/src/postgres/src/backend/utils/adt/ri_triggers.c

Source
/*-------------------------------------------------------------------------
 *
 * ri_triggers.c
 *
 *  Generic trigger procedures for referential integrity constraint
 *  checks.
 *
 *  Note about memory management: the private hashtables kept here live
 *  across query and transaction boundaries, in fact they live as long as
 *  the backend does.  This works because the hashtable structures
 *  themselves are allocated by dynahash.c in its permanent DynaHashCxt,
 *  and the SPI plans they point to are saved using SPI_keepplan().
 *  There is not currently any provision for throwing away a no-longer-needed
 *  plan --- consider improving this someday.
 *
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 *
 * src/backend/utils/adt/ri_triggers.c
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include "access/htup_details.h"
#include "access/sysattr.h"
#include "access/table.h"
#include "access/tableam.h"
#include "access/xact.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_constraint.h"
#include "commands/trigger.h"
#include "executor/executor.h"
#include "executor/spi.h"
#include "lib/ilist.h"
#include "miscadmin.h"
#include "parser/parse_coerce.h"
#include "parser/parse_relation.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/datum.h"
#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/rls.h"
#include "utils/ruleutils.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"

/*
 * Local definitions
 */

#define RI_MAX_NUMKEYS          INDEX_MAX_KEYS

#define RI_INIT_CONSTRAINTHASHSIZE    64
#define RI_INIT_QUERYHASHSIZE     (RI_INIT_CONSTRAINTHASHSIZE * 4)

#define RI_KEYS_ALL_NULL        0
#define RI_KEYS_SOME_NULL       1
#define RI_KEYS_NONE_NULL       2

/* RI query type codes */
/* these queries are executed against the PK (referenced) table: */
#define RI_PLAN_CHECK_LOOKUPPK      1
#define RI_PLAN_CHECK_LOOKUPPK_FROM_PK  2
#define RI_PLAN_LAST_ON_PK        RI_PLAN_CHECK_LOOKUPPK_FROM_PK
/* these queries are executed against the FK (referencing) table: */
#define RI_PLAN_CASCADE_ONDELETE    3
#define RI_PLAN_CASCADE_ONUPDATE    4
#define RI_PLAN_NO_ACTION       5
/* For RESTRICT, the same plan can be used for both ON DELETE and ON UPDATE triggers. */
#define RI_PLAN_RESTRICT        6
#define RI_PLAN_SETNULL_ONDELETE    7
#define RI_PLAN_SETNULL_ONUPDATE    8
#define RI_PLAN_SETDEFAULT_ONDELETE   9
#define RI_PLAN_SETDEFAULT_ONUPDATE   10

#define MAX_QUOTED_NAME_LEN  (NAMEDATALEN*2+3)
#define MAX_QUOTED_REL_NAME_LEN  (MAX_QUOTED_NAME_LEN*2)

#define RIAttName(rel, attnum)  NameStr(*attnumAttName(rel, attnum))
#define RIAttType(rel, attnum)  attnumTypeId(rel, attnum)
#define RIAttCollation(rel, attnum) attnumCollationId(rel, attnum)

#define RI_TRIGTYPE_INSERT 1
#define RI_TRIGTYPE_UPDATE 2
#define RI_TRIGTYPE_DELETE 3


/*
 * RI_ConstraintInfo
 *
 * Information extracted from an FK pg_constraint entry.  This is cached in
 * ri_constraint_cache.
 *
 * Note that pf/pp/ff_eq_oprs may hold the overlaps operator instead of equals
 * for the PERIOD part of a temporal foreign key.
 */
typedef struct RI_ConstraintInfo
{
  Oid     constraint_id;  /* OID of pg_constraint entry (hash key) */
  bool    valid;      /* successfully initialized? */
  Oid     constraint_root_id; /* OID of topmost ancestor constraint;
                   * same as constraint_id if not inherited */
  uint32    oidHashValue; /* hash value of constraint_id */
  uint32    rootHashValue;  /* hash value of constraint_root_id */
  NameData  conname;    /* name of the FK constraint */
  Oid     pk_relid;   /* referenced relation */
  Oid     fk_relid;   /* referencing relation */
  char    confupdtype;  /* foreign key's ON UPDATE action */
  char    confdeltype;  /* foreign key's ON DELETE action */
  int     ndelsetcols;  /* number of columns referenced in ON DELETE
                 * SET clause */
  int16   confdelsetcols[RI_MAX_NUMKEYS]; /* attnums of cols to set on
                         * delete */
  char    confmatchtype;  /* foreign key's match type */
  bool    hasperiod;    /* if the foreign key uses PERIOD */
  int     nkeys;      /* number of key columns */
  int16   pk_attnums[RI_MAX_NUMKEYS]; /* attnums of referenced cols */
  int16   fk_attnums[RI_MAX_NUMKEYS]; /* attnums of referencing cols */
  Oid     pf_eq_oprs[RI_MAX_NUMKEYS]; /* equality operators (PK = FK) */
  Oid     pp_eq_oprs[RI_MAX_NUMKEYS]; /* equality operators (PK = PK) */
  Oid     ff_eq_oprs[RI_MAX_NUMKEYS]; /* equality operators (FK = FK) */
  Oid     period_contained_by_oper; /* anyrange <@ anyrange */
  Oid     agged_period_contained_by_oper; /* fkattr <@ range_agg(pkattr) */
  Oid     period_intersect_oper;  /* anyrange * anyrange */
  dlist_node  valid_link;   /* Link in list of valid entries */
} RI_ConstraintInfo;

/*
 * RI_QueryKey
 *
 * The key identifying a prepared SPI plan in our query hashtable
 */
typedef struct RI_QueryKey
{
  Oid     constr_id;    /* OID of pg_constraint entry */
  int32   constr_queryno; /* query type ID, see RI_PLAN_XXX above */
} RI_QueryKey;

/*
 * RI_QueryHashEntry
 */
typedef struct RI_QueryHashEntry
{
  RI_QueryKey key;
  SPIPlanPtr  plan;
} RI_QueryHashEntry;

/*
 * RI_CompareKey
 *
 * The key identifying an entry showing how to compare two values
 */
typedef struct RI_CompareKey
{
  Oid     eq_opr;     /* the equality operator to apply */
  Oid     typeid;     /* the data type to apply it to */
} RI_CompareKey;

/*
 * RI_CompareHashEntry
 */
typedef struct RI_CompareHashEntry
{
  RI_CompareKey key;
  bool    valid;      /* successfully initialized? */
  FmgrInfo  eq_opr_finfo; /* call info for equality fn */
  FmgrInfo  cast_func_finfo;  /* in case we must coerce input */
} RI_CompareHashEntry;


/*
 * Local data
 */
static HTAB *ri_constraint_cache = NULL;
static HTAB *ri_query_cache = NULL;
static HTAB *ri_compare_cache = NULL;
static dclist_head ri_constraint_cache_valid_list;


/*
 * Local function prototypes
 */
static bool ri_Check_Pk_Match(Relation pk_rel, Relation fk_rel,
                TupleTableSlot *oldslot,
                const RI_ConstraintInfo *riinfo);
static Datum ri_restrict(TriggerData *trigdata, bool is_no_action);
static Datum ri_set(TriggerData *trigdata, bool is_set_null, int tgkind);
static void quoteOneName(char *buffer, const char *name);
static void quoteRelationName(char *buffer, Relation rel);
static void ri_GenerateQual(StringInfo buf,
              const char *sep,
              const char *leftop, Oid leftoptype,
              Oid opoid,
              const char *rightop, Oid rightoptype);
static void ri_GenerateQualCollation(StringInfo buf, Oid collation);
static int  ri_NullCheck(TupleDesc tupDesc, TupleTableSlot *slot,
             const RI_ConstraintInfo *riinfo, bool rel_is_pk);
static void ri_BuildQueryKey(RI_QueryKey *key,
               const RI_ConstraintInfo *riinfo,
               int32 constr_queryno);
static bool ri_KeysEqual(Relation rel, TupleTableSlot *oldslot, TupleTableSlot *newslot,
             const RI_ConstraintInfo *riinfo, bool rel_is_pk);
static bool ri_CompareWithCast(Oid eq_opr, Oid typeid, Oid collid,
                 Datum lhs, Datum rhs);

static void ri_InitHashTables(void);
static void InvalidateConstraintCacheCallBack(Datum arg, int cacheid, uint32 hashvalue);
static SPIPlanPtr ri_FetchPreparedPlan(RI_QueryKey *key);
static void ri_HashPreparedPlan(RI_QueryKey *key, SPIPlanPtr plan);
static RI_CompareHashEntry *ri_HashCompareOp(Oid eq_opr, Oid typeid);

static void ri_CheckTrigger(FunctionCallInfo fcinfo, const char *funcname,
              int tgkind);
static const RI_ConstraintInfo *ri_FetchConstraintInfo(Trigger *trigger,
                             Relation trig_rel, bool rel_is_pk);
static const RI_ConstraintInfo *ri_LoadConstraintInfo(Oid constraintOid);
static Oid  get_ri_constraint_root(Oid constrOid);
static SPIPlanPtr ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes,
                 RI_QueryKey *qkey, Relation fk_rel, Relation pk_rel);
static bool ri_PerformCheck(const RI_ConstraintInfo *riinfo,
              RI_QueryKey *qkey, SPIPlanPtr qplan,
              Relation fk_rel, Relation pk_rel,
              TupleTableSlot *oldslot, TupleTableSlot *newslot,
              bool is_restrict,
              bool detectNewRows, int expect_OK);
static void ri_ExtractValues(Relation rel, TupleTableSlot *slot,
               const RI_ConstraintInfo *riinfo, bool rel_is_pk,
               Datum *vals, char *nulls);
pg_noreturn static void ri_ReportViolation(const RI_ConstraintInfo *riinfo,
                       Relation pk_rel, Relation fk_rel,
                       TupleTableSlot *violatorslot, TupleDesc tupdesc,
                       int queryno, bool is_restrict, bool partgone);


/*
 * RI_FKey_check -
 *
 * Check foreign key existence (combined for INSERT and UPDATE).
 */
static Datum
RI_FKey_check(TriggerData *trigdata)
{
  const RI_ConstraintInfo *riinfo;
  Relation  fk_rel;
  Relation  pk_rel;
  TupleTableSlot *newslot;
  RI_QueryKey qkey;
  SPIPlanPtr  qplan;

  riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
                  trigdata->tg_relation, false);

  if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
    newslot = trigdata->tg_newslot;
  else
    newslot = trigdata->tg_trigslot;

  /*
   * We should not even consider checking the row if it is no longer valid,
   * since it was either deleted (so the deferred check should be skipped)
   * or updated (in which case only the latest version of the row should be
   * checked).  Test its liveness according to SnapshotSelf.  We need pin
   * and lock on the buffer to call HeapTupleSatisfiesVisibility.  Caller
   * should be holding pin, but not lock.
   */
  if (!table_tuple_satisfies_snapshot(trigdata->tg_relation, newslot, SnapshotSelf))
    return PointerGetDatum(NULL);

  /*
   * Get the relation descriptors of the FK and PK tables.
   *
   * pk_rel is opened in RowShareLock mode since that's what our eventual
   * SELECT FOR KEY SHARE will get on it.
   */
  fk_rel = trigdata->tg_relation;
  pk_rel = table_open(riinfo->pk_relid, RowShareLock);

  switch (ri_NullCheck(RelationGetDescr(fk_rel), newslot, riinfo, false))
  {
    case RI_KEYS_ALL_NULL:

      /*
       * No further check needed - an all-NULL key passes every type of
       * foreign key constraint.
       */
      table_close(pk_rel, RowShareLock);
      return PointerGetDatum(NULL);

    case RI_KEYS_SOME_NULL:

      /*
       * This is the only case that differs between the three kinds of
       * MATCH.
       */
      switch (riinfo->confmatchtype)
      {
        case FKCONSTR_MATCH_FULL:

          /*
           * Not allowed - MATCH FULL says either all or none of the
           * attributes can be NULLs
           */
          ereport(ERROR,
              (errcode(ERRCODE_FOREIGN_KEY_VIOLATION),
               errmsg("insert or update on table \"%s\" violates foreign key constraint \"%s\"",
                  RelationGetRelationName(fk_rel),
                  NameStr(riinfo->conname)),
               errdetail("MATCH FULL does not allow mixing of null and nonnull key values."),
               errtableconstraint(fk_rel,
                        NameStr(riinfo->conname))));
          table_close(pk_rel, RowShareLock);
          return PointerGetDatum(NULL);

        case FKCONSTR_MATCH_SIMPLE:

          /*
           * MATCH SIMPLE - if ANY column is null, the key passes
           * the constraint.
           */
          table_close(pk_rel, RowShareLock);
          return PointerGetDatum(NULL);

#ifdef NOT_USED
        case FKCONSTR_MATCH_PARTIAL:

          /*
           * MATCH PARTIAL - all non-null columns must match. (not
           * implemented, can be done by modifying the query below
           * to only include non-null columns, or by writing a
           * special version here)
           */
          break;
#endif
      }

    case RI_KEYS_NONE_NULL:

      /*
       * Have a full qualified key - continue below for all three kinds
       * of MATCH.
       */
      break;
  }

  SPI_connect();

  /* Fetch or prepare a saved plan for the real check */
  ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_CHECK_LOOKUPPK);

  if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
  {
    StringInfoData querybuf;
    char    pkrelname[MAX_QUOTED_REL_NAME_LEN];
    char    attname[MAX_QUOTED_NAME_LEN];
    char    paramname[16];
    const char *querysep;
    Oid     queryoids[RI_MAX_NUMKEYS];
    const char *pk_only;

