Neil Whelchel <neil.whelchel@xxxxxxxxx> writes: > Insert the data into one table: > crash:~# time psql -U test test -q < log.sql > real 679m43.678s > user 1m4.948s > sys 13m1.893s > crash:~# echo 3 > /proc/sys/vm/drop_caches > crash:~# time psql -U test test -c "SELECT count(*) FROM log;" > count > ---------- > 10050886 > (1 row) > real 0m11.812s > user 0m0.000s > sys 0m0.004s > crash:~# time psql -U test test -c "SELECT count(*) FROM log;" > count > ---------- > 10050886 > (1 row) > real 0m3.737s > user 0m0.000s > sys 0m0.000s > As can be seen here, the cache helps.. That's probably got little to do with caching and everything to do with setting hint bits on the first SELECT pass. I concur with Mark's question about whether your UPDATE pushed the table size across the limit of what would fit in RAM. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
