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Clean up logging for extended-query-protocol operations, as per my recent

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proposal.  Parameter logging works even for binary-format parameters, and
logging overhead is avoided when disabled.

log_statement = all output for the src/test/examples/testlibpq3.c example
now looks like

LOG:  statement: execute <unnamed>: SELECT * FROM test1 WHERE t = $1
DETAIL:  parameters: $1 = 'joe''s place'
LOG:  statement: execute <unnamed>: SELECT * FROM test1 WHERE i = $1::int4
DETAIL:  parameters: $1 = '2'

and log_min_duration_statement = 0 results in

LOG:  duration: 2.431 ms  parse <unnamed>: SELECT * FROM test1 WHERE t = $1
LOG:  duration: 2.335 ms  bind <unnamed> to <unnamed>: SELECT * FROM test1 WHERE t = $1
DETAIL:  parameters: $1 = 'joe''s place'
LOG:  duration: 0.394 ms  execute <unnamed>: SELECT * FROM test1 WHERE t = $1
DETAIL:  parameters: $1 = 'joe''s place'
LOG:  duration: 1.251 ms  parse <unnamed>: SELECT * FROM test1 WHERE i = $1::int4
LOG:  duration: 0.566 ms  bind <unnamed> to <unnamed>: SELECT * FROM test1 WHERE i = $1::int4
DETAIL:  parameters: $1 = '2'
LOG:  duration: 0.173 ms  execute <unnamed>: SELECT * FROM test1 WHERE i = $1::int4
DETAIL:  parameters: $1 = '2'

(This example demonstrates the folly of ignoring parse/bind steps for duration
logging purposes, BTW.)

Along the way, create a less ad-hoc mechanism for determining which commands
are logged by log_statement = mod and log_statement = ddl.  The former coding
was actually missing quite a few things that look like ddl to me, and it
did not handle EXECUTE or extended query protocol correctly at all.

This commit does not do anything about the question of whether log_duration
should be removed or made less redundant with log_min_duration_statement.
This commit is contained in:
Tom Lane
2006-09-07 22:52:01 +00:00
parent b6eab50ce4
commit 893632be4e
10 changed files with 828 additions and 319 deletions
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98
doc/src/sgml/config.sgml
View File

@@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.83 2006/09/03 19:06:15 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.84 2006/09/07 22:51:59 tgl Exp $ -->
<chapter Id="runtime-config">
<title>Server Configuration</title>
@@ -2492,18 +2492,36 @@ SELECT * FROM parent WHERE key = 2400;
</indexterm>
<listitem>
<para>
Logs the statement and its duration on a single log line if its
duration is greater than or equal to the specified number of
milliseconds. Setting this to zero will print all statements
and their durations. Minus-one (the default) disables the
feature. For example, if you set it to <literal>250</literal>
Causes the duration of each completed statement to be logged
if the statement ran for at least the specified number of
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>250</literal>
then all SQL statements that run 250ms or longer will be
logged. Enabling this parameter can be useful in tracking down
unoptimized queries in your applications. This setting is
independent of <varname>log_statement</varname> and
<varname>log_duration</varname>. Only superusers can change
this setting.
logged. Enabling this parameter can be helpful in tracking down
unoptimized queries in your applications.
Only superusers can change this setting.
</para>
<para>
For clients using extended query protocol, durations of the Parse,
Bind, and Execute steps are logged independently.
</para>
<note>
<para>
When using this option together with
<xref linkend="guc-log-statement">,
the text of statements that are logged because of
<varname>log_statement</> will not be repeated in the
duration log message.
If you are not using <application>syslog</>, it is recommended
that you log the PID or session ID using
<xref linkend="guc-log-line-prefix">
so that you can link the statement message to the later
duration message using the process ID or session ID.
</para>
</note>
</listitem>
</varlistentry>
@@ -2695,14 +2713,30 @@ SELECT * FROM parent WHERE key = 2400;
</indexterm>
<listitem>
<para>
Causes the duration of every completed statement which satisfies
<varname>log_statement</> to be logged. When using this option,
if you are not using <application>syslog</>, it is recommended
that you log the PID or session ID using <varname>log_line_prefix</>
so that you can link the statement message to the later
duration message using the process ID or session ID. The default is
<literal>off</>. Only superusers can change this setting.
Causes the duration of every completed statement to be logged.
The default is <literal>off</>.
Only superusers can change this setting.
</para>
<para>
For clients using extended query protocol, durations of the Parse,
Bind, and Execute steps are logged independently.
</para>
<note>
<para>
When using this option together with
<xref linkend="guc-log-statement">,
the text of statements that are logged because of
<varname>log_statement</> will not be repeated in the
duration log message.
If you are not using <application>syslog</>, it is recommended
that you log the PID or session ID using
<xref linkend="guc-log-line-prefix">
so that you can link the statement message to the later
duration message using the process ID or session ID.
</para>
</note>
</listitem>
</varlistentry>
@@ -2829,18 +2863,20 @@ SELECT * FROM parent WHERE key = 2400;
Controls which SQL statements are logged. Valid values are
<literal>none</>, <literal>ddl</>, <literal>mod</>, and
<literal>all</>. <literal>ddl</> logs all data definition
commands like <literal>CREATE</>, <literal>ALTER</>, and
<literal>DROP</> commands. <literal>mod</> logs all
<literal>ddl</> statements, plus <literal>INSERT</>,
<literal>UPDATE</>, <literal>DELETE</>, <literal>TRUNCATE</>,
and <literal>COPY FROM</>. <literal>PREPARE</> and
<literal>EXPLAIN ANALYZE</> statements are also logged if their
contained command is of an appropriate type. Protocol-level
prepare, bind, and execute commands are logged only if
<varname>log_statement</> is <literal>all</>. Bind parameter
values are also logged if they are supplied in <literal>text</>
format (literal single quotes are doubled).
statements, such as <command>CREATE</>, <command>ALTER</>, and
<command>DROP</> statements. <literal>mod</> logs all
<literal>ddl</> statements, plus data-modifying statements
such as <command>INSERT</>,
<command>UPDATE</>, <command>DELETE</>, <command>TRUNCATE</>,
and <command>COPY FROM</>.
<command>PREPARE</>, <command>EXECUTE</>, and
<command>EXPLAIN ANALYZE</> statements are also logged if their
contained command is of an appropriate type. For clients using
extended query protocol, logging occurs when an Execute message
is received, and values of the Bind parameters are included
(with any embedded single-quote marks doubled).
</para>
<para>
The default is <literal>none</>. Only superusers can change this
setting.
@@ -2848,9 +2884,7 @@ SELECT * FROM parent WHERE key = 2400;
<note>
<para>
The <command>EXECUTE</command> statement is not considered a
<literal>ddl</> or <literal>mod</> statement. Statements that
generate syntax errors are not logged. Set
Statements that generate syntax errors are not logged. Set
<varname>log_min_error_statement</> to <literal>error</> to
log such statements.
</para>