    /* ----------
     * The query string built is
     *  SELECT 1 FROM [ONLY] <pktable> x WHERE pkatt1 = $1 [AND ...]
     *       FOR KEY SHARE OF x
     * The type id's for the $ parameters are those of the
     * corresponding FK attributes.
     *
     * But for temporal FKs we need to make sure
     * the FK's range is completely covered.
     * So we use this query instead:
     *  SELECT 1
     *  FROM  (
     *    SELECT pkperiodatt AS r
     *    FROM   [ONLY] pktable x
     *    WHERE  pkatt1 = $1 [AND ...]
     *    AND    pkperiodatt && $n
     *    FOR KEY SHARE OF x
     *  ) x1
     *  HAVING $n <@ range_agg(x1.r)
     * Note if FOR KEY SHARE ever allows GROUP BY and HAVING
     * we can make this a bit simpler.
     * ----------
     */
    initStringInfo(&querybuf);
    pk_only = pk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
      "" : "ONLY ";
    quoteRelationName(pkrelname, pk_rel);
    if (riinfo->hasperiod)
    {
      quoteOneName(attname,
             RIAttName(pk_rel, riinfo->pk_attnums[riinfo->nkeys - 1]));

      appendStringInfo(&querybuf,
               "SELECT 1 FROM (SELECT %s AS r FROM %s%s x",
               attname, pk_only, pkrelname);
    }
    else
    {
      appendStringInfo(&querybuf, "SELECT 1 FROM %s%s x",
               pk_only, pkrelname);
    }
    querysep = "WHERE";
    for (int i = 0; i < riinfo->nkeys; i++)
    {
      Oid     pk_type = RIAttType(pk_rel, riinfo->pk_attnums[i]);
      Oid     fk_type = RIAttType(fk_rel, riinfo->fk_attnums[i]);

      quoteOneName(attname,
             RIAttName(pk_rel, riinfo->pk_attnums[i]));
      sprintf(paramname, "$%d", i + 1);
      ri_GenerateQual(&querybuf, querysep,
              attname, pk_type,
              riinfo->pf_eq_oprs[i],
              paramname, fk_type);
      querysep = "AND";
      queryoids[i] = fk_type;
    }
    appendStringInfoString(&querybuf, " FOR KEY SHARE OF x");
    if (riinfo->hasperiod)
    {
      Oid     fk_type = RIAttType(fk_rel, riinfo->fk_attnums[riinfo->nkeys - 1]);

      appendStringInfoString(&querybuf, ") x1 HAVING ");
      sprintf(paramname, "$%d", riinfo->nkeys);
      ri_GenerateQual(&querybuf, "",
              paramname, fk_type,
              riinfo->agged_period_contained_by_oper,
              "pg_catalog.range_agg", ANYMULTIRANGEOID);
      appendStringInfoString(&querybuf, "(x1.r)");
    }

    /* Prepare and save the plan */
    qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
               &qkey, fk_rel, pk_rel);
  }

  /*
   * Now check that foreign key exists in PK table
   *
   * XXX detectNewRows must be true when a partitioned table is on the
   * referenced side.  The reason is that our snapshot must be fresh in
   * order for the hack in find_inheritance_children() to work.
   */
  ri_PerformCheck(riinfo, &qkey, qplan,
          fk_rel, pk_rel,
          NULL, newslot,
          false,
          pk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE,
          SPI_OK_SELECT);

  if (SPI_finish() != SPI_OK_FINISH)
    elog(ERROR, "SPI_finish failed");

  table_close(pk_rel, RowShareLock);

  return PointerGetDatum(NULL);
}


/*
 * RI_FKey_check_ins -
 *
 * Check foreign key existence at insert event on FK table.
 */
Datum
RI_FKey_check_ins(PG_FUNCTION_ARGS)
{
  /* Check that this is a valid trigger call on the right time and event. */
  ri_CheckTrigger(fcinfo, "RI_FKey_check_ins", RI_TRIGTYPE_INSERT);

  /* Share code with UPDATE case. */
  return RI_FKey_check((TriggerData *) fcinfo->context);
}


/*
 * RI_FKey_check_upd -
 *
 * Check foreign key existence at update event on FK table.
 */
Datum
RI_FKey_check_upd(PG_FUNCTION_ARGS)
{
  /* Check that this is a valid trigger call on the right time and event. */
  ri_CheckTrigger(fcinfo, "RI_FKey_check_upd", RI_TRIGTYPE_UPDATE);

  /* Share code with INSERT case. */
  return RI_FKey_check((TriggerData *) fcinfo->context);
}


/*
 * ri_Check_Pk_Match
 *
 * Check to see if another PK row has been created that provides the same
 * key values as the "oldslot" that's been modified or deleted in our trigger
 * event.  Returns true if a match is found in the PK table.
 *
 * We assume the caller checked that the oldslot contains no NULL key values,
 * since otherwise a match is impossible.
 */
static bool
ri_Check_Pk_Match(Relation pk_rel, Relation fk_rel,
          TupleTableSlot *oldslot,
          const RI_ConstraintInfo *riinfo)
{
  SPIPlanPtr  qplan;
  RI_QueryKey qkey;
  bool    result;

  /* Only called for non-null rows */
  Assert(ri_NullCheck(RelationGetDescr(pk_rel), oldslot, riinfo, true) == RI_KEYS_NONE_NULL);

  SPI_connect();

  /*
   * Fetch or prepare a saved plan for checking PK table with values coming
   * from a PK row
   */
  ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_CHECK_LOOKUPPK_FROM_PK);

  if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
  {
    StringInfoData querybuf;
    char    pkrelname[MAX_QUOTED_REL_NAME_LEN];
    char    attname[MAX_QUOTED_NAME_LEN];
    char    paramname[16];
    const char *querysep;
    const char *pk_only;
    Oid     queryoids[RI_MAX_NUMKEYS];

    /* ----------
     * The query string built is
     *  SELECT 1 FROM [ONLY] <pktable> x WHERE pkatt1 = $1 [AND ...]
     *       FOR KEY SHARE OF x
     * The type id's for the $ parameters are those of the
     * PK attributes themselves.
     *
     * But for temporal FKs we need to make sure
     * the old PK's range is completely covered.
     * So we use this query instead:
     *  SELECT 1
     *  FROM    (
     *    SELECT pkperiodatt AS r
     *    FROM   [ONLY] pktable x
     *    WHERE  pkatt1 = $1 [AND ...]
     *    AND    pkperiodatt && $n
     *    FOR KEY SHARE OF x
     *  ) x1
     *  HAVING $n <@ range_agg(x1.r)
     * Note if FOR KEY SHARE ever allows GROUP BY and HAVING
     * we can make this a bit simpler.
     * ----------
     */
    initStringInfo(&querybuf);
    pk_only = pk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
      "" : "ONLY ";
    quoteRelationName(pkrelname, pk_rel);
    if (riinfo->hasperiod)
    {
      quoteOneName(attname, RIAttName(pk_rel, riinfo->pk_attnums[riinfo->nkeys - 1]));

      appendStringInfo(&querybuf,
               "SELECT 1 FROM (SELECT %s AS r FROM %s%s x",
               attname, pk_only, pkrelname);
    }
    else
    {
      appendStringInfo(&querybuf, "SELECT 1 FROM %s%s x",
               pk_only, pkrelname);
    }
    querysep = "WHERE";
    for (int i = 0; i < riinfo->nkeys; i++)
    {
      Oid     pk_type = RIAttType(pk_rel, riinfo->pk_attnums[i]);

      quoteOneName(attname,
             RIAttName(pk_rel, riinfo->pk_attnums[i]));
      sprintf(paramname, "$%d", i + 1);
      ri_GenerateQual(&querybuf, querysep,
              attname, pk_type,
              riinfo->pp_eq_oprs[i],
              paramname, pk_type);
      querysep = "AND";
      queryoids[i] = pk_type;
    }
    appendStringInfoString(&querybuf, " FOR KEY SHARE OF x");
    if (riinfo->hasperiod)
    {
      Oid     fk_type = RIAttType(fk_rel, riinfo->fk_attnums[riinfo->nkeys - 1]);

      appendStringInfoString(&querybuf, ") x1 HAVING ");
      sprintf(paramname, "$%d", riinfo->nkeys);
      ri_GenerateQual(&querybuf, "",
              paramname, fk_type,
              riinfo->agged_period_contained_by_oper,
              "pg_catalog.range_agg", ANYMULTIRANGEOID);
      appendStringInfoString(&querybuf, "(x1.r)");
    }

    /* Prepare and save the plan */
    qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
               &qkey, fk_rel, pk_rel);
  }

  /*
   * We have a plan now. Run it.
   */
  result = ri_PerformCheck(riinfo, &qkey, qplan,
               fk_rel, pk_rel,
               oldslot, NULL,
               false,
               true, /* treat like update */
               SPI_OK_SELECT);

  if (SPI_finish() != SPI_OK_FINISH)
    elog(ERROR, "SPI_finish failed");

  return result;
}


/*
 * RI_FKey_noaction_del -
 *
 * Give an error and roll back the current transaction if the
 * delete has resulted in a violation of the given referential
 * integrity constraint.
 */
Datum
RI_FKey_noaction_del(PG_FUNCTION_ARGS)
{
  /* Check that this is a valid trigger call on the right time and event. */
  ri_CheckTrigger(fcinfo, "RI_FKey_noaction_del", RI_TRIGTYPE_DELETE);

  /* Share code with RESTRICT/UPDATE cases. */
  return ri_restrict((TriggerData *) fcinfo->context, true);
}

/*
 * RI_FKey_restrict_del -
 *
 * Restrict delete from PK table to rows unreferenced by foreign key.
 *
 * The SQL standard intends that this referential action occur exactly when
 * the delete is performed, rather than after.  This appears to be
 * the only difference between "NO ACTION" and "RESTRICT".  In Postgres
 * we still implement this as an AFTER trigger, but it's non-deferrable.
 */
Datum
RI_FKey_restrict_del(PG_FUNCTION_ARGS)
{
  /* Check that this is a valid trigger call on the right time and event. */
  ri_CheckTrigger(fcinfo, "RI_FKey_restrict_del", RI_TRIGTYPE_DELETE);

  /* Share code with NO ACTION/UPDATE cases. */
  return ri_restrict((TriggerData *) fcinfo->context, false);
}

/*
 * RI_FKey_noaction_upd -
 *
 * Give an error and roll back the current transaction if the
 * update has resulted in a violation of the given referential
 * integrity constraint.
 */
Datum
RI_FKey_noaction_upd(PG_FUNCTION_ARGS)
{
  /* Check that this is a valid trigger call on the right time and event. */
  ri_CheckTrigger(fcinfo, "RI_FKey_noaction_upd", RI_TRIGTYPE_UPDATE);

  /* Share code with RESTRICT/DELETE cases. */
  return ri_restrict((TriggerData *) fcinfo->context, true);
}

/*
 * RI_FKey_restrict_upd -
 *
 * Restrict update of PK to rows unreferenced by foreign key.
 *
 * The SQL standard intends that this referential action occur exactly when
 * the update is performed, rather than after.  This appears to be
 * the only difference between "NO ACTION" and "RESTRICT".  In Postgres
 * we still implement this as an AFTER trigger, but it's non-deferrable.
 */
Datum
RI_FKey_restrict_upd(PG_FUNCTION_ARGS)
{
  /* Check that this is a valid trigger call on the right time and event. */
  ri_CheckTrigger(fcinfo, "RI_FKey_restrict_upd", RI_TRIGTYPE_UPDATE);

  /* Share code with NO ACTION/DELETE cases. */
  return ri_restrict((TriggerData *) fcinfo->context, false);
}

/*
 * ri_restrict -
 *
 * Common code for ON DELETE RESTRICT, ON DELETE NO ACTION,
 * ON UPDATE RESTRICT, and ON UPDATE NO ACTION.
 */
static Datum
ri_restrict(TriggerData *trigdata, bool is_no_action)
{
  const RI_ConstraintInfo *riinfo;
  Relation  fk_rel;
  Relation  pk_rel;
  TupleTableSlot *oldslot;
  RI_QueryKey qkey;
  SPIPlanPtr  qplan;

  riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
                  trigdata->tg_relation, true);

  /*
   * Get the relation descriptors of the FK and PK tables and the old tuple.
   *
   * fk_rel is opened in RowShareLock mode since that's what our eventual
   * SELECT FOR KEY SHARE will get on it.
   */
  fk_rel = table_open(riinfo->fk_relid, RowShareLock);
  pk_rel = trigdata->tg_relation;
  oldslot = trigdata->tg_trigslot;

  /*
   * If another PK row now exists providing the old key values, we should
   * not do anything.  However, this check should only be made in the NO
   * ACTION case; in RESTRICT cases we don't wish to allow another row to be
   * substituted.
   *
   * If the foreign key has PERIOD, we incorporate looking for replacement
   * rows in the main SQL query below, so we needn't do it here.
   */
  if (is_no_action && !riinfo->hasperiod &&
    ri_Check_Pk_Match(pk_rel, fk_rel, oldslot, riinfo))
  {
    table_close(fk_rel, RowShareLock);
    return PointerGetDatum(NULL);
  }

  SPI_connect();

  /*
   * Fetch or prepare a saved plan for the restrict lookup (it's the same
   * query for delete and update cases)
   */
  ri_BuildQueryKey(&qkey, riinfo, is_no_action ? RI_PLAN_NO_ACTION : RI_PLAN_RESTRICT);

  if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
  {
    StringInfoData querybuf;
    char    pkrelname[MAX_QUOTED_REL_NAME_LEN];
    char    fkrelname[MAX_QUOTED_REL_NAME_LEN];
    char    attname[MAX_QUOTED_NAME_LEN];
    char    periodattname[MAX_QUOTED_NAME_LEN];
    char    paramname[16];
    const char *querysep;
    Oid     queryoids[RI_MAX_NUMKEYS];
    const char *fk_only;

    /* ----------
     * The query string built is
     *  SELECT 1 FROM [ONLY] <fktable> x WHERE $1 = fkatt1 [AND ...]
     *       FOR KEY SHARE OF x
     * The type id's for the $ parameters are those of the
     * corresponding PK attributes.
     * ----------
     */
    initStringInfo(&querybuf);
    fk_only = fk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
      "" : "ONLY ";
    quoteRelationName(fkrelname, fk_rel);
    appendStringInfo(&querybuf, "SELECT 1 FROM %s%s x",
             fk_only, fkrelname);
    querysep = "WHERE";
    for (int i = 0; i < riinfo->nkeys; i++)
    {
      Oid     pk_type = RIAttType(pk_rel, riinfo->pk_attnums[i]);
      Oid     fk_type = RIAttType(fk_rel, riinfo->fk_attnums[i]);

      quoteOneName(attname,
             RIAttName(fk_rel, riinfo->fk_attnums[i]));
      sprintf(paramname, "$%d", i + 1);
      ri_GenerateQual(&querybuf, querysep,
              paramname, pk_type,
              riinfo->pf_eq_oprs[i],
              attname, fk_type);
      querysep = "AND";
      queryoids[i] = pk_type;
    }

