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<chapter Id="runtime-config">

<title>Server Configuration</title>

consisting of two 4-byte hexadecimal numbers (without leading zeros)

separated by a dot. The numbers are the process start time and the

process ID, so <literal>%c</> can also be used as a space saving way

of printing those items.

of printing those items. For example, to generate the session

identifier from <literal>pg_stat_activity</>, use:

<programlisting>

SELECT to_hex(EXTRACT(EPOCH FROM backend_start)::integer) || '.' ||

to_hex(procpid)

FROM pg_stat_activity;

</programlisting>

</para>

<tip>