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Fix up foreign-key mechanism so that there is a sound semantic basis for the

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equality checks it applies, instead of a random dependence on whatever
operators might be named "=".  The equality operators will now be selected
from the opfamily of the unique index that the FK constraint depends on to
enforce uniqueness of the referenced columns; therefore they are certain to be
consistent with that index's notion of equality.  Among other things this
should fix the problem noted awhile back that pg_dump may fail for foreign-key
constraints on user-defined types when the required operators aren't in the
search path.  This also means that the former warning condition about "foreign
key constraint will require costly sequential scans" is gone: if the
comparison condition isn't indexable then we'll reject the constraint
entirely. All per past discussions.

Along the way, make the RI triggers look into pg_constraint for their
information, instead of using pg_trigger.tgargs; and get rid of the always
error-prone fixed-size string buffers in ri_triggers.c in favor of building up
the RI queries in StringInfo buffers.

initdb forced due to columns added to pg_constraint and pg_trigger.
This commit is contained in:
Tom Lane
2007-02-14 01:58:58 +00:00
parent 65e2f55031
commit 7bddca3450
33 changed files with 1731 additions and 1665 deletions
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48
src/backend/utils/adt/ruleutils.c
View File

@@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.248 2007/02/03 14:06:54 petere Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.249 2007/02/14 01:58:57 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -875,30 +875,15 @@ static char *
pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
int prettyFlags)
{
StringInfoData buf;
Relation conDesc;
SysScanDesc conscan;
ScanKeyData skey[1];
HeapTuple tup;
Form_pg_constraint conForm;
StringInfoData buf;
/*
* Fetch the pg_constraint row. There's no syscache for pg_constraint so
* we must do it the hard way.
*/
conDesc = heap_open(ConstraintRelationId, AccessShareLock);
ScanKeyInit(&skey[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(constraintId));
conscan = systable_beginscan(conDesc, ConstraintOidIndexId, true,
SnapshotNow, 1, skey);
tup = systable_getnext(conscan);
if (!HeapTupleIsValid(tup))
elog(ERROR, "could not find tuple for constraint %u", constraintId);
tup = SearchSysCache(CONSTROID,
ObjectIdGetDatum(constraintId),
0, 0, 0);
if (!HeapTupleIsValid(tup)) /* should not happen */
elog(ERROR, "cache lookup failed for constraint %u", constraintId);
conForm = (Form_pg_constraint) GETSTRUCT(tup);
initStringInfo(&buf);
@@ -922,8 +907,8 @@ pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
appendStringInfo(&buf, "FOREIGN KEY (");
/* Fetch and build referencing-column list */
val = heap_getattr(tup, Anum_pg_constraint_conkey,
RelationGetDescr(conDesc), &isnull);
val = SysCacheGetAttr(CONSTROID, tup,
Anum_pg_constraint_conkey, &isnull);
if (isnull)
elog(ERROR, "null conkey for constraint %u",
constraintId);
@@ -935,8 +920,8 @@ pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
generate_relation_name(conForm->confrelid));
/* Fetch and build referenced-column list */
val = heap_getattr(tup, Anum_pg_constraint_confkey,
RelationGetDescr(conDesc), &isnull);
val = SysCacheGetAttr(CONSTROID, tup,
Anum_pg_constraint_confkey, &isnull);
if (isnull)
elog(ERROR, "null confkey for constraint %u",
constraintId);
@@ -1038,8 +1023,8 @@ pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
appendStringInfo(&buf, "UNIQUE (");
/* Fetch and build target column list */
val = heap_getattr(tup, Anum_pg_constraint_conkey,
RelationGetDescr(conDesc), &isnull);
val = SysCacheGetAttr(CONSTROID, tup,
Anum_pg_constraint_conkey, &isnull);
if (isnull)
elog(ERROR, "null conkey for constraint %u",
constraintId);
@@ -1071,8 +1056,8 @@ pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
List *context;
/* Fetch constraint expression in parsetree form */
val = heap_getattr(tup, Anum_pg_constraint_conbin,
RelationGetDescr(conDesc), &isnull);
val = SysCacheGetAttr(CONSTROID, tup,
Anum_pg_constraint_conbin, &isnull);
if (isnull)
elog(ERROR, "null conbin for constraint %u",
constraintId);
@@ -1115,8 +1100,7 @@ pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
}
/* Cleanup */
systable_endscan(conscan);
heap_close(conDesc, AccessShareLock);
ReleaseSysCache(tup);
return buf.data;
}