<para>

Causes the duration of each completed statement to be logged

if the statement ran for at least the specified number of

milliseconds, modulated by <varname>log_statement_sample_rate</varname>.

Setting this to zero prints all statement durations.

<literal>-1</literal> (the default) disables logging statements due to

exceeding duration threshold; for example, if you set it to

<literal>250ms</literal>, then all SQL statements that run 250ms or

longer will be logged. Enabling this parameter can be helpful in

tracking down unoptimized queries in your applications.

milliseconds. Setting this to zero prints all statement durations.

Minus-one (the default) disables logging statement durations.

For example, if you set it to <literal>250ms</literal>

then all SQL statements that run 250ms or longer will be

logged. Enabling this parameter can be helpful in tracking down

unoptimized queries in your applications.

Only superusers can change this setting.

</para>

</listitem>

</varlistentry>

<varlistentry id="guc-log-statement-sample-rate" xreflabel="log_statement_sample_rate">

<term><varname>log_statement_sample_rate</varname> (<type>real</type>)

<indexterm>

<primary><varname>log_statement_sample_rate</varname> configuration parameter</primary>

</indexterm>

</term>

<listitem>

<para>

Determines the fraction of statements that exceed

<xref linkend="guc-log-min-duration-statement"/> to be logged.

The default is <literal>1.0</literal>, meaning log all such

statements.

Setting this to zero disables logging by duration, same as setting

<varname>log_min_duration_statement</varname> to

<literal>-1</literal>.

<varname>log_statement_sample_rate</varname> is helpful when the

traffic is too high to log all queries.

</para>

</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>

intusecs;

intmsecs;

boolexceeded;

boolin_sample;

TimestampDifference(GetCurrentStatementStartTimestamp(),

GetCurrentTimestamp(),

(secs>log_min_duration_statement /1000||

secs*1000+msecs >=log_min_duration_statement)));

if (exceeded)

(log_statement_sample_rate==1||

random() <=log_statement_sample_rate*MAX_RANDOM_VALUE);

if ((exceeded&&in_sample)||log_duration||xact_is_sampled)

if (exceeded||log_duration||xact_is_sampled)

{

snprintf(msec_str,32,"%ld.%03d",

secs*1000+msecs,usecs %1000);

intclient_min_messages=NOTICE;

intlog_min_duration_statement=-1;

intlog_temp_files=-1;

doublelog_statement_sample_rate=1.0;

doublelog_xact_sample_rate=0;

inttrace_recovery_messages=LOG;

{"log_min_duration_statement",PGC_SUSET,LOGGING_WHEN,

gettext_noop("Sets the minimum execution time above which "

"statements will be logged."),

gettext_noop("Zero prints all queries, subject to log_statement_sample_rate. "

"-1 turns this feature off."),

gettext_noop("Zero prints all queries. -1 turns this feature off."),

},

&log_min_duration_statement,

NULL,NULL,NULL

},

{

{"log_statement_sample_rate",PGC_SUSET,LOGGING_WHEN,

gettext_noop("Fraction of statements exceeding log_min_duration_statement to be logged."),

gettext_noop("If you only want a sample, use a value between 0.0 (never "

"log) and 1.0 (always log).")

},

&log_statement_sample_rate,

1.0,0.0,1.0,

NULL,NULL,NULL

},

{

{"log_transaction_sample_rate",PGC_SUSET,LOGGING_WHEN,

gettext_noop("Set the fraction of transactions to log for new transactions."),

# fatal

# panic (effectively off)

#log_min_duration_statement = -1# logs statements and their durations

# according to log_statement_sample_rate. -1 is disabled,

# 0 logs all statements, > 0 logs only statements running

# at least this number of milliseconds.

#log_statement_sample_rate = 1.0# Fraction of logged statements exceeding

# log_min_duration_statement to be logged.

# 1.0 logs all such statements, 0.0 never logs.

#log_min_duration_statement = -1# -1 is disabled, 0 logs all statements

# and their durations, > 0 logs only

# statements running at least this number

# of milliseconds

#log_transaction_sample_rate = 0.0# Fraction of transactions whose statements

# are logged regardless of their duration. 1.0 logs all

externPGDLLIMPORTintclient_min_messages;

externintlog_min_duration_statement;

externintlog_temp_files;

externdoublelog_statement_sample_rate;

externdoublelog_xact_sample_rate;

externinttemp_file_limit;