Re: [COMMITTERS] pgsql: Revert "commit_delay" change; just add comment that we don't hav

On 15 August 2012 14:39, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> If you wanted to re-implement all the guc.c logic for supporting
> unit-ified values such that it would also work with floats, we could
> do that. It seems like way more mechanism than the problem is worth
> however.

Fair enough.

I'm not quite comfortable recommending a switch to milliseconds if
that implies a loss of sub-millisecond granularity. I know that
someone is going to point out that in some particularly benchmark,
they can get another relatively modest increase in throughput (perhaps
2%-3%) by splitting the difference between two adjoining millisecond
integer values. In that scenario, I'd be tempted to point out that
that increase is quite unlikely to carry over to real-world benefits,
because the setting is then right on the cusp of where increasing
commit_delay stops helping throughput and starts hurting it. The
improvement is likely to get lost in the noise in the context of a
real-world application, where for example the actually cost of an
fsync is more variable. I'm just not sure that that's the right
attitude.

--
Peter Geoghegan http://www.2ndQuadrant.com/
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