Re: max_wal_senders must die - Mailing list pgsql-hackers

From Josh Berkus
Subject Re: max_wal_senders must die
Date
Msg-id 4CBF6A7B.9060103@agliodbs.com
Whole thread Raw
In response to Re: max_wal_senders must die  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: max_wal_senders must die
Re: max_wal_senders must die
List pgsql-hackers
> Quite.  Josh, have you got any evidence showing that the penalty is
> only 10%?  There are cases, such as COPY and ALTER TABLE, where
> you'd be looking at 2X or worse penalties, because of the existing
> optimizations that avoid writing WAL at all for operations where a
> single final fsync can serve the purpose.  I'm not sure what the
> penalty for "typical" workloads is, partly because I'm not sure what
> should be considered a "typical" workload for this purpose.

If we could agree on some workloads, I could run some benchmarks.  I'm
not sure what those would be though, given that COPY and ALTER TABLE
aren't generally included in most benchmarks.  I could see how
everything else is effected, though.

--                                  -- Josh Berkus                                    PostgreSQL Experts Inc.
                        http://www.pgexperts.com
 


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