Cache the results of ri_FetchConstraintInfo in a backend-local cache.
authorTom Lane <tgl@sss.pgh.pa.us>
Wed, 20 Jun 2012 21:24:14 +0000 (17:24 -0400)
committerTom Lane <tgl@sss.pgh.pa.us>
Wed, 20 Jun 2012 21:24:14 +0000 (17:24 -0400)
Extracting data from pg_constraint turned out to take as much as 10% of the
runtime in a bulk-update case where the foreign key column wasn't changing,
because we did it over again for each tuple.  Fix that by maintaining a
backend-local cache of the results.  This is really a pretty small patch,
but converting the trigger functions to work with pointers rather than
local struct variables requires a lot of mechanical changes.

src/backend/utils/adt/ri_triggers.c

index d61d1e0b3658b25cf7cebe740f23e1c64b44606d..c24396724f4411be78303bf5189a9c9d5c97c527 100644 (file)
@@ -45,6 +45,7 @@
 #include "utils/builtins.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"
@@ -60,7 +61,8 @@
 
 #define RI_MAX_NUMKEYS                 INDEX_MAX_KEYS
 
-#define RI_INIT_QUERYHASHSIZE          128
+#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
 /* ----------
  * RI_ConstraintInfo
  *
- * Information extracted from an FK pg_constraint entry.
+ * Information extracted from an FK pg_constraint entry.  This is cached in
+ * ri_constraint_cache.
  * ----------
  */
 typedef struct RI_ConstraintInfo
 {
-   Oid         constraint_id;  /* OID of pg_constraint entry */
+   Oid         constraint_id;  /* OID of pg_constraint entry (hash key) */
+   bool        valid;          /* successfully initialized? */
+   uint32      oidHashValue;   /* hash value of pg_constraint OID */
    NameData    conname;        /* name of the FK constraint */
    Oid         pk_relid;       /* referenced relation */
    Oid         fk_relid;       /* referencing relation */
@@ -174,6 +179,7 @@ typedef struct RI_CompareHashEntry
  * Local data
  * ----------
  */
+static HTAB *ri_constraint_cache = NULL;
 static HTAB *ri_query_cache = NULL;
 static HTAB *ri_compare_cache = NULL;
 
@@ -207,14 +213,16 @@ static bool ri_AttributesEqual(Oid eq_opr, Oid typeid,
                   Datum oldvalue, Datum newvalue);
 
 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 void ri_FetchConstraintInfo(RI_ConstraintInfo *riinfo,
-                      Trigger *trigger, Relation trig_rel, bool rel_is_pk);
+static const RI_ConstraintInfo *ri_FetchConstraintInfo(Trigger *trigger,
+                      Relation trig_rel, bool rel_is_pk);
+static const RI_ConstraintInfo *ri_LoadConstraintInfo(Oid constraintOid);
 static SPIPlanPtr ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes,
             RI_QueryKey *qkey, Relation fk_rel, Relation pk_rel,
             bool cache_plan);
@@ -241,7 +249,7 @@ static void ri_ReportViolation(const RI_ConstraintInfo *riinfo,
 static Datum
 RI_FKey_check(TriggerData *trigdata)
 {
-   RI_ConstraintInfo riinfo;
+   const RI_ConstraintInfo *riinfo;
    Relation    fk_rel;
    Relation    pk_rel;
    HeapTuple   new_row;
@@ -253,8 +261,8 @@ RI_FKey_check(TriggerData *trigdata)
    /*
     * Get arguments.
     */
-   ri_FetchConstraintInfo(&riinfo,
-                        trigdata->tg_trigger, trigdata->tg_relation, false);
+   riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
+                                   trigdata->tg_relation, false);
 
    if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
    {
@@ -293,7 +301,7 @@ RI_FKey_check(TriggerData *trigdata)
     * SELECT FOR SHARE will get on it.
     */
    fk_rel = trigdata->tg_relation;
-   pk_rel = heap_open(riinfo.pk_relid, RowShareLock);
+   pk_rel = heap_open(riinfo->pk_relid, RowShareLock);
 
    /* ----------
     * SQL:2008 4.17.3 <Table constraints>
@@ -305,12 +313,12 @@ RI_FKey_check(TriggerData *trigdata)
     *      standard too); it's just there for future enhancements.
     * ----------
     */
-   if (riinfo.nkeys == 0)
+   if (riinfo->nkeys == 0)
    {
        if (SPI_connect() != SPI_OK_CONNECT)
            elog(ERROR, "SPI_connect failed");
 
-       ri_BuildQueryKey(&qkey, &riinfo, RI_PLAN_CHECK_LOOKUPPK);
+       ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_CHECK_LOOKUPPK);
 
        if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
        {
@@ -335,7 +343,7 @@ RI_FKey_check(TriggerData *trigdata)
        /*
         * Execute the plan
         */
-       ri_PerformCheck(&riinfo, &qkey, qplan,
+       ri_PerformCheck(riinfo, &qkey, qplan,
                        fk_rel, pk_rel,
                        NULL, NULL,
                        false,
@@ -349,12 +357,12 @@ RI_FKey_check(TriggerData *trigdata)
        return PointerGetDatum(NULL);
    }
 
-   if (riinfo.confmatchtype == FKCONSTR_MATCH_PARTIAL)
+   if (riinfo->confmatchtype == FKCONSTR_MATCH_PARTIAL)
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("MATCH PARTIAL not yet implemented")));
 
-   switch (ri_NullCheck(new_row, &riinfo, false))
+   switch (ri_NullCheck(new_row, riinfo, false))
    {
        case RI_KEYS_ALL_NULL:
 
@@ -371,7 +379,7 @@ RI_FKey_check(TriggerData *trigdata)
             * This is the only case that differs between the three kinds of
             * MATCH.
             */
-           switch (riinfo.confmatchtype)
+           switch (riinfo->confmatchtype)
            {
                case FKCONSTR_MATCH_FULL:
 
@@ -383,7 +391,7 @@ RI_FKey_check(TriggerData *trigdata)
                            (errcode(ERRCODE_FOREIGN_KEY_VIOLATION),
                             errmsg("insert or update on table \"%s\" violates foreign key constraint \"%s\"",
                              RelationGetRelationName(trigdata->tg_relation),
-                                   NameStr(riinfo.conname)),
+                                   NameStr(riinfo->conname)),
                             errdetail("MATCH FULL does not allow mixing of null and nonnull key values.")));
                    heap_close(pk_rel, RowShareLock);
                    return PointerGetDatum(NULL);
@@ -413,7 +421,7 @@ RI_FKey_check(TriggerData *trigdata)
 
                default:
                    elog(ERROR, "unrecognized confmatchtype: %d",
-                        riinfo.confmatchtype);
+                        riinfo->confmatchtype);
                    break;
            }
 
