2009/12/22 Takahiro Itagaki <itagaki.takah...@oss.ntt.co.jp>: > > Cedric Villemain <cedric.villem...@dalibo.com> wrote: > >> Le vendredi 18 decembre 2009 09:44:40, Takahiro Itagaki a ecrit : >> > I'd like to add per-query buffer usage into contrib/pg_stat_statements. > > Here is a patch to add buffer usage columns into pg_stat_statements. > It also changes initialzation of the result TupleDesc from manually > coded routines to get_call_result_type(). > >> Perhaps it can be usefull to have the percentage for hit/read ratio computed >> in the view ? > > I think different DBAs want different derived values; Some of them might want > the buffer hit ratio, but others might request numbers per query. I'd like to > privide only raw values from pg_stat_statements to keep it simple, but I added > a computational expression of hit percentage in the documentation.
Yes, you are right. > > ! bench=# SELECT query, calls, total_time, rows, 100.0 * shared_blks_hit / > ! nullif(shared_blks_hit + shared_blks_read, 0) AS hit_percent > ! FROM pg_stat_statements ORDER BY total_time DESC LIMIT 5; > ! -[ RECORD 1 > ]--------------------------------------------------------------------- > ! query | UPDATE pgbench_branches SET bbalance = bbalance + $1 WHERE > bid = $2; > ! calls | 3000 > ! total_time | 9.60900100000002 > ! rows | 2836 > ! hit_percent | 99.9778970000200936 > > Regards, > --- > Takahiro Itagaki > NTT Open Source Software Center > > > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers > > -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