    /*----------
     * For temporal foreign keys, a reference could still be valid if the
     * referenced range didn't change too much.  Also if a referencing
     * range extends past the current PK row, we don't want to check that
     * part: some other PK row should fulfill it.  We only want to check
     * the part matching the PK record we've changed.  Therefore to find
     * invalid records we do this:
     *
     * SELECT 1 FROM [ONLY] <fktable> x WHERE $1 = x.fkatt1 [AND ...]
     * -- begin temporal
     * AND $n && x.fkperiod
     * AND NOT coalesce((x.fkperiod * $n) <@
     *  (SELECT range_agg(r)
     *   FROM (SELECT y.pkperiod r
     *         FROM [ONLY] <pktable> y
     *         WHERE $1 = y.pkatt1 [AND ...] AND $n && y.pkperiod
     *         FOR KEY SHARE OF y) y2), false)
     * -- end temporal
     * FOR KEY SHARE OF x
     *
     * We need the coalesce in case the first subquery returns no rows.
     * We need the second subquery because FOR KEY SHARE doesn't support
     * aggregate queries.
     */
    if (riinfo->hasperiod && is_no_action)
    {
      Oid     pk_period_type = RIAttType(pk_rel, riinfo->pk_attnums[riinfo->nkeys - 1]);
      Oid     fk_period_type = RIAttType(fk_rel, riinfo->fk_attnums[riinfo->nkeys - 1]);
      StringInfoData intersectbuf;
      StringInfoData replacementsbuf;
      char     *pk_only = pk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
        "" : "ONLY ";

      quoteOneName(attname, RIAttName(fk_rel, riinfo->fk_attnums[riinfo->nkeys - 1]));
      sprintf(paramname, "$%d", riinfo->nkeys);

      appendStringInfoString(&querybuf, " AND NOT coalesce(");

      /* Intersect the fk with the old pk range */
      initStringInfo(&intersectbuf);
      appendStringInfoChar(&intersectbuf, '(');
      ri_GenerateQual(&intersectbuf, "",
              attname, fk_period_type,
              riinfo->period_intersect_oper,
              paramname, pk_period_type);
      appendStringInfoChar(&intersectbuf, ')');

      /* Find the remaining history */
      initStringInfo(&replacementsbuf);
      appendStringInfoString(&replacementsbuf, "(SELECT pg_catalog.range_agg(r) FROM ");

      quoteOneName(periodattname, RIAttName(pk_rel, riinfo->pk_attnums[riinfo->nkeys - 1]));
      quoteRelationName(pkrelname, pk_rel);
      appendStringInfo(&replacementsbuf, "(SELECT y.%s r FROM %s%s y",
               periodattname, pk_only, pkrelname);

      /* Restrict pk rows to what matches */
      querysep = "WHERE";
      for (int i = 0; i < riinfo->nkeys; i++)
      {
        Oid     pk_type = RIAttType(pk_rel, riinfo->pk_attnums[i]);

        quoteOneName(attname,
               RIAttName(pk_rel, riinfo->pk_attnums[i]));
        sprintf(paramname, "$%d", i + 1);
        ri_GenerateQual(&replacementsbuf, querysep,
                paramname, pk_type,
                riinfo->pp_eq_oprs[i],
                attname, pk_type);
        querysep = "AND";
        queryoids[i] = pk_type;
      }
      appendStringInfoString(&replacementsbuf, " FOR KEY SHARE OF y) y2)");

      ri_GenerateQual(&querybuf, "",
              intersectbuf.data, fk_period_type,
              riinfo->agged_period_contained_by_oper,
              replacementsbuf.data, ANYMULTIRANGEOID);
      /* end of coalesce: */
      appendStringInfoString(&querybuf, ", false)");
    }

    appendStringInfoString(&querybuf, " FOR KEY SHARE OF x");

    /* Prepare and save the plan */
    qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
               &qkey, fk_rel, pk_rel);
  }

  /*
   * We have a plan now. Run it to check for existing references.
   */
  ri_PerformCheck(riinfo, &qkey, qplan,
          fk_rel, pk_rel,
          oldslot, NULL,
          !is_no_action,
          true,   /* must detect new rows */
          SPI_OK_SELECT);

  if (SPI_finish() != SPI_OK_FINISH)
    elog(ERROR, "SPI_finish failed");

  table_close(fk_rel, RowShareLock);

  return PointerGetDatum(NULL);
}


/*
 * RI_FKey_cascade_del -
 *
 * Cascaded delete foreign key references at delete event on PK table.
 */
Datum
RI_FKey_cascade_del(PG_FUNCTION_ARGS)
{
  TriggerData *trigdata = (TriggerData *) fcinfo->context;
  const RI_ConstraintInfo *riinfo;
  Relation  fk_rel;
  Relation  pk_rel;
  TupleTableSlot *oldslot;
  RI_QueryKey qkey;
  SPIPlanPtr  qplan;

  /* Check that this is a valid trigger call on the right time and event. */
  ri_CheckTrigger(fcinfo, "RI_FKey_cascade_del", RI_TRIGTYPE_DELETE);

  riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
                  trigdata->tg_relation, true);

  /*
   * Get the relation descriptors of the FK and PK tables and the old tuple.
   *
   * fk_rel is opened in RowExclusiveLock mode since that's what our
   * eventual DELETE will get on it.
   */
  fk_rel = table_open(riinfo->fk_relid, RowExclusiveLock);
  pk_rel = trigdata->tg_relation;
  oldslot = trigdata->tg_trigslot;

  SPI_connect();

  /* Fetch or prepare a saved plan for the cascaded delete */
  ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_CASCADE_ONDELETE);

  if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
  {
    StringInfoData querybuf;
    char    fkrelname[MAX_QUOTED_REL_NAME_LEN];
    char    attname[MAX_QUOTED_NAME_LEN];
    char    paramname[16];
    const char *querysep;
    Oid     queryoids[RI_MAX_NUMKEYS];
    const char *fk_only;

    /* ----------
     * The query string built is
     *  DELETE FROM [ONLY] <fktable> WHERE $1 = fkatt1 [AND ...]
     * The type id's for the $ parameters are those of the
     * corresponding PK attributes.
     * ----------
     */
    initStringInfo(&querybuf);
    fk_only = fk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
      "" : "ONLY ";
    quoteRelationName(fkrelname, fk_rel);
    appendStringInfo(&querybuf, "DELETE FROM %s%s",
             fk_only, fkrelname);
    querysep = "WHERE";
    for (int i = 0; i < riinfo->nkeys; i++)
    {
      Oid     pk_type = RIAttType(pk_rel, riinfo->pk_attnums[i]);
      Oid     fk_type = RIAttType(fk_rel, riinfo->fk_attnums[i]);

      quoteOneName(attname,
             RIAttName(fk_rel, riinfo->fk_attnums[i]));
      sprintf(paramname, "$%d", i + 1);
      ri_GenerateQual(&querybuf, querysep,
              paramname, pk_type,
              riinfo->pf_eq_oprs[i],
              attname, fk_type);
      querysep = "AND";
      queryoids[i] = pk_type;
    }

    /* Prepare and save the plan */
    qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
               &qkey, fk_rel, pk_rel);
  }

  /*
   * We have a plan now. Build up the arguments from the key values in the
   * deleted PK tuple and delete the referencing rows
   */
  ri_PerformCheck(riinfo, &qkey, qplan,
          fk_rel, pk_rel,
          oldslot, NULL,
          false,
          true,   /* must detect new rows */
          SPI_OK_DELETE);

  if (SPI_finish() != SPI_OK_FINISH)
    elog(ERROR, "SPI_finish failed");

  table_close(fk_rel, RowExclusiveLock);

  return PointerGetDatum(NULL);
}


/*
 * RI_FKey_cascade_upd -
 *
 * Cascaded update foreign key references at update event on PK table.
 */
Datum
RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
{
  TriggerData *trigdata = (TriggerData *) fcinfo->context;
  const RI_ConstraintInfo *riinfo;
  Relation  fk_rel;
  Relation  pk_rel;
  TupleTableSlot *newslot;
  TupleTableSlot *oldslot;
  RI_QueryKey qkey;
  SPIPlanPtr  qplan;

  /* Check that this is a valid trigger call on the right time and event. */
  ri_CheckTrigger(fcinfo, "RI_FKey_cascade_upd", RI_TRIGTYPE_UPDATE);

  riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
                  trigdata->tg_relation, true);

  /*
   * Get the relation descriptors of the FK and PK tables and the new and
   * old tuple.
   *
   * fk_rel is opened in RowExclusiveLock mode since that's what our
   * eventual UPDATE will get on it.
   */
  fk_rel = table_open(riinfo->fk_relid, RowExclusiveLock);
  pk_rel = trigdata->tg_relation;
  newslot = trigdata->tg_newslot;
  oldslot = trigdata->tg_trigslot;

  SPI_connect();

  /* Fetch or prepare a saved plan for the cascaded update */
  ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_CASCADE_ONUPDATE);

  if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
  {
    StringInfoData querybuf;
    StringInfoData qualbuf;
    char    fkrelname[MAX_QUOTED_REL_NAME_LEN];
    char    attname[MAX_QUOTED_NAME_LEN];
    char    paramname[16];
    const char *querysep;
    const char *qualsep;
    Oid     queryoids[RI_MAX_NUMKEYS * 2];
    const char *fk_only;

    /* ----------
     * The query string built is
     *  UPDATE [ONLY] <fktable> SET fkatt1 = $1 [, ...]
     *      WHERE $n = fkatt1 [AND ...]
     * The type id's for the $ parameters are those of the
     * corresponding PK attributes.  Note that we are assuming
     * there is an assignment cast from the PK to the FK type;
     * else the parser will fail.
     * ----------
     */
    initStringInfo(&querybuf);
    initStringInfo(&qualbuf);
    fk_only = fk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
      "" : "ONLY ";
    quoteRelationName(fkrelname, fk_rel);
    appendStringInfo(&querybuf, "UPDATE %s%s SET",
             fk_only, fkrelname);
    querysep = "";
    qualsep = "WHERE";
    for (int i = 0, j = riinfo->nkeys; i < riinfo->nkeys; i++, j++)
    {
      Oid     pk_type = RIAttType(pk_rel, riinfo->pk_attnums[i]);
      Oid     fk_type = RIAttType(fk_rel, riinfo->fk_attnums[i]);

      quoteOneName(attname,
             RIAttName(fk_rel, riinfo->fk_attnums[i]));
      appendStringInfo(&querybuf,
               "%s %s = $%d",
               querysep, attname, i + 1);
      sprintf(paramname, "$%d", j + 1);
      ri_GenerateQual(&qualbuf, qualsep,
              paramname, pk_type,
              riinfo->pf_eq_oprs[i],
              attname, fk_type);
      querysep = ",";
      qualsep = "AND";
      queryoids[i] = pk_type;
      queryoids[j] = pk_type;
    }
    appendBinaryStringInfo(&querybuf, qualbuf.data, qualbuf.len);

    /* Prepare and save the plan */
    qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys * 2, queryoids,
               &qkey, fk_rel, pk_rel);
  }

  /*
   * We have a plan now. Run it to update the existing references.
   */
  ri_PerformCheck(riinfo, &qkey, qplan,
          fk_rel, pk_rel,
          oldslot, newslot,
          false,
          true,   /* must detect new rows */
          SPI_OK_UPDATE);

  if (SPI_finish() != SPI_OK_FINISH)
    elog(ERROR, "SPI_finish failed");

  table_close(fk_rel, RowExclusiveLock);

  return PointerGetDatum(NULL);
}


/*
 * RI_FKey_setnull_del -
 *
 * Set foreign key references to NULL values at delete event on PK table.
 */
Datum
RI_FKey_setnull_del(PG_FUNCTION_ARGS)
{
  /* Check that this is a valid trigger call on the right time and event. */
  ri_CheckTrigger(fcinfo, "RI_FKey_setnull_del", RI_TRIGTYPE_DELETE);

  /* Share code with UPDATE case */
  return ri_set((TriggerData *) fcinfo->context, true, RI_TRIGTYPE_DELETE);
}

/*
 * RI_FKey_setnull_upd -
 *
 * Set foreign key references to NULL at update event on PK table.
 */
Datum
RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
{
  /* Check that this is a valid trigger call on the right time and event. */
  ri_CheckTrigger(fcinfo, "RI_FKey_setnull_upd", RI_TRIGTYPE_UPDATE);

  /* Share code with DELETE case */
  return ri_set((TriggerData *) fcinfo->context, true, RI_TRIGTYPE_UPDATE);
}

/*
 * RI_FKey_setdefault_del -
 *
 * Set foreign key references to defaults at delete event on PK table.
 */
Datum
RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
{
  /* Check that this is a valid trigger call on the right time and event. */
  ri_CheckTrigger(fcinfo, "RI_FKey_setdefault_del", RI_TRIGTYPE_DELETE);

  /* Share code with UPDATE case */
  return ri_set((TriggerData *) fcinfo->context, false, RI_TRIGTYPE_DELETE);
}

/*
 * RI_FKey_setdefault_upd -
 *
 * Set foreign key references to defaults at update event on PK table.
 */
Datum
RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
{
  /* Check that this is a valid trigger call on the right time and event. */
  ri_CheckTrigger(fcinfo, "RI_FKey_setdefault_upd", RI_TRIGTYPE_UPDATE);

  /* Share code with DELETE case */
  return ri_set((TriggerData *) fcinfo->context, false, RI_TRIGTYPE_UPDATE);
}

