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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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34
src/backend/utils/cache/lsyscache.c vendored
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.147 2007/01/30 01:33:36 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.148 2007/02/14 01:58:57 tgl Exp $
*
* NOTES
* Eventually, the index information should go through here, too.
@ -20,6 +20,7 @@
#include "bootstrap/bootstrap.h"
#include "catalog/pg_amop.h"
#include "catalog/pg_amproc.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_operator.h"
@ -897,10 +898,37 @@ get_atttypetypmod(Oid relid, AttrNumber attnum,
ReleaseSysCache(tp);
}
/* ---------- INDEX CACHE ---------- */
/* ---------- CONSTRAINT CACHE ---------- */
/* watch this space...
/*
* get_constraint_name
* Returns the name of a given pg_constraint entry.
*
* Returns a palloc'd copy of the string, or NULL if no such constraint.
*
* NOTE: since constraint name is not unique, be wary of code that uses this
* for anything except preparing error messages.
*/
char *
get_constraint_name(Oid conoid)
{
HeapTuple tp;
tp = SearchSysCache(CONSTROID,
ObjectIdGetDatum(conoid),
0, 0, 0);
if (HeapTupleIsValid(tp))
{
Form_pg_constraint contup = (Form_pg_constraint) GETSTRUCT(tp);
char *result;
result = pstrdup(NameStr(contup->conname));
ReleaseSysCache(tp);
return result;
}
else
return NULL;
}
/* ---------- OPCLASS CACHE ---------- */