Smith. Along with Japanese doc updation by Tasuo Ishii.
> This patch changes the way pgbench outputs its latency log files so that
> every transaction gets a timestamp and notes which transaction type was
> executed. It's a one-line change that just dumps some additional
> information that was already sitting in that area of code. I also made a
> couple of documentation corrections and clarifications on some of the more
> confusing features of pgbench.
>
> It's straightforward to parse log files in this format to analyze what
> happened during the test at a higher level than was possible with the
> original format. You can find some rough sample code to convert this
> latency format into CVS files and then into graphs at
> http://www.westnet.com/~gsmith/content/postgresql/pgbench.htm which I'll
> be expanding on once I get all my little patches sent in here.
Also tweak README.pgbench/README.pgbench_jis:
Remove history after pgbench was added to PostgreSQL contrib module.
Those info was not only redundant since it has already been in CVS
log, but also incomplete.
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The attached is a patch to optimize contrib/pgbench using new 8.3 features.
- Use DROP IF EXISTS to suppress errors for initial loadings.
- Use a combination of TRUNCATE and COPY to reduce WAL on creating
the accounts table.
Also, there are some cosmetic changes.
- Change the output of -v option from "starting full vacuum..."
to "starting vacuum accounts..." in reflection of the fact.
- Shape duplicated error checks into executeStatement().
There is a big performance win in "COPY with no WAL" feature.
Thanks for the efforts!
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scenarios. With multiple clinets, only the first client got the right
scaling factor and this gave a illusion of better performance in case
of the scaling factor greater than 1.
- predefined variable "tps"
The value of variable tps is taken from the scaling factor
specified by -s option.
- -D option
Variable values can be defined by -D option.
- \set command now allows arithmetic calculations.
> Hi Tatsuo,
>
> I've attached a patch for the version of pgbench in CVS. It includes the
> following changes:
>
> - fix some spelling mistakes, indentation stuff, etc.
>
> - minor code cleanup -- (void) args instead of (), etc.
>
> - allocate the state array dynamically, so that it is only as
> large as needed. This reduces the memory consumption of pgbench
> slightly, and makes a larger MAXCLIENTS setting possible
>
> - (the only controversial change) add an option "-l" to log
> transaction latencies to a file. The "transaction latency"
> is the time between when the BEGIN is issued and the transaction
> commits. This is written to a file, along with the client #
> and the transaction #. The data in the file can then be used
> for things like:
>
> - consistency analysis: is the TPS the same through the
> entire run of pgbench, or does it change?
>
> - more detailed stats: what is the average latency, worse-case
> latency, best-case latency?
>
> - graphs: feed the data to gnuplot, graph latency versus. time
>
> - etc.
>
> I was going to store this data in memory and write it to disk
> at the end of the pgbench run, but that isn't feasible because
> the data can be very large: for example, ~70MB if benchmarking
> 128 clients doing 100,000 transactions each.
>
> Cheers,
>
> Neil
Tatsuo Ishii
Tom Lane
Bruce Momjian