/*        ---------- FUNCTION CACHE ----------           */

/*
 * get_func_name
 *    returns the name of the function with the given funcid
 *
 * Note: returns a palloc'd copy of the string, or NULL if no such function.
 */
char *
get_func_name(Oid funcid)
{
  HeapTuple tp;

  tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_proc functup = (Form_pg_proc) GETSTRUCT(tp);
    char     *result;

    result = pstrdup(NameStr(functup->proname));
    ReleaseSysCache(tp);
    return result;
  }
  else
    return NULL;
}

/*
 * get_func_namespace
 *
 *    Returns the pg_namespace OID associated with a given function.
 */
Oid
get_func_namespace(Oid funcid)
{
  HeapTuple tp;

  tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_proc functup = (Form_pg_proc) GETSTRUCT(tp);
    Oid     result;

    result = functup->pronamespace;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * get_func_rettype
 *    Given procedure id, return the function's result type.
 */
Oid
get_func_rettype(Oid funcid)
{
  HeapTuple tp;
  Oid     result;

  tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for function %u", funcid);

  result = ((Form_pg_proc) GETSTRUCT(tp))->prorettype;
  ReleaseSysCache(tp);
  return result;
}

/*
 * get_func_nargs
 *    Given procedure id, return the number of arguments.
 */
int
get_func_nargs(Oid funcid)
{
  HeapTuple tp;
  int     result;

  tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for function %u", funcid);

  result = ((Form_pg_proc) GETSTRUCT(tp))->pronargs;
  ReleaseSysCache(tp);
  return result;
}

/*
 * get_func_signature
 *    Given procedure id, return the function's argument and result types.
 *    (The return value is the result type.)
 *
 * The arguments are returned as a palloc'd array.
 */
Oid
get_func_signature(Oid funcid, Oid **argtypes, int *nargs)
{
  HeapTuple tp;
  Form_pg_proc procstruct;
  Oid     result;

  tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for function %u", funcid);

  procstruct = (Form_pg_proc) GETSTRUCT(tp);

  result = procstruct->prorettype;
  *nargs = (int) procstruct->pronargs;
  Assert(*nargs == procstruct->proargtypes.dim1);
  *argtypes = (Oid *) palloc(*nargs * sizeof(Oid));
  memcpy(*argtypes, procstruct->proargtypes.values, *nargs * sizeof(Oid));

  ReleaseSysCache(tp);
  return result;
}

/*
 * get_func_variadictype
 *    Given procedure id, return the function's provariadic field.
 */
Oid
get_func_variadictype(Oid funcid)
{
  HeapTuple tp;
  Oid     result;

  tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for function %u", funcid);

  result = ((Form_pg_proc) GETSTRUCT(tp))->provariadic;
  ReleaseSysCache(tp);
  return result;
}

/*
 * get_func_retset
 *    Given procedure id, return the function's proretset flag.
 */
bool
get_func_retset(Oid funcid)
{
  HeapTuple tp;
  bool    result;

  tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for function %u", funcid);

  result = ((Form_pg_proc) GETSTRUCT(tp))->proretset;
  ReleaseSysCache(tp);
  return result;
}

/*
 * func_strict
 *    Given procedure id, return the function's proisstrict flag.
 */
bool
func_strict(Oid funcid)
{
  HeapTuple tp;
  bool    result;

  tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for function %u", funcid);

  result = ((Form_pg_proc) GETSTRUCT(tp))->proisstrict;
  ReleaseSysCache(tp);
  return result;
}

/*
 * func_volatile
 *    Given procedure id, return the function's provolatile flag.
 */
char
func_volatile(Oid funcid)
{
  HeapTuple tp;
  char    result;

  tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for function %u", funcid);

  result = ((Form_pg_proc) GETSTRUCT(tp))->provolatile;
  ReleaseSysCache(tp);
  return result;
}

/*
 * func_parallel
 *    Given procedure id, return the function's proparallel flag.
 */
char
func_parallel(Oid funcid)
{
  HeapTuple tp;
  char    result;

  tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for function %u", funcid);

  result = ((Form_pg_proc) GETSTRUCT(tp))->proparallel;
  ReleaseSysCache(tp);
  return result;
}

/*
 * get_func_prokind
 *     Given procedure id, return the routine kind.
 */
char
get_func_prokind(Oid funcid)
{
  HeapTuple tp;
  char    result;

  tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for function %u", funcid);

  result = ((Form_pg_proc) GETSTRUCT(tp))->prokind;
  ReleaseSysCache(tp);
  return result;
}

/*
 * get_func_leakproof
 *     Given procedure id, return the function's leakproof field.
 */
bool
get_func_leakproof(Oid funcid)
{
  HeapTuple tp;
  bool    result;

  tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for function %u", funcid);

  result = ((Form_pg_proc) GETSTRUCT(tp))->proleakproof;
  ReleaseSysCache(tp);
  return result;
}

/*
 * get_func_support
 *
 *    Returns the support function OID associated with a given function,
 *    or InvalidOid if there is none.
 */
RegProcedure
get_func_support(Oid funcid)
{
  HeapTuple tp;

  tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_proc functup = (Form_pg_proc) GETSTRUCT(tp);
    RegProcedure result;

    result = functup->prosupport;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return (RegProcedure) InvalidOid;
}

/*        ---------- RELATION CACHE ----------           */

/*
 * get_relname_relid
 *    Given name and namespace of a relation, look up the OID.
 *
 * Returns InvalidOid if there is no such relation.
 */
Oid
get_relname_relid(const char *relname, Oid relnamespace)
{
  return GetSysCacheOid2(RELNAMENSP, Anum_pg_class_oid,
               PointerGetDatum(relname),
               ObjectIdGetDatum(relnamespace));
}

#ifdef NOT_USED
/*
 * get_relnatts
 *
 *    Returns the number of attributes for a given relation.
 */
int
get_relnatts(Oid relid)
{
  HeapTuple tp;

  tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_class reltup = (Form_pg_class) GETSTRUCT(tp);
    int     result;

    result = reltup->relnatts;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidAttrNumber;
}
#endif