@@ -432,7 +440,7 @@ RI_FKey_check(TriggerData *trigdata)
    /*
     * Fetch or prepare a saved plan for the real check
     */
-   ri_BuildQueryKey(&qkey, &riinfo, RI_PLAN_CHECK_LOOKUPPK);
+   ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_CHECK_LOOKUPPK);
 
    if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
    {
@@ -454,17 +462,17 @@ RI_FKey_check(TriggerData *trigdata)
        quoteRelationName(pkrelname, pk_rel);
        appendStringInfo(&querybuf, "SELECT 1 FROM ONLY %s x", pkrelname);
        querysep = "WHERE";
-       for (i = 0; i < riinfo.nkeys; i++)
+       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_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]));
+                        RIAttName(pk_rel, riinfo->pk_attnums[i]));
            sprintf(paramname, "$%d", i + 1);
            ri_GenerateQual(&querybuf, querysep,
                            attname, pk_type,
-                           riinfo.pf_eq_oprs[i],
+                           riinfo->pf_eq_oprs[i],
                            paramname, fk_type);
            querysep = "AND";
            queryoids[i] = fk_type;
@@ -472,14 +480,14 @@ RI_FKey_check(TriggerData *trigdata)
        appendStringInfo(&querybuf, " FOR SHARE OF x");
 
        /* Prepare and save the plan */
-       qplan = ri_PlanCheck(querybuf.data, riinfo.nkeys, queryoids,
+       qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
                             &qkey, fk_rel, pk_rel, true);
    }
 
    /*
     * Now check that foreign key exists in PK table
     */
-   ri_PerformCheck(&riinfo, &qkey, qplan,
+   ri_PerformCheck(riinfo, &qkey, qplan,
                    fk_rel, pk_rel,
                    NULL, new_row,
                    false,
@@ -682,7 +690,7 @@ RI_FKey_restrict_del(PG_FUNCTION_ARGS)
 static Datum
 ri_restrict_del(TriggerData *trigdata, bool is_no_action)
 {
-   RI_ConstraintInfo riinfo;
+   const RI_ConstraintInfo *riinfo;
    Relation    fk_rel;
    Relation    pk_rel;
    HeapTuple   old_row;
@@ -693,13 +701,13 @@ ri_restrict_del(TriggerData *trigdata, bool is_no_action)
    /*
     * Get arguments.
     */
-   ri_FetchConstraintInfo(&riinfo,
-                          trigdata->tg_trigger, trigdata->tg_relation, true);
+   riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
+                                   trigdata->tg_relation, true);
 
    /*
     * Nothing to do if no column names to compare given
     */
-   if (riinfo.nkeys == 0)
+   if (riinfo->nkeys == 0)
        return PointerGetDatum(NULL);
 
    /*
@@ -708,11 +716,11 @@ ri_restrict_del(TriggerData *trigdata, bool is_no_action)
     * fk_rel is opened in RowShareLock mode since that's what our eventual
     * SELECT FOR SHARE will get on it.
     */
-   fk_rel = heap_open(riinfo.fk_relid, RowShareLock);
+   fk_rel = heap_open(riinfo->fk_relid, RowShareLock);
    pk_rel = trigdata->tg_relation;
    old_row = trigdata->tg_trigtuple;
 
-   switch (riinfo.confmatchtype)
+   switch (riinfo->confmatchtype)
    {
            /* ----------
             * SQL:2008 15.17 <Execution of referential actions>
@@ -723,7 +731,7 @@ ri_restrict_del(TriggerData *trigdata, bool is_no_action)
             */
        case FKCONSTR_MATCH_SIMPLE:
        case FKCONSTR_MATCH_FULL:
-           switch (ri_NullCheck(old_row, &riinfo, true))
+           switch (ri_NullCheck(old_row, riinfo, true))
            {
                case RI_KEYS_ALL_NULL:
                case RI_KEYS_SOME_NULL:
@@ -750,7 +758,7 @@ ri_restrict_del(TriggerData *trigdata, bool is_no_action)
             * allow another row to be substituted.
             */
            if (is_no_action &&
-               ri_Check_Pk_Match(pk_rel, fk_rel, old_row, &riinfo))
+               ri_Check_Pk_Match(pk_rel, fk_rel, old_row, riinfo))
            {
                heap_close(fk_rel, RowShareLock);
                return PointerGetDatum(NULL);
@@ -762,7 +770,7 @@ ri_restrict_del(TriggerData *trigdata, bool is_no_action)
            /*
             * Fetch or prepare a saved plan for the restrict delete lookup
             */
-           ri_BuildQueryKey(&qkey, &riinfo, RI_PLAN_RESTRICT_DEL_CHECKREF);
+           ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_RESTRICT_DEL_CHECKREF);
 
            if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
            {
@@ -785,17 +793,17 @@ ri_restrict_del(TriggerData *trigdata, bool is_no_action)
                appendStringInfo(&querybuf, "SELECT 1 FROM ONLY %s x",
                                 fkrelname);
                querysep = "WHERE";
-               for (i = 0; i < riinfo.nkeys; i++)
+               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_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]));
+                                RIAttName(fk_rel, riinfo->fk_attnums[i]));
                    sprintf(paramname, "$%d", i + 1);
                    ri_GenerateQual(&querybuf, querysep,
                                    paramname, pk_type,
-                                   riinfo.pf_eq_oprs[i],
+                                   riinfo->pf_eq_oprs[i],
                                    attname, fk_type);
                    querysep = "AND";
                    queryoids[i] = pk_type;
@@ -803,14 +811,14 @@ ri_restrict_del(TriggerData *trigdata, bool is_no_action)
                appendStringInfo(&querybuf, " FOR SHARE OF x");
 
                /* Prepare and save the plan */
-               qplan = ri_PlanCheck(querybuf.data, riinfo.nkeys, queryoids,
+               qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
                                     &qkey, fk_rel, pk_rel, true);
            }
 
            /*
             * We have a plan now. Run it to check for existing references.
             */
-           ri_PerformCheck(&riinfo, &qkey, qplan,
+           ri_PerformCheck(riinfo, &qkey, qplan,
                            fk_rel, pk_rel,
                            old_row, NULL,
                            true,       /* must detect new rows */
@@ -834,7 +842,7 @@ ri_restrict_del(TriggerData *trigdata, bool is_no_action)
 
        default:
            elog(ERROR, "unrecognized confmatchtype: %d",
-                riinfo.confmatchtype);
+                riinfo->confmatchtype);
            break;
    }
 
@@ -899,7 +907,7 @@ RI_FKey_restrict_upd(PG_FUNCTION_ARGS)
 static Datum
 ri_restrict_upd(TriggerData *trigdata, bool is_no_action)
 {
-   RI_ConstraintInfo riinfo;
+   const RI_ConstraintInfo *riinfo;
    Relation    fk_rel;
    Relation    pk_rel;
    HeapTuple   new_row;
@@ -911,13 +919,13 @@ ri_restrict_upd(TriggerData *trigdata, bool is_no_action)
    /*
     * Get arguments.
     */
-   ri_FetchConstraintInfo(&riinfo,
-                          trigdata->tg_trigger, trigdata->tg_relation, true);
+   riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
+                                   trigdata->tg_relation, true);
 
    /*
     * Nothing to do if no column names to compare given
     */
-   if (riinfo.nkeys == 0)
+   if (riinfo->nkeys == 0)
        return PointerGetDatum(NULL);
 
    /*
@@ -927,12 +935,12 @@ ri_restrict_upd(TriggerData *trigdata, bool is_no_action)
     * fk_rel is opened in RowShareLock mode since that's what our eventual
     * SELECT FOR SHARE will get on it.
     */
-   fk_rel = heap_open(riinfo.fk_relid, RowShareLock);
+   fk_rel = heap_open(riinfo->fk_relid, RowShareLock);
    pk_rel = trigdata->tg_relation;
    new_row = trigdata->tg_newtuple;
    old_row = trigdata->tg_trigtuple;
 
