Yes, not in the "core", but as extensions added: pg_stat_statements pg_autoexplain pg_buffercache pg_adminpack pg_freespacemap pgstattuple etc... On Thu, Dec 6, 2012 at 3:44 PM, Matthew Zito <matt@xxxxxxxxxxxxxxxxx> wrote: > I seem to remember reading somewhere that in Postgres 8.4+ and 9+, there's > a lot more performance statistics available, though there's definitely not > as many tools to help analyze them compared to Oracle. > > > On Thu, Dec 6, 2012 at 3:35 PM, Igor Neyman <igor.neyman@xxxxxxxxx> wrote: > >> Years ago, when for some specific reason we were forced to switch from >> Oracle to Postgres, I compiled this short list that describes Postgres >> specifics for Oracle DBA: >> -- # of data files: in PG every segment (table, index) is stored in >> one or more OS files dedicated to this segment >> -- no control over the size of data files (versus oracle's >> "autoincrement", "maxsize") >> -- different implementation of MVCC (multiversion concurrency >> control), there are write-ahead logs, but no rollback segments (or >> UNDO tablespace) >> - requires regular "vacuuming"/autovacuuming, otherwise tables >> will get bloated >> -- there is also "autovacuuming" that collects statistics used when >> execution plan created by query optimizer >> -- PG "visibility" problem (UNDO/Rollback info stored in the table >> itself) (index -> table) >> -- no updates in "in place" >> -- PG use of OS file cache (limiting upper limit for db buffer cache) >> -- under Win env.: PG's multiple processes versus Oracle >> multi-threaded architecture >> -- in PG no built-in connection polling (like Oracle's shared >> servers), but very good external connection polling tools, i.e. >> pgbouncer, pgpool >> -- PG is not instrumented as well as Oracle (though there are some >> some db objects "access" stats collected in appropriate pg_..._stats >> tables/views) >> -- no statspack, AWR - but some info about db instance is available >> and could be stored in "hand-made" repository >> -- autotrace, 10046 - in PG: "explain analyze", "auto_explain" contrib >> module >> -- PG version upgrades "in place" (without db dump/restore) comes only >> when upgrading from 8.4 and up >> >> -- rather similar procedural language (PlPgSQL - PL/SQL), but no >> support for anonymous PL/sql blocks (at least untill version 9.0) >> -- no stored procedures, no packages in PG (there are in Enterprize DB) >> -- some support for partitioning >> -- PG doesn't support synonyms >> All in all solid database. >> And, oh yes readers don't block writers (or vice verse) >> >> Regards, >> Igor Neyman >> >> >> -- //www.freelists.org/webpage/oracle-l