#include "postgres.h"
#include "access/htup_details.h"
+#include "access/skey.h"
#include "access/sysattr.h"
#include "access/table.h"
#include "access/tableam.h"
#include "access/xact.h"
+#include "catalog/index.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_constraint.h"
+#include "catalog/pg_namespace.h"
#include "commands/trigger.h"
#include "executor/executor.h"
#include "executor/spi.h"
#define RI_TRIGTYPE_UPDATE 2
#define RI_TRIGTYPE_DELETE 3
+typedef struct FastPathMeta FastPathMeta;
/*
* RI_ConstraintInfo
Oid period_intersect_oper; /* anyrange * anyrange (or
* multiranges) */
dlist_node valid_link; /* Link in list of valid entries */
+
+ Oid conindid;
+ bool pk_is_partitioned;
+
+ FastPathMeta *fpmeta;
} RI_ConstraintInfo;
+typedef struct RI_CompareHashEntry RI_CompareHashEntry;
+
+/* Fast-path metadata for RI checks on foreign key referencing tables */
+typedef struct FastPathMeta
+{
+ RI_CompareHashEntry *compare_entries[RI_MAX_NUMKEYS];
+ RegProcedure regops[RI_MAX_NUMKEYS];
+ Oid subtypes[RI_MAX_NUMKEYS];
+ int strats[RI_MAX_NUMKEYS];
+} FastPathMeta;
+
/*
* RI_QueryKey
*
TupleTableSlot *oldslot, TupleTableSlot *newslot,
bool is_restrict,
bool detectNewRows, int expect_OK);
+static void ri_FastPathCheck(const RI_ConstraintInfo *riinfo,
+ Relation fk_rel, TupleTableSlot *newslot);
+static bool ri_FastPathProbeOne(Relation pk_rel, Relation idx_rel,
+ IndexScanDesc scandesc, TupleTableSlot *slot,
+ Snapshot snapshot, const RI_ConstraintInfo *riinfo,
+ ScanKeyData *skey, int nkeys);
+static bool ri_LockPKTuple(Relation pk_rel, TupleTableSlot *slot, Snapshot snap,
+ bool *concurrently_updated);
+static bool ri_fastpath_is_applicable(const RI_ConstraintInfo *riinfo);
+static void ri_CheckPermissions(Relation query_rel);
+static bool recheck_matched_pk_tuple(Relation idxrel, ScanKeyData *skeys,
+ TupleTableSlot *new_slot);
+static void build_index_scankeys(const RI_ConstraintInfo *riinfo,
+ Relation idx_rel, Datum *pk_vals,
+ char *pk_nulls, ScanKey skeys);
+static void ri_populate_fastpath_metadata(RI_ConstraintInfo *riinfo,
+ Relation fk_rel, Relation idx_rel);
static void ri_ExtractValues(Relation rel, TupleTableSlot *slot,
const RI_ConstraintInfo *riinfo, bool rel_is_pk,
Datum *vals, char *nulls);
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))
{
* 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:
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
break;
}
+ /*
+ * Fast path: probe the PK unique index directly, bypassing SPI.
+ *
+ * For non-partitioned, non-temporal FKs, we can skip the SPI machinery
+ * (plan cache, executor setup, etc.) and do a direct index scan + tuple
+ * lock. This is semantically equivalent to the SPI path below but avoids
+ * the per-row executor overhead.
+ *
+ * ri_FastPathCheck() reports the violation itself (via ereport) if no
+ * matching PK row is found, so it only returns on success.
+ */
+ if (ri_fastpath_is_applicable(riinfo))
+ {
+ ri_FastPathCheck(riinfo, fk_rel, newslot);
+ return PointerGetDatum(NULL);
+ }
+
SPI_connect();
+ /*
+ * pk_rel is opened in RowShareLock mode since that's what our eventual
+ * SELECT FOR KEY SHARE will get on it.