-   switch (riinfo.confmatchtype)
+   switch (riinfo->confmatchtype)
    {
            /* ----------
             * SQL:2008 15.17 <Execution of referential actions>
@@ -943,7 +951,7 @@ ri_restrict_upd(TriggerData *trigdata, bool is_no_action)
             */
        case FKCONSTR_MATCH_SIMPLE:
        case FKCONSTR_MATCH_FULL:
-           switch (ri_NullCheck(old_row, &riinfo, true))
+           switch (ri_NullCheck(old_row, riinfo, true))
            {
                case RI_KEYS_ALL_NULL:
                case RI_KEYS_SOME_NULL:
@@ -966,7 +974,7 @@ ri_restrict_upd(TriggerData *trigdata, bool is_no_action)
            /*
             * No need to check anything if old and new keys are equal
             */
-           if (ri_KeysEqual(pk_rel, old_row, new_row, &riinfo, true))
+           if (ri_KeysEqual(pk_rel, old_row, new_row, riinfo, true))
            {
                heap_close(fk_rel, RowShareLock);
                return PointerGetDatum(NULL);
@@ -979,7 +987,7 @@ ri_restrict_upd(TriggerData *trigdata, bool is_no_action)
             * allow another row to be substituted.
             */
            if (is_no_action &&
-               ri_Check_Pk_Match(pk_rel, fk_rel, old_row, &riinfo))
+               ri_Check_Pk_Match(pk_rel, fk_rel, old_row, riinfo))
            {
                heap_close(fk_rel, RowShareLock);
                return PointerGetDatum(NULL);
@@ -991,7 +999,7 @@ ri_restrict_upd(TriggerData *trigdata, bool is_no_action)
            /*
             * Fetch or prepare a saved plan for the restrict update lookup
             */
-           ri_BuildQueryKey(&qkey, &riinfo, RI_PLAN_RESTRICT_UPD_CHECKREF);
+           ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_RESTRICT_UPD_CHECKREF);
 
            if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
            {
@@ -1014,17 +1022,17 @@ ri_restrict_upd(TriggerData *trigdata, bool is_no_action)
                appendStringInfo(&querybuf, "SELECT 1 FROM ONLY %s x",
                                 fkrelname);
                querysep = "WHERE";
-               for (i = 0; i < riinfo.nkeys; i++)
+               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_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]));
+                                RIAttName(fk_rel, riinfo->fk_attnums[i]));
                    sprintf(paramname, "$%d", i + 1);
                    ri_GenerateQual(&querybuf, querysep,
                                    paramname, pk_type,
-                                   riinfo.pf_eq_oprs[i],
+                                   riinfo->pf_eq_oprs[i],
                                    attname, fk_type);
                    querysep = "AND";
                    queryoids[i] = pk_type;
@@ -1032,14 +1040,14 @@ ri_restrict_upd(TriggerData *trigdata, bool is_no_action)
                appendStringInfo(&querybuf, " FOR SHARE OF x");
 
                /* Prepare and save the plan */
-               qplan = ri_PlanCheck(querybuf.data, riinfo.nkeys, queryoids,
+               qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
                                     &qkey, fk_rel, pk_rel, true);
            }
 
            /*
             * We have a plan now. Run it to check for existing references.
             */
-           ri_PerformCheck(&riinfo, &qkey, qplan,
+           ri_PerformCheck(riinfo, &qkey, qplan,
                            fk_rel, pk_rel,
                            old_row, NULL,
                            true,       /* must detect new rows */
@@ -1063,7 +1071,7 @@ ri_restrict_upd(TriggerData *trigdata, bool is_no_action)
 
        default:
            elog(ERROR, "unrecognized confmatchtype: %d",
-                riinfo.confmatchtype);
+                riinfo->confmatchtype);
            break;
    }
 
@@ -1082,7 +1090,7 @@ Datum
 RI_FKey_cascade_del(PG_FUNCTION_ARGS)
 {
    TriggerData *trigdata = (TriggerData *) fcinfo->context;
-   RI_ConstraintInfo riinfo;
+   const RI_ConstraintInfo *riinfo;
    Relation    fk_rel;
    Relation    pk_rel;
    HeapTuple   old_row;
@@ -1098,13 +1106,13 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
    /*
     * Get arguments.
     */
-   ri_FetchConstraintInfo(&riinfo,
-                          trigdata->tg_trigger, trigdata->tg_relation, true);
+   riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
+                                   trigdata->tg_relation, true);
 
    /*
     * Nothing to do if no column names to compare given
     */
-   if (riinfo.nkeys == 0)
+   if (riinfo->nkeys == 0)
        return PointerGetDatum(NULL);
 
    /*
@@ -1113,11 +1121,11 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
     * fk_rel is opened in RowExclusiveLock mode since that's what our
     * eventual DELETE will get on it.
     */
-   fk_rel = heap_open(riinfo.fk_relid, RowExclusiveLock);
+   fk_rel = heap_open(riinfo->fk_relid, RowExclusiveLock);
    pk_rel = trigdata->tg_relation;
    old_row = trigdata->tg_trigtuple;
 
-   switch (riinfo.confmatchtype)
+   switch (riinfo->confmatchtype)
    {
            /* ----------
             * SQL:2008 15.17 <Execution of referential actions>
@@ -1128,7 +1136,7 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
             */
        case FKCONSTR_MATCH_SIMPLE:
        case FKCONSTR_MATCH_FULL:
-           switch (ri_NullCheck(old_row, &riinfo, true))
+           switch (ri_NullCheck(old_row, riinfo, true))
            {
                case RI_KEYS_ALL_NULL:
                case RI_KEYS_SOME_NULL:
@@ -1154,7 +1162,7 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
            /*
             * Fetch or prepare a saved plan for the cascaded delete
             */
-           ri_BuildQueryKey(&qkey, &riinfo, RI_PLAN_CASCADE_DEL_DODELETE);
+           ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_CASCADE_DEL_DODELETE);
 
            if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
            {
@@ -1176,24 +1184,24 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
                quoteRelationName(fkrelname, fk_rel);
                appendStringInfo(&querybuf, "DELETE FROM ONLY %s", fkrelname);
                querysep = "WHERE";
-               for (i = 0; i < riinfo.nkeys; i++)
+               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_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]));
+                                RIAttName(fk_rel, riinfo->fk_attnums[i]));
                    sprintf(paramname, "$%d", i + 1);
                    ri_GenerateQual(&querybuf, querysep,
                                    paramname, pk_type,
-                                   riinfo.pf_eq_oprs[i],
+                                   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,
+               qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
                                     &qkey, fk_rel, pk_rel, true);
            }
 
@@ -1201,7 +1209,7 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
             * 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,
+           ri_PerformCheck(riinfo, &qkey, qplan,
                            fk_rel, pk_rel,
                            old_row, NULL,
                            true,       /* must detect new rows */
@@ -1225,7 +1233,7 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
 
        default:
            elog(ERROR, "unrecognized confmatchtype: %d",
-                riinfo.confmatchtype);
+                riinfo->confmatchtype);
            break;
    }
 
