Hi Alvaro,
I re-analyzed this issue, and here is my analysis process.
step 1: CREATE TABLE p ( id bigint PRIMARY KEY )
PARTITION BY list (id);
step2: CREATE TABLE p_1 PARTITION OF p FOR VALUES IN (1);
step3: CREATE TABLE r_1 (
id bigint PRIMARY KEY,
p_id bigint NOT NULL,
FOREIGN KEY (p_id) REFERENCES p (id)
);
After above step 3 operations, we have below catalog tuples:
postgres=# select oid, relname from pg_class where relname = 'p';
oid | relname
-------+---------
16384 | p
(1 row)
postgres=# select oid, relname from pg_class where relname = 'p_1';
oid | relname
-------+---------
16389 | p_1
(1 row)
postgres=# select oid, relname from pg_class where relname = 'r_1';
oid | relname
-------+---------
16394 | r_1
(1 row)
postgres=# select oid, conname,conrelid,conparentid,confrelid from
pg_constraint where conrelid = 16394;
oid | conname | conrelid | conparentid | confrelid
-------+-------------------+----------+-------------+-----------
16397 | r_1_p_id_not_null | 16394 | 0 | 0
16399 | r_1_pkey | 16394 | 0 | 0
16400 | r_1_p_id_fkey | 16394 | 0 | 16384
16403 | r_1_p_id_fkey1 | 16394 | 16400 | 16389
(4 rows)
postgres=# select oid, tgrelid, tgparentid,
tgconstrrelid,tgconstrindid,tgconstraint from pg_trigger where tgconstraint
= 16403;
oid | tgrelid | tgparentid | tgconstrrelid | tgconstrindid | tgconstraint
-------+---------+------------+---------------+---------------+--------------
16404 | 16389 | 16401 | 16394 | 16392 | 16403
16405 | 16389 | 16402 | 16394 | 16392 | 16403
(2 rows)
postgres=# select oid, tgrelid, tgparentid,
tgconstrrelid,tgconstrindid,tgconstraint from pg_trigger where tgconstraint
= 16400;
oid | tgrelid | tgparentid | tgconstrrelid | tgconstrindid | tgconstraint
-------+---------+------------+---------------+---------------+--------------
16401 | 16384 | 0 | 16394 | 16387 | 16400
16402 | 16384 | 0 | 16394 | 16387 | 16400
16406 | 16394 | 0 | 16384 | 16387 | 16400
16407 | 16394 | 0 | 16384 | 16387 | 16400
(4 rows)
Because table p is partitioned table and it has one child table p_1. So
when r_1 add foreign key constraint, according to addFkRecurseReferenced(),
each partition should have one pg_constraint row(e.g. r_1_p_id_fkey1).
After called addFkRecurseReferenced() in ATAddForeignKeyConstraint(),
addFkRecurseReferencing() will be called, in which
it will add INSERT check trigger and UPDATE check trigger for r_1_p_id_fkey
but not for r_1_p_id_fkey1.
So when detach r_1 from r, according to DetachPartitionFinalize(), the
inherited fks should unlink relationship from parent.
The created INSERT and UPDATE check triggers should unlink relationship
link fks. But just like I said above, the r_1_p_id_fkey1
actually doesn't have INSERT check trigger.
I slightly modified the previous patch，but I didn't add test case, because
I found another issue.