/*
 * get_rel_name
 *    Returns the name of a given relation.
 *
 * Returns a palloc'd copy of the string, or NULL if no such relation.
 *
 * NOTE: since relation name is not unique, be wary of code that uses this
 * for anything except preparing error messages.
 */
char *
get_rel_name(Oid relid)
{
  HeapTuple tp;

  tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_class reltup = (Form_pg_class) GETSTRUCT(tp);
    char     *result;

    result = pstrdup(NameStr(reltup->relname));
    ReleaseSysCache(tp);
    return result;
  }
  else
    return NULL;
}

/*
 * get_rel_namespace
 *
 *    Returns the pg_namespace OID associated with a given relation.
 */
Oid
get_rel_namespace(Oid relid)
{
  HeapTuple tp;

  tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_class reltup = (Form_pg_class) GETSTRUCT(tp);
    Oid     result;

    result = reltup->relnamespace;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * get_rel_type_id
 *
 *    Returns the pg_type OID associated with a given relation.
 *
 * Note: not all pg_class entries have associated pg_type OIDs; so be
 * careful to check for InvalidOid result.
 */
Oid
get_rel_type_id(Oid relid)
{
  HeapTuple tp;

  tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_class reltup = (Form_pg_class) GETSTRUCT(tp);
    Oid     result;

    result = reltup->reltype;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * get_rel_relkind
 *
 *    Returns the relkind associated with a given relation.
 */
char
get_rel_relkind(Oid relid)
{
  HeapTuple tp;

  tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_class reltup = (Form_pg_class) GETSTRUCT(tp);
    char    result;

    result = reltup->relkind;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return '\0';
}

/*
 * get_rel_relispartition
 *
 *    Returns the relispartition flag associated with a given relation.
 */
bool
get_rel_relispartition(Oid relid)
{
  HeapTuple tp;

  tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_class reltup = (Form_pg_class) GETSTRUCT(tp);
    bool    result;

    result = reltup->relispartition;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return false;
}

/*
 * get_rel_tablespace
 *
 *    Returns the pg_tablespace OID associated with a given relation.
 *
 * Note: InvalidOid might mean either that we couldn't find the relation,
 * or that it is in the database's default tablespace.
 */
Oid
get_rel_tablespace(Oid relid)
{
  HeapTuple tp;

  tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_class reltup = (Form_pg_class) GETSTRUCT(tp);
    Oid     result;

    result = reltup->reltablespace;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * get_rel_persistence
 *
 *    Returns the relpersistence associated with a given relation.
 */
char
get_rel_persistence(Oid relid)
{
  HeapTuple tp;
  Form_pg_class reltup;
  char    result;

  tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for relation %u", relid);
  reltup = (Form_pg_class) GETSTRUCT(tp);
  result = reltup->relpersistence;
  ReleaseSysCache(tp);

  return result;
}

/*
 * get_rel_relam
 *
 *    Returns the relam associated with a given relation.
 */
Oid
get_rel_relam(Oid relid)
{
  HeapTuple tp;
  Form_pg_class reltup;
  Oid     result;

  tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for relation %u", relid);
  reltup = (Form_pg_class) GETSTRUCT(tp);
  result = reltup->relam;
  ReleaseSysCache(tp);

  return result;
}


/*        ---------- TRANSFORM CACHE ----------            */

Oid
get_transform_fromsql(Oid typid, Oid langid, List *trftypes)
{
  HeapTuple tup;

  if (!list_member_oid(trftypes, typid))
    return InvalidOid;

  tup = SearchSysCache2(TRFTYPELANG, ObjectIdGetDatum(typid),
              ObjectIdGetDatum(langid));
  if (HeapTupleIsValid(tup))
  {
    Oid     funcid;

    funcid = ((Form_pg_transform) GETSTRUCT(tup))->trffromsql;
    ReleaseSysCache(tup);
    return funcid;
  }
  else
    return InvalidOid;
}

Oid
get_transform_tosql(Oid typid, Oid langid, List *trftypes)
{
  HeapTuple tup;

  if (!list_member_oid(trftypes, typid))
    return InvalidOid;

  tup = SearchSysCache2(TRFTYPELANG, ObjectIdGetDatum(typid),
              ObjectIdGetDatum(langid));
  if (HeapTupleIsValid(tup))
  {
    Oid     funcid;

    funcid = ((Form_pg_transform) GETSTRUCT(tup))->trftosql;
    ReleaseSysCache(tup);
    return funcid;
  }
  else
    return InvalidOid;
}


/*        ---------- TYPE CACHE ----------             */

/*
 * get_typisdefined
 *
 *    Given the type OID, determine whether the type is defined
 *    (if not, it's only a shell).
 */
bool
get_typisdefined(Oid typid)
{
  HeapTuple tp;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
    bool    result;

    result = typtup->typisdefined;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return false;
}

/*
 * get_typlen
 *
 *    Given the type OID, return the length of the type.
 */
int16
get_typlen(Oid typid)
{
  HeapTuple tp;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
    int16   result;

    result = typtup->typlen;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return 0;
}

/*
 * get_typbyval
 *
 *    Given the type OID, determine whether the type is returned by value or
 *    not.  Returns true if by value, false if by reference.
 */
bool
get_typbyval(Oid typid)
{
  HeapTuple tp;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
    bool    result;

    result = typtup->typbyval;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return false;
}

/*
 * get_typlenbyval
 *
 *    A two-fer: given the type OID, return both typlen and typbyval.
 *
 *    Since both pieces of info are needed to know how to copy a Datum,
 *    many places need both.  Might as well get them with one cache lookup
 *    instead of two.  Also, this routine raises an error instead of
 *    returning a bogus value when given a bad type OID.
 */
void
get_typlenbyval(Oid typid, int16 *typlen, bool *typbyval)
{
  HeapTuple tp;
  Form_pg_type typtup;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for type %u", typid);
  typtup = (Form_pg_type) GETSTRUCT(tp);
  *typlen = typtup->typlen;
  *typbyval = typtup->typbyval;
  ReleaseSysCache(tp);
}