@@ -1244,7 +1252,7 @@ Datum
 RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
 {
    TriggerData *trigdata = (TriggerData *) fcinfo->context;
-   RI_ConstraintInfo riinfo;
+   const RI_ConstraintInfo *riinfo;
    Relation    fk_rel;
    Relation    pk_rel;
    HeapTuple   new_row;
@@ -1262,13 +1270,13 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
    /*
     * Get arguments.
     */
-   ri_FetchConstraintInfo(&riinfo,
-                          trigdata->tg_trigger, trigdata->tg_relation, true);
+   riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
+                                   trigdata->tg_relation, true);
 
    /*
     * Nothing to do if no column names to compare given
     */
-   if (riinfo.nkeys == 0)
+   if (riinfo->nkeys == 0)
        return PointerGetDatum(NULL);
 
    /*
@@ -1278,12 +1286,12 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
     * fk_rel is opened in RowExclusiveLock mode since that's what our
     * eventual UPDATE will get on it.
     */
-   fk_rel = heap_open(riinfo.fk_relid, RowExclusiveLock);
+   fk_rel = heap_open(riinfo->fk_relid, RowExclusiveLock);
    pk_rel = trigdata->tg_relation;
    new_row = trigdata->tg_newtuple;
    old_row = trigdata->tg_trigtuple;
 
-   switch (riinfo.confmatchtype)
+   switch (riinfo->confmatchtype)
    {
            /* ----------
             * SQL:2008 15.17 <Execution of referential actions>
@@ -1294,7 +1302,7 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
             */
        case FKCONSTR_MATCH_SIMPLE:
        case FKCONSTR_MATCH_FULL:
-           switch (ri_NullCheck(old_row, &riinfo, true))
+           switch (ri_NullCheck(old_row, riinfo, true))
            {
                case RI_KEYS_ALL_NULL:
                case RI_KEYS_SOME_NULL:
@@ -1317,7 +1325,7 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
            /*
             * No need to do anything if old and new keys are equal
             */
-           if (ri_KeysEqual(pk_rel, old_row, new_row, &riinfo, true))
+           if (ri_KeysEqual(pk_rel, old_row, new_row, riinfo, true))
            {
                heap_close(fk_rel, RowExclusiveLock);
                return PointerGetDatum(NULL);
@@ -1329,7 +1337,7 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
            /*
             * Fetch or prepare a saved plan for the cascaded update
             */
-           ri_BuildQueryKey(&qkey, &riinfo, RI_PLAN_CASCADE_UPD_DOUPDATE);
+           ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_CASCADE_UPD_DOUPDATE);
 
            if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
            {
@@ -1358,20 +1366,20 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
                appendStringInfo(&querybuf, "UPDATE ONLY %s SET", fkrelname);
                querysep = "";
                qualsep = "WHERE";
-               for (i = 0, j = riinfo.nkeys; i < riinfo.nkeys; i++, j++)
+               for (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]);
+                   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]));
+                                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],
+                                   riinfo->pf_eq_oprs[i],
                                    attname, fk_type);
                    querysep = ",";
                    qualsep = "AND";
@@ -1381,14 +1389,14 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
                appendStringInfoString(&querybuf, qualbuf.data);
 
                /* Prepare and save the plan */
-               qplan = ri_PlanCheck(querybuf.data, riinfo.nkeys * 2, queryoids,
+               qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys * 2, queryoids,
                                     &qkey, fk_rel, pk_rel, true);
            }
 
            /*
             * We have a plan now. Run it to update the existing references.
             */
-           ri_PerformCheck(&riinfo, &qkey, qplan,
+           ri_PerformCheck(riinfo, &qkey, qplan,
                            fk_rel, pk_rel,
                            old_row, new_row,
                            true,       /* must detect new rows */
@@ -1412,7 +1420,7 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
 
        default:
            elog(ERROR, "unrecognized confmatchtype: %d",
-                riinfo.confmatchtype);
+                riinfo->confmatchtype);
            break;
    }
 
@@ -1431,7 +1439,7 @@ Datum
 RI_FKey_setnull_del(PG_FUNCTION_ARGS)
 {
    TriggerData *trigdata = (TriggerData *) fcinfo->context;
-   RI_ConstraintInfo riinfo;
+   const RI_ConstraintInfo *riinfo;
    Relation    fk_rel;
    Relation    pk_rel;
    HeapTuple   old_row;
@@ -1447,13 +1455,13 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
    /*
     * Get arguments.
     */
-   ri_FetchConstraintInfo(&riinfo,
-                          trigdata->tg_trigger, trigdata->tg_relation, true);
+   riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
+                                   trigdata->tg_relation, true);
 
    /*
     * Nothing to do if no column names to compare given
     */
-   if (riinfo.nkeys == 0)
+   if (riinfo->nkeys == 0)
        return PointerGetDatum(NULL);
 
    /*
@@ -1462,11 +1470,11 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
     * fk_rel is opened in RowExclusiveLock mode since that's what our
     * eventual UPDATE will get on it.
     */
-   fk_rel = heap_open(riinfo.fk_relid, RowExclusiveLock);
+   fk_rel = heap_open(riinfo->fk_relid, RowExclusiveLock);
    pk_rel = trigdata->tg_relation;
    old_row = trigdata->tg_trigtuple;
 
-   switch (riinfo.confmatchtype)
+   switch (riinfo->confmatchtype)
    {
            /* ----------
             * SQL:2008 15.17 <Execution of referential actions>
@@ -1477,7 +1485,7 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
             */
        case FKCONSTR_MATCH_SIMPLE:
        case FKCONSTR_MATCH_FULL:
-           switch (ri_NullCheck(old_row, &riinfo, true))
+           switch (ri_NullCheck(old_row, riinfo, true))
            {
                case RI_KEYS_ALL_NULL:
                case RI_KEYS_SOME_NULL:
@@ -1503,7 +1511,7 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
            /*
             * Fetch or prepare a saved plan for the set null delete operation
             */
-           ri_BuildQueryKey(&qkey, &riinfo, RI_PLAN_SETNULL_DEL_DOUPDATE);
+           ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_SETNULL_DEL_DOUPDATE);
 
            if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
            {
@@ -1530,20 +1538,20 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
                appendStringInfo(&querybuf, "UPDATE ONLY %s SET", fkrelname);
                querysep = "";
                qualsep = "WHERE";
-               for (i = 0; i < riinfo.nkeys; i++)
+               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_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]));
+                                RIAttName(fk_rel, riinfo->fk_attnums[i]));
                    appendStringInfo(&querybuf,
                                     "%s %s = NULL",
                                     querysep, attname);
                    sprintf(paramname, "$%d", i + 1);
                    ri_GenerateQual(&qualbuf, qualsep,
                                    paramname, pk_type,
-                                   riinfo.pf_eq_oprs[i],
+                                   riinfo->pf_eq_oprs[i],
                                    attname, fk_type);
                    querysep = ",";
                    qualsep = "AND";
@@ -1552,14 +1560,14 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
                appendStringInfoString(&querybuf, qualbuf.data);
 
                /* Prepare and save the plan */
-               qplan = ri_PlanCheck(querybuf.data, riinfo.nkeys, queryoids,
+               qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
                                     &qkey, fk_rel, pk_rel, true);
            }
 
