Re: PATCH: pgbench - random sampling of transaction written into log

On Thu, Aug 30, 2012 at 3:48 PM, Tomas Vondra <tv(at)fuzzy(dot)cz> wrote:
> That sounds like a pretty trivial patch. I've been thinking about yet
> another option - histograms (regular or with exponential bins).

I thought about that, too, but I think high-outliers is a lot more
useful. At least for the kinds of things I worry about.

> What I'm not sure about is which of these options should be allowed at the
> same time - to me, combinations like 'sampling + aggregation' don't make
> much sense. Maybe except 'latency-only-if-more-than + aggregation'.

Maybe, but perhaps not even. I don't have a problem with saying that
the user is allowed to pick at most one method of reducing the output
volume. I think we could say: either sample, or take high outliers,
or aggregate. If we want to make some of those work in combination,
fine, but I don't think it's absolutely required. What WILL be
required is a clear error message telling you what you did wrong if
you use an unsupported combination.

BTW, I think that using any of these options should automatically
enable -l, rather than requiring it to be specified separately.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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