May 2018
Intermediate to advanced
576 pages
30h 25m
English
postgres=# SELECT avg(id) FROM events; avg --------------------- 500000.500 (1 row) postgres=# SELECT avg(id) FROM events TABLESAMPLE system(1); avg --------------------- 507434.635 (1 row) postgres=# EXPLAIN (ANALYZE, BUFFERS) SELECT avg(id) FROM events; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------ Aggregate (cost=16925.00..16925.01 rows=1 width=32) (actual time=204.841..204.841 rows=1 loops=1) ...