/*
 * ri_set -
 *
 * Common code for ON DELETE SET NULL, ON DELETE SET DEFAULT, ON UPDATE SET
 * NULL, and ON UPDATE SET DEFAULT.
 */
static Datum
ri_set(TriggerData *trigdata, bool is_set_null, int tgkind)
{
  const RI_ConstraintInfo *riinfo;
  Relation  fk_rel;
  Relation  pk_rel;
  TupleTableSlot *oldslot;
  RI_QueryKey qkey;
  SPIPlanPtr  qplan;
  int32   queryno;

  riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
                  trigdata->tg_relation, true);

  /*
   * Get the relation descriptors of the FK and PK tables and the old tuple.
   *
   * fk_rel is opened in RowExclusiveLock mode since that's what our
   * eventual UPDATE will get on it.
   */
  fk_rel = table_open(riinfo->fk_relid, RowExclusiveLock);
  pk_rel = trigdata->tg_relation;
  oldslot = trigdata->tg_trigslot;

  SPI_connect();

  /*
   * Fetch or prepare a saved plan for the trigger.
   */
  switch (tgkind)
  {
    case RI_TRIGTYPE_UPDATE:
      queryno = is_set_null
        ? RI_PLAN_SETNULL_ONUPDATE
        : RI_PLAN_SETDEFAULT_ONUPDATE;
      break;
    case RI_TRIGTYPE_DELETE:
      queryno = is_set_null
        ? RI_PLAN_SETNULL_ONDELETE
        : RI_PLAN_SETDEFAULT_ONDELETE;
      break;
    default:
      elog(ERROR, "invalid tgkind passed to ri_set");
  }

  ri_BuildQueryKey(&qkey, riinfo, queryno);

  if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
  {
    StringInfoData querybuf;
    char    fkrelname[MAX_QUOTED_REL_NAME_LEN];
    char    attname[MAX_QUOTED_NAME_LEN];
    char    paramname[16];
    const char *querysep;
    const char *qualsep;
    Oid     queryoids[RI_MAX_NUMKEYS];
    const char *fk_only;
    int     num_cols_to_set;
    const int16 *set_cols;

    switch (tgkind)
    {
      case RI_TRIGTYPE_UPDATE:
        num_cols_to_set = riinfo->nkeys;
        set_cols = riinfo->fk_attnums;
        break;
      case RI_TRIGTYPE_DELETE:

        /*
         * If confdelsetcols are present, then we only update the
         * columns specified in that array, otherwise we update all
         * the referencing columns.
         */
        if (riinfo->ndelsetcols != 0)
        {
          num_cols_to_set = riinfo->ndelsetcols;
          set_cols = riinfo->confdelsetcols;
        }
        else
        {
          num_cols_to_set = riinfo->nkeys;
          set_cols = riinfo->fk_attnums;
        }
        break;
      default:
        elog(ERROR, "invalid tgkind passed to ri_set");
    }

    /* ----------
     * The query string built is
     *  UPDATE [ONLY] <fktable> SET fkatt1 = {NULL|DEFAULT} [, ...]
     *      WHERE $1 = fkatt1 [AND ...]
     * The type id's for the $ parameters are those of the
     * corresponding PK attributes.
     * ----------
     */
    initStringInfo(&querybuf);
    fk_only = fk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
      "" : "ONLY ";
    quoteRelationName(fkrelname, fk_rel);
    appendStringInfo(&querybuf, "UPDATE %s%s SET",
             fk_only, fkrelname);

    /*
     * Add assignment clauses
     */
    querysep = "";
    for (int i = 0; i < num_cols_to_set; i++)
    {
      quoteOneName(attname, RIAttName(fk_rel, set_cols[i]));
      appendStringInfo(&querybuf,
               "%s %s = %s",
               querysep, attname,
               is_set_null ? "NULL" : "DEFAULT");
      querysep = ",";
    }

    /*
     * Add WHERE clause
     */
    qualsep = "WHERE";
    for (int i = 0; i < riinfo->nkeys; i++)
    {
      Oid     pk_type = RIAttType(pk_rel, riinfo->pk_attnums[i]);
      Oid     fk_type = RIAttType(fk_rel, riinfo->fk_attnums[i]);

      quoteOneName(attname,
             RIAttName(fk_rel, riinfo->fk_attnums[i]));

      sprintf(paramname, "$%d", i + 1);
      ri_GenerateQual(&querybuf, qualsep,
              paramname, pk_type,
              riinfo->pf_eq_oprs[i],
              attname, fk_type);
      qualsep = "AND";
      queryoids[i] = pk_type;
    }

    /* Prepare and save the plan */
    qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
               &qkey, fk_rel, pk_rel);
  }

  /*
   * We have a plan now. Run it to update the existing references.
   */
  ri_PerformCheck(riinfo, &qkey, qplan,
          fk_rel, pk_rel,
          oldslot, NULL,
          false,
          true,   /* must detect new rows */
          SPI_OK_UPDATE);

  if (SPI_finish() != SPI_OK_FINISH)
    elog(ERROR, "SPI_finish failed");

  table_close(fk_rel, RowExclusiveLock);

  if (is_set_null)
    return PointerGetDatum(NULL);
  else
  {
    /*
     * If we just deleted or updated the PK row whose key was equal to the
     * FK columns' default values, and a referencing row exists in the FK
     * table, we would have updated that row to the same values it already
     * had --- and RI_FKey_fk_upd_check_required would hence believe no
     * check is necessary.  So we need to do another lookup now and in
     * case a reference still exists, abort the operation.  That is
     * already implemented in the NO ACTION trigger, so just run it. (This
     * recheck is only needed in the SET DEFAULT case, since CASCADE would
     * remove such rows in case of a DELETE operation or would change the
     * FK key values in case of an UPDATE, while SET NULL is certain to
     * result in rows that satisfy the FK constraint.)
     */
    return ri_restrict(trigdata, true);
  }
}


/*
 * RI_FKey_pk_upd_check_required -
 *
 * Check if we really need to fire the RI trigger for an update or delete to a PK
 * relation.  This is called by the AFTER trigger queue manager to see if
 * it can skip queuing an instance of an RI trigger.  Returns true if the
 * trigger must be fired, false if we can prove the constraint will still
 * be satisfied.
 *
 * newslot will be NULL if this is called for a delete.
 */
bool
RI_FKey_pk_upd_check_required(Trigger *trigger, Relation pk_rel,
                TupleTableSlot *oldslot, TupleTableSlot *newslot)
{
  const RI_ConstraintInfo *riinfo;

  riinfo = ri_FetchConstraintInfo(trigger, pk_rel, true);

  /*
   * If any old key value is NULL, the row could not have been referenced by
   * an FK row, so no check is needed.
   */
  if (ri_NullCheck(RelationGetDescr(pk_rel), oldslot, riinfo, true) != RI_KEYS_NONE_NULL)
    return false;

  /* If all old and new key values are equal, no check is needed */
  if (newslot && ri_KeysEqual(pk_rel, oldslot, newslot, riinfo, true))
    return false;

  /* Else we need to fire the trigger. */
  return true;
}

/*
 * RI_FKey_fk_upd_check_required -
 *
 * Check if we really need to fire the RI trigger for an update to an FK
 * relation.  This is called by the AFTER trigger queue manager to see if
 * it can skip queuing an instance of an RI trigger.  Returns true if the
 * trigger must be fired, false if we can prove the constraint will still
 * be satisfied.
 */
bool
RI_FKey_fk_upd_check_required(Trigger *trigger, Relation fk_rel,
                TupleTableSlot *oldslot, TupleTableSlot *newslot)
{
  const RI_ConstraintInfo *riinfo;
  int     ri_nullcheck;

  /*
   * AfterTriggerSaveEvent() handles things such that this function is never
   * called for partitioned tables.
   */
  Assert(fk_rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE);

  riinfo = ri_FetchConstraintInfo(trigger, fk_rel, false);

  ri_nullcheck = ri_NullCheck(RelationGetDescr(fk_rel), newslot, riinfo, false);

  /*
   * If all new key values are NULL, the row satisfies the constraint, so no
   * check is needed.
   */
  if (ri_nullcheck == RI_KEYS_ALL_NULL)
    return false;

  /*
   * If some new key values are NULL, the behavior depends on the match
   * type.
   */
  else if (ri_nullcheck == RI_KEYS_SOME_NULL)
  {
    switch (riinfo->confmatchtype)
    {
      case FKCONSTR_MATCH_SIMPLE:

        /*
         * If any new key value is NULL, the row must satisfy the
         * constraint, so no check is needed.
         */
        return false;

      case FKCONSTR_MATCH_PARTIAL:

        /*
         * Don't know, must run full check.
         */
        break;

      case FKCONSTR_MATCH_FULL:

        /*
         * If some new key values are NULL, the row fails the
         * constraint.  We must not throw error here, because the row
         * might get invalidated before the constraint is to be
         * checked, but we should queue the event to apply the check
         * later.
         */
        return true;
    }
  }

  /*
   * Continues here for no new key values are NULL, or we couldn't decide
   * yet.
   */

  /*
   * If the original row was inserted by our own transaction, we must fire
   * the trigger whether or not the keys are equal.  This is because our
   * UPDATE will invalidate the INSERT so that the INSERT RI trigger will
   * not do anything; so we had better do the UPDATE check.  (We could skip
   * this if we knew the INSERT trigger already fired, but there is no easy
   * way to know that.)
   */
  if (slot_is_current_xact_tuple(oldslot))
    return true;

  /* If all old and new key values are equal, no check is needed */
  if (ri_KeysEqual(fk_rel, oldslot, newslot, riinfo, false))
    return false;

  /* Else we need to fire the trigger. */
  return true;
}

/*
 * RI_Initial_Check -
 *
 * Check an entire table for non-matching values using a single query.
 * This is not a trigger procedure, but is called during ALTER TABLE
 * ADD FOREIGN KEY to validate the initial table contents.
 *
 * We expect that the caller has made provision to prevent any problems
 * caused by concurrent actions. This could be either by locking rel and
 * pkrel at ShareRowExclusiveLock or higher, or by otherwise ensuring
 * that triggers implementing the checks are already active.
 * Hence, we do not need to lock individual rows for the check.
 *
 * If the check fails because the current user doesn't have permissions
 * to read both tables, return false to let our caller know that they will
 * need to do something else to check the constraint.
 */
bool
RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
{
  const RI_ConstraintInfo *riinfo;
  StringInfoData querybuf;
  char    pkrelname[MAX_QUOTED_REL_NAME_LEN];
  char    fkrelname[MAX_QUOTED_REL_NAME_LEN];
  char    pkattname[MAX_QUOTED_NAME_LEN + 3];
  char    fkattname[MAX_QUOTED_NAME_LEN + 3];
  RangeTblEntry *rte;
  RTEPermissionInfo *pk_perminfo;
  RTEPermissionInfo *fk_perminfo;
  List     *rtes = NIL;
  List     *perminfos = NIL;
  const char *sep;
  const char *fk_only;
  const char *pk_only;
  int     save_nestlevel;
  char    workmembuf[32];
  int     spi_result;
  SPIPlanPtr  qplan;

  riinfo = ri_FetchConstraintInfo(trigger, fk_rel, false);

  /*
   * Check to make sure current user has enough permissions to do the test
   * query.  (If not, caller can fall back to the trigger method, which
   * works because it changes user IDs on the fly.)
   *
   * XXX are there any other show-stopper conditions to check?
   */
  pk_perminfo = makeNode(RTEPermissionInfo);
  pk_perminfo->relid = RelationGetRelid(pk_rel);
  pk_perminfo->requiredPerms = ACL_SELECT;
  perminfos = lappend(perminfos, pk_perminfo);
  rte = makeNode(RangeTblEntry);
  rte->rtekind = RTE_RELATION;
  rte->relid = RelationGetRelid(pk_rel);
  rte->relkind = pk_rel->rd_rel->relkind;
  rte->rellockmode = AccessShareLock;
  rte->perminfoindex = list_length(perminfos);
  rtes = lappend(rtes, rte);

  fk_perminfo = makeNode(RTEPermissionInfo);
  fk_perminfo->relid = RelationGetRelid(fk_rel);
  fk_perminfo->requiredPerms = ACL_SELECT;
  perminfos = lappend(perminfos, fk_perminfo);
  rte = makeNode(RangeTblEntry);
  rte->rtekind = RTE_RELATION;
  rte->relid = RelationGetRelid(fk_rel);
  rte->relkind = fk_rel->rd_rel->relkind;
  rte->rellockmode = AccessShareLock;
  rte->perminfoindex = list_length(perminfos);
  rtes = lappend(rtes, rte);

  for (int i = 0; i < riinfo->nkeys; i++)
  {
    int     attno;

    attno = riinfo->pk_attnums[i] - FirstLowInvalidHeapAttributeNumber;
    pk_perminfo->selectedCols = bms_add_member(pk_perminfo->selectedCols, attno);

    attno = riinfo->fk_attnums[i] - FirstLowInvalidHeapAttributeNumber;
    fk_perminfo->selectedCols = bms_add_member(fk_perminfo->selectedCols, attno);
  }

  if (!ExecCheckPermissions(rtes, perminfos, false))
    return false;

  /*
   * Also punt if RLS is enabled on either table unless this role has the
   * bypassrls right or is the table owner of the table(s) involved which
   * have RLS enabled.
   */
  if (!has_bypassrls_privilege(GetUserId()) &&
    ((pk_rel->rd_rel->relrowsecurity &&
      !object_ownercheck(RelationRelationId, RelationGetRelid(pk_rel),
               GetUserId())) ||
     (fk_rel->rd_rel->relrowsecurity &&
      !object_ownercheck(RelationRelationId, RelationGetRelid(fk_rel),
               GetUserId()))))
    return false;

