postgresql - Postgres ignores indexes after upgrade to 9.5 -
we have upgraded our oltp production db (2tb) v9.2.9.21 9.5.1.6 using pg_upgrade.
the upgrade went without incident , have been running week, have found optimizer ignoring indexes on 2 of our largest partitioned tables. (note: different issue 38943115, data migrated no issues).
the tables constructed individual btree indexes on bigint columns, optimizer return queries on sub-second. post-upgrade queries take 16 minutes (unusable our customers). partitions <100gb, 2-3 partitions per table.
we suspected index corruption , tried adding duplicate indexes , analyzing, new indexes still ignored unless force using enable_seqscan=no or reduce random_page_cost 2 (not practical system-wide). query response times using new indexes still appalling (16 minutes).
we have tried increasing effective_cache_size no effect. db 24x7 cannot reindex tables/ partitions.
the indexes defined so:
create index table1_column1_index on table1 using btree (column1); create index table1part1_column1_index on table1 using btree (column1); create index table1part2_column1_index on table1 using btree (column1); create index table1part3_column1_index on table1 using btree (column1);
....and repeats each subsequent column in query (the query plan isn't using composite indexes).
has encountered or suggest further steps?
Comments
Post a Comment