/*
 * get_typlenbyvalalign
 *
 *    A three-fer: given the type OID, return typlen, typbyval, typalign.
 */
void
get_typlenbyvalalign(Oid typid, int16 *typlen, bool *typbyval,
           char *typalign)
{
  HeapTuple tp;
  Form_pg_type typtup;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for type %u", typid);
  typtup = (Form_pg_type) GETSTRUCT(tp);
  *typlen = typtup->typlen;
  *typbyval = typtup->typbyval;
  *typalign = typtup->typalign;
  ReleaseSysCache(tp);
}

/*
 * getTypeIOParam
 *    Given a pg_type row, select the type OID to pass to I/O functions
 *
 * Formerly, all I/O functions were passed pg_type.typelem as their second
 * parameter, but we now have a more complex rule about what to pass.
 * This knowledge is intended to be centralized here --- direct references
 * to typelem elsewhere in the code are wrong, if they are associated with
 * I/O calls and not with actual subscripting operations!  (But see
 * bootstrap.c's boot_get_type_io_data() if you need to change this.)
 *
 * As of PostgreSQL 8.1, output functions receive only the value itself
 * and not any auxiliary parameters, so the name of this routine is now
 * a bit of a misnomer ... it should be getTypeInputParam.
 */
Oid
getTypeIOParam(HeapTuple typeTuple)
{
  Form_pg_type typeStruct = (Form_pg_type) GETSTRUCT(typeTuple);

  /*
   * Array types get their typelem as parameter; everybody else gets their
   * own type OID as parameter.
   */
  if (OidIsValid(typeStruct->typelem))
    return typeStruct->typelem;
  else
    return typeStruct->oid;
}

/*
 * get_type_io_data
 *
 *    A six-fer:  given the type OID, return typlen, typbyval, typalign,
 *          typdelim, typioparam, and IO function OID. The IO function
 *          returned is controlled by IOFuncSelector
 */
void
get_type_io_data(Oid typid,
         IOFuncSelector which_func,
         int16 *typlen,
         bool *typbyval,
         char *typalign,
         char *typdelim,
         Oid *typioparam,
         Oid *func)
{
  HeapTuple typeTuple;
  Form_pg_type typeStruct;

  /*
   * In bootstrap mode, pass it off to bootstrap.c.  This hack allows us to
   * use array_in and array_out during bootstrap.
   */
  if (IsBootstrapProcessingMode())
  {
    Oid     typinput;
    Oid     typoutput;

    boot_get_type_io_data(typid,
                typlen,
                typbyval,
                typalign,
                typdelim,
                typioparam,
                &typinput,
                &typoutput);
    switch (which_func)
    {
      case IOFunc_input:
        *func = typinput;
        break;
      case IOFunc_output:
        *func = typoutput;
        break;
      default:
        elog(ERROR, "binary I/O not supported during bootstrap");
        break;
    }
    return;
  }

  typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (!HeapTupleIsValid(typeTuple))
    elog(ERROR, "cache lookup failed for type %u", typid);
  typeStruct = (Form_pg_type) GETSTRUCT(typeTuple);

  *typlen = typeStruct->typlen;
  *typbyval = typeStruct->typbyval;
  *typalign = typeStruct->typalign;
  *typdelim = typeStruct->typdelim;
  *typioparam = getTypeIOParam(typeTuple);
  switch (which_func)
  {
    case IOFunc_input:
      *func = typeStruct->typinput;
      break;
    case IOFunc_output:
      *func = typeStruct->typoutput;
      break;
    case IOFunc_receive:
      *func = typeStruct->typreceive;
      break;
    case IOFunc_send:
      *func = typeStruct->typsend;
      break;
  }
  ReleaseSysCache(typeTuple);
}

#ifdef NOT_USED
char
get_typalign(Oid typid)
{
  HeapTuple tp;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
    char    result;

    result = typtup->typalign;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return TYPALIGN_INT;
}
#endif

char
get_typstorage(Oid typid)
{
  HeapTuple tp;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
    char    result;

    result = typtup->typstorage;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return TYPSTORAGE_PLAIN;
}

/*
 * get_typdefault
 *    Given a type OID, return the type's default value, if any.
 *
 *    The result is a palloc'd expression node tree, or NULL if there
 *    is no defined default for the datatype.
 *
 * NB: caller should be prepared to coerce result to correct datatype;
 * the returned expression tree might produce something of the wrong type.
 */
Node *
get_typdefault(Oid typid)
{
  HeapTuple typeTuple;
  Form_pg_type type;
  Datum   datum;
  bool    isNull;
  Node     *expr;

  typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (!HeapTupleIsValid(typeTuple))
    elog(ERROR, "cache lookup failed for type %u", typid);
  type = (Form_pg_type) GETSTRUCT(typeTuple);

  /*
   * typdefault and typdefaultbin are potentially null, so don't try to
   * access 'em as struct fields. Must do it the hard way with
   * SysCacheGetAttr.
   */
  datum = SysCacheGetAttr(TYPEOID,
              typeTuple,
              Anum_pg_type_typdefaultbin,
              &isNull);

  if (!isNull)
  {
    /* We have an expression default */
    expr = stringToNode(TextDatumGetCString(datum));
  }
  else
  {
    /* Perhaps we have a plain literal default */
    datum = SysCacheGetAttr(TYPEOID,
                typeTuple,
                Anum_pg_type_typdefault,
                &isNull);

    if (!isNull)
    {
      char     *strDefaultVal;

      /* Convert text datum to C string */
      strDefaultVal = TextDatumGetCString(datum);
      /* Convert C string to a value of the given type */
      datum = OidInputFunctionCall(type->typinput, strDefaultVal,
                     getTypeIOParam(typeTuple), -1);
      /* Build a Const node containing the value */
      expr = (Node *) makeConst(typid,
                    -1,
                    type->typcollation,
                    type->typlen,
                    datum,
                    false,
                    type->typbyval);
      pfree(strDefaultVal);
    }
    else
    {
      /* No default */
      expr = NULL;
    }
  }

