Hi All, Example on optimizer =============== postgres=# create table test(id int); CREATE TABLE postgres=# insert into test VALUES (1); INSERT 0 1 postgres=# select * from test; id ---- 1 (1 row) postgres=# explain select * from test; QUERY PLAN -------------------------------------------------------- Seq Scan on test (cost=0.00..34.00 *rows=2400* width=4) (1 row) In the above, example the optimizer is retreiving those many rows where there is only one row in that table. If i analyze am geting one row.
postgres=# ANALYZE test; ANALYZE postgres=# explain select * from test; QUERY PLAN ---------------------------------------------------- Seq Scan on test (cost=0.00..1.01 *rows=1* width=4) (1 row) My question here is, what it retreiving as rows when there is no such. One more thing, if i wont do analyze and run the explain plan for three or more times, then catalogs getting updated automatically and resulting the correct row as 1. Q2. Does explain , will update the catalogs automatically. Regards Raghavendra