  /*----------
   * The query string built is:
   *  SELECT fk.keycols FROM [ONLY] relname fk
   *   LEFT OUTER JOIN [ONLY] pkrelname pk
   *   ON (pk.pkkeycol1=fk.keycol1 [AND ...])
   *   WHERE pk.pkkeycol1 IS NULL AND
   * For MATCH SIMPLE:
   *   (fk.keycol1 IS NOT NULL [AND ...])
   * For MATCH FULL:
   *   (fk.keycol1 IS NOT NULL [OR ...])
   *
   * We attach COLLATE clauses to the operators when comparing columns
   * that have different collations.
   *----------
   */
  initStringInfo(&querybuf);
  appendStringInfoString(&querybuf, "SELECT ");
  sep = "";
  for (int i = 0; i < riinfo->nkeys; i++)
  {
    quoteOneName(fkattname,
           RIAttName(fk_rel, riinfo->fk_attnums[i]));
    appendStringInfo(&querybuf, "%sfk.%s", sep, fkattname);
    sep = ", ";
  }

  quoteRelationName(pkrelname, pk_rel);
  quoteRelationName(fkrelname, fk_rel);
  fk_only = fk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
    "" : "ONLY ";
  pk_only = pk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
    "" : "ONLY ";
  appendStringInfo(&querybuf,
           " FROM %s%s fk LEFT OUTER JOIN %s%s pk ON",
           fk_only, fkrelname, pk_only, pkrelname);

  strcpy(pkattname, "pk.");
  strcpy(fkattname, "fk.");
  sep = "(";
  for (int i = 0; i < riinfo->nkeys; i++)
  {
    Oid     pk_type = RIAttType(pk_rel, riinfo->pk_attnums[i]);
    Oid     fk_type = RIAttType(fk_rel, riinfo->fk_attnums[i]);
    Oid     pk_coll = RIAttCollation(pk_rel, riinfo->pk_attnums[i]);
    Oid     fk_coll = RIAttCollation(fk_rel, riinfo->fk_attnums[i]);

    quoteOneName(pkattname + 3,
           RIAttName(pk_rel, riinfo->pk_attnums[i]));
    quoteOneName(fkattname + 3,
           RIAttName(fk_rel, riinfo->fk_attnums[i]));
    ri_GenerateQual(&querybuf, sep,
            pkattname, pk_type,
            riinfo->pf_eq_oprs[i],
            fkattname, fk_type);
    if (pk_coll != fk_coll)
      ri_GenerateQualCollation(&querybuf, pk_coll);
    sep = "AND";
  }

  /*
   * It's sufficient to test any one pk attribute for null to detect a join
   * failure.
   */
  quoteOneName(pkattname, RIAttName(pk_rel, riinfo->pk_attnums[0]));
  appendStringInfo(&querybuf, ") WHERE pk.%s IS NULL AND (", pkattname);

  sep = "";
  for (int i = 0; i < riinfo->nkeys; i++)
  {
    quoteOneName(fkattname, RIAttName(fk_rel, riinfo->fk_attnums[i]));
    appendStringInfo(&querybuf,
             "%sfk.%s IS NOT NULL",
             sep, fkattname);
    switch (riinfo->confmatchtype)
    {
      case FKCONSTR_MATCH_SIMPLE:
        sep = " AND ";
        break;
      case FKCONSTR_MATCH_FULL:
        sep = " OR ";
        break;
    }
  }
  appendStringInfoChar(&querybuf, ')');

  /*
   * Temporarily increase work_mem so that the check query can be executed
   * more efficiently.  It seems okay to do this because the query is simple
   * enough to not use a multiple of work_mem, and one typically would not
   * have many large foreign-key validations happening concurrently.  So
   * this seems to meet the criteria for being considered a "maintenance"
   * operation, and accordingly we use maintenance_work_mem.  However, we
   * must also set hash_mem_multiplier to 1, since it is surely not okay to
   * let that get applied to the maintenance_work_mem value.
   *
   * We use the equivalent of a function SET option to allow the setting to
   * persist for exactly the duration of the check query.  guc.c also takes
   * care of undoing the setting on error.
   */
  save_nestlevel = NewGUCNestLevel();

  snprintf(workmembuf, sizeof(workmembuf), "%d", maintenance_work_mem);
  (void) set_config_option("work_mem", workmembuf,
               PGC_USERSET, PGC_S_SESSION,
               GUC_ACTION_SAVE, true, 0, false);
  (void) set_config_option("hash_mem_multiplier", "1",
               PGC_USERSET, PGC_S_SESSION,
               GUC_ACTION_SAVE, true, 0, false);

  SPI_connect();

  /*
   * Generate the plan.  We don't need to cache it, and there are no
   * arguments to the plan.
   */
  qplan = SPI_prepare(querybuf.data, 0, NULL);

  if (qplan == NULL)
    elog(ERROR, "SPI_prepare returned %s for %s",
       SPI_result_code_string(SPI_result), querybuf.data);

  /*
   * Run the plan.  For safety we force a current snapshot to be used. (In
   * transaction-snapshot mode, this arguably violates transaction isolation
   * rules, but we really haven't got much choice.) We don't need to
   * register the snapshot, because SPI_execute_snapshot will see to it. We
   * need at most one tuple returned, so pass limit = 1.
   */
  spi_result = SPI_execute_snapshot(qplan,
                    NULL, NULL,
                    GetLatestSnapshot(),
                    InvalidSnapshot,
                    true, false, 1);

  /* Check result */
  if (spi_result != SPI_OK_SELECT)
    elog(ERROR, "SPI_execute_snapshot returned %s", SPI_result_code_string(spi_result));

  /* Did we find a tuple violating the constraint? */
  if (SPI_processed > 0)
  {
    TupleTableSlot *slot;
    HeapTuple tuple = SPI_tuptable->vals[0];
    TupleDesc tupdesc = SPI_tuptable->tupdesc;
    RI_ConstraintInfo fake_riinfo;

    slot = MakeSingleTupleTableSlot(tupdesc, &TTSOpsVirtual);

    heap_deform_tuple(tuple, tupdesc,
              slot->tts_values, slot->tts_isnull);
    ExecStoreVirtualTuple(slot);

    /*
     * The columns to look at in the result tuple are 1..N, not whatever
     * they are in the fk_rel.  Hack up riinfo so that the subroutines
     * called here will behave properly.
     *
     * In addition to this, we have to pass the correct tupdesc to
     * ri_ReportViolation, overriding its normal habit of using the pk_rel
     * or fk_rel's tupdesc.
     */
    memcpy(&fake_riinfo, riinfo, sizeof(RI_ConstraintInfo));
    for (int i = 0; i < fake_riinfo.nkeys; i++)
      fake_riinfo.fk_attnums[i] = i + 1;

    /*
     * If it's MATCH FULL, and there are any nulls in the FK keys,
     * complain about that rather than the lack of a match.  MATCH FULL
     * disallows partially-null FK rows.
     */
    if (fake_riinfo.confmatchtype == FKCONSTR_MATCH_FULL &&
      ri_NullCheck(tupdesc, slot, &fake_riinfo, false) != RI_KEYS_NONE_NULL)
      ereport(ERROR,
          (errcode(ERRCODE_FOREIGN_KEY_VIOLATION),
           errmsg("insert or update on table \"%s\" violates foreign key constraint \"%s\"",
              RelationGetRelationName(fk_rel),
              NameStr(fake_riinfo.conname)),
           errdetail("MATCH FULL does not allow mixing of null and nonnull key values."),
           errtableconstraint(fk_rel,
                    NameStr(fake_riinfo.conname))));

    /*
     * We tell ri_ReportViolation we were doing the RI_PLAN_CHECK_LOOKUPPK
     * query, which isn't true, but will cause it to use
     * fake_riinfo.fk_attnums as we need.
     */
    ri_ReportViolation(&fake_riinfo,
               pk_rel, fk_rel,
               slot, tupdesc,
               RI_PLAN_CHECK_LOOKUPPK, false, false);

    ExecDropSingleTupleTableSlot(slot);
  }

  if (SPI_finish() != SPI_OK_FINISH)
    elog(ERROR, "SPI_finish failed");

  /*
   * Restore work_mem and hash_mem_multiplier.
   */
  AtEOXact_GUC(true, save_nestlevel);

  return true;
}

/*
 * RI_PartitionRemove_Check -
 *
 * Verify no referencing values exist, when a partition is detached on
 * the referenced side of a foreign key constraint.
 */
void
RI_PartitionRemove_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
{
  const RI_ConstraintInfo *riinfo;
  StringInfoData querybuf;
  char     *constraintDef;
  char    pkrelname[MAX_QUOTED_REL_NAME_LEN];
  char    fkrelname[MAX_QUOTED_REL_NAME_LEN];
  char    pkattname[MAX_QUOTED_NAME_LEN + 3];
  char    fkattname[MAX_QUOTED_NAME_LEN + 3];
  const char *sep;
  const char *fk_only;
  int     save_nestlevel;
  char    workmembuf[32];
  int     spi_result;
  SPIPlanPtr  qplan;
  int     i;

  riinfo = ri_FetchConstraintInfo(trigger, fk_rel, false);

  /*
   * We don't check permissions before displaying the error message, on the
   * assumption that the user detaching the partition must have enough
   * privileges to examine the table contents anyhow.
   */

  /*----------
   * The query string built is:
   *  SELECT fk.keycols FROM [ONLY] relname fk
   *    JOIN pkrelname pk
   *    ON (pk.pkkeycol1=fk.keycol1 [AND ...])
   *    WHERE (<partition constraint>) AND
   * For MATCH SIMPLE:
   *   (fk.keycol1 IS NOT NULL [AND ...])
   * For MATCH FULL:
   *   (fk.keycol1 IS NOT NULL [OR ...])
   *
   * We attach COLLATE clauses to the operators when comparing columns
   * that have different collations.
   *----------
   */
  initStringInfo(&querybuf);
  appendStringInfoString(&querybuf, "SELECT ");
  sep = "";
  for (i = 0; i < riinfo->nkeys; i++)
  {
    quoteOneName(fkattname,
           RIAttName(fk_rel, riinfo->fk_attnums[i]));
    appendStringInfo(&querybuf, "%sfk.%s", sep, fkattname);
    sep = ", ";
  }

  quoteRelationName(pkrelname, pk_rel);
  quoteRelationName(fkrelname, fk_rel);
  fk_only = fk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
    "" : "ONLY ";
  appendStringInfo(&querybuf,
           " FROM %s%s fk JOIN %s pk ON",
           fk_only, fkrelname, pkrelname);
  strcpy(pkattname, "pk.");
  strcpy(fkattname, "fk.");
  sep = "(";
  for (i = 0; i < riinfo->nkeys; i++)
  {
    Oid     pk_type = RIAttType(pk_rel, riinfo->pk_attnums[i]);
    Oid     fk_type = RIAttType(fk_rel, riinfo->fk_attnums[i]);
    Oid     pk_coll = RIAttCollation(pk_rel, riinfo->pk_attnums[i]);
    Oid     fk_coll = RIAttCollation(fk_rel, riinfo->fk_attnums[i]);

    quoteOneName(pkattname + 3,
           RIAttName(pk_rel, riinfo->pk_attnums[i]));
    quoteOneName(fkattname + 3,
           RIAttName(fk_rel, riinfo->fk_attnums[i]));
    ri_GenerateQual(&querybuf, sep,
            pkattname, pk_type,
            riinfo->pf_eq_oprs[i],
            fkattname, fk_type);
    if (pk_coll != fk_coll)
      ri_GenerateQualCollation(&querybuf, pk_coll);
    sep = "AND";
  }

  /*
   * Start the WHERE clause with the partition constraint (except if this is
   * the default partition and there's no other partition, because the
   * partition constraint is the empty string in that case.)
   */
  constraintDef = pg_get_partconstrdef_string(RelationGetRelid(pk_rel), "pk");
  if (constraintDef && constraintDef[0] != '\0')
    appendStringInfo(&querybuf, ") WHERE %s AND (",
             constraintDef);
  else
    appendStringInfoString(&querybuf, ") WHERE (");

  sep = "";
  for (i = 0; i < riinfo->nkeys; i++)
  {
    quoteOneName(fkattname, RIAttName(fk_rel, riinfo->fk_attnums[i]));
    appendStringInfo(&querybuf,
             "%sfk.%s IS NOT NULL",
             sep, fkattname);
    switch (riinfo->confmatchtype)
    {
      case FKCONSTR_MATCH_SIMPLE:
        sep = " AND ";
        break;
      case FKCONSTR_MATCH_FULL:
        sep = " OR ";
        break;
    }
  }
  appendStringInfoChar(&querybuf, ')');

  /*
   * Temporarily increase work_mem so that the check query can be executed
   * more efficiently.  It seems okay to do this because the query is simple
   * enough to not use a multiple of work_mem, and one typically would not
   * have many large foreign-key validations happening concurrently.  So
   * this seems to meet the criteria for being considered a "maintenance"
   * operation, and accordingly we use maintenance_work_mem.  However, we
   * must also set hash_mem_multiplier to 1, since it is surely not okay to
   * let that get applied to the maintenance_work_mem value.
   *
   * We use the equivalent of a function SET option to allow the setting to
   * persist for exactly the duration of the check query.  guc.c also takes
   * care of undoing the setting on error.
   */
  save_nestlevel = NewGUCNestLevel();

  snprintf(workmembuf, sizeof(workmembuf), "%d", maintenance_work_mem);
  (void) set_config_option("work_mem", workmembuf,
               PGC_USERSET, PGC_S_SESSION,
               GUC_ACTION_SAVE, true, 0, false);
  (void) set_config_option("hash_mem_multiplier", "1",
               PGC_USERSET, PGC_S_SESSION,
               GUC_ACTION_SAVE, true, 0, false);

  SPI_connect();

  /*
   * Generate the plan.  We don't need to cache it, and there are no
   * arguments to the plan.
   */
  qplan = SPI_prepare(querybuf.data, 0, NULL);

  if (qplan == NULL)
    elog(ERROR, "SPI_prepare returned %s for %s",
       SPI_result_code_string(SPI_result), querybuf.data);

  /*
   * Run the plan.  For safety we force a current snapshot to be used. (In
   * transaction-snapshot mode, this arguably violates transaction isolation
   * rules, but we really haven't got much choice.) We don't need to
   * register the snapshot, because SPI_execute_snapshot will see to it. We
   * need at most one tuple returned, so pass limit = 1.
   */
  spi_result = SPI_execute_snapshot(qplan,
                    NULL, NULL,
                    GetLatestSnapshot(),
                    InvalidSnapshot,
                    true, false, 1);

  /* Check result */
  if (spi_result != SPI_OK_SELECT)
    elog(ERROR, "SPI_execute_snapshot returned %s", SPI_result_code_string(spi_result));