  ReleaseSysCache(typeTuple);

  return expr;
}

/*
 * getBaseType
 *    If the given type is a domain, return its base type;
 *    otherwise return the type's own OID.
 */
Oid
getBaseType(Oid typid)
{
  int32   typmod = -1;

  return getBaseTypeAndTypmod(typid, &typmod);
}

/*
 * getBaseTypeAndTypmod
 *    If the given type is a domain, return its base type and typmod;
 *    otherwise return the type's own OID, and leave *typmod unchanged.
 *
 * Note that the "applied typmod" should be -1 for every domain level
 * above the bottommost; therefore, if the passed-in typid is indeed
 * a domain, *typmod should be -1.
 */
Oid
getBaseTypeAndTypmod(Oid typid, int32 *typmod)
{
  /*
   * We loop to find the bottom base type in a stack of domains.
   */
  for (;;)
  {
    HeapTuple tup;
    Form_pg_type typTup;

    tup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
    if (!HeapTupleIsValid(tup))
      elog(ERROR, "cache lookup failed for type %u", typid);
    typTup = (Form_pg_type) GETSTRUCT(tup);
    if (typTup->typtype != TYPTYPE_DOMAIN)
    {
      /* Not a domain, so done */
      ReleaseSysCache(tup);
      break;
    }

    Assert(*typmod == -1);
    typid = typTup->typbasetype;
    *typmod = typTup->typtypmod;

    ReleaseSysCache(tup);
  }

  return typid;
}

/*
 * get_typavgwidth
 *
 *    Given a type OID and a typmod value (pass -1 if typmod is unknown),
 *    estimate the average width of values of the type.  This is used by
 *    the planner, which doesn't require absolutely correct results;
 *    it's OK (and expected) to guess if we don't know for sure.
 */
int32
get_typavgwidth(Oid typid, int32 typmod)
{
  int     typlen = get_typlen(typid);
  int32   maxwidth;

  /*
   * Easy if it's a fixed-width type
   */
  if (typlen > 0)
    return typlen;

  /*
   * type_maximum_size knows the encoding of typmod for some datatypes;
   * don't duplicate that knowledge here.
   */
  maxwidth = type_maximum_size(typid, typmod);
  if (maxwidth > 0)
  {
    /*
     * For BPCHAR, the max width is also the only width.  Otherwise we
     * need to guess about the typical data width given the max. A sliding
     * scale for percentage of max width seems reasonable.
     */
    if (typid == BPCHAROID)
      return maxwidth;
    if (maxwidth <= 32)
      return maxwidth; /* assume full width */
    if (maxwidth < 1000)
      return 32 + (maxwidth - 32) / 2; /* assume 50% */

    /*
     * Beyond 1000, assume we're looking at something like
     * "varchar(10000)" where the limit isn't actually reached often, and
     * use a fixed estimate.
     */
    return 32 + (1000 - 32) / 2;
  }

  /*
   * Oops, we have no idea ... wild guess time.
   */
  return 32;
}

/*
 * get_typtype
 *
 *    Given the type OID, find if it is a basic type, a complex type, etc.
 *    It returns the null char if the cache lookup fails...
 */
char
get_typtype(Oid typid)
{
  HeapTuple tp;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
    char    result;

    result = typtup->typtype;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return '\0';
}

/*
 * type_is_rowtype
 *
 *    Convenience function to determine whether a type OID represents
 *    a "rowtype" type --- either RECORD or a named composite type
 *    (including a domain over a named composite type).
 */
bool
type_is_rowtype(Oid typid)
{
  if (typid == RECORDOID)
    return true;     /* easy case */
  switch (get_typtype(typid))
  {
    case TYPTYPE_COMPOSITE:
      return true;
    case TYPTYPE_DOMAIN:
      if (get_typtype(getBaseType(typid)) == TYPTYPE_COMPOSITE)
        return true;
      break;
    default:
      break;
  }
  return false;
}

/*
 * type_is_enum
 *    Returns true if the given type is an enum type.
 */
bool
type_is_enum(Oid typid)
{
  return (get_typtype(typid) == TYPTYPE_ENUM);
}

/*
 * type_is_range
 *    Returns true if the given type is a range type.
 */
bool
type_is_range(Oid typid)
{
  return (get_typtype(typid) == TYPTYPE_RANGE);
}

/*
 * type_is_multirange
 *    Returns true if the given type is a multirange type.
 */
bool
type_is_multirange(Oid typid)
{
  return (get_typtype(typid) == TYPTYPE_MULTIRANGE);
}

/*
 * get_type_category_preferred
 *
 *    Given the type OID, fetch its category and preferred-type status.
 *    Throws error on failure.
 */
void
get_type_category_preferred(Oid typid, char *typcategory, bool *typispreferred)
{
  HeapTuple tp;
  Form_pg_type typtup;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for type %u", typid);
  typtup = (Form_pg_type) GETSTRUCT(tp);
  *typcategory = typtup->typcategory;
  *typispreferred = typtup->typispreferred;
  ReleaseSysCache(tp);
}

/*
 * get_typ_typrelid
 *
 *    Given the type OID, get the typrelid (InvalidOid if not a complex
 *    type).
 */
Oid
get_typ_typrelid(Oid typid)
{
  HeapTuple tp;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
    Oid     result;

    result = typtup->typrelid;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * get_element_type
 *
 *    Given the type OID, get the typelem (InvalidOid if not an array type).
 *
 * NB: this only succeeds for "true" arrays having array_subscript_handler
 * as typsubscript.  For other types, InvalidOid is returned independently
 * of whether they have typelem or typsubscript set.
 */
Oid
get_element_type(Oid typid)
{
  HeapTuple tp;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
    Oid     result;

    if (IsTrueArrayType(typtup))
      result = typtup->typelem;
    else
      result = InvalidOid;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * get_array_type
 *
 *    Given the type OID, get the corresponding "true" array type.
 *    Returns InvalidOid if no array type can be found.
 */
Oid
get_array_type(Oid typid)
{
  HeapTuple tp;
  Oid     result = InvalidOid;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (HeapTupleIsValid(tp))
  {
    result = ((Form_pg_type) GETSTRUCT(tp))->typarray;
    ReleaseSysCache(tp);
  }
  return result;
}

/*
 * get_promoted_array_type
 *
 *    The "promoted" type is what you'd get from an ARRAY(SELECT ...)
 *    construct, that is, either the corresponding "true" array type
 *    if the input is a scalar type that has such an array type,
 *    or the same type if the input is already a "true" array type.
 *    Returns InvalidOid if neither rule is satisfied.
 */
Oid
get_promoted_array_type(Oid typid)
{
  Oid     array_type = get_array_type(typid);

  if (OidIsValid(array_type))
    return array_type;
  if (OidIsValid(get_element_type(typid)))
    return typid;
  return InvalidOid;
}

