On Sun, 2019-04-14 at 20:15 +0200, I wrote:
> I wrote:
> > Identity columns don't work if they own more than one sequence.
>
> Alternatively, maybe getOwnedSequence should only consider sequences
> with an "internal" dependency on the column. That would avoid the problem
> without forbidding anything, since normal OWNED BY dependencies are "auto".
>
> What do you think?
Here is a patch that illustrates the second approach.
I'll add this thread to the next commitfest.
Yours,
Laurenz Albe
From 7f7bae5315b7770f1327a80eb192bb098ee9df89 Mon Sep 17 00:00:00 2001
From: Laurenz Albe <laurenz.a...@cybertec.at>
Date: Wed, 24 Apr 2019 16:46:39 +0200
Subject: [PATCH] Change getOwnedSequence to only find sequences for identity
columns
This makes identity columns work even if there is another sequence
owned by the column (with an auto dependency).
---
src/backend/catalog/pg_depend.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/src/backend/catalog/pg_depend.c b/src/backend/catalog/pg_depend.c
index d63bf5e56d..4d8c333243 100644
--- a/src/backend/catalog/pg_depend.c
+++ b/src/backend/catalog/pg_depend.c
@@ -684,14 +684,18 @@ getOwnedSequences(Oid relid, AttrNumber attnum)
Form_pg_depend deprec = (Form_pg_depend) GETSTRUCT(tup);
/*
- * We assume any auto or internal dependency of a sequence on a column
- * must be what we are looking for. (We need the relkind test because
- * indexes can also have auto dependencies on columns.)
+ * If no "attnum" was given, we are looking for sequences with an
+ * auto or internal dependency.
+ * If "attnum" was given, only look for sequences with an internal
+ * dependency, because that is what we need for identity columns.
+ * (We need the relkind test because indexes can also have auto
+ * dependencies on columns.)
*/
if (deprec->classid == RelationRelationId &&
deprec->objsubid == 0 &&
deprec->refobjsubid != 0 &&
- (deprec->deptype == DEPENDENCY_AUTO || deprec->deptype == DEPENDENCY_INTERNAL) &&
+ ((!attnum && deprec->deptype == DEPENDENCY_AUTO) ||
+ deprec->deptype == DEPENDENCY_INTERNAL) &&
get_rel_relkind(deprec->objid) == RELKIND_SEQUENCE)
{
result = lappend_oid(result, deprec->objid);
--
2.20.1
