/*------------------------------------------------------------------------- * * 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 "catalog/pg_proc.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/rangetypes.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] 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] 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] 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] 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] 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] 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] 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] 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 () 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; }