[PERFORM] Another weird one with an UPDATE

[David Griffiths]

I am running an update-query to benchmark various databases; the postgres version is,   UPDATE user_account SET last_name = 'abc' WHERE user_account_id IN (SELECT user_account_id FROM commercial_entity, commercial_service WHERE yw_account_id IS NULL AND commercial_entity.commercial_entity_id = commercial_service.commercial_entity_id);     The inner query (the select), run by itself, takes about a second. Add the outer query (the update-portion), and the query dies. The machine has been vacuum-analzyed. Here is the explain-analyze:   benchtest=# EXPLAIN ANALYZE UPDATE user_account SET last_name = 'abc' benchtest-# WHERE user_account_id IN (SELECT user_account_id FROM commercial_entity, commercial_service WHERE yw_account_id IS NULL benchtest(# AND commercial_entity.commercial_entity_id = commercial_service.commercial_entity_id);  Seq Scan on user_account  (cost=0.00..813608944.88 rows=36242 width=718) (actual time=15696258.98..16311130.29 rows=3075 loops=1)   Filter: (subplan)    SubPlan      ->  Materialize  (cost=11224.77..11224.77 rows=86952 width=36) (actual time=0.06..106.40 rows=84831 loops=72483)            ->  Merge Join  (cost=0.00..11224.77 rows=86952 width=36) (actual time=0.21..1845.13 rows=85158 loops=1)                  Merge Cond: ("outer".commercial_entity_id = "inner".commercial_entity_id)                  ->  Index Scan using commercial_entity_pkey on commercial_entity  (cost=0.00..6787.27 rows=77862 width=24) (actual time=0.06..469.56 rows=78132 loops=1)                        Filter: (yw_account_id IS NULL)                  ->  Index Scan using comm_serv_comm_ent_id_i on commercial_service  (cost=0.00..2952.42 rows=88038 width=12) (actual time=0.03..444.80 rows=88038 loops=1)  Total runtime: 16332976.21 msec (10 rows)   Here are the relevant parts of the schema:       USER_ACCOUNT               Column             |            Type             |          Modifiers -------------------------------+-----------------------------+-----------------------------  user_account_id               | numeric(10,0)               | not null  first_name                    | character varying(100)      |  last_name                     | character varying(100)      | Indexes: user_account_pkey primary key btree (user_account_id),          usr_acc_last_name_i btree (last_name), Foreign Key constraints: $1 FOREIGN KEY (lang_id) REFERENCES lang(lang_id) ON UPDATE NO ACTION ON DELETE NO ACTION,                          $2 FOREIGN KEY (source_id) REFERENCES source(source_id) ON UPDATE NO ACTION ON DELETE NO ACTION,                          $3 FOREIGN KEY (user_role_id) REFERENCES user_role(user_role_id) ON UPDATE NO ACTION ON DELETE NO ACTION       COMMERCIAL_ENTITY             Column           |            Type             |                          Modifiers ---------------------------+-----------------------------+-------------------------------------------------------------  commercial_entity_id      | numeric(10,0)               | not null  yw_account_id             | numeric(10,0)               | Indexes: commercial_entity_pkey primary key btree (commercial_entity_id),          comm_ent_yw_acc_id_i btree (yw_account_id) Foreign Key constraints: $1 FOREIGN KEY (source_id) REFERENCES source(source_id) ON UPDATE NO ACTION ON DELETE NO ACTION,                          $2 FOREIGN KEY (user_account_id) REFERENCES user_account(user_account_id) ON UPDATE NO ACTION ON DELETE NO ACTION       COMMERCIAL_SERVICE           Column        |     Type      | Modifiers ----------------------+---------------+-----------  commercial_entity_id | numeric(10,0) | not null  service_type_id      | numeric(10,0) | not null  source_id            | numeric(10,0) | not null Indexes: commercial_service_pkey primary key btree (commercial_entity_id, service_type_id),          comm_serv_comm_ent_id_i btree (commercial_entity_id),          comm_serv_serv_type_id_i btree (service_type_id),          comm_serv_source_id_i btree (source_id) Foreign Key constraints: $1 FOREIGN KEY (commercial_entity_id) REFERENCES commercial_entity(commercial_entity_id) ON UPDATE NO ACTION ON DELETE NO ACTION,                          $2 FOREIGN KEY (source_id) REFERENCES source(source_id) ON UPDATE NO ACTION ON DELETE NO ACTION,                          $3 FOREIGN KEY (service_type_id) REFERENCES service_type(service_type_id) ON UPDATE NO ACTION ON DELETE NO ACTION     Here is the postgres.conf (or the variables that are not commented out):   tcpip_socket = true max_connections = 500 shared_buffers = 32768          # min max_connections*2 or 16, 8KB each wal_buffers = 128               # min 4, typically 8KB each sort_mem = 4096                 # min 64, size in KB effective_cache_size = 50000    # typically 8KB each   Is it a problem with "IN"?   David