+ */
+ pk_rel = table_open(riinfo->pk_relid, RowShareLock);
+
/* Fetch or prepare a saved plan for the real check */
ri_BuildQueryKey(&qkey, riinfo, RI_PLAN_CHECK_LOOKUPPK);
riinfo->valid = true;
+ riinfo->conindid = conForm->conindid;
+ riinfo->pk_is_partitioned =
+ (get_rel_relkind(riinfo->pk_relid) == RELKIND_PARTITIONED_TABLE);
+
+ riinfo->fpmeta = NULL;
+
return riinfo;
}
return SPI_processed != 0;
}
+/*
+ * ri_FastPathCheck
+ * Perform FK existence check via direct index probe, bypassing SPI.
+ *
+ * If no matching PK row exists, report the violation via ri_ReportViolation(),
+ * otherwise, the function returns normally.
+ */
+static void
+ri_FastPathCheck(const RI_ConstraintInfo *riinfo,
+ Relation fk_rel, TupleTableSlot *newslot)
+{
+ Relation pk_rel;
+ Relation idx_rel;
+ IndexScanDesc scandesc;
+ TupleTableSlot *slot;
+ Datum pk_vals[INDEX_MAX_KEYS];
+ char pk_nulls[INDEX_MAX_KEYS];
+ ScanKeyData skey[INDEX_MAX_KEYS];
+ bool found = false;
+ Oid saved_userid;
+ int saved_sec_context;
+ Snapshot snapshot;
+
+ /*
+ * Advance the command counter so the snapshot sees the effects of prior
+ * triggers in this statement. Mirrors what the SPI path does in
+ * ri_PerformCheck().
+ */
+ CommandCounterIncrement();
+ snapshot = RegisterSnapshot(GetTransactionSnapshot());
+
+ pk_rel = table_open(riinfo->pk_relid, RowShareLock);
+ idx_rel = index_open(riinfo->conindid, AccessShareLock);
+
+ slot = table_slot_create(pk_rel, NULL);
+ scandesc = index_beginscan(pk_rel, idx_rel,
+ snapshot, NULL,
+ riinfo->nkeys, 0,
+ SO_NONE);
+
+ if (riinfo->fpmeta == NULL)
+ ri_populate_fastpath_metadata((RI_ConstraintInfo *) riinfo,
+ fk_rel, idx_rel);
+ Assert(riinfo->fpmeta);
+
+ GetUserIdAndSecContext(&saved_userid, &saved_sec_context);
+ SetUserIdAndSecContext(RelationGetForm(pk_rel)->relowner,
+ saved_sec_context |
+ SECURITY_LOCAL_USERID_CHANGE |
+ SECURITY_NOFORCE_RLS);
+ ri_CheckPermissions(pk_rel);
+
+ ri_ExtractValues(fk_rel, newslot, riinfo, false, pk_vals, pk_nulls);
+ build_index_scankeys(riinfo, idx_rel, pk_vals, pk_nulls, skey);
+ found = ri_FastPathProbeOne(pk_rel, idx_rel, scandesc, slot,
+ snapshot, riinfo, skey, riinfo->nkeys);
+ SetUserIdAndSecContext(saved_userid, saved_sec_context);
+ index_endscan(scandesc);
+ ExecDropSingleTupleTableSlot(slot);
+ UnregisterSnapshot(snapshot);
+
+ if (!found)
+ ri_ReportViolation(riinfo, pk_rel, fk_rel,
+ newslot, NULL,
+ RI_PLAN_CHECK_LOOKUPPK, false, false);
+
+ index_close(idx_rel, NoLock);
+ table_close(pk_rel, NoLock);
+}
+
+/*
+ * ri_FastPathProbeOne
+ * Probe the PK index for one set of scan keys, lock the matching
+ * tuple
+ *
+ * Returns true if a matching PK row was found, locked, and (if
+ * applicable) visible to the transaction snapshot.