/*
 * get_base_element_type
 *    Given the type OID, get the typelem, looking "through" any domain
 *    to its underlying array type.
 *
 * This is equivalent to get_element_type(getBaseType(typid)), but avoids
 * an extra cache lookup.  Note that it fails to provide any information
 * about the typmod of the array.
 */
Oid
get_base_element_type(Oid typid)
{
  /*
   * We loop to find the bottom base type in a stack of domains.
   */
  for (;;)
  {
    HeapTuple tup;
    Form_pg_type typTup;

    tup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
    if (!HeapTupleIsValid(tup))
      break;
    typTup = (Form_pg_type) GETSTRUCT(tup);
    if (typTup->typtype != TYPTYPE_DOMAIN)
    {
      /* Not a domain, so stop descending */
      Oid     result;

      /* This test must match get_element_type */
      if (IsTrueArrayType(typTup))
        result = typTup->typelem;
      else
        result = InvalidOid;
      ReleaseSysCache(tup);
      return result;
    }

    typid = typTup->typbasetype;
    ReleaseSysCache(tup);
  }

  /* Like get_element_type, silently return InvalidOid for bogus input */
  return InvalidOid;
}

/*
 * getTypeInputInfo
 *
 *    Get info needed for converting values of a type to internal form
 */
void
getTypeInputInfo(Oid type, Oid *typInput, Oid *typIOParam)
{
  HeapTuple typeTuple;
  Form_pg_type pt;

  typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(type));
  if (!HeapTupleIsValid(typeTuple))
    elog(ERROR, "cache lookup failed for type %u", type);
  pt = (Form_pg_type) GETSTRUCT(typeTuple);

  if (!pt->typisdefined)
    ereport(ERROR,
        (errcode(ERRCODE_UNDEFINED_OBJECT),
         errmsg("type %s is only a shell",
            format_type_be(type))));
  if (!OidIsValid(pt->typinput))
    ereport(ERROR,
        (errcode(ERRCODE_UNDEFINED_FUNCTION),
         errmsg("no input function available for type %s",
            format_type_be(type))));

  *typInput = pt->typinput;
  *typIOParam = getTypeIOParam(typeTuple);

  ReleaseSysCache(typeTuple);
}

/*
 * getTypeOutputInfo
 *
 *    Get info needed for printing values of a type
 */
void
getTypeOutputInfo(Oid type, Oid *typOutput, bool *typIsVarlena)
{
  HeapTuple typeTuple;
  Form_pg_type pt;

  typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(type));
  if (!HeapTupleIsValid(typeTuple))
    elog(ERROR, "cache lookup failed for type %u", type);
  pt = (Form_pg_type) GETSTRUCT(typeTuple);

  if (!pt->typisdefined)
    ereport(ERROR,
        (errcode(ERRCODE_UNDEFINED_OBJECT),
         errmsg("type %s is only a shell",
            format_type_be(type))));
  if (!OidIsValid(pt->typoutput))
    ereport(ERROR,
        (errcode(ERRCODE_UNDEFINED_FUNCTION),
         errmsg("no output function available for type %s",
            format_type_be(type))));

  *typOutput = pt->typoutput;
  *typIsVarlena = (!pt->typbyval) && (pt->typlen == -1);

  ReleaseSysCache(typeTuple);
}

/*
 * getTypeBinaryInputInfo
 *
 *    Get info needed for binary input of values of a type
 */
void
getTypeBinaryInputInfo(Oid type, Oid *typReceive, Oid *typIOParam)
{
  HeapTuple typeTuple;
  Form_pg_type pt;

  typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(type));
  if (!HeapTupleIsValid(typeTuple))
    elog(ERROR, "cache lookup failed for type %u", type);
  pt = (Form_pg_type) GETSTRUCT(typeTuple);

  if (!pt->typisdefined)
    ereport(ERROR,
        (errcode(ERRCODE_UNDEFINED_OBJECT),
         errmsg("type %s is only a shell",
            format_type_be(type))));
  if (!OidIsValid(pt->typreceive))
    ereport(ERROR,
        (errcode(ERRCODE_UNDEFINED_FUNCTION),
         errmsg("no binary input function available for type %s",
            format_type_be(type))));

  *typReceive = pt->typreceive;
  *typIOParam = getTypeIOParam(typeTuple);

  ReleaseSysCache(typeTuple);
}

/*
 * getTypeBinaryOutputInfo
 *
 *    Get info needed for binary output of values of a type
 */
void
getTypeBinaryOutputInfo(Oid type, Oid *typSend, bool *typIsVarlena)
{
  HeapTuple typeTuple;
  Form_pg_type pt;

  typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(type));
  if (!HeapTupleIsValid(typeTuple))
    elog(ERROR, "cache lookup failed for type %u", type);
  pt = (Form_pg_type) GETSTRUCT(typeTuple);

  if (!pt->typisdefined)
    ereport(ERROR,
        (errcode(ERRCODE_UNDEFINED_OBJECT),
         errmsg("type %s is only a shell",
            format_type_be(type))));
  if (!OidIsValid(pt->typsend))
    ereport(ERROR,
        (errcode(ERRCODE_UNDEFINED_FUNCTION),
         errmsg("no binary output function available for type %s",
            format_type_be(type))));

  *typSend = pt->typsend;
  *typIsVarlena = (!pt->typbyval) && (pt->typlen == -1);

  ReleaseSysCache(typeTuple);
}

/*
 * get_typmodin
 *
 *    Given the type OID, return the type's typmodin procedure, if any.
 */
Oid
get_typmodin(Oid typid)
{
  HeapTuple tp;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
    Oid     result;

    result = typtup->typmodin;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

#ifdef NOT_USED
/*
 * get_typmodout
 *
 *    Given the type OID, return the type's typmodout procedure, if any.
 */
Oid
get_typmodout(Oid typid)
{
  HeapTuple tp;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
    Oid     result;

    result = typtup->typmodout;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}
#endif              /* NOT_USED */