            /*
             * We have a plan now. Run it to check for existing references.
             */
-           ri_PerformCheck(&riinfo, &qkey, qplan,
+           ri_PerformCheck(riinfo, &qkey, qplan,
                            fk_rel, pk_rel,
                            old_row, NULL,
                            true,       /* must detect new rows */
@@ -1583,7 +1591,7 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
 
        default:
            elog(ERROR, "unrecognized confmatchtype: %d",
-                riinfo.confmatchtype);
+                riinfo->confmatchtype);
            break;
    }
 
@@ -1602,7 +1610,7 @@ Datum
 RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
 {
    TriggerData *trigdata = (TriggerData *) fcinfo->context;
-   RI_ConstraintInfo riinfo;
+   const RI_ConstraintInfo *riinfo;
    Relation    fk_rel;
    Relation    pk_rel;
    HeapTuple   new_row;
@@ -1619,13 +1627,13 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
    /*
     * Get arguments.
     */
-   ri_FetchConstraintInfo(&riinfo,
-                          trigdata->tg_trigger, trigdata->tg_relation, true);
+   riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
+                                   trigdata->tg_relation, true);
 
    /*
     * Nothing to do if no column names to compare given
     */
-   if (riinfo.nkeys == 0)
+   if (riinfo->nkeys == 0)
        return PointerGetDatum(NULL);
 
    /*
@@ -1634,12 +1642,12 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
     * fk_rel is opened in RowExclusiveLock mode since that's what our
     * eventual UPDATE will get on it.
     */
-   fk_rel = heap_open(riinfo.fk_relid, RowExclusiveLock);
+   fk_rel = heap_open(riinfo->fk_relid, RowExclusiveLock);
    pk_rel = trigdata->tg_relation;
    new_row = trigdata->tg_newtuple;
    old_row = trigdata->tg_trigtuple;
 
-   switch (riinfo.confmatchtype)
+   switch (riinfo->confmatchtype)
    {
            /* ----------
             * SQL:2008 15.17 <Execution of referential actions>
@@ -1650,7 +1658,7 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
             */
        case FKCONSTR_MATCH_SIMPLE:
        case FKCONSTR_MATCH_FULL:
-           switch (ri_NullCheck(old_row, &riinfo, true))
+           switch (ri_NullCheck(old_row, riinfo, true))
            {
                case RI_KEYS_ALL_NULL:
                case RI_KEYS_SOME_NULL:
@@ -1673,7 +1681,7 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
            /*
             * No need to do anything if old and new keys are equal
             */
-           if (ri_KeysEqual(pk_rel, old_row, new_row, &riinfo, true))
+           if (ri_KeysEqual(pk_rel, old_row, new_row, riinfo, true))
            {
                heap_close(fk_rel, RowExclusiveLock);
                return PointerGetDatum(NULL);
@@ -1685,7 +1693,7 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
            /*
             * Fetch or prepare a saved plan for the set null update operation
             */
-           ri_BuildQueryKey(&qkey, &riinfo, RI_PLAN_SETNULL_UPD_DOUPDATE);
+           ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_SETNULL_UPD_DOUPDATE);
 
            if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
            {
@@ -1712,20 +1720,20 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
                appendStringInfo(&querybuf, "UPDATE ONLY %s SET", fkrelname);
                querysep = "";
                qualsep = "WHERE";
-               for (i = 0; i < riinfo.nkeys; i++)
+               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_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]));
+                                RIAttName(fk_rel, riinfo->fk_attnums[i]));
                    appendStringInfo(&querybuf,
                                     "%s %s = NULL",
                                     querysep, attname);
                    sprintf(paramname, "$%d", i + 1);
                    ri_GenerateQual(&qualbuf, qualsep,
                                    paramname, pk_type,
-                                   riinfo.pf_eq_oprs[i],
+                                   riinfo->pf_eq_oprs[i],
                                    attname, fk_type);
                    querysep = ",";
                    qualsep = "AND";
@@ -1734,14 +1742,14 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
                appendStringInfoString(&querybuf, qualbuf.data);
 
                /* Prepare and save the plan */
-               qplan = ri_PlanCheck(querybuf.data, riinfo.nkeys, queryoids,
+               qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
                                     &qkey, fk_rel, pk_rel, true);
            }
 
            /*
             * We have a plan now. Run it to update the existing references.
             */
-           ri_PerformCheck(&riinfo, &qkey, qplan,
+           ri_PerformCheck(riinfo, &qkey, qplan,
                            fk_rel, pk_rel,
                            old_row, NULL,
                            true,       /* must detect new rows */
@@ -1765,7 +1773,7 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
 
        default:
            elog(ERROR, "unrecognized confmatchtype: %d",
-                riinfo.confmatchtype);
+                riinfo->confmatchtype);
            break;
    }
 
@@ -1784,7 +1792,7 @@ Datum
 RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
 {
    TriggerData *trigdata = (TriggerData *) fcinfo->context;
-   RI_ConstraintInfo riinfo;
+   const RI_ConstraintInfo *riinfo;
    Relation    fk_rel;
    Relation    pk_rel;
    HeapTuple   old_row;
@@ -1799,13 +1807,13 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
    /*
     * Get arguments.
     */
-   ri_FetchConstraintInfo(&riinfo,
-                          trigdata->tg_trigger, trigdata->tg_relation, true);
+   riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
+                                   trigdata->tg_relation, true);
 
    /*
     * Nothing to do if no column names to compare given
     */
-   if (riinfo.nkeys == 0)
+   if (riinfo->nkeys == 0)
        return PointerGetDatum(NULL);
 
    /*
@@ -1814,11 +1822,11 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
     * fk_rel is opened in RowExclusiveLock mode since that's what our
     * eventual UPDATE will get on it.
     */
-   fk_rel = heap_open(riinfo.fk_relid, RowExclusiveLock);
+   fk_rel = heap_open(riinfo->fk_relid, RowExclusiveLock);
    pk_rel = trigdata->tg_relation;
    old_row = trigdata->tg_trigtuple;
 
-   switch (riinfo.confmatchtype)
+   switch (riinfo->confmatchtype)
    {
            /* ----------
             * SQL:2008 15.17 <Execution of referential actions>
@@ -1829,7 +1837,7 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
             */
        case FKCONSTR_MATCH_SIMPLE:
        case FKCONSTR_MATCH_FULL:
-           switch (ri_NullCheck(old_row, &riinfo, true))
+           switch (ri_NullCheck(old_row, riinfo, true))
            {
                case RI_KEYS_ALL_NULL:
                case RI_KEYS_SOME_NULL:
@@ -1856,7 +1864,7 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
             * Fetch or prepare a saved plan for the set default delete
             * operation
             */
-           ri_BuildQueryKey(&qkey, &riinfo, RI_PLAN_SETDEFAULT_DEL_DOUPDATE);
+           ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_SETDEFAULT_DEL_DOUPDATE);
 
            if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
            {
@@ -1884,20 +1892,20 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
                appendStringInfo(&querybuf, "UPDATE ONLY %s SET", fkrelname);
                querysep = "";
                qualsep = "WHERE";
-               for (i = 0; i < riinfo.nkeys; i++)
+               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_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]));
+                                RIAttName(fk_rel, riinfo->fk_attnums[i]));
                    appendStringInfo(&querybuf,
                                     "%s %s = DEFAULT",
                                     querysep, attname);
                    sprintf(paramname, "$%d", i + 1);
                    ri_GenerateQual(&qualbuf, qualsep,
                                    paramname, pk_type,
-                                   riinfo.pf_eq_oprs[i],
+                                   riinfo->pf_eq_oprs[i],
                                    attname, fk_type);
                    querysep = ",";
                    qualsep = "AND";
@@ -1906,14 +1914,14 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
                appendStringInfoString(&querybuf, qualbuf.data);
 