After done ALTER TABLE r ATTACH PARTITION r_1 FOR VALUES IN (1);
I run the oidjoins.sql and has warnings as belwo:
psql:/tender/postgres/src/test/regress/sql/oidjoins.sql:49: WARNING: FK
VIOLATION IN pg_trigger({tgparentid}): ("(0,3)",16401)
psql:/tender/postgres/src/test/regress/sql/oidjoins.sql:49: WARNING: FK
VIOLATION IN pg_trigger({tgparentid}): ("(0,4)",16402)
postgres=# select oid, tgrelid, tgparentid,
tgconstrrelid,tgconstrindid,tgconstraint from pg_trigger where oid >= 16384;
oid | tgrelid | tgparentid | tgconstrrelid | tgconstrindid |
tgconstraint
-------+---------+------------+---------------+---------------+--------------
16404 | 16389 | 16401 | 16394 | 16392 | 16403
16405 | 16389 | 16402 | 16394 | 16392 | 16403
16415 | 16384 | 0 | 16408 | 16387 | 16414
16416 | 16384 | 0 | 16408 | 16387 | 16414
16418 | 16389 | 16415 | 16408 | 16392 | 16417
16419 | 16389 | 16416 | 16408 | 16392 | 16417
16420 | 16408 | 0 | 16384 | 16387 | 16414
16421 | 16408 | 0 | 16384 | 16387 | 16414
16406 | 16394 | 16420 | 16384 | 16387 | 16400
16407 | 16394 | 16421 | 16384 | 16387 | 16400
(10 rows)
oid = 16401 and oid = 16402 has been deleted.
The two trigger tuples are deleted in tryAttachPartitionForeignKey called
by CloneFkReferencing.
/*
* Looks good! Attach this constraint. The action triggers in the new
* partition become redundant -- the parent table already has equivalent
* ones, and those will be able to reach the partition. Remove the ones
* in the partition. We identify them because they have our constraint
* OID, as well as being on the referenced rel.
*/
The attached patch can't fix above issue. I'm not sure about the impact of
this issue. Maybe redundant triggers no need removed.
But it surely make oidjoings.sql fail if I add test case into v2 patch, so
I don't add test case in v2 patch.
No test case is not good patch. I just share my idea about this issue. Hope
to get your reply.
Alvaro Herrera <alvhe...@alvh.no-ip.org> 于2023年10月25日周三 20:13写道：
> On 2023-Oct-25, tender wang wrote:
>
> > Hi
> > Is there any conclusion to this issue?
>
> None yet. I intend to work on this at some point, hopefully soon.
>
> --
> Álvaro Herrera PostgreSQL Developer —
> https://www.EnterpriseDB.com/
>
From 24491419ad65871e54207d3ef481d8abe529e1e1 Mon Sep 17 00:00:00 2001
From: "tender.wang" <tender.wang@openpie.com>
Date: Fri, 27 Oct 2023 13:48:48 +0800
Subject: [PATCH v2] Fix partition detach issue.
---
src/backend/commands/tablecmds.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 416a98e7ce..3b897b620a 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -19356,7 +19356,9 @@ DetachPartitionFinalize(Relation rel, Relation partRel, bool concurrent,
{
ForeignKeyCacheInfo *fk = lfirst(cell);
HeapTuple contup;
+ HeapTuple parentConTup;
Form_pg_constraint conform;
+ Form_pg_constraint parentConForm;
Constraint *fkconstraint;
Oid insertTriggerOid,
updateTriggerOid;
@@ -19374,6 +19376,24 @@ DetachPartitionFinalize(Relation rel, Relation partRel, bool concurrent,
continue;
}
+ /* For referenced-side, if it is partitioned table, each partition
+ * has one row in pg_constraint. But it doesn't have INSERT CHECK trigger
+ */
+ Assert(OidIsValid(conform->conparentid));
+ parentConTup = SearchSysCache1(CONSTROID,
+ ObjectIdGetDatum(conform->conparentid));
+ if (!HeapTupleIsValid(parentConTup))
+ elog(ERROR, "cache lookup failed for constraint %u",
+ conform->conparentid);
+ parentConForm = (Form_pg_constraint)GETSTRUCT(parentConTup);
+ if (parentConForm->confrelid != conform->confrelid &&
+ parentConForm->conrelid == conform->conrelid)
+ {
+ ReleaseSysCache(contup);
+ ReleaseSysCache(parentConTup);
+ continue;
+ }
+
/* unset conparentid and adjust conislocal, coninhcount, etc. */
ConstraintSetParentConstraint(fk->conoid, InvalidOid, InvalidOid);
@@ -19421,6 +19441,7 @@ DetachPartitionFinalize(Relation rel, Relation partRel, bool concurrent,
NULL, NULL);
ReleaseSysCache(contup);
+ ReleaseSysCache(parentConTup);
}
list_free_deep(fks);
if (trigrel)
--
2.25.1