/*
 * get_typcollation
 *
 *    Given the type OID, return the type's typcollation attribute.
 */
Oid
get_typcollation(Oid typid)
{
  HeapTuple tp;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
    Oid     result;

    result = typtup->typcollation;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}


/*
 * type_is_collatable
 *
 *    Return whether the type cares about collations
 */
bool
type_is_collatable(Oid typid)
{
  return OidIsValid(get_typcollation(typid));
}


/*
 * get_typsubscript
 *
 *    Given the type OID, return the type's subscripting handler's OID,
 *    if it has one.
 *
 * If typelemp isn't NULL, we also store the type's typelem value there.
 * This saves some callers an extra catalog lookup.
 */
RegProcedure
get_typsubscript(Oid typid, Oid *typelemp)
{
  HeapTuple tp;

  tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_type typform = (Form_pg_type) GETSTRUCT(tp);
    RegProcedure handler = typform->typsubscript;

    if (typelemp)
      *typelemp = typform->typelem;
    ReleaseSysCache(tp);
    return handler;
  }
  else
  {
    if (typelemp)
      *typelemp = InvalidOid;
    return InvalidOid;
  }
}

/*
 * getSubscriptingRoutines
 *
 *    Given the type OID, fetch the type's subscripting methods struct.
 *    Return NULL if type is not subscriptable.
 *
 * If typelemp isn't NULL, we also store the type's typelem value there.
 * This saves some callers an extra catalog lookup.
 */
const struct SubscriptRoutines *
getSubscriptingRoutines(Oid typid, Oid *typelemp)
{
  RegProcedure typsubscript = get_typsubscript(typid, typelemp);

  if (!OidIsValid(typsubscript))
    return NULL;

  return (const struct SubscriptRoutines *)
    DatumGetPointer(OidFunctionCall0(typsubscript));
}


/*        ---------- STATISTICS CACHE ----------           */

/*
 * get_attavgwidth
 *
 *    Given the table and attribute number of a column, get the average
 *    width of entries in the column.  Return zero if no data available.
 *
 * Currently this is only consulted for individual tables, not for inheritance
 * trees, so we don't need an "inh" parameter.
 *
 * Calling a hook at this point looks somewhat strange, but is required
 * because the optimizer calls this function without any other way for
 * plug-ins to control the result.
 */
int32
get_attavgwidth(Oid relid, AttrNumber attnum)
{
  HeapTuple tp;
  int32   stawidth;

  if (get_attavgwidth_hook)
  {
    stawidth = (*get_attavgwidth_hook) (relid, attnum);
    if (stawidth > 0)
      return stawidth;
  }
  tp = SearchSysCache3(STATRELATTINH,
             ObjectIdGetDatum(relid),
             Int16GetDatum(attnum),
             BoolGetDatum(false));
  if (HeapTupleIsValid(tp))
  {
    stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
    ReleaseSysCache(tp);
    if (stawidth > 0)
      return stawidth;
  }
  return 0;
}

/*
 * get_attstatsslot
 *
 *    Extract the contents of a "slot" of a pg_statistic tuple.
 *    Returns true if requested slot type was found, else false.
 *
 * Unlike other routines in this file, this takes a pointer to an
 * already-looked-up tuple in the pg_statistic cache.  We do this since
 * most callers will want to extract more than one value from the cache
 * entry, and we don't want to repeat the cache lookup unnecessarily.
 * Also, this API allows this routine to be used with statistics tuples
 * that have been provided by a stats hook and didn't really come from
 * pg_statistic.
 *
 * sslot: pointer to output area (typically, a local variable in the caller).
 * statstuple: pg_statistic tuple to be examined.
 * reqkind: STAKIND code for desired statistics slot kind.
 * reqop: STAOP value wanted, or InvalidOid if don't care.
 * flags: bitmask of ATTSTATSSLOT_VALUES and/or ATTSTATSSLOT_NUMBERS.
 *
 * If a matching slot is found, true is returned, and *sslot is filled thus:
 * staop: receives the actual STAOP value.
 * stacoll: receives the actual STACOLL value.
 * valuetype: receives actual datatype of the elements of stavalues.
 * values: receives pointer to an array of the slot's stavalues.
 * nvalues: receives number of stavalues.
 * numbers: receives pointer to an array of the slot's stanumbers (as float4).
 * nnumbers: receives number of stanumbers.
 *
 * valuetype/values/nvalues are InvalidOid/NULL/0 if ATTSTATSSLOT_VALUES
 * wasn't specified.  Likewise, numbers/nnumbers are NULL/0 if
 * ATTSTATSSLOT_NUMBERS wasn't specified.
 *
 * If no matching slot is found, false is returned, and *sslot is zeroed.
 *
 * Note that the current API doesn't allow for searching for a slot with
 * a particular collation.  If we ever actually support recording more than
 * one collation, we'll have to extend the API, but for now simple is good.
 *
 * The data referred to by the fields of sslot is locally palloc'd and
 * is independent of the original pg_statistic tuple.  When the caller
 * is done with it, call free_attstatsslot to release the palloc'd data.
 *
 * If it's desirable to call free_attstatsslot when get_attstatsslot might
 * not have been called, memset'ing sslot to zeroes will allow that.
 *
 * Passing flags=0 can be useful to quickly check if the requested slot type
 * exists.  In this case no arrays are extracted, so free_attstatsslot need
 * not be called.
 */
bool
get_attstatsslot(AttStatsSlot *sslot, HeapTuple statstuple,
         int reqkind, Oid reqop, int flags)
{
  Form_pg_statistic stats = (Form_pg_statistic) GETSTRUCT(statstuple);
  int     i;
  Datum   val;
  ArrayType  *statarray;
  Oid     arrayelemtype;
  int     narrayelem;
  HeapTuple typeTuple;
  Form_pg_type typeForm;

  /* initialize *sslot properly */
  memset(sslot, 0, sizeof(AttStatsSlot));

  for (i = 0; i < STATISTIC_NUM_SLOTS; i++)
  {
    if ((&stats->stakind1)[i] == reqkind &&
      (reqop == InvalidOid || (&stats->staop1)[i] == reqop))
      break;
  }
  if (i >= STATISTIC_NUM_SLOTS)
    return false;     /* not there */

  sslot->staop = (&stats->staop1)[i];
  sslot->stacoll = (&stats->stacoll1)[i];

  if (flags & ATTSTATSSLOT_VALUES)
  {
    val = SysCacheGetAttrNotNull(STATRELATTINH, statstuple,
                   Anum_pg_statistic_stavalues1 + i);

