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Allow NOT VALID foreign key constraints on partitioned tables

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This feature was intentionally omitted when FKs were first implemented
for partitioned tables, and had been requested a few times; the
usefulness is clear.

Validation can happen for each partition individually, which is useful
to contain the number of locks held and the duration; or it can be
executed for the partitioning hierarchy as a single command, which
validates all child constraints that haven't been validated already.

This is also useful to implement NOT ENFORCED constraints on top.

Author: Amul Sul <sulamul@gmail.com>
Discussion: https://postgr.es/m/CAAJ_b96Bp=-ZwihPPtuaNX=SrZ0U6ZsXD3+fgARO0JuKa8v2jQ@mail.gmail.com
This commit is contained in:
Álvaro Herrera
2025-01-23 15:54:38 +01:00
parent b35434b134
commit b663b9436e
4 changed files with 263 additions and 58 deletions
Download Patch File Download Diff File Expand all files Collapse all files

150
src/backend/commands/tablecmds.c
View File

@ -574,8 +574,9 @@ static void createForeignKeyActionTriggers(Relation rel, Oid refRelOid,
Oid indexOid,
Oid parentDelTrigger, Oid parentUpdTrigger,
Oid *deleteTrigOid, Oid *updateTrigOid);
static bool tryAttachPartitionForeignKey(ForeignKeyCacheInfo *fk,
Oid partRelid,
static bool tryAttachPartitionForeignKey(List **wqueue,
ForeignKeyCacheInfo *fk,
Relation partition,
Oid parentConstrOid, int numfks,
AttrNumber *mapped_conkey, AttrNumber *confkey,
Oid *conpfeqop,
@ -9772,22 +9773,12 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
* Validity checks (permission checks wait till we have the column
* numbers)
*/
if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
{
if (!recurse)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot use ONLY for foreign key on partitioned table \"%s\" referencing relation \"%s\"",
RelationGetRelationName(rel),
RelationGetRelationName(pkrel))));
if (fkconstraint->skip_validation && !fkconstraint->initially_valid)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot add NOT VALID foreign key on partitioned table \"%s\" referencing relation \"%s\"",
RelationGetRelationName(rel),
RelationGetRelationName(pkrel)),
errdetail("This feature is not yet supported on partitioned tables.")));
}
if (!recurse && rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
ereport(ERROR,
errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot use ONLY for foreign key on partitioned table \"%s\" referencing relation \"%s\"",
RelationGetRelationName(rel),
RelationGetRelationName(pkrel)));
if (pkrel->rd_rel->relkind != RELKIND_RELATION &&
pkrel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
@ -10782,14 +10773,12 @@ addFkRecurseReferencing(List **wqueue, Constraint *fkconstraint, Relation rel,
*/
for (int i = 0; i < pd->nparts; i++)
{
Oid partitionId = pd->oids[i];
Relation partition = table_open(partitionId, lockmode);
Relation partition = table_open(pd->oids[i], lockmode);
List *partFKs;
AttrMap *attmap;
AttrNumber mapped_fkattnum[INDEX_MAX_KEYS];
bool attached;
ObjectAddress address;
ListCell *cell;
CheckAlterTableIsSafe(partition);
@ -10802,13 +10791,11 @@ addFkRecurseReferencing(List **wqueue, Constraint *fkconstraint, Relation rel,
/* Check whether an existing constraint can be repurposed */
partFKs = copyObject(RelationGetFKeyList(partition));
attached = false;
foreach(cell, partFKs)
foreach_node(ForeignKeyCacheInfo, fk, partFKs)
{
ForeignKeyCacheInfo *fk;
fk = lfirst_node(ForeignKeyCacheInfo, cell);
if (tryAttachPartitionForeignKey(fk,
partitionId,
if (tryAttachPartitionForeignKey(wqueue,
fk,
partition,
parentConstr,
numfks,
mapped_fkattnum,
@ -11260,8 +11247,9 @@ CloneFkReferencing(List **wqueue, Relation parentRel, Relation partRel)
{
ForeignKeyCacheInfo *fk = lfirst_node(ForeignKeyCacheInfo, lc);
if (tryAttachPartitionForeignKey(fk,
RelationGetRelid(partRel),
if (tryAttachPartitionForeignKey(wqueue,
fk,
partRel,
parentConstrOid,
numfks,
mapped_conkey,
@ -11364,8 +11352,9 @@ CloneFkReferencing(List **wqueue, Relation parentRel, Relation partRel)
* return false.
*/
static bool
tryAttachPartitionForeignKey(ForeignKeyCacheInfo *fk,
Oid partRelid,
tryAttachPartitionForeignKey(List **wqueue,
ForeignKeyCacheInfo *fk,
Relation partition,
Oid parentConstrOid,
int numfks,
AttrNumber *mapped_conkey,
@ -11379,6 +11368,7 @@ tryAttachPartitionForeignKey(ForeignKeyCacheInfo *fk,
Form_pg_constraint parentConstr;
HeapTuple partcontup;
Form_pg_constraint partConstr;
bool queueValidation;
ScanKeyData key;
SysScanDesc scan;
HeapTuple trigtup;
@ -11411,18 +11401,12 @@ tryAttachPartitionForeignKey(ForeignKeyCacheInfo *fk,
}
}
/*
* Looks good so far; do some more extensive checks. Presumably the check
* for 'convalidated' could be dropped, since we don't really care about
* that, but let's be careful for now.
*/
partcontup = SearchSysCache1(CONSTROID,