+ */
+static bool
+ri_FastPathProbeOne(Relation pk_rel, Relation idx_rel,
+ IndexScanDesc scandesc, TupleTableSlot *slot,
+ Snapshot snapshot, const RI_ConstraintInfo *riinfo,
+ ScanKeyData *skey, int nkeys)
+{
+ bool found = false;
+
+ index_rescan(scandesc, skey, nkeys, NULL, 0);
+
+ if (index_getnext_slot(scandesc, ForwardScanDirection, slot))
+ {
+ bool concurrently_updated;
+
+ if (ri_LockPKTuple(pk_rel, slot, snapshot,
+ &concurrently_updated))
+ {
+ if (concurrently_updated)
+ found = recheck_matched_pk_tuple(idx_rel, skey, slot);
+ else
+ found = true;
+ }
+ }
+
+ return found;
+}
+
+/*
+ * ri_LockPKTuple
+ * Lock a PK tuple found by the fast-path index scan.
+ *
+ * Calls table_tuple_lock() directly with handling specific to RI checks.
+ * Returns true if the tuple was successfully locked.
+ *
+ * Sets *concurrently_updated to true if the locked tuple was reached
+ * by following an update chain (tmfd.traversed), indicating the caller
+ * should recheck the key.
+ */
+static bool
+ri_LockPKTuple(Relation pk_rel, TupleTableSlot *slot, Snapshot snap,
+ bool *concurrently_updated)
+{
+ TM_FailureData tmfd;
+ TM_Result result;
+ int lockflags = TUPLE_LOCK_FLAG_LOCK_UPDATE_IN_PROGRESS;
+
+ *concurrently_updated = false;
+
+ if (!IsolationUsesXactSnapshot())
+ lockflags |= TUPLE_LOCK_FLAG_FIND_LAST_VERSION;
+
+ result = table_tuple_lock(pk_rel, &slot->tts_tid, snap,
+ slot, GetCurrentCommandId(false),
+ LockTupleKeyShare, LockWaitBlock,
+ lockflags, &tmfd);
+
+ switch (result)
+ {
+ case TM_Ok:
+ if (tmfd.traversed)
+ *concurrently_updated = true;
+ return true;
+
+ case TM_Deleted:
+ if (IsolationUsesXactSnapshot())
+ ereport(ERROR,
+ (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
+ errmsg("could not serialize access due to concurrent update")));
+ return false;
+
+ case TM_Updated:
+ if (IsolationUsesXactSnapshot())
+ ereport(ERROR,
+ (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
+ errmsg("could not serialize access due to concurrent update")));
+
+ /*
+ * In READ COMMITTED, FIND_LAST_VERSION should have chased the
+ * chain and returned TM_Ok. Getting here means something
+ * unexpected -- fall through to error.
+ */
+ elog(ERROR, "unexpected table_tuple_lock status: %u", result);
+ break;
+
+ case TM_SelfModified:
+
+ /*
+ * The current command or a later command in this transaction
+ * modified the PK row. This shouldn't normally happen during an
+ * FK check (we're not modifying pk_rel), but handle it safely by
+ * treating the tuple as not found.
+ */
+ return false;
+
+ case TM_Invisible:
+ elog(ERROR, "attempted to lock invisible tuple");
+ break;
+
+ default:
+ elog(ERROR, "unrecognized table_tuple_lock status: %u", result);
+ break;
+ }
+
+ return false; /* keep compiler quiet */
+}
+
+static bool
+ri_fastpath_is_applicable(const RI_ConstraintInfo *riinfo)
+{
+ /*
+ * Partitioned referenced tables are skipped for simplicity, since they
+ * require routing the probe through the correct partition using
+ * PartitionDirectory.
+ */
+ if (riinfo->pk_is_partitioned)
+ return false;
+
+ /*
+ * Temporal foreign keys use range overlap and containment semantics (&&,
+ * <@, range_agg()) that inherently involve aggregation and multiple-row
+ * reasoning, so they stay on the SPI path.