    /*
     * Detoast the array if needed, and in any case make a copy that's
     * under control of this AttStatsSlot.
     */
    statarray = DatumGetArrayTypePCopy(val);

    /*
     * Extract the actual array element type, and pass it back in case the
     * caller needs it.
     */
    sslot->valuetype = arrayelemtype = ARR_ELEMTYPE(statarray);

    /* Need info about element type */
    typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(arrayelemtype));
    if (!HeapTupleIsValid(typeTuple))
      elog(ERROR, "cache lookup failed for type %u", arrayelemtype);
    typeForm = (Form_pg_type) GETSTRUCT(typeTuple);

    /* Deconstruct array into Datum elements; NULLs not expected */
    deconstruct_array(statarray,
              arrayelemtype,
              typeForm->typlen,
              typeForm->typbyval,
              typeForm->typalign,
              &sslot->values, NULL, &sslot->nvalues);

    /*
     * If the element type is pass-by-reference, we now have a bunch of
     * Datums that are pointers into the statarray, so we need to keep
     * that until free_attstatsslot.  Otherwise, all the useful info is in
     * sslot->values[], so we can free the array object immediately.
     */
    if (!typeForm->typbyval)
      sslot->values_arr = statarray;
    else
      pfree(statarray);

    ReleaseSysCache(typeTuple);
  }

  if (flags & ATTSTATSSLOT_NUMBERS)
  {
    val = SysCacheGetAttrNotNull(STATRELATTINH, statstuple,
                   Anum_pg_statistic_stanumbers1 + i);

    /*
     * Detoast the array if needed, and in any case make a copy that's
     * under control of this AttStatsSlot.
     */
    statarray = DatumGetArrayTypePCopy(val);

    /*
     * We expect the array to be a 1-D float4 array; verify that. We don't
     * need to use deconstruct_array() since the array data is just going
     * to look like a C array of float4 values.
     */
    narrayelem = ARR_DIMS(statarray)[0];
    if (ARR_NDIM(statarray) != 1 || narrayelem <= 0 ||
      ARR_HASNULL(statarray) ||
      ARR_ELEMTYPE(statarray) != FLOAT4OID)
      elog(ERROR, "stanumbers is not a 1-D float4 array");

    /* Give caller a pointer directly into the statarray */
    sslot->numbers = (float4 *) ARR_DATA_PTR(statarray);
    sslot->nnumbers = narrayelem;

    /* We'll free the statarray in free_attstatsslot */
    sslot->numbers_arr = statarray;
  }

  return true;
}

/*
 * free_attstatsslot
 *    Free data allocated by get_attstatsslot
 */
void
free_attstatsslot(AttStatsSlot *sslot)
{
  /* The values[] array was separately palloc'd by deconstruct_array */
  if (sslot->values)
    pfree(sslot->values);
  /* The numbers[] array points into numbers_arr, do not pfree it */
  /* Free the detoasted array objects, if any */
  if (sslot->values_arr)
    pfree(sslot->values_arr);
  if (sslot->numbers_arr)
    pfree(sslot->numbers_arr);
}

/*        ---------- PG_NAMESPACE CACHE ----------         */

/*
 * get_namespace_name
 *    Returns the name of a given namespace
 *
 * Returns a palloc'd copy of the string, or NULL if no such namespace.
 */
char *
get_namespace_name(Oid nspid)
{
  HeapTuple tp;

  tp = SearchSysCache1(NAMESPACEOID, ObjectIdGetDatum(nspid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_namespace nsptup = (Form_pg_namespace) GETSTRUCT(tp);
    char     *result;

    result = pstrdup(NameStr(nsptup->nspname));
    ReleaseSysCache(tp);
    return result;
  }
  else
    return NULL;
}

/*
 * get_namespace_name_or_temp
 *    As above, but if it is this backend's temporary namespace, return
 *    "pg_temp" instead.
 */
char *
get_namespace_name_or_temp(Oid nspid)
{
  if (isTempNamespace(nspid))
    return pstrdup("pg_temp");
  else
    return get_namespace_name(nspid);
}

/*        ---------- PG_RANGE CACHES ----------        */

/*
 * get_range_subtype
 *    Returns the subtype of a given range type
 *
 * Returns InvalidOid if the type is not a range type.
 */
Oid
get_range_subtype(Oid rangeOid)
{
  HeapTuple tp;

  tp = SearchSysCache1(RANGETYPE, ObjectIdGetDatum(rangeOid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_range rngtup = (Form_pg_range) GETSTRUCT(tp);
    Oid     result;

    result = rngtup->rngsubtype;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * get_range_collation
 *    Returns the collation of a given range type
 *
 * Returns InvalidOid if the type is not a range type,
 * or if its subtype is not collatable.
 */
Oid
get_range_collation(Oid rangeOid)
{
  HeapTuple tp;

  tp = SearchSysCache1(RANGETYPE, ObjectIdGetDatum(rangeOid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_range rngtup = (Form_pg_range) GETSTRUCT(tp);
    Oid     result;

    result = rngtup->rngcollation;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * get_range_multirange
 *    Returns the multirange type of a given range type
 *
 * Returns InvalidOid if the type is not a range type.
 */
Oid
get_range_multirange(Oid rangeOid)
{
  HeapTuple tp;

  tp = SearchSysCache1(RANGETYPE, ObjectIdGetDatum(rangeOid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_range rngtup = (Form_pg_range) GETSTRUCT(tp);
    Oid     result;

    result = rngtup->rngmultitypid;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*
 * get_multirange_range
 *    Returns the range type of a given multirange
 *
 * Returns InvalidOid if the type is not a multirange.
 */
Oid
get_multirange_range(Oid multirangeOid)
{
  HeapTuple tp;

  tp = SearchSysCache1(RANGEMULTIRANGE, ObjectIdGetDatum(multirangeOid));
  if (HeapTupleIsValid(tp))
  {
    Form_pg_range rngtup = (Form_pg_range) GETSTRUCT(tp);
    Oid     result;

    result = rngtup->rngtypid;
    ReleaseSysCache(tp);
    return result;
  }
  else
    return InvalidOid;
}