                /* Prepare and save the plan */
-               qplan = ri_PlanCheck(querybuf.data, riinfo.nkeys, queryoids,
+               qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
                                     &qkey, fk_rel, pk_rel, true);
            }
 
            /*
             * We have a plan now. Run it to update the existing references.
             */
-           ri_PerformCheck(&riinfo, &qkey, qplan,
+           ri_PerformCheck(riinfo, &qkey, qplan,
                            fk_rel, pk_rel,
                            old_row, NULL,
                            true,       /* must detect new rows */
@@ -1951,7 +1959,7 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
 
        default:
            elog(ERROR, "unrecognized confmatchtype: %d",
-                riinfo.confmatchtype);
+                riinfo->confmatchtype);
            break;
    }
 
@@ -1970,7 +1978,7 @@ Datum
 RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
 {
    TriggerData *trigdata = (TriggerData *) fcinfo->context;
-   RI_ConstraintInfo riinfo;
+   const RI_ConstraintInfo *riinfo;
    Relation    fk_rel;
    Relation    pk_rel;
    HeapTuple   new_row;
@@ -1986,13 +1994,13 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
    /*
     * Get arguments.
     */
-   ri_FetchConstraintInfo(&riinfo,
-                          trigdata->tg_trigger, trigdata->tg_relation, true);
+   riinfo = ri_FetchConstraintInfo(trigdata->tg_trigger,
+                                   trigdata->tg_relation, true);
 
    /*
     * Nothing to do if no column names to compare given
     */
-   if (riinfo.nkeys == 0)
+   if (riinfo->nkeys == 0)
        return PointerGetDatum(NULL);
 
    /*
@@ -2001,12 +2009,12 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
     * fk_rel is opened in RowExclusiveLock mode since that's what our
     * eventual UPDATE will get on it.
     */
-   fk_rel = heap_open(riinfo.fk_relid, RowExclusiveLock);
+   fk_rel = heap_open(riinfo->fk_relid, RowExclusiveLock);
    pk_rel = trigdata->tg_relation;
    new_row = trigdata->tg_newtuple;
    old_row = trigdata->tg_trigtuple;
 
-   switch (riinfo.confmatchtype)
+   switch (riinfo->confmatchtype)
    {
            /* ----------
             * SQL:2008 15.17 <Execution of referential actions>
@@ -2017,7 +2025,7 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
             */
        case FKCONSTR_MATCH_SIMPLE:
        case FKCONSTR_MATCH_FULL:
-           switch (ri_NullCheck(old_row, &riinfo, true))
+           switch (ri_NullCheck(old_row, riinfo, true))
            {
                case RI_KEYS_ALL_NULL:
                case RI_KEYS_SOME_NULL:
@@ -2040,7 +2048,7 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
            /*
             * No need to do anything if old and new keys are equal
             */
-           if (ri_KeysEqual(pk_rel, old_row, new_row, &riinfo, true))
+           if (ri_KeysEqual(pk_rel, old_row, new_row, riinfo, true))
            {
                heap_close(fk_rel, RowExclusiveLock);
                return PointerGetDatum(NULL);
@@ -2053,7 +2061,7 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
             * Fetch or prepare a saved plan for the set default update
             * operation
             */
-           ri_BuildQueryKey(&qkey, &riinfo, RI_PLAN_SETDEFAULT_UPD_DOUPDATE);
+           ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_SETDEFAULT_UPD_DOUPDATE);
 
            if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
            {
@@ -2081,20 +2089,20 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
                appendStringInfo(&querybuf, "UPDATE ONLY %s SET", fkrelname);
                querysep = "";
                qualsep = "WHERE";
-               for (i = 0; i < riinfo.nkeys; i++)
+               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_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]));
+                                RIAttName(fk_rel, riinfo->fk_attnums[i]));
                    appendStringInfo(&querybuf,
                                     "%s %s = DEFAULT",
                                     querysep, attname);
                    sprintf(paramname, "$%d", i + 1);
                    ri_GenerateQual(&qualbuf, qualsep,
                                    paramname, pk_type,
-                                   riinfo.pf_eq_oprs[i],
+                                   riinfo->pf_eq_oprs[i],
                                    attname, fk_type);
                    querysep = ",";
                    qualsep = "AND";
@@ -2103,14 +2111,14 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
                appendStringInfoString(&querybuf, qualbuf.data);
 
                /* Prepare and save the plan */
-               qplan = ri_PlanCheck(querybuf.data, riinfo.nkeys, queryoids,
+               qplan = ri_PlanCheck(querybuf.data, riinfo->nkeys, queryoids,
                                     &qkey, fk_rel, pk_rel, true);
            }
 
            /*
             * We have a plan now. Run it to update the existing references.
             */
-           ri_PerformCheck(&riinfo, &qkey, qplan,
+           ri_PerformCheck(riinfo, &qkey, qplan,
                            fk_rel, pk_rel,
                            old_row, NULL,
                            true,       /* must detect new rows */
@@ -2148,7 +2156,7 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
 
        default:
            elog(ERROR, "unrecognized confmatchtype: %d",
-                riinfo.confmatchtype);
+                riinfo->confmatchtype);
            break;
    }
 
@@ -2171,21 +2179,21 @@ bool
 RI_FKey_pk_upd_check_required(Trigger *trigger, Relation pk_rel,
                              HeapTuple old_row, HeapTuple new_row)
 {
-   RI_ConstraintInfo riinfo;
+   const RI_ConstraintInfo *riinfo;
 
    /*
     * Get arguments.
     */
-   ri_FetchConstraintInfo(&riinfo, trigger, pk_rel, true);
+   riinfo = ri_FetchConstraintInfo(trigger, pk_rel, true);
 
    /*
     * Nothing to do if no columns (satisfaction of such a constraint only
     * requires existence of a PK row, and this update won't change that).
     */
-   if (riinfo.nkeys == 0)
+   if (riinfo->nkeys == 0)
        return false;
 
-   switch (riinfo.confmatchtype)
+   switch (riinfo->confmatchtype)
    {
        case FKCONSTR_MATCH_SIMPLE:
        case FKCONSTR_MATCH_FULL:
@@ -2194,11 +2202,11 @@ RI_FKey_pk_upd_check_required(Trigger *trigger, Relation pk_rel,
             * 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(old_row, &riinfo, true) != RI_KEYS_NONE_NULL)
+           if (ri_NullCheck(old_row, riinfo, true) != RI_KEYS_NONE_NULL)
                return false;
 
            /* If all old and new key values are equal, no check is needed */
-           if (ri_KeysEqual(pk_rel, old_row, new_row, &riinfo, true))
+           if (ri_KeysEqual(pk_rel, old_row, new_row, riinfo, true))
                return false;
 
