Date: Wed, 12 Aug 2020 18:48:28 -0400
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Dependencies for partitioned indexes are still a mess
Message-ID: <20200812224828.GA3888@alvherre.pgsql>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="AqsLC8rIMeq19msA"
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <3170626.1594842723@sss.pgh.pa.us>
User-Agent: Mutt/1.10.1 (2018-07-13)
Precedence: bulk


--AqsLC8rIMeq19msA
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit

On 2020-Jul-15, Tom Lane wrote:

> Issue #2: parallel restore does not work
> 
> 1. dropdb r2; createdb r2
> 2. pg_restore -j8 -d r2 regression.dump 
> 
> This is fairly timing-dependent, but some attempts fail with messages
> like
> 
> pg_restore: while PROCESSING TOC:
> pg_restore: from TOC entry 6684; 2606 29166 FK CONSTRAINT fk fk_a_fkey postgres
> pg_restore: error: could not execute query: ERROR:  there is no unique constraint matching given keys for referenced table "pk"
> Command was: ALTER TABLE fkpart3.fk
>     ADD CONSTRAINT fk_a_fkey FOREIGN KEY (a) REFERENCES fkpart3.pk(a);

Hmm, we do make the FK constraint depend on the ATTACH for the direct
children; what I think we're lacking is dependencies on descendants
twice-removed (?) or higher.  This mock patch seems to fix this problem
by adding dependencies recursively on all children of the index; I no
longer see this problem with it.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

--AqsLC8rIMeq19msA
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment; filename="add-recursive-deps.patch"

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 42391b0b2c..c78bbd7d00 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -7412,6 +7412,24 @@ getExtendedStatistics(Archive *fout)
 	destroyPQExpBuffer(query);
 }
 
+/* recursive bit of getConstraints */
+static void
+addConstrChildIdxDeps(DumpableObject *dobj, IndxInfo *refidx)
+{
+	SimplePtrListCell *cell;
+
+	for (cell = refidx->partattaches.head; cell; cell = cell->next)
+	{
+		DumpableObject *childobj = (DumpableObject *) cell->ptr;
+		IndexAttachInfo *attach = (IndexAttachInfo *) childobj;
+
+		addObjectDependency(dobj, childobj->dumpId);
+
+		if (attach->partitionIdx->partattaches.head != NULL)
+			addConstrChildIdxDeps(dobj, attach->partitionIdx);
+	}
+}
+
 /*
  * getConstraints
  *
@@ -7517,25 +7535,20 @@ getConstraints(Archive *fout, TableInfo tblinfo[], int numTables)
 			reftable = findTableByOid(constrinfo[j].confrelid);
 			if (reftable && reftable->relkind == RELKIND_PARTITIONED_TABLE)
 			{
-				IndxInfo   *refidx;
 				Oid			indexOid = atooid(PQgetvalue(res, j, i_conindid));
 
 				if (indexOid != InvalidOid)
 				{
 					for (int k = 0; k < reftable->numIndexes; k++)
 					{
-						SimplePtrListCell *cell;
+						IndxInfo   *refidx;
 
 						/* not our index? */
 						if (reftable->indexes[k].dobj.catId.oid != indexOid)
 							continue;
 
 						refidx = &reftable->indexes[k];
-						for (cell = refidx->partattaches.head; cell;
-							 cell = cell->next)
-							addObjectDependency(&constrinfo[j].dobj,
-												((DumpableObject *)
-												 cell->ptr)->dumpId);
+						addConstrChildIdxDeps(&constrinfo[j].dobj, refidx);
 						break;
 					}
 				}

--AqsLC8rIMeq19msA--