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Diffstat (limited to 'doc/src')
-rw-r--r-- | doc/src/sgml/pgbench.sgml | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/doc/src/sgml/pgbench.sgml b/doc/src/sgml/pgbench.sgml index 437fceab2e4..91530abe5b0 100644 --- a/doc/src/sgml/pgbench.sgml +++ b/doc/src/sgml/pgbench.sgml @@ -317,6 +317,24 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</> </varlistentry> <varlistentry> + <term><option>--sampling-rate</option> <replaceable>rate</></term> + <listitem> + <para> + Sampling rate, used when writing data into the log, to reduce the + amount of log generated. If this option is given, only the specified + fraction of transactions are logged. 1.0 means all transactions will + be logged, 0.05 means only 5% of the transactions will be logged. + </para> + <para> + Remember to take the sampling rate into account when processing the + log file. For example, when computing tps values, you need to multiply + the numbers accordingly (e.g. with 0.01 sample rate, you'll only get + 1/100 of the actual tps). + </para> + </listitem> + </varlistentry> + + <varlistentry> <term><option>-M</option> <replaceable>querymode</></term> <listitem> <para> @@ -750,6 +768,12 @@ END; 0 201 2513 0 1175850569 608 0 202 2038 0 1175850569 2663 </screen></para> + + <para> + When running a long test on hardware that can handle a lot of transactions, + the log files can become very large. The <option>--sampling-rate</> option + can be used to log only a random sample of transactions. + </para> </refsect2> <refsect2> |