            /* Else we need to fire the trigger. */
@@ -2213,7 +2221,7 @@ RI_FKey_pk_upd_check_required(Trigger *trigger, Relation pk_rel,
 
        default:
            elog(ERROR, "unrecognized confmatchtype: %d",
-                riinfo.confmatchtype);
+                riinfo->confmatchtype);
            break;
    }
 
@@ -2235,28 +2243,28 @@ bool
 RI_FKey_fk_upd_check_required(Trigger *trigger, Relation fk_rel,
                              HeapTuple old_row, HeapTuple new_row)
 {
-   RI_ConstraintInfo riinfo;
+   const RI_ConstraintInfo *riinfo;
 
    /*
     * Get arguments.
     */
-   ri_FetchConstraintInfo(&riinfo, trigger, fk_rel, false);
+   riinfo = ri_FetchConstraintInfo(trigger, fk_rel, false);
 
    /*
     * Nothing to do if no columns (satisfaction of such a constraint only
     * requires existence of a PK row, and this update won't change that).
     */
-   if (riinfo.nkeys == 0)
+   if (riinfo->nkeys == 0)
        return false;
 
-   switch (riinfo.confmatchtype)
+   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.
             */
-           if (ri_NullCheck(new_row, &riinfo, false) != RI_KEYS_NONE_NULL)
+           if (ri_NullCheck(new_row, riinfo, false) != RI_KEYS_NONE_NULL)
                return false;
 
            /*
@@ -2271,7 +2279,7 @@ RI_FKey_fk_upd_check_required(Trigger *trigger, Relation fk_rel,
                return true;
 
            /* If all old and new key values are equal, no check is needed */
-           if (ri_KeysEqual(fk_rel, old_row, new_row, &riinfo, false))
+           if (ri_KeysEqual(fk_rel, old_row, new_row, riinfo, false))
                return false;
 
            /* Else we need to fire the trigger. */
@@ -2286,7 +2294,7 @@ RI_FKey_fk_upd_check_required(Trigger *trigger, Relation fk_rel,
             * invalidated before the constraint is to be checked, but we
             * should queue the event to apply the check later.
             */
-           switch (ri_NullCheck(new_row, &riinfo, false))
+           switch (ri_NullCheck(new_row, riinfo, false))
            {
                case RI_KEYS_ALL_NULL:
                    return false;
@@ -2308,7 +2316,7 @@ RI_FKey_fk_upd_check_required(Trigger *trigger, Relation fk_rel,
                return true;
 
            /* If all old and new key values are equal, no check is needed */
-           if (ri_KeysEqual(fk_rel, old_row, new_row, &riinfo, false))
+           if (ri_KeysEqual(fk_rel, old_row, new_row, riinfo, false))
                return false;
 
            /* Else we need to fire the trigger. */
@@ -2323,7 +2331,7 @@ RI_FKey_fk_upd_check_required(Trigger *trigger, Relation fk_rel,
 
        default:
            elog(ERROR, "unrecognized confmatchtype: %d",
-                riinfo.confmatchtype);
+                riinfo->confmatchtype);
            break;
    }
 
@@ -2352,7 +2360,7 @@ RI_FKey_fk_upd_check_required(Trigger *trigger, Relation fk_rel,
 bool
 RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
 {
-   RI_ConstraintInfo riinfo;
+   const RI_ConstraintInfo *riinfo;
    StringInfoData querybuf;
    char        pkrelname[MAX_QUOTED_REL_NAME_LEN];
    char        fkrelname[MAX_QUOTED_REL_NAME_LEN];
@@ -2368,7 +2376,7 @@ RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
    SPIPlanPtr  qplan;
 
    /* Fetch constraint info. */
-   ri_FetchConstraintInfo(&riinfo, trigger, fk_rel, false);
+   riinfo = ri_FetchConstraintInfo(trigger, fk_rel, false);
 
    /*
     * Check to make sure current user has enough permissions to do the test
@@ -2389,14 +2397,14 @@ RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
    fkrte->relkind = fk_rel->rd_rel->relkind;
    fkrte->requiredPerms = ACL_SELECT;
 
-   for (i = 0; i < riinfo.nkeys; i++)
+   for (i = 0; i < riinfo->nkeys; i++)
    {
        int         attno;
 
-       attno = riinfo.pk_attnums[i] - FirstLowInvalidHeapAttributeNumber;
+       attno = riinfo->pk_attnums[i] - FirstLowInvalidHeapAttributeNumber;
        pkrte->selectedCols = bms_add_member(pkrte->selectedCols, attno);
 
-       attno = riinfo.fk_attnums[i] - FirstLowInvalidHeapAttributeNumber;
+       attno = riinfo->fk_attnums[i] - FirstLowInvalidHeapAttributeNumber;
        fkrte->selectedCols = bms_add_member(fkrte->selectedCols, attno);
    }
 
@@ -2421,10 +2429,10 @@ RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
    initStringInfo(&querybuf);
    appendStringInfo(&querybuf, "SELECT ");
    sep = "";
-   for (i = 0; i < riinfo.nkeys; i++)
+   for (i = 0; i < riinfo->nkeys; i++)
    {
        quoteOneName(fkattname,
-                    RIAttName(fk_rel, riinfo.fk_attnums[i]));
+                    RIAttName(fk_rel, riinfo->fk_attnums[i]));
        appendStringInfo(&querybuf, "%sfk.%s", sep, fkattname);
        sep = ", ";
    }
@@ -2438,20 +2446,20 @@ RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
    strcpy(pkattname, "pk.");
    strcpy(fkattname, "fk.");
    sep = "(";
-   for (i = 0; i < riinfo.nkeys; i++)
+   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]);
+       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]));
+                    RIAttName(pk_rel, riinfo->pk_attnums[i]));
        quoteOneName(fkattname + 3,
-                    RIAttName(fk_rel, riinfo.fk_attnums[i]));
+                    RIAttName(fk_rel, riinfo->fk_attnums[i]));
        ri_GenerateQual(&querybuf, sep,
                        pkattname, pk_type,
-                       riinfo.pf_eq_oprs[i],
+                       riinfo->pf_eq_oprs[i],
                        fkattname, fk_type);
        if (pk_coll != fk_coll)
            ri_GenerateQualCollation(&querybuf, pk_coll);
@@ -2462,17 +2470,17 @@ RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
     * 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]));
+   quoteOneName(pkattname, RIAttName(pk_rel, riinfo->pk_attnums[0]));
    appendStringInfo(&querybuf, ") WHERE pk.%s IS NULL AND (", pkattname);
 
    sep = "";
-   for (i = 0; i < riinfo.nkeys; i++)
+   for (i = 0; i < riinfo->nkeys; i++)
    {
-       quoteOneName(fkattname, RIAttName(fk_rel, riinfo.fk_attnums[i]));
+       quoteOneName(fkattname, RIAttName(fk_rel, riinfo->fk_attnums[i]));
        appendStringInfo(&querybuf,
                         "%sfk.%s IS NOT NULL",
                         sep, fkattname);
-       switch (riinfo.confmatchtype)
+       switch (riinfo->confmatchtype)
        {
            case FKCONSTR_MATCH_SIMPLE:
                sep = " AND ";
@@ -2487,7 +2495,7 @@ RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
                break;
            default:
                elog(ERROR, "unrecognized confmatchtype: %d",
-                    riinfo.confmatchtype);
+                    riinfo->confmatchtype);
                break;
        }
    }
@@ -2547,6 +2555,7 @@ RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
    {
        HeapTuple   tuple = SPI_tuptable->vals[0];
        TupleDesc   tupdesc = SPI_tuptable->tupdesc;
+       RI_ConstraintInfo fake_riinfo;
 