+ */
+ if (riinfo->hasperiod)
+ return false;
+
+ return true;
+}
+
+/*
+ * ri_CheckPermissions
+ * Check that the current user has permissions to look into the schema of
+ * and SELECT from 'query_rel'
+ */
+static void
+ri_CheckPermissions(Relation query_rel)
+{
+ AclResult aclresult;
+
+ /* USAGE on schema. */
+ aclresult = object_aclcheck(NamespaceRelationId,
+ RelationGetNamespace(query_rel),
+ GetUserId(), ACL_USAGE);
+ if (aclresult != ACLCHECK_OK)
+ aclcheck_error(aclresult, OBJECT_SCHEMA,
+ get_namespace_name(RelationGetNamespace(query_rel)));
+
+ /* SELECT on relation. */
+ aclresult = pg_class_aclcheck(RelationGetRelid(query_rel), GetUserId(),
+ ACL_SELECT);
+ if (aclresult != ACLCHECK_OK)
+ aclcheck_error(aclresult, OBJECT_TABLE,
+ RelationGetRelationName(query_rel));
+}
+
+/*
+ * recheck_matched_pk_tuple
+ * After following an update chain (tmfd.traversed), verify that
+ * the locked PK tuple still matches the original search keys.
+ *
+ * A non-key update (e.g. changing a non-PK column) creates a new tuple version
+ * that we've now locked, but the key is unchanged -- that's fine. A key
+ * update means the value we were looking for is gone, so we should treat it as
+ * not found.
+ */
+static bool
+recheck_matched_pk_tuple(Relation idxrel, ScanKeyData *skeys,
+ TupleTableSlot *new_slot)
+{
+ /*
+ * TODO: BuildIndexInfo does a syscache lookup + palloc on every call.
+ * This only fires on the concurrent-update path (tmfd.traversed), which
+ * should be rare, so the cost is acceptable for now. If profiling shows
+ * otherwise, cache the IndexInfo in FastPathMeta.
+ */
+ IndexInfo *indexInfo = BuildIndexInfo(idxrel);
+ Datum values[INDEX_MAX_KEYS];
+ bool isnull[INDEX_MAX_KEYS];
+ bool matched = true;
+
+ /* PK indexes never have these. */
+ Assert(indexInfo->ii_Expressions == NIL &&
+ indexInfo->ii_ExclusionOps == NULL);
+
+ /* Form the index values and isnull flags given the table tuple. */
+ FormIndexDatum(indexInfo, new_slot, NULL, values, isnull);
+ for (int i = 0; i < indexInfo->ii_NumIndexKeyAttrs; i++)
+ {
+ ScanKeyData *skey = &skeys[i];
+
+ /* A PK column can never be set to NULL. */
+ Assert(!isnull[i]);
+ if (!DatumGetBool(FunctionCall2Coll(&skey->sk_func,
+ skey->sk_collation,
+ values[i],
+ skey->sk_argument)))
+ {
+ matched = false;
+ break;
+ }
+ }
+
+ return matched;
+}
+
+/*
+ * build_index_scankeys
+ * Build ScanKeys for a direct index probe of the PK's unique index.
+ *
+ * Uses cached compare entries, operator procedures, and strategy numbers
+ * from ri_populate_fastpath_metadata() rather than looking them up on
+ * each invocation. Casts FK values to the operator's expected input
+ * type if needed.
+ */
+static void
+build_index_scankeys(const RI_ConstraintInfo *riinfo,
+ Relation idx_rel, Datum *pk_vals,
+ char *pk_nulls, ScanKey skeys)
+{
+ FastPathMeta *fpmeta = riinfo->fpmeta;
+
+ Assert(fpmeta);
+
+ /*
+ * May need to cast each of the individual values of the foreign key to
+ * the corresponding PK column's type if the equality operator demands it.