/*        ---------- PG_INDEX CACHE ----------         */

/*
 * get_index_column_opclass
 *
 *    Given the index OID and column number,
 *    return opclass of the index column
 *      or InvalidOid if the index was not found
 *        or column is non-key one.
 */
Oid
get_index_column_opclass(Oid index_oid, int attno)
{
  HeapTuple tuple;
  Form_pg_index rd_index;
  Datum   datum;
  oidvector  *indclass;
  Oid     opclass;

  /* First we need to know the column's opclass. */

  tuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(index_oid));
  if (!HeapTupleIsValid(tuple))
    return InvalidOid;

  rd_index = (Form_pg_index) GETSTRUCT(tuple);

  /* caller is supposed to guarantee this */
  Assert(attno > 0 && attno <= rd_index->indnatts);

  /* Non-key attributes don't have an opclass */
  if (attno > rd_index->indnkeyatts)
  {
    ReleaseSysCache(tuple);
    return InvalidOid;
  }

  datum = SysCacheGetAttrNotNull(INDEXRELID, tuple, Anum_pg_index_indclass);
  indclass = ((oidvector *) DatumGetPointer(datum));

  Assert(attno <= indclass->dim1);
  opclass = indclass->values[attno - 1];

  ReleaseSysCache(tuple);

  return opclass;
}

/*
 * get_index_isreplident
 *
 *    Given the index OID, return pg_index.indisreplident.
 */
bool
get_index_isreplident(Oid index_oid)
{
  HeapTuple tuple;
  Form_pg_index rd_index;
  bool    result;

  tuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(index_oid));
  if (!HeapTupleIsValid(tuple))
    return false;

  rd_index = (Form_pg_index) GETSTRUCT(tuple);
  result = rd_index->indisreplident;
  ReleaseSysCache(tuple);

  return result;
}

/*
 * get_index_isvalid
 *
 *    Given the index OID, return pg_index.indisvalid.
 */
bool
get_index_isvalid(Oid index_oid)
{
  bool    isvalid;
  HeapTuple tuple;
  Form_pg_index rd_index;

  tuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(index_oid));
  if (!HeapTupleIsValid(tuple))
    elog(ERROR, "cache lookup failed for index %u", index_oid);

  rd_index = (Form_pg_index) GETSTRUCT(tuple);
  isvalid = rd_index->indisvalid;
  ReleaseSysCache(tuple);

  return isvalid;
}

/*
 * get_index_isclustered
 *
 *    Given the index OID, return pg_index.indisclustered.
 */
bool
get_index_isclustered(Oid index_oid)
{
  bool    isclustered;
  HeapTuple tuple;
  Form_pg_index rd_index;

  tuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(index_oid));
  if (!HeapTupleIsValid(tuple))
    elog(ERROR, "cache lookup failed for index %u", index_oid);

  rd_index = (Form_pg_index) GETSTRUCT(tuple);
  isclustered = rd_index->indisclustered;
  ReleaseSysCache(tuple);

  return isclustered;
}

/*
 * get_publication_oid - given a publication name, look up the OID
 *
 * If missing_ok is false, throw an error if name not found.  If true, just
 * return InvalidOid.
 */
Oid
get_publication_oid(const char *pubname, bool missing_ok)
{
  Oid     oid;

  oid = GetSysCacheOid1(PUBLICATIONNAME, Anum_pg_publication_oid,
              CStringGetDatum(pubname));
  if (!OidIsValid(oid) && !missing_ok)
    ereport(ERROR,
        (errcode(ERRCODE_UNDEFINED_OBJECT),
         errmsg("publication \"%s\" does not exist", pubname)));
  return oid;
}

/*
 * get_publication_name - given a publication Oid, look up the name
 *
 * If missing_ok is false, throw an error if name not found.  If true, just
 * return NULL.
 */
char *
get_publication_name(Oid pubid, bool missing_ok)
{
  HeapTuple tup;
  char     *pubname;
  Form_pg_publication pubform;

  tup = SearchSysCache1(PUBLICATIONOID, ObjectIdGetDatum(pubid));

  if (!HeapTupleIsValid(tup))
  {
    if (!missing_ok)
      elog(ERROR, "cache lookup failed for publication %u", pubid);
    return NULL;
  }

  pubform = (Form_pg_publication) GETSTRUCT(tup);
  pubname = pstrdup(NameStr(pubform->pubname));

  ReleaseSysCache(tup);

  return pubname;
}

/*
 * get_subscription_oid - given a subscription name, look up the OID
 *
 * If missing_ok is false, throw an error if name not found.  If true, just
 * return InvalidOid.
 */
Oid
get_subscription_oid(const char *subname, bool missing_ok)
{
  Oid     oid;

  oid = GetSysCacheOid2(SUBSCRIPTIONNAME, Anum_pg_subscription_oid,
              ObjectIdGetDatum(MyDatabaseId), CStringGetDatum(subname));
  if (!OidIsValid(oid) && !missing_ok)
    ereport(ERROR,
        (errcode(ERRCODE_UNDEFINED_OBJECT),
         errmsg("subscription \"%s\" does not exist", subname)));
  return oid;
}

/*
 * get_subscription_name - given a subscription OID, look up the name
 *
 * If missing_ok is false, throw an error if name not found.  If true, just
 * return NULL.
 */
char *
get_subscription_name(Oid subid, bool missing_ok)
{
  HeapTuple tup;
  char     *subname;
  Form_pg_subscription subform;

  tup = SearchSysCache1(SUBSCRIPTIONOID, ObjectIdGetDatum(subid));

  if (!HeapTupleIsValid(tup))
  {
    if (!missing_ok)
      elog(ERROR, "cache lookup failed for subscription %u", subid);
    return NULL;
  }

  subform = (Form_pg_subscription) GETSTRUCT(tup);
  subname = pstrdup(NameStr(subform->subname));

  ReleaseSysCache(tup);

  return subname;
}

Coverage Report

Created: 2025-08-12 06:43