From: | Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> |
---|---|
To: | Andres Freund <andres(at)2ndquadrant(dot)com> |
Cc: | PostgreSQL Developers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: PATCH: pgbench - merging transaction logs |
Date: | 2015-03-23 19:00:04 |
Message-ID: | alpine.DEB.2.10.1503231924320.29534@sto |
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Thread: | |
Lists: | pgsql-hackers |
> Guys, I don't see this theoretical discussion going anywhere. I think
> it's time to simply implement this and evaluate it on a bigger
> machine.
Sure. I was kind of hoping that someone else would implement it, because
I'm a reviewer on this one, and I do not have the bigger machine at hand
either:-) If nothing happens and when I have some time, I'll do it.
> It can't take very long to implement tosimply just write to one
> file instead of the multiple files as now.
Sure.
> The posix guaranteed fprintf locking should already take care of the
> rest.
I think I would try with snprintf to reduce locking.
Note that I'm first trying to evaluate logging overhead, but I'm quite far
from Tomas figures at the moment, looks more like 20% overhead (12 threads
read-only load, runs at about 130000 tps with full logging, 160000
without, repeated 5 times with the similar results).
In such a case, a mutex would be a bad idea, but I must add that detailed
logging is a plain bad idea as well!
--
Fabien.
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