+ */
+ for (int i = 0; i < riinfo->nkeys; i++)
+ {
+ if (pk_nulls[i] != 'n')
+ {
+ RI_CompareHashEntry *entry = fpmeta->compare_entries[i];
+
+ if (OidIsValid(entry->cast_func_finfo.fn_oid))
+ pk_vals[i] = FunctionCall3(&entry->cast_func_finfo,
+ pk_vals[i],
+ Int32GetDatum(-1), /* typmod */
+ BoolGetDatum(false)); /* implicit coercion */
+ }
+ }
+
+ /*
+ * Set up ScanKeys for the index scan. This is essentially how
+ * ExecIndexBuildScanKeys() sets them up.
+ */
+ for (int i = 0; i < riinfo->nkeys; i++)
+ {
+ int pkattrno = i + 1;
+
+ ScanKeyEntryInitialize(&skeys[i], 0, pkattrno,
+ fpmeta->strats[i], fpmeta->subtypes[i],
+ idx_rel->rd_indcollation[i], fpmeta->regops[i],
+ pk_vals[i]);
+ }
+}
+
+/*
+ * ri_populate_fastpath_metadata
+ * Cache per-key metadata needed by build_index_scankeys().
+ *
+ * Looks up the compare hash entry, operator procedure OID, and index
+ * strategy/subtype for each key column. Called lazily on first use
+ * and persists for the lifetime of the RI_ConstraintInfo entry.
+ */
+static void
+ri_populate_fastpath_metadata(RI_ConstraintInfo *riinfo,
+ Relation fk_rel, Relation idx_rel)
+{
+ FastPathMeta *fpmeta;
+ MemoryContext oldcxt = MemoryContextSwitchTo(TopMemoryContext);
+
+ Assert(riinfo != NULL && riinfo->valid);
+
+ fpmeta = palloc_object(FastPathMeta);
+ for (int i = 0; i < riinfo->nkeys; i++)
+ {
+ Oid eq_opr = riinfo->pf_eq_oprs[i];
+ Oid typeid = RIAttType(fk_rel, riinfo->fk_attnums[i]);
+ Oid lefttype;
+ RI_CompareHashEntry *entry = ri_HashCompareOp(eq_opr, typeid);
+
+ fpmeta->compare_entries[i] = entry;
+ fpmeta->regops[i] = get_opcode(eq_opr);
+
+ get_op_opfamily_properties(eq_opr,
+ idx_rel->rd_opfamily[i],
+ false,
+ &fpmeta->strats[i],
+ &lefttype,
+ &fpmeta->subtypes[i]);
+ }
+
+ riinfo->fpmeta = fpmeta;
+ MemoryContextSwitchTo(oldcxt);
+}
+
/*
* Extract fields from a tuple into Datum/nulls arrays
*/
/*
* ri_HashCompareOp -
*
- * See if we know how to compare two values, and create a new hash entry
- * if not.
+ * Look up or create a cache entry for the given equality operator and
+ * the caller's value type (typeid). The entry holds the operator's
+ * FmgrInfo and, if typeid doesn't match what the operator expects as
+ * its right-hand input, a cast function to coerce the value before
+ * comparison.
*/
static RI_CompareHashEntry *
ri_HashCompareOp(Oid eq_opr, Oid typeid)
* moment since that will never be generated for implicit coercions.
*/
op_input_types(eq_opr, &lefttype, &righttype);
- Assert(lefttype == righttype);
- if (typeid == lefttype)
+
+ /*
+ * pf_eq_oprs (used by the fast path) can be cross-type when the FK
+ * and PK columns differ in type, e.g. int48eq for int4 PK / int8 FK.
+ * If the FK column's type already matches what the operator expects
+ * as its right-hand input, no cast is needed.
+ */
+ if (typeid == righttype)
castfunc = InvalidOid; /* simplest case */
else
{
projects / thirdparty / postgresql.git / commitdiff
