From 41faafbd75a5c70fa94bf57e408e6b29c4425ceb Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Mon, 6 Apr 2020 11:05:54 +0900 Subject: Preserve clustered index after rewrites with ALTER TABLE A table rewritten by ALTER TABLE would lose tracking of an index usable for CLUSTER. This setting is tracked by pg_index.indisclustered and is controlled by ALTER TABLE, so some extra work was needed to restore it properly. Note that ALTER TABLE only marks the index that can be used for clustering, and does not do the actual operation. Author: Amit Langote, Justin Pryzby Reviewed-by: Ibrar Ahmed, Michael Paquier Discussion: https://postgr.es/m/20200202161718.GI13621@telsasoft.com Backpatch-through: 9.5 --- src/backend/utils/cache/lsyscache.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) (limited to 'src/backend/utils/cache/lsyscache.c') diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c index 047a8ced02f..913cad35105 100644 --- a/src/backend/utils/cache/lsyscache.c +++ b/src/backend/utils/cache/lsyscache.c @@ -3181,3 +3181,26 @@ get_index_isreplident(Oid index_oid) return result; } + +/* + * get_index_isclustered + * + * Given the index OID, return pg_index.indisclustered. + */ +bool +get_index_isclustered(Oid index_oid) +{ + bool isclustered; + HeapTuple tuple; + Form_pg_index rd_index; + + tuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(index_oid)); + if (!HeapTupleIsValid(tuple)) + elog(ERROR, "cache lookup failed for index %u", index_oid); + + rd_index = (Form_pg_index) GETSTRUCT(tuple); + isclustered = rd_index->indisclustered; + ReleaseSysCache(tuple); + + return isclustered; +} -- cgit v1.2.3