2014-08-13 15:22 GMT+02:00 MauMau <maumau...@gmail.com>: > From: "Pavel Stehule" <pavel.steh...@gmail.com> > >> 2014-08-13 13:59 GMT+02:00 MauMau <maumau...@gmail.com>: >> >>> Are you concerned about the impactof collection overhead on the queries >>> >>> diagnosed? Maybe not light, but I'm optimistic. Oracle has the track >>> record of long use, and MySQL provides performance schema starting from >>> 5.6. >>> >> >> >> partially, I afraid about total performance (about impact on IO) - when we >> use a usual tables, then any analyses without indexes are slow, so you >> need >> a indexes, and we cannot deferred index update. You should thinking about >> retention policy - and without partitioning you got massive deletes. So I >> cannot to imagine a usage of table based solution together with some >> higher >> load. Our MVCC storage is not practical for storing only inserted data, >> and >> some custom storage has no indexes - so this design is relative big >> project. >> >> I prefer a possibility to read log via SQL (maybe some FDW) than use >> tables >> for storing log. These tables can be relative very large in few days - and >> we cannot to write specialized engine like MySQL simply. >> > > I didn't mean performance statistics data to be stored in database tables. > I just meant: > > * pg_stat_system_events is a view to show data on memory, which returns > one row for each event across the system. This is similar to > V$SYSTEM_EVENT in Oracle. > > * pg_stat_session_events is a view to show data on memory, which returns > one row for each event on one session. This is similar to V$SESSION_EVENT > in Oracle. > > * The above views represent the current accumulated data like other > pg_stat_xxx views. > > * EXPLAIN ANALYZE and auto_explain shows all events for one query. The > lock waits you are trying to record in the server log is one of the events. >
I am little bit sceptic about only memory based structure. Is it this concept acceptable for commiters? Pavel > > Regards > MauMau > >