  /* Did we find a tuple that would violate the constraint? */
  if (SPI_processed > 0)
  {
    TupleTableSlot *slot;
    HeapTuple tuple = SPI_tuptable->vals[0];
    TupleDesc tupdesc = SPI_tuptable->tupdesc;
    RI_ConstraintInfo fake_riinfo;

    slot = MakeSingleTupleTableSlot(tupdesc, &TTSOpsVirtual);

    heap_deform_tuple(tuple, tupdesc,
              slot->tts_values, slot->tts_isnull);
    ExecStoreVirtualTuple(slot);

    /*
     * The columns to look at in the result tuple are 1..N, not whatever
     * they are in the fk_rel.  Hack up riinfo so that ri_ReportViolation
     * will behave properly.
     *
     * In addition to this, we have to pass the correct tupdesc to
     * ri_ReportViolation, overriding its normal habit of using the pk_rel
     * or fk_rel's tupdesc.
     */
    memcpy(&fake_riinfo, riinfo, sizeof(RI_ConstraintInfo));
    for (i = 0; i < fake_riinfo.nkeys; i++)
      fake_riinfo.pk_attnums[i] = i + 1;

    ri_ReportViolation(&fake_riinfo, pk_rel, fk_rel,
               slot, tupdesc, 0, false, true);
  }

  if (SPI_finish() != SPI_OK_FINISH)
    elog(ERROR, "SPI_finish failed");

  /*
   * Restore work_mem and hash_mem_multiplier.
   */
  AtEOXact_GUC(true, save_nestlevel);
}


/* ----------
 * Local functions below
 * ----------
 */


/*
 * quoteOneName --- safely quote a single SQL name
 *
 * buffer must be MAX_QUOTED_NAME_LEN long (includes room for \0)
 */
static void
quoteOneName(char *buffer, const char *name)
{
  /* Rather than trying to be smart, just always quote it. */
  *buffer++ = '"';
  while (*name)
  {
    if (*name == '"')
      *buffer++ = '"';
    *buffer++ = *name++;
  }
  *buffer++ = '"';
  *buffer = '\0';
}

/*
 * quoteRelationName --- safely quote a fully qualified relation name
 *
 * buffer must be MAX_QUOTED_REL_NAME_LEN long (includes room for \0)
 */
static void
quoteRelationName(char *buffer, Relation rel)
{
  quoteOneName(buffer, get_namespace_name(RelationGetNamespace(rel)));
  buffer += strlen(buffer);
  *buffer++ = '.';
  quoteOneName(buffer, RelationGetRelationName(rel));
}

/*
 * ri_GenerateQual --- generate a WHERE clause equating two variables
 *
 * This basically appends " sep leftop op rightop" to buf, adding casts
 * and schema qualification as needed to ensure that the parser will select
 * the operator we specify.  leftop and rightop should be parenthesized
 * if they aren't variables or parameters.
 */
static void
ri_GenerateQual(StringInfo buf,
        const char *sep,
        const char *leftop, Oid leftoptype,
        Oid opoid,
        const char *rightop, Oid rightoptype)
{
  appendStringInfo(buf, " %s ", sep);
  generate_operator_clause(buf, leftop, leftoptype, opoid,
               rightop, rightoptype);
}

/*
 * ri_GenerateQualCollation --- add a COLLATE spec to a WHERE clause
 *
 * We only have to use this function when directly comparing the referencing
 * and referenced columns, if they are of different collations; else the
 * parser will fail to resolve the collation to use.  We don't need to use
 * this function for RI queries that compare a variable to a $n parameter.
 * Since parameter symbols always have default collation, the effect will be
 * to use the variable's collation.
 *
 * Note that we require that the collations of the referencing and the
 * referenced column have the same notion of equality: Either they have to
 * both be deterministic or else they both have to be the same.  (See also
 * ATAddForeignKeyConstraint().)
 */
static void
ri_GenerateQualCollation(StringInfo buf, Oid collation)
{
  HeapTuple tp;
  Form_pg_collation colltup;
  char     *collname;
  char    onename[MAX_QUOTED_NAME_LEN];

  /* Nothing to do if it's a noncollatable data type */
  if (!OidIsValid(collation))
    return;

  tp = SearchSysCache1(COLLOID, ObjectIdGetDatum(collation));
  if (!HeapTupleIsValid(tp))
    elog(ERROR, "cache lookup failed for collation %u", collation);
  colltup = (Form_pg_collation) GETSTRUCT(tp);
  collname = NameStr(colltup->collname);

  /*
   * We qualify the name always, for simplicity and to ensure the query is
   * not search-path-dependent.
   */
  quoteOneName(onename, get_namespace_name(colltup->collnamespace));
  appendStringInfo(buf, " COLLATE %s", onename);
  quoteOneName(onename, collname);
  appendStringInfo(buf, ".%s", onename);

  ReleaseSysCache(tp);
}

/* ----------
 * ri_BuildQueryKey -
 *
 *  Construct a hashtable key for a prepared SPI plan of an FK constraint.
 *
 *    key: output argument, *key is filled in based on the other arguments
 *    riinfo: info derived from pg_constraint entry
 *    constr_queryno: an internal number identifying the query type
 *      (see RI_PLAN_XXX constants at head of file)
 * ----------
 */
static void
ri_BuildQueryKey(RI_QueryKey *key, const RI_ConstraintInfo *riinfo,
         int32 constr_queryno)
{
  /*
   * Inherited constraints with a common ancestor can share ri_query_cache
   * entries for all query types except RI_PLAN_CHECK_LOOKUPPK_FROM_PK.
   * Except in that case, the query processes the other table involved in
   * the FK constraint (i.e., not the table on which the trigger has been
   * fired), and so it will be the same for all members of the inheritance
   * tree.  So we may use the root constraint's OID in the hash key, rather
   * than the constraint's own OID.  This avoids creating duplicate SPI
   * plans, saving lots of work and memory when there are many partitions
   * with similar FK constraints.
   *
   * (Note that we must still have a separate RI_ConstraintInfo for each
   * constraint, because partitions can have different column orders,
   * resulting in different pk_attnums[] or fk_attnums[] array contents.)
   *
   * We assume struct RI_QueryKey contains no padding bytes, else we'd need
   * to use memset to clear them.
   */
  if (constr_queryno != RI_PLAN_CHECK_LOOKUPPK_FROM_PK)
    key->constr_id = riinfo->constraint_root_id;
  else
    key->constr_id = riinfo->constraint_id;
  key->constr_queryno = constr_queryno;
}

/*
 * Check that RI trigger function was called in expected context
 */
static void
ri_CheckTrigger(FunctionCallInfo fcinfo, const char *funcname, int tgkind)
{
  TriggerData *trigdata = (TriggerData *) fcinfo->context;

  if (!CALLED_AS_TRIGGER(fcinfo))
    ereport(ERROR,
        (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
         errmsg("function \"%s\" was not called by trigger manager", funcname)));

  /*
   * Check proper event
   */
  if (!TRIGGER_FIRED_AFTER(trigdata->tg_event) ||
    !TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
    ereport(ERROR,
        (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
         errmsg("function \"%s\" must be fired AFTER ROW", funcname)));

  switch (tgkind)
  {
    case RI_TRIGTYPE_INSERT:
      if (!TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
        ereport(ERROR,
            (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
             errmsg("function \"%s\" must be fired for INSERT", funcname)));
      break;
    case RI_TRIGTYPE_UPDATE:
      if (!TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
        ereport(ERROR,
            (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
             errmsg("function \"%s\" must be fired for UPDATE", funcname)));
      break;
    case RI_TRIGTYPE_DELETE:
      if (!TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
        ereport(ERROR,
            (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
             errmsg("function \"%s\" must be fired for DELETE", funcname)));
      break;
  }
}


/*
 * Fetch the RI_ConstraintInfo struct for the trigger's FK constraint.
 */
static const RI_ConstraintInfo *
ri_FetchConstraintInfo(Trigger *trigger, Relation trig_rel, bool rel_is_pk)
{
  Oid     constraintOid = trigger->tgconstraint;
  const RI_ConstraintInfo *riinfo;

  /*
   * Check that the FK constraint's OID is available; it might not be if
   * we've been invoked via an ordinary trigger or an old-style "constraint
   * trigger".
   */
  if (!OidIsValid(constraintOid))
    ereport(ERROR,
        (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
         errmsg("no pg_constraint entry for trigger \"%s\" on table \"%s\"",
            trigger->tgname, RelationGetRelationName(trig_rel)),
         errhint("Remove this referential integrity trigger and its mates, then do ALTER TABLE ADD CONSTRAINT.")));

  /* Find or create a hashtable entry for the constraint */
  riinfo = ri_LoadConstraintInfo(constraintOid);

  /* Do some easy cross-checks against the trigger call data */
  if (rel_is_pk)
  {
    if (riinfo->fk_relid != trigger->tgconstrrelid ||
      riinfo->pk_relid != RelationGetRelid(trig_rel))
      elog(ERROR, "wrong pg_constraint entry for trigger \"%s\" on table \"%s\"",
         trigger->tgname, RelationGetRelationName(trig_rel));
  }
  else
  {
    if (riinfo->fk_relid != RelationGetRelid(trig_rel) ||
      riinfo->pk_relid != trigger->tgconstrrelid)
      elog(ERROR, "wrong pg_constraint entry for trigger \"%s\" on table \"%s\"",
         trigger->tgname, RelationGetRelationName(trig_rel));
  }

  if (riinfo->confmatchtype != FKCONSTR_MATCH_FULL &&
    riinfo->confmatchtype != FKCONSTR_MATCH_PARTIAL &&
    riinfo->confmatchtype != FKCONSTR_MATCH_SIMPLE)
    elog(ERROR, "unrecognized confmatchtype: %d",
       riinfo->confmatchtype);

  if (riinfo->confmatchtype == FKCONSTR_MATCH_PARTIAL)
    ereport(ERROR,
        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
         errmsg("MATCH PARTIAL not yet implemented")));

  return riinfo;
}

/*
 * Fetch or create the RI_ConstraintInfo struct for an FK constraint.
 */
static const RI_ConstraintInfo *
ri_LoadConstraintInfo(Oid constraintOid)
{
  RI_ConstraintInfo *riinfo;
  bool    found;
  HeapTuple tup;
  Form_pg_constraint conForm;

  /*
   * On the first call initialize the hashtable
   */
  if (!ri_constraint_cache)
    ri_InitHashTables();

  /*
   * Find or create a hash entry.  If we find a valid one, just return it.
   */
  riinfo = (RI_ConstraintInfo *) hash_search(ri_constraint_cache,
                         &constraintOid,
                         HASH_ENTER, &found);
  if (!found)
    riinfo->valid = false;
  else if (riinfo->valid)
    return riinfo;

  /*
   * Fetch the pg_constraint row so we can fill in the entry.
   */
  tup = SearchSysCache1(CONSTROID, ObjectIdGetDatum(constraintOid));
  if (!HeapTupleIsValid(tup)) /* should not happen */
    elog(ERROR, "cache lookup failed for constraint %u", constraintOid);
  conForm = (Form_pg_constraint) GETSTRUCT(tup);

  if (conForm->contype != CONSTRAINT_FOREIGN) /* should not happen */
    elog(ERROR, "constraint %u is not a foreign key constraint",
       constraintOid);

  /* And extract data */
  Assert(riinfo->constraint_id == constraintOid);
  if (OidIsValid(conForm->conparentid))
    riinfo->constraint_root_id =
      get_ri_constraint_root(conForm->conparentid);
  else
    riinfo->constraint_root_id = constraintOid;
  riinfo->oidHashValue = GetSysCacheHashValue1(CONSTROID,
                         ObjectIdGetDatum(constraintOid));
  riinfo->rootHashValue = GetSysCacheHashValue1(CONSTROID,
                          ObjectIdGetDatum(riinfo->constraint_root_id));
  memcpy(&riinfo->conname, &conForm->conname, sizeof(NameData));
  riinfo->pk_relid = conForm->confrelid;
  riinfo->fk_relid = conForm->conrelid;
  riinfo->confupdtype = conForm->confupdtype;
  riinfo->confdeltype = conForm->confdeltype;
  riinfo->confmatchtype = conForm->confmatchtype;
  riinfo->hasperiod = conForm->conperiod;

  DeconstructFkConstraintRow(tup,
                 &riinfo->nkeys,
                 riinfo->fk_attnums,
                 riinfo->pk_attnums,
                 riinfo->pf_eq_oprs,
                 riinfo->pp_eq_oprs,
                 riinfo->ff_eq_oprs,
                 &riinfo->ndelsetcols,
                 riinfo->confdelsetcols);

  /*
   * For temporal FKs, get the operators and functions we need. We ask the
   * opclass of the PK element for these. This all gets cached (as does the
   * generated plan), so there's no performance issue.
   */
  if (riinfo->hasperiod)
  {
    Oid     opclass = get_index_column_opclass(conForm->conindid, riinfo->nkeys);

    FindFKPeriodOpers(opclass,
              &riinfo->period_contained_by_oper,
              &riinfo->agged_period_contained_by_oper,
              &riinfo->period_intersect_oper);
  }

  ReleaseSysCache(tup);

  /*
   * For efficient processing of invalidation messages below, we keep a
   * doubly-linked count list of all currently valid entries.
   */
  dclist_push_tail(&ri_constraint_cache_valid_list, &riinfo->valid_link);

  riinfo->valid = true;

  return riinfo;
}

/*
 * get_ri_constraint_root
 *    Returns the OID of the constraint's root parent
 */
static Oid
get_ri_constraint_root(Oid constrOid)
{
  for (;;)
  {
    HeapTuple tuple;
    Oid     constrParentOid;

    tuple = SearchSysCache1(CONSTROID, ObjectIdGetDatum(constrOid));
    if (!HeapTupleIsValid(tuple))
      elog(ERROR, "cache lookup failed for constraint %u", constrOid);
    constrParentOid = ((Form_pg_constraint) GETSTRUCT(tuple))->conparentid;
    ReleaseSysCache(tuple);
    if (!OidIsValid(constrParentOid))
      break;       /* we reached the root constraint */
    constrOid = constrParentOid;
  }
  return constrOid;
}

