Log all statements from a sample of transactions

This is useful to obtain a view of the different transaction types in an
application, regardless of the durations of the statements each runs.

Author: Adrien Nayrat
Reviewed-by: Masahiko Sawada, Hayato Kuroda, Andres Freund

1 files changed, 26 insertions, 0 deletions

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 2166b99fc4e..915296310ce 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -5871,6 +5871,32 @@ local0.*    /var/log/postgresql
        </listitem>
       </varlistentry>
 
+     <varlistentry id="guc-log-transaction-sample-rate" xreflabel="log_transaction_sample_rate">
+      <term><varname>log_transaction_sample_rate</varname> (<type>real</type>)
+      <indexterm>
+       <primary><varname>log_transaction_sample_rate</varname> configuration parameter</primary>
+      </indexterm>
+      </term>
+       <listitem>
+        <para>
+         Set the fraction of transactions whose statements are all logged,
+         in addition to statements logged for other reasons.  It applies to
+         each new transaction regardless of its statements' durations.
+         The default is <literal>0</literal>, meaning not to log statements
+         from any additional transaction.  Setting this to <literal>1</literal>
+         logs all statements for all transactions.
+         <varname>log_transaction_sample_rate</varname> is helpful to track a
+         sample of transaction.
+        </para>
+       <note>
+        <para>
+         Like all statement-logging options, this option can add significant
+         overhead.
+        </para>
+       </note>
+       </listitem>
+     </varlistentry>
+
      </variablelist>
 
     <para>