staticboolauto_explain_log_verbose= false;

staticboolauto_explain_log_buffers= false;

staticboolauto_explain_log_triggers= false;

staticboolauto_explain_log_timing=false;

staticboolauto_explain_log_timing=true;

staticintauto_explain_log_format=EXPLAIN_FORMAT_TEXT;

staticboolauto_explain_log_nested_statements= false;

queryDesc->instrument_options |=INSTRUMENT_TIMER;

queryDesc->instrument_options |=INSTRUMENT_ROWS;

if (auto_explain_log_buffers)

queryDesc->instrument_options |=INSTRUMENT_BUFFERS;

}

es.analyze= (queryDesc->instrument_options&&auto_explain_log_analyze);

es.verbose=auto_explain_log_verbose;

es.buffers= (es.analyze&&auto_explain_log_buffers);

es.timing= (es.analyze&&auto_explain_log_timing);

es.format=auto_explain_log_format;

ExplainBeginOutput(&es);

When this parameter is on, per-plan-node timing occurs for all

statements executed, whether or not they run long enough to actually

get logged. This can have an extremely negative impact on performance.

Turning off <varname>auto_explain.log_timing</varname> ameliorates the

performance cost, at the price of obtaining less information.

</para>

</note>

</listitem>

</varlistentry>

<varlistentry>

<term>

<varname>auto_explain.log_verbose</varname> (<type>boolean</type>)

<varname>auto_explain.log_buffers</varname> (<type>boolean</type>)

<indexterm>

<primary><varname>auto_explain.log_verbose</> configuration parameter</primary>

<primary><varname>auto_explain.log_buffers</> configuration parameter</primary>

</indexterm>

</term>

<listitem>

<para>

<varname>auto_explain.log_verbose</varname> causes <command>EXPLAIN VERBOSE</>

output, rather than just <command>EXPLAIN</> output, to be printed

when an execution plan is logged. This parameter is off by default.

<varname>auto_explain.log_buffers</varname> controls whether buffer

usage statistics are printed when an execution plan is logged; it's

equivalent to the <literal>BUFFERS</> option of <command>EXPLAIN</>.

This parameter has no effect

unless <varname>auto_explain.log_analyze</varname> is enabled.

This parameter is off by default.

Only superusers can change this setting.

</para>

</listitem>

</varlistentry>

<varlistentry>

<term>

<varname>auto_explain.log_buffers</varname> (<type>boolean</type>)

<varname>auto_explain.log_timing</varname> (<type>boolean</type>)

<indexterm>

<primary><varname>auto_explain.log_buffers</> configuration parameter</primary>

<primary><varname>auto_explain.log_timing</> configuration parameter</primary>

</indexterm>

</term>

<listitem>

<para>

<varname>auto_explain.log_buffers</varname> causes <command>EXPLAIN

(ANALYZE, BUFFERS)</> output, rather than just <command>EXPLAIN</>

output, to be printed when an execution plan is logged. This parameter is

off by default. Only superusers can change this setting. This

parameter has no effect unless <varname>auto_explain.log_analyze</>

parameter is set.

<varname>auto_explain.log_timing</varname> controls whether per-node

timing information is printed when an execution plan is logged; it's

equivalent to the <literal>TIMING</> option of <command>EXPLAIN</>.

The overhead of repeatedly reading the system clock can slow down

queries significantly on some systems, so it may be useful to set this

parameter to off when only actual row counts, and not exact times, are

needed.

This parameter has no effect

unless <varname>auto_explain.log_analyze</varname> is enabled.

This parameter is on by default.

Only superusers can change this setting.

</para>

</listitem>

</varlistentry>

<para>

<varname>auto_explain.log_triggers</varname> causes trigger

execution statistics to be included when an execution plan is logged.

This parameter is off by default. Only superusers can change this

setting. This parameter has no effect unless

<varname>auto_explain.log_analyze</> parameter is set.

This parameter has no effect

unless <varname>auto_explain.log_analyze</varname> is enabled.

This parameter is off by default.

Only superusers can change this setting.

</para>

</listitem>

</varlistentry>

<varlistentry>

<term>

<varname>auto_explain.log_format</varname> (<type>enum</type>)

<varname>auto_explain.log_verbose</varname> (<type>boolean</type>)

<indexterm>

<primary><varname>auto_explain.log_format</> configuration parameter</primary>

<primary><varname>auto_explain.log_verbose</> configuration parameter</primary>

</indexterm>

</term>

<listitem>

<para>

<varname>auto_explain.log_format</varname>selects the

The allowed values are<literal>text</literal>, <literal>xml</literal>,

<literal>json</literal>, and <literal>yaml</literal>. The default is text.

<varname>auto_explain.log_verbose</varname>controls whether verbose

equivalent to the<literal>VERBOSE</> option of <command>EXPLAIN</>.

This parameter is off by default.

Only superusers can change this setting.

</para>

</listitem>

</varlistentry>

<varlistentry>

<term>

<varname>auto_explain.log_timing</varname> (<type>boolean</type>)

<varname>auto_explain.log_format</varname> (<type>enum</type>)

<indexterm>

<primary><varname>auto_explain.log_timing</> configuration parameter</primary>

<primary><varname>auto_explain.log_format</> configuration parameter</primary>

</indexterm>

</term>

<listitem>

<para>

<varname>auto_explain.log_timing</varname> causes <command>EXPLAIN

(ANALYZE, TIMING off)</> output, rather than just <command>EXPLAIN (ANALYZE)</>

output. The overhead of repeatedly reading the system clock can slow down the

query significantly on some systems, so it may be useful to set this

parameter to off when only actual row counts, and not exact times, are needed.

This parameter is only effective when <varname>auto_explain.log_analyze</varname>

is also enabled. This parameter is on by default.

<varname>auto_explain.log_format</varname> selects the

<command>EXPLAIN</> output format to be used.

The allowed values are <literal>text</literal>, <literal>xml</literal>,

<literal>json</literal>, and <literal>yaml</literal>. The default is text.

Only superusers can change this setting.

</para>

</listitem>

</varlistentry>

<varlistentry>

<term>

<varname>auto_explain.log_nested_statements</varname> (<type>boolean</type>)

</variablelist>

<para>

These parameters must be set in <filename>postgresql.conf</>.

In ordinary usage, these parameters are set

in <filename>postgresql.conf</>, although superusers can alter them

on-the-fly within their own sessions.

Typical usage might be:

</para>

<programlisting>

postgres=# LOAD 'auto_explain';

postgres=# SET auto_explain.log_min_duration = 0;

postgres=# SET auto_explain.log_analyze = true;

postgres=# SELECT count(*)

FROM pg_class, pg_index

WHERE oid = indrelid AND indisunique;