/*
 * Callback for pg_constraint inval events
 *
 * While most syscache callbacks just flush all their entries, pg_constraint
 * gets enough update traffic that it's probably worth being smarter.
 * Invalidate any ri_constraint_cache entry associated with the syscache
 * entry with the specified hash value, or all entries if hashvalue == 0.
 *
 * Note: at the time a cache invalidation message is processed there may be
 * active references to the cache.  Because of this we never remove entries
 * from the cache, but only mark them invalid, which is harmless to active
 * uses.  (Any query using an entry should hold a lock sufficient to keep that
 * data from changing under it --- but we may get cache flushes anyway.)
 */
static void
InvalidateConstraintCacheCallBack(Datum arg, int cacheid, uint32 hashvalue)
{
  dlist_mutable_iter iter;

  Assert(ri_constraint_cache != NULL);

  /*
   * If the list of currently valid entries gets excessively large, we mark
   * them all invalid so we can empty the list.  This arrangement avoids
   * O(N^2) behavior in situations where a session touches many foreign keys
   * and also does many ALTER TABLEs, such as a restore from pg_dump.
   */
  if (dclist_count(&ri_constraint_cache_valid_list) > 1000)
    hashvalue = 0;     /* pretend it's a cache reset */

  dclist_foreach_modify(iter, &ri_constraint_cache_valid_list)
  {
    RI_ConstraintInfo *riinfo = dclist_container(RI_ConstraintInfo,
                           valid_link, iter.cur);

    /*
     * We must invalidate not only entries directly matching the given
     * hash value, but also child entries, in case the invalidation
     * affects a root constraint.
     */
    if (hashvalue == 0 ||
      riinfo->oidHashValue == hashvalue ||
      riinfo->rootHashValue == hashvalue)
    {
      riinfo->valid = false;
      /* Remove invalidated entries from the list, too */
      dclist_delete_from(&ri_constraint_cache_valid_list, iter.cur);
    }
  }
}


/*
 * Prepare execution plan for a query to enforce an RI restriction
 */
static SPIPlanPtr
ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes,
       RI_QueryKey *qkey, Relation fk_rel, Relation pk_rel)
{
  SPIPlanPtr  qplan;
  Relation  query_rel;
  Oid     save_userid;
  int     save_sec_context;

  /*
   * Use the query type code to determine whether the query is run against
   * the PK or FK table; we'll do the check as that table's owner
   */
  if (qkey->constr_queryno <= RI_PLAN_LAST_ON_PK)
    query_rel = pk_rel;
  else
    query_rel = fk_rel;

  /* Switch to proper UID to perform check as */
  GetUserIdAndSecContext(&save_userid, &save_sec_context);
  SetUserIdAndSecContext(RelationGetForm(query_rel)->relowner,
               save_sec_context | SECURITY_LOCAL_USERID_CHANGE |
               SECURITY_NOFORCE_RLS);

  /* Create the plan */
  qplan = SPI_prepare(querystr, nargs, argtypes);

  if (qplan == NULL)
    elog(ERROR, "SPI_prepare returned %s for %s", SPI_result_code_string(SPI_result), querystr);

  /* Restore UID and security context */
  SetUserIdAndSecContext(save_userid, save_sec_context);

  /* Save the plan */
  SPI_keepplan(qplan);
  ri_HashPreparedPlan(qkey, qplan);

  return qplan;
}

/*
 * Perform a query to enforce an RI restriction
 */
static bool
ri_PerformCheck(const RI_ConstraintInfo *riinfo,
        RI_QueryKey *qkey, SPIPlanPtr qplan,
        Relation fk_rel, Relation pk_rel,
        TupleTableSlot *oldslot, TupleTableSlot *newslot,
        bool is_restrict,
        bool detectNewRows, int expect_OK)
{
  Relation  query_rel,
        source_rel;
  bool    source_is_pk;
  Snapshot  test_snapshot;
  Snapshot  crosscheck_snapshot;
  int     limit;
  int     spi_result;
  Oid     save_userid;
  int     save_sec_context;
  Datum   vals[RI_MAX_NUMKEYS * 2];
  char    nulls[RI_MAX_NUMKEYS * 2];

  /*
   * Use the query type code to determine whether the query is run against
   * the PK or FK table; we'll do the check as that table's owner
   */
  if (qkey->constr_queryno <= RI_PLAN_LAST_ON_PK)
    query_rel = pk_rel;
  else
    query_rel = fk_rel;

  /*
   * The values for the query are taken from the table on which the trigger
   * is called - it is normally the other one with respect to query_rel. An
   * exception is ri_Check_Pk_Match(), which uses the PK table for both (and
   * sets queryno to RI_PLAN_CHECK_LOOKUPPK_FROM_PK).  We might eventually
   * need some less klugy way to determine this.
   */
  if (qkey->constr_queryno == RI_PLAN_CHECK_LOOKUPPK)
  {
    source_rel = fk_rel;
    source_is_pk = false;
  }
  else
  {
    source_rel = pk_rel;
    source_is_pk = true;
  }

  /* Extract the parameters to be passed into the query */
  if (newslot)
  {
    ri_ExtractValues(source_rel, newslot, riinfo, source_is_pk,
             vals, nulls);
    if (oldslot)
      ri_ExtractValues(source_rel, oldslot, riinfo, source_is_pk,
               vals + riinfo->nkeys, nulls + riinfo->nkeys);
  }
  else
  {
    ri_ExtractValues(source_rel, oldslot, riinfo, source_is_pk,
             vals, nulls);
  }

  /*
   * In READ COMMITTED mode, we just need to use an up-to-date regular
   * snapshot, and we will see all rows that could be interesting. But in
   * transaction-snapshot mode, we can't change the transaction snapshot. If
   * the caller passes detectNewRows == false then it's okay to do the query
   * with the transaction snapshot; otherwise we use a current snapshot, and
   * tell the executor to error out if it finds any rows under the current
   * snapshot that wouldn't be visible per the transaction snapshot.  Note
   * that SPI_execute_snapshot will register the snapshots, so we don't need
   * to bother here.
   */
  if (IsolationUsesXactSnapshot() && detectNewRows)
  {
    CommandCounterIncrement();  /* be sure all my own work is visible */
    test_snapshot = GetLatestSnapshot();
    crosscheck_snapshot = GetTransactionSnapshot();
  }
  else
  {
    /* the default SPI behavior is okay */
    test_snapshot = InvalidSnapshot;
    crosscheck_snapshot = InvalidSnapshot;
  }

  /*
   * If this is a select query (e.g., for a 'no action' or 'restrict'
   * trigger), we only need to see if there is a single row in the table,
   * matching the key.  Otherwise, limit = 0 - because we want the query to
   * affect ALL the matching rows.
   */
  limit = (expect_OK == SPI_OK_SELECT) ? 1 : 0;

  /* Switch to proper UID to perform check as */
  GetUserIdAndSecContext(&save_userid, &save_sec_context);
  SetUserIdAndSecContext(RelationGetForm(query_rel)->relowner,
               save_sec_context | SECURITY_LOCAL_USERID_CHANGE |
               SECURITY_NOFORCE_RLS);

  /* Finally we can run the query. */
  spi_result = SPI_execute_snapshot(qplan,
                    vals, nulls,
                    test_snapshot, crosscheck_snapshot,
                    false, false, limit);

  /* Restore UID and security context */
  SetUserIdAndSecContext(save_userid, save_sec_context);

  /* Check result */
  if (spi_result < 0)
    elog(ERROR, "SPI_execute_snapshot returned %s", SPI_result_code_string(spi_result));

  if (expect_OK >= 0 && spi_result != expect_OK)
    ereport(ERROR,
        (errcode(ERRCODE_INTERNAL_ERROR),
         errmsg("referential integrity query on \"%s\" from constraint \"%s\" on \"%s\" gave unexpected result",
            RelationGetRelationName(pk_rel),
            NameStr(riinfo->conname),
            RelationGetRelationName(fk_rel)),
         errhint("This is most likely due to a rule having rewritten the query.")));

  /* XXX wouldn't it be clearer to do this part at the caller? */
  if (qkey->constr_queryno != RI_PLAN_CHECK_LOOKUPPK_FROM_PK &&
    expect_OK == SPI_OK_SELECT &&
    (SPI_processed == 0) == (qkey->constr_queryno == RI_PLAN_CHECK_LOOKUPPK))
    ri_ReportViolation(riinfo,
               pk_rel, fk_rel,
               newslot ? newslot : oldslot,
               NULL,
               qkey->constr_queryno, is_restrict, false);

  return SPI_processed != 0;
}

/*
 * Extract fields from a tuple into Datum/nulls arrays
 */
static void
ri_ExtractValues(Relation rel, TupleTableSlot *slot,
         const RI_ConstraintInfo *riinfo, bool rel_is_pk,
         Datum *vals, char *nulls)
{
  const int16 *attnums;
  bool    isnull;

  if (rel_is_pk)
    attnums = riinfo->pk_attnums;
  else
    attnums = riinfo->fk_attnums;

  for (int i = 0; i < riinfo->nkeys; i++)
  {
    vals[i] = slot_getattr(slot, attnums[i], &isnull);
    nulls[i] = isnull ? 'n' : ' ';
  }
}

/*
 * Produce an error report
 *
 * If the failed constraint was on insert/update to the FK table,
 * we want the key names and values extracted from there, and the error
 * message to look like 'key blah is not present in PK'.
 * Otherwise, the attr names and values come from the PK table and the
 * message looks like 'key blah is still referenced from FK'.
 */
static void
ri_ReportViolation(const RI_ConstraintInfo *riinfo,
           Relation pk_rel, Relation fk_rel,
           TupleTableSlot *violatorslot, TupleDesc tupdesc,
           int queryno, bool is_restrict, bool partgone)
{
  StringInfoData key_names;
  StringInfoData key_values;
  bool    onfk;
  const int16 *attnums;
  Oid     rel_oid;
  AclResult aclresult;
  bool    has_perm = true;

  /*
   * Determine which relation to complain about.  If tupdesc wasn't passed
   * by caller, assume the violator tuple came from there.
   */
  onfk = (queryno == RI_PLAN_CHECK_LOOKUPPK);
  if (onfk)
  {
    attnums = riinfo->fk_attnums;
    rel_oid = fk_rel->rd_id;
    if (tupdesc == NULL)
      tupdesc = fk_rel->rd_att;
  }
  else
  {
    attnums = riinfo->pk_attnums;
    rel_oid = pk_rel->rd_id;
    if (tupdesc == NULL)
      tupdesc = pk_rel->rd_att;
  }

  /*
   * Check permissions- if the user does not have access to view the data in
   * any of the key columns then we don't include the errdetail() below.
   *
   * Check if RLS is enabled on the relation first.  If so, we don't return
   * any specifics to avoid leaking data.
   *
   * Check table-level permissions next and, failing that, column-level
   * privileges.
   *
   * When a partition at the referenced side is being detached/dropped, we
   * needn't check, since the user must be the table owner anyway.
   */
  if (partgone)
    has_perm = true;
  else if (check_enable_rls(rel_oid, InvalidOid, true) != RLS_ENABLED)
  {
    aclresult = pg_class_aclcheck(rel_oid, GetUserId(), ACL_SELECT);
    if (aclresult != ACLCHECK_OK)
    {
      /* Try for column-level permissions */
      for (int idx = 0; idx < riinfo->nkeys; idx++)
      {
        aclresult = pg_attribute_aclcheck(rel_oid, attnums[idx],
                          GetUserId(),
                          ACL_SELECT);

        /* No access to the key */
        if (aclresult != ACLCHECK_OK)
        {
          has_perm = false;
          break;
        }
      }
    }
  }
  else
    has_perm = false;

  if (has_perm)
  {
    /* Get printable versions of the keys involved */
    initStringInfo(&key_names);
    initStringInfo(&key_values);
    for (int idx = 0; idx < riinfo->nkeys; idx++)
    {
      int     fnum = attnums[idx];
      Form_pg_attribute att = TupleDescAttr(tupdesc, fnum - 1);
      char     *name,
             *val;
      Datum   datum;
      bool    isnull;

      name = NameStr(att->attname);

      datum = slot_getattr(violatorslot, fnum, &isnull);
      if (!isnull)
      {
        Oid     foutoid;
        bool    typisvarlena;

        getTypeOutputInfo(att->atttypid, &foutoid, &typisvarlena);
        val = OidOutputFunctionCall(foutoid, datum);
      }
      else
        val = "null";

      if (idx > 0)
      {
        appendStringInfoString(&key_names, ", ");
        appendStringInfoString(&key_values, ", ");
      }
      appendStringInfoString(&key_names, name);
      appendStringInfoString(&key_values, val);
    }
  }

  if (partgone)
    ereport(ERROR,
        (errcode(ERRCODE_FOREIGN_KEY_VIOLATION),
         errmsg("removing partition \"%s\" violates foreign key constraint \"%s\"",
            RelationGetRelationName(pk_rel),
            NameStr(riinfo->conname)),
         errdetail("Key (%s)=(%s) is still referenced from table \"%s\".",
               key_names.data, key_values.data,
               RelationGetRelationName(fk_rel)),
         errtableconstraint(fk_rel, NameStr(riinfo->conname))));
  else if (onfk)
    ereport(ERROR,
        (errcode(ERRCODE_FOREIGN_KEY_VIOLATION),
         errmsg("insert or update on table \"%s\" violates foreign key constraint \"%s\"",
            RelationGetRelationName(fk_rel),
            NameStr(riinfo->conname)),
         has_perm ?
         errdetail("Key (%s)=(%s) is not present in table \"%s\".",
               key_names.data, key_values.data,
               RelationGetRelationName(pk_rel)) :
         errdetail("Key is not present in table \"%s\".",
               RelationGetRelationName(pk_rel)),
         errtableconstraint(fk_rel, NameStr(riinfo->conname))));
  else if (is_restrict)
    ereport(ERROR,
        (errcode(ERRCODE_RESTRICT_VIOLATION),
         errmsg("update or delete on table \"%s\" violates RESTRICT setting of foreign key constraint \"%s\" on table \"%s\"",
            RelationGetRelationName(pk_rel),
            NameStr(riinfo->conname),
            RelationGetRelationName(fk_rel)),
         has_perm ?
         errdetail("Key (%s)=(%s) is referenced from table \"%s\".",
               key_names.data, key_values.data,
               RelationGetRelationName(fk_rel)) :
         errdetail("Key is referenced from table \"%s\".",
               RelationGetRelationName(fk_rel)),
         errtableconstraint(fk_rel, NameStr(riinfo->conname))));
  else
    ereport(ERROR,
        (errcode(ERRCODE_FOREIGN_KEY_VIOLATION),
         errmsg("update or delete on table \"%s\" violates foreign key constraint \"%s\" on table \"%s\"",
            RelationGetRelationName(pk_rel),
            NameStr(riinfo->conname),
            RelationGetRelationName(fk_rel)),
         has_perm ?
         errdetail("Key (%s)=(%s) is still referenced from table \"%s\".",
               key_names.data, key_values.data,
               RelationGetRelationName(fk_rel)) :
         errdetail("Key is still referenced from table \"%s\".",
               RelationGetRelationName(fk_rel)),
         errtableconstraint(fk_rel, NameStr(riinfo->conname))));
}


