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Create action triggers when partitions are detached

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Detaching a partition from a partitioned table that's constrained by
foreign keys requires additional action triggers on the referenced side;
otherwise, DELETE/UPDATE actions there fail to notice rows in the table
that was partition, and so are incorrectly allowed through.  With this
commit, those triggers are now created.  Conversely, when a table that
has a foreign key is attached as a partition to a table that also has
the same foreign key, those action triggers are no longer needed, so we
remove them.

Add a minimal test case verifying (part of) this.

Authors: Amit Langote, Álvaro Herrera
Discussion: https://postgr.es/m/f2b8ead5-4131-d5a8-8016-2ea0a31250af@lab.ntt.co.jp
This commit is contained in:
Alvaro Herrera
2019-01-21 19:59:07 -03:00
parent 1755440935
commit 0464fdf07f
3 changed files with 113 additions and 5 deletions
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71
src/backend/commands/tablecmds.c
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@ -7851,6 +7851,10 @@ CloneFkReferencing(Relation pg_constraint, Relation parentRel,
ForeignKeyCacheInfo *fk = lfirst_node(ForeignKeyCacheInfo, cell);
Form_pg_constraint partConstr;
HeapTuple partcontup;
Relation trigrel;
HeapTuple trigtup;
SysScanDesc scan;
ScanKeyData key;
attach_it = true;
@ -7902,7 +7906,39 @@ CloneFkReferencing(Relation pg_constraint, Relation parentRel,
ReleaseSysCache(partcontup);
/* looks good! Attach this constraint */
/*
* Looks good! Attach this constraint. Note that the action
* triggers are no longer needed, so remove them. We identify
* them because they have our constraint OID, as well as being
* on the referenced rel.
*/
trigrel = heap_open(TriggerRelationId, RowExclusiveLock);
ScanKeyInit(&key,
Anum_pg_trigger_tgconstraint,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(fk->conoid));
scan = systable_beginscan(trigrel, TriggerConstraintIndexId, true,
NULL, 1, &key);
while ((trigtup = systable_getnext(scan)) != NULL)
{
Form_pg_trigger trgform = (Form_pg_trigger) GETSTRUCT(trigtup);
if (trgform->tgconstrrelid != fk->conrelid)
continue;
if (trgform->tgrelid != fk->confrelid)
continue;
deleteDependencyRecordsForClass(TriggerRelationId,
trgform->oid,
ConstraintRelationId,
DEPENDENCY_INTERNAL);
CatalogTupleDelete(trigrel, &trigtup->t_self);
}
systable_endscan(scan);
heap_close(trigrel, RowExclusiveLock);
ConstraintSetParentConstraint(fk->conoid, parentConstrOid);
CommandCounterIncrement();
attach_it = true;
@ -15073,19 +15109,50 @@ ATExecDetachPartition(Relation rel, RangeVar *name)
}
table_close(classRel, RowExclusiveLock);
/* Detach foreign keys */
/*
* Detach any foreign keys that are inherited. This includes creating
* additional action triggers.
*/
fks = copyObject(RelationGetFKeyList(partRel));
foreach(cell, fks)
{
ForeignKeyCacheInfo *fk = lfirst(cell);
HeapTuple contup;
Form_pg_constraint conform;
Constraint *fkconstraint;
contup = SearchSysCache1(CONSTROID, ObjectIdGetDatum(fk->conoid));
if (!contup)
elog(ERROR, "cache lookup failed for constraint %u", fk->conoid);
conform = (Form_pg_constraint) GETSTRUCT(contup);
/* consider only the inherited foreign keys */
if (conform->contype != CONSTRAINT_FOREIGN ||
!OidIsValid(conform->conparentid))
{
ReleaseSysCache(contup);
continue;
}
/* unset conparentid and adjust conislocal, coninhcount, etc. */
ConstraintSetParentConstraint(fk->conoid, InvalidOid);
/*
* Make the action triggers on the referenced relation. When this was
* a partition the action triggers pointed to the parent rel (they
* still do), but now we need separate ones of our own.
*/
fkconstraint = makeNode(Constraint);
fkconstraint->conname = pstrdup(NameStr(conform->conname));
fkconstraint->fk_upd_action = conform->confupdtype;
fkconstraint->fk_del_action = conform->confdeltype;
fkconstraint->deferrable = conform->condeferrable;
fkconstraint->initdeferred = conform->condeferred;
createForeignKeyActionTriggers(partRel, conform->confrelid,
fkconstraint, fk->conoid,
conform->conindid);
ReleaseSysCache(contup);
}
list_free_deep(fks);