ObjectIdGetDatum(fk->conoid));
/* Looks good so far; perform more extensive checks. */
partcontup = SearchSysCache1(CONSTROID, ObjectIdGetDatum(fk->conoid));
if (!HeapTupleIsValid(partcontup))
elog(ERROR, "cache lookup failed for constraint %u", fk->conoid);
partConstr = (Form_pg_constraint) GETSTRUCT(partcontup);
if (OidIsValid(partConstr->conparentid) ||
!partConstr->convalidated ||
partConstr->condeferrable != parentConstr->condeferrable ||
partConstr->condeferred != parentConstr->condeferred ||
partConstr->confupdtype != parentConstr->confupdtype ||
@ -11434,6 +11418,13 @@ tryAttachPartitionForeignKey(ForeignKeyCacheInfo *fk,
return false;
}
/*
* Will we need to validate this constraint? A valid parent constraint
* implies that all child constraints have been validated, so if this one
* isn't, we must trigger phase 3 validation.
*/
queueValidation = parentConstr->convalidated && !partConstr->convalidated;
ReleaseSysCache(partcontup);
ReleaseSysCache(parentConstrTup);
@ -11481,7 +11472,8 @@ tryAttachPartitionForeignKey(ForeignKeyCacheInfo *fk,
systable_endscan(scan);
ConstraintSetParentConstraint(fk->conoid, parentConstrOid, partRelid);
ConstraintSetParentConstraint(fk->conoid, parentConstrOid,
RelationGetRelid(partition));
/*
* Like the constraint, attach partition's "check" triggers to the
@ -11492,10 +11484,10 @@ tryAttachPartitionForeignKey(ForeignKeyCacheInfo *fk,
&insertTriggerOid, &updateTriggerOid);
Assert(OidIsValid(insertTriggerOid) && OidIsValid(parentInsTrigger));
TriggerSetParentTrigger(trigrel, insertTriggerOid, parentInsTrigger,
partRelid);
RelationGetRelid(partition));
Assert(OidIsValid(updateTriggerOid) && OidIsValid(parentUpdTrigger));
TriggerSetParentTrigger(trigrel, updateTriggerOid, parentUpdTrigger,
partRelid);
RelationGetRelid(partition));
/*
* If the referenced table is partitioned, then the partition we're
@ -11572,7 +11564,33 @@ tryAttachPartitionForeignKey(ForeignKeyCacheInfo *fk,
table_close(pg_constraint, RowShareLock);
}
CommandCounterIncrement();
/* If validation is needed, put it in the queue now. */
if (queueValidation)
{
Relation conrel;
/*
* We updated this pg_constraint row above to set its parent;
* validating it will cause its convalidated flag to change, so we
* need CCI here. XXX it might work better to effect the convalidated
* changes for all constraints together during phase 3, but that
* requires more invasive code surgery.
*/
CommandCounterIncrement();
conrel = table_open(ConstraintRelationId, RowExclusiveLock);
partcontup = SearchSysCache1(CONSTROID, ObjectIdGetDatum(fk->conoid));
if (!HeapTupleIsValid(partcontup))
elog(ERROR, "cache lookup failed for constraint %u", fk->conoid);
/* Use the same lock as for AT_ValidateConstraint */
QueueFKConstraintValidation(wqueue, conrel, partition, partcontup,
ShareUpdateExclusiveLock);
ReleaseSysCache(partcontup);
table_close(conrel, RowExclusiveLock);
}
return true;
}
@ -12113,7 +12131,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
*
* Add an entry to the wqueue to validate the given foreign key constraint in
* Phase 3 and update the convalidated field in the pg_constraint catalog
* for the specified relation.
* for the specified relation and all its children.
*/
static void
QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation rel,
@ -12126,6 +12144,7 @@ QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation rel,
con = (Form_pg_constraint) GETSTRUCT(contuple);
Assert(con->contype == CONSTRAINT_FOREIGN);
Assert(!con->convalidated);
if (rel->rd_rel->relkind == RELKIND_RELATION)
{
@ -12151,9 +12170,48 @@ QueueFKConstraintValidation(List **wqueue, Relation conrel, Relation rel,
}
/*
* We disallow creating invalid foreign keys to or from partitioned
* tables, so ignoring the recursion bit is okay.
* If the table at either end of the constraint is partitioned, we need to
* recurse and handle every constraint that is a child of this constraint.
*/
if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ||
get_rel_relkind(con->confrelid) == RELKIND_PARTITIONED_TABLE)
{
ScanKeyData pkey;
SysScanDesc pscan;
HeapTuple childtup;
ScanKeyInit(&pkey,
Anum_pg_constraint_conparentid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(con->oid));
pscan = systable_beginscan(conrel, ConstraintParentIndexId,
true, NULL, 1, &pkey);
while (HeapTupleIsValid(childtup = systable_getnext(pscan)))
{
Form_pg_constraint childcon;
Relation childrel;
childcon = (Form_pg_constraint) GETSTRUCT(childtup);
/*
* If the child constraint has already been validated, no further
* action is required for it or its descendants, as they are all
* valid.
*/
if (childcon->convalidated)
continue;
childrel = table_open(childcon->conrelid, lockmode);
QueueFKConstraintValidation(wqueue, conrel, childrel, childtup,
lockmode);
table_close(childrel, NoLock);
}
systable_endscan(pscan);
}
/*
* Now update the catalog, while we have the door open.