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Back-patch Jan's fix to avoid primary key lookup (and lock) if foreign key

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does not change on UPDATE.
This commit is contained in:
Tom Lane
2003-05-21 18:14:46 +00:00
parent af1850fc1a
commit 3284e342a2
2 changed files with 34 additions and 8 deletions
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40
src/backend/utils/adt/ri_triggers.c
View File

@ -17,7 +17,7 @@
*
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
*
* $Header: /cvsroot/pgsql/src/backend/utils/adt/ri_triggers.c,v 1.43.2.2 2003/04/26 22:21:58 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/ri_triggers.c,v 1.43.2.3 2003/05/21 18:14:46 tgl Exp $
*
* ----------
*/
@ -395,13 +395,19 @@ RI_FKey_check(PG_FUNCTION_ARGS)
}
/*
* Note: We cannot avoid the check on UPDATE, even if old and new key
* are the same. Otherwise, someone could DELETE the PK that consists
* of the DEFAULT values, and if there are any references, a ON DELETE
* SET DEFAULT action would update the references to exactly these
* values but we wouldn't see that weired case (this is the only place
* to see it).
* No need to check anything if old and new references are the
* same on UPDATE.
*/
if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
{
if (ri_KeysEqual(fk_rel, old_row, new_row, &qkey,
RI_KEYPAIR_FK_IDX))
{
heap_close(pk_rel, RowShareLock);
return PointerGetDatum(NULL);
}
}
if (SPI_connect() != SPI_OK_CONNECT)
elog(WARNING, "SPI_connect() failed in RI_FKey_check()");
@ -2741,6 +2747,16 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
heap_close(fk_rel, RowExclusiveLock);
/*
* In the case we delete the row who's key is equal to the
* default values AND a referencing row in the foreign key
* table exists, we would just have updated it to the same
* values. We need to do another lookup now and in case a
* reference exists, abort the operation. That is already
* implemented in the NO ACTION trigger.
*/
RI_FKey_noaction_del(fcinfo);
return PointerGetDatum(NULL);
/*
@ -3010,6 +3026,16 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
heap_close(fk_rel, RowExclusiveLock);
/*
* In the case we updated the row who's key was equal to the
* default values AND a referencing row in the foreign key
* table exists, we would just have updated it to the same
* values. We need to do another lookup now and in case a
* reference exists, abort the operation. That is already
* implemented in the NO ACTION trigger.
*/
RI_FKey_noaction_upd(fcinfo);
return PointerGetDatum(NULL);
/*

2
src/test/regress/expected/foreign_key.out
View File

@ -882,7 +882,7 @@ delete from pktable where base1=2;
ERROR: $1 referential integrity violation - key in pktable still referenced from pktable
-- fails (1,1) is being referenced (twice)
update pktable set base1=3 where base1=1;
ERROR: $1 referential integrity violation - key referenced from pktable not found in pktable
ERROR: $1 referential integrity violation - key in pktable still referenced from pktable
-- this sequence of two deletes will work, since after the first there will be no (2,*) references
delete from pktable where base2=2;
delete from pktable where base1=2;