        /*
         * The columns to look at in the result tuple are 1..N, not whatever
@@ -2557,29 +2566,30 @@ RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
         * ri_ReportViolation, overriding its normal habit of using the pk_rel
         * or fk_rel's tupdesc.
         */
-       for (i = 0; i < riinfo.nkeys; i++)
-           riinfo.fk_attnums[i] = i + 1;
+       memcpy(&fake_riinfo, riinfo, sizeof(RI_ConstraintInfo));
+       for (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 (riinfo.confmatchtype == FKCONSTR_MATCH_FULL &&
-           ri_NullCheck(tuple, &riinfo, false) != RI_KEYS_NONE_NULL)
+       if (fake_riinfo.confmatchtype == FKCONSTR_MATCH_FULL &&
+           ri_NullCheck(tuple, &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(riinfo.conname)),
+                           NameStr(fake_riinfo.conname)),
                     errdetail("MATCH FULL does not allow mixing of null and nonnull key values.")));
 
        /*
         * We tell ri_ReportViolation we were doing the RI_PLAN_CHECK_LOOKUPPK
-        * query, which isn't true, but will cause it to use riinfo.fk_attnums
-        * as we need.
+        * query, which isn't true, but will cause it to use
+        * fake_riinfo.fk_attnums as we need.
         */
-       ri_ReportViolation(&riinfo,
+       ri_ReportViolation(&fake_riinfo,
                           pk_rel, fk_rel,
                           tuple, tupdesc,
                           RI_PLAN_CHECK_LOOKUPPK, false);
@@ -2828,19 +2838,13 @@ ri_CheckTrigger(FunctionCallInfo fcinfo, const char *funcname, int tgkind)
 
 
 /*
- * Fetch the pg_constraint entry for the FK constraint, and fill *riinfo
+ * Fetch the RI_ConstraintInfo struct for the trigger's FK constraint.
  */
-static void
-ri_FetchConstraintInfo(RI_ConstraintInfo *riinfo,
-                      Trigger *trigger, Relation trig_rel, bool rel_is_pk)
+static const RI_ConstraintInfo *
+ri_FetchConstraintInfo(Trigger *trigger, Relation trig_rel, bool rel_is_pk)
 {
    Oid         constraintOid = trigger->tgconstraint;
-   HeapTuple   tup;
-   Form_pg_constraint conForm;
-   Datum       adatum;
-   bool        isNull;
-   ArrayType  *arr;
-   int         numkeys;
+   const RI_ConstraintInfo *riinfo;
 
    /*
     * Check that the FK constraint's OID is available; it might not be if
@@ -2854,32 +2858,76 @@ ri_FetchConstraintInfo(RI_ConstraintInfo *riinfo,
                 trigger->tgname, RelationGetRelationName(trig_rel)),
                 errhint("Remove this referential integrity trigger and its mates, then do ALTER TABLE ADD CONSTRAINT.")));
 
-   /* OK, fetch the tuple */
-   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);
+   /* 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 (conForm->contype != CONSTRAINT_FOREIGN ||
-           conForm->conrelid != trigger->tgconstrrelid ||
-           conForm->confrelid != RelationGetRelid(trig_rel))
+       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 (conForm->contype != CONSTRAINT_FOREIGN ||
-           conForm->conrelid != RelationGetRelid(trig_rel) ||
-           conForm->confrelid != trigger->tgconstrrelid)
+       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));
    }
 
+   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;
+   Datum       adatum;
+   bool        isNull;
+   ArrayType  *arr;
+   int         numkeys;
+
+   /*
+    * 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,
+                                              (void *) &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 */
-   riinfo->constraint_id = constraintOid;
+   Assert(riinfo->constraint_id == constraintOid);
+   riinfo->oidHashValue = GetSysCacheHashValue1(CONSTROID,
+                                            ObjectIdGetDatum(constraintOid));
    memcpy(&riinfo->conname, &conForm->conname, sizeof(NameData));
    riinfo->pk_relid = conForm->confrelid;
    riinfo->fk_relid = conForm->conrelid;
@@ -2975,6 +3023,34 @@ ri_FetchConstraintInfo(RI_ConstraintInfo *riinfo,
        pfree(arr);             /* free de-toasted copy, if any */
 
    ReleaseSysCache(tup);
+
+   riinfo->valid = true;
+
+   return riinfo;
+}
+
+/*
+ * 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.
+ */
+static void
+InvalidateConstraintCacheCallBack(Datum arg, int cacheid, uint32 hashvalue)
+{
+   HASH_SEQ_STATUS status;
+   RI_ConstraintInfo *hentry;
+
+   Assert(ri_constraint_cache != NULL);
+
+   hash_seq_init(&status, ri_constraint_cache);
+   while ((hentry = (RI_ConstraintInfo *) hash_seq_search(&status)) != NULL)
+   {
+       if (hashvalue == 0 || hentry->oidHashValue == hashvalue)
+           hentry->valid = false;
+   }
 }
 
 
@@ -3339,8 +3415,7 @@ ri_NullCheck(HeapTuple tup,
 /* ----------
  * ri_InitHashTables -
  *
- * Initialize our internal hash tables for prepared
- * query plans and comparison operators.
+ * Initialize our internal hash tables.
  * ----------
  */
 static void
@@ -3348,18 +3423,33 @@ ri_InitHashTables(void)
 {
    HASHCTL     ctl;
 
+   memset(&ctl, 0, sizeof(ctl));
+   ctl.keysize = sizeof(Oid);
+   ctl.entrysize = sizeof(RI_ConstraintInfo);
+   ctl.hash = oid_hash;
+   ri_constraint_cache = hash_create("RI constraint cache",
+                                     RI_INIT_CONSTRAINTHASHSIZE,
+                                     &ctl, HASH_ELEM | HASH_FUNCTION);
+
+   /* Arrange to flush cache on pg_constraint changes */
+   CacheRegisterSyscacheCallback(CONSTROID,
+                                 InvalidateConstraintCacheCallBack,
+                                 (Datum) 0);
+
    memset(&ctl, 0, sizeof(ctl));
    ctl.keysize = sizeof(RI_QueryKey);
    ctl.entrysize = sizeof(RI_QueryHashEntry);
    ctl.hash = tag_hash;
-   ri_query_cache = hash_create("RI query cache", RI_INIT_QUERYHASHSIZE,
+   ri_query_cache = hash_create("RI query cache",
+                                RI_INIT_QUERYHASHSIZE,
                                 &ctl, HASH_ELEM | HASH_FUNCTION);
 
    memset(&ctl, 0, sizeof(ctl));
    ctl.keysize = sizeof(RI_CompareKey);
    ctl.entrysize = sizeof(RI_CompareHashEntry);
    ctl.hash = tag_hash;
-   ri_compare_cache = hash_create("RI compare cache", RI_INIT_QUERYHASHSIZE,
+   ri_compare_cache = hash_create("RI compare cache",
+                                  RI_INIT_QUERYHASHSIZE,
                                   &ctl, HASH_ELEM | HASH_FUNCTION);
 }