/*
 * ri_NullCheck -
 *
 * Determine the NULL state of all key values in a tuple
 *
 * Returns one of RI_KEYS_ALL_NULL, RI_KEYS_NONE_NULL or RI_KEYS_SOME_NULL.
 */
static int
ri_NullCheck(TupleDesc tupDesc,
       TupleTableSlot *slot,
       const RI_ConstraintInfo *riinfo, bool rel_is_pk)
{
  const int16 *attnums;
  bool    allnull = true;
  bool    nonenull = true;

  if (rel_is_pk)
    attnums = riinfo->pk_attnums;
  else
    attnums = riinfo->fk_attnums;

  for (int i = 0; i < riinfo->nkeys; i++)
  {
    if (slot_attisnull(slot, attnums[i]))
      nonenull = false;
    else
      allnull = false;
  }

  if (allnull)
    return RI_KEYS_ALL_NULL;

  if (nonenull)
    return RI_KEYS_NONE_NULL;

  return RI_KEYS_SOME_NULL;
}


/*
 * ri_InitHashTables -
 *
 * Initialize our internal hash tables.
 */
static void
ri_InitHashTables(void)
{
  HASHCTL   ctl;

  ctl.keysize = sizeof(Oid);
  ctl.entrysize = sizeof(RI_ConstraintInfo);
  ri_constraint_cache = hash_create("RI constraint cache",
                    RI_INIT_CONSTRAINTHASHSIZE,
                    &ctl, HASH_ELEM | HASH_BLOBS);

  /* Arrange to flush cache on pg_constraint changes */
  CacheRegisterSyscacheCallback(CONSTROID,
                  InvalidateConstraintCacheCallBack,
                  (Datum) 0);

  ctl.keysize = sizeof(RI_QueryKey);
  ctl.entrysize = sizeof(RI_QueryHashEntry);
  ri_query_cache = hash_create("RI query cache",
                 RI_INIT_QUERYHASHSIZE,
                 &ctl, HASH_ELEM | HASH_BLOBS);

  ctl.keysize = sizeof(RI_CompareKey);
  ctl.entrysize = sizeof(RI_CompareHashEntry);
  ri_compare_cache = hash_create("RI compare cache",
                   RI_INIT_QUERYHASHSIZE,
                   &ctl, HASH_ELEM | HASH_BLOBS);
}


/*
 * ri_FetchPreparedPlan -
 *
 * Lookup for a query key in our private hash table of prepared
 * and saved SPI execution plans. Return the plan if found or NULL.
 */
static SPIPlanPtr
ri_FetchPreparedPlan(RI_QueryKey *key)
{
  RI_QueryHashEntry *entry;
  SPIPlanPtr  plan;

  /*
   * On the first call initialize the hashtable
   */
  if (!ri_query_cache)
    ri_InitHashTables();

  /*
   * Lookup for the key
   */
  entry = (RI_QueryHashEntry *) hash_search(ri_query_cache,
                        key,
                        HASH_FIND, NULL);
  if (entry == NULL)
    return NULL;

  /*
   * Check whether the plan is still valid.  If it isn't, we don't want to
   * simply rely on plancache.c to regenerate it; rather we should start
   * from scratch and rebuild the query text too.  This is to cover cases
   * such as table/column renames.  We depend on the plancache machinery to
   * detect possible invalidations, though.
   *
   * CAUTION: this check is only trustworthy if the caller has already
   * locked both FK and PK rels.
   */
  plan = entry->plan;
  if (plan && SPI_plan_is_valid(plan))
    return plan;

  /*
   * Otherwise we might as well flush the cached plan now, to free a little
   * memory space before we make a new one.
   */
  entry->plan = NULL;
  if (plan)
    SPI_freeplan(plan);

  return NULL;
}


/*
 * ri_HashPreparedPlan -
 *
 * Add another plan to our private SPI query plan hashtable.
 */
static void
ri_HashPreparedPlan(RI_QueryKey *key, SPIPlanPtr plan)
{
  RI_QueryHashEntry *entry;
  bool    found;

  /*
   * On the first call initialize the hashtable
   */
  if (!ri_query_cache)
    ri_InitHashTables();

  /*
   * Add the new plan.  We might be overwriting an entry previously found
   * invalid by ri_FetchPreparedPlan.
   */
  entry = (RI_QueryHashEntry *) hash_search(ri_query_cache,
                        key,
                        HASH_ENTER, &found);
  Assert(!found || entry->plan == NULL);
  entry->plan = plan;
}


/*
 * ri_KeysEqual -
 *
 * Check if all key values in OLD and NEW are "equivalent":
 * For normal FKs we check for equality.
 * For temporal FKs we check that the PK side is a superset of its old value,
 * or the FK side is a subset of its old value.
 *
 * Note: at some point we might wish to redefine this as checking for
 * "IS NOT DISTINCT" rather than "=", that is, allow two nulls to be
 * considered equal.  Currently there is no need since all callers have
 * previously found at least one of the rows to contain no nulls.
 */
static bool
ri_KeysEqual(Relation rel, TupleTableSlot *oldslot, TupleTableSlot *newslot,
       const RI_ConstraintInfo *riinfo, bool rel_is_pk)
{
  const int16 *attnums;

  if (rel_is_pk)
    attnums = riinfo->pk_attnums;
  else
    attnums = riinfo->fk_attnums;

  /* XXX: could be worthwhile to fetch all necessary attrs at once */
  for (int i = 0; i < riinfo->nkeys; i++)
  {
    Datum   oldvalue;
    Datum   newvalue;
    bool    isnull;

    /*
     * Get one attribute's oldvalue. If it is NULL - they're not equal.
     */
    oldvalue = slot_getattr(oldslot, attnums[i], &isnull);
    if (isnull)
      return false;

    /*
     * Get one attribute's newvalue. If it is NULL - they're not equal.
     */
    newvalue = slot_getattr(newslot, attnums[i], &isnull);
    if (isnull)
      return false;

    if (rel_is_pk)
    {
      /*
       * If we are looking at the PK table, then do a bytewise
       * comparison.  We must propagate PK changes if the value is
       * changed to one that "looks" different but would compare as
       * equal using the equality operator.  This only makes a
       * difference for ON UPDATE CASCADE, but for consistency we treat
       * all changes to the PK the same.
       */
      CompactAttribute *att = TupleDescCompactAttr(oldslot->tts_tupleDescriptor, attnums[i] - 1);

      if (!datum_image_eq(oldvalue, newvalue, att->attbyval, att->attlen))
        return false;
    }
    else
    {
      Oid     eq_opr;

      /*
       * When comparing the PERIOD columns we can skip the check
       * whenever the referencing column stayed equal or shrank, so test
       * with the contained-by operator instead.
       */
      if (riinfo->hasperiod && i == riinfo->nkeys - 1)
        eq_opr = riinfo->period_contained_by_oper;
      else
        eq_opr = riinfo->ff_eq_oprs[i];

      /*
       * For the FK table, compare with the appropriate equality
       * operator.  Changes that compare equal will still satisfy the
       * constraint after the update.
       */
      if (!ri_CompareWithCast(eq_opr, RIAttType(rel, attnums[i]), RIAttCollation(rel, attnums[i]),
                  newvalue, oldvalue))
        return false;
    }
  }

  return true;
}


/*
 * ri_CompareWithCast -
 *
 * Call the appropriate comparison operator for two values.
 * Normally this is equality, but for the PERIOD part of foreign keys
 * it is ContainedBy, so the order of lhs vs rhs is significant.
 * See below for how the collation is applied.
 *
 * NB: we have already checked that neither value is null.
 */
static bool
ri_CompareWithCast(Oid eq_opr, Oid typeid, Oid collid,
           Datum lhs, Datum rhs)
{
  RI_CompareHashEntry *entry = ri_HashCompareOp(eq_opr, typeid);

  /* Do we need to cast the values? */
  if (OidIsValid(entry->cast_func_finfo.fn_oid))
  {
    lhs = FunctionCall3(&entry->cast_func_finfo,
              lhs,
              Int32GetDatum(-1),  /* typmod */
              BoolGetDatum(false)); /* implicit coercion */
    rhs = FunctionCall3(&entry->cast_func_finfo,
              rhs,
              Int32GetDatum(-1),  /* typmod */
              BoolGetDatum(false)); /* implicit coercion */
  }

  /*
   * Apply the comparison operator.
   *
   * Note: This function is part of a call stack that determines whether an
   * update to a row is significant enough that it needs checking or action
   * on the other side of a foreign-key constraint.  Therefore, the
   * comparison here would need to be done with the collation of the *other*
   * table.  For simplicity (e.g., we might not even have the other table
   * open), we'll use our own collation.  This is fine because we require
   * that both collations have the same notion of equality (either they are
   * both deterministic or else they are both the same).
   *
   * With range/multirangetypes, the collation of the base type is stored as
   * part of the rangetype (pg_range.rngcollation), and always used, so
   * there is no danger of inconsistency even using a non-equals operator.
   * But if we support arbitrary types with PERIOD, we should perhaps just
   * always force a re-check.
   */
  return DatumGetBool(FunctionCall2Coll(&entry->eq_opr_finfo, collid, lhs, rhs));
}

/*
 * ri_HashCompareOp -
 *
 * See if we know how to compare two values, and create a new hash entry
 * if not.
 */
static RI_CompareHashEntry *
ri_HashCompareOp(Oid eq_opr, Oid typeid)
{
  RI_CompareKey key;
  RI_CompareHashEntry *entry;
  bool    found;

  /*
   * On the first call initialize the hashtable
   */
  if (!ri_compare_cache)
    ri_InitHashTables();

  /*
   * Find or create a hash entry.  Note we're assuming RI_CompareKey
   * contains no struct padding.
   */
  key.eq_opr = eq_opr;
  key.typeid = typeid;
  entry = (RI_CompareHashEntry *) hash_search(ri_compare_cache,
                        &key,
                        HASH_ENTER, &found);
  if (!found)
    entry->valid = false;

  /*
   * If not already initialized, do so.  Since we'll keep this hash entry
   * for the life of the backend, put any subsidiary info for the function
   * cache structs into TopMemoryContext.
   */
  if (!entry->valid)
  {
    Oid     lefttype,
          righttype,
          castfunc;
    CoercionPathType pathtype;

    /* We always need to know how to call the equality operator */
    fmgr_info_cxt(get_opcode(eq_opr), &entry->eq_opr_finfo,
            TopMemoryContext);

    /*
     * If we chose to use a cast from FK to PK type, we may have to apply
     * the cast function to get to the operator's input type.
     *
     * XXX eventually it would be good to support array-coercion cases
     * here and in ri_CompareWithCast().  At the moment there is no point
     * because cases involving nonidentical array types will be rejected
     * at constraint creation time.
     *
     * XXX perhaps also consider supporting CoerceViaIO?  No need at the
     * moment since that will never be generated for implicit coercions.
     */
    op_input_types(eq_opr, &lefttype, &righttype);
    Assert(lefttype == righttype);
    if (typeid == lefttype)
      castfunc = InvalidOid; /* simplest case */
    else
    {
      pathtype = find_coercion_pathway(lefttype, typeid,
                       COERCION_IMPLICIT,
                       &castfunc);
      if (pathtype != COERCION_PATH_FUNC &&
        pathtype != COERCION_PATH_RELABELTYPE)
      {
        /*
         * The declared input type of the eq_opr might be a
         * polymorphic type such as ANYARRAY or ANYENUM, or other
         * special cases such as RECORD; find_coercion_pathway
         * currently doesn't subsume these special cases.
         */
        if (!IsBinaryCoercible(typeid, lefttype))
          elog(ERROR, "no conversion function from %s to %s",
             format_type_be(typeid),
             format_type_be(lefttype));
      }
    }
    if (OidIsValid(castfunc))
      fmgr_info_cxt(castfunc, &entry->cast_func_finfo,
              TopMemoryContext);
    else
      entry->cast_func_finfo.fn_oid = InvalidOid;
    entry->valid = true;
  }

  return entry;
}


/*
 * Given a trigger function OID, determine whether it is an RI trigger,
 * and if so whether it is attached to PK or FK relation.
 */
int
RI_FKey_trigger_type(Oid tgfoid)
{
  switch (tgfoid)
  {
    case F_RI_FKEY_CASCADE_DEL:
    case F_RI_FKEY_CASCADE_UPD:
    case F_RI_FKEY_RESTRICT_DEL:
    case F_RI_FKEY_RESTRICT_UPD:
    case F_RI_FKEY_SETNULL_DEL:
    case F_RI_FKEY_SETNULL_UPD:
    case F_RI_FKEY_SETDEFAULT_DEL:
    case F_RI_FKEY_SETDEFAULT_UPD:
    case F_RI_FKEY_NOACTION_DEL:
    case F_RI_FKEY_NOACTION_UPD:
      return RI_TRIGGER_PK;

    case F_RI_FKEY_CHECK_INS:
    case F_RI_FKEY_CHECK_UPD:
      return RI_TRIGGER_FK;
  }

  return RI_TRIGGER_NONE;
}

Coverage Report

Created: 2025-10-09 06:07