Interesting, Hubert.
Where/how do you get the data for:
- number of transactions per second
periodically (every 5 minutes) i do:
select sum(xact_commit) + sum(xact_rollback) from pg_stat_database
and then just check against previous value, and calculate "per/second". this is actually handled nicely by mrtg itself.
- duration of longest query
select * from pg_stat_activity where current_query !~ '<IDLE>' order by query_start asc limit 1;
this has some problems though, but are more or less easily avoidable.
depesz
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