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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >Error Reporting and Logging</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REV="MADE" HREF="mailto:pgsql-docs@postgresql.org"><LINK REL="HOME" TITLE="PostgreSQL 9.2.24 Documentation" HREF="index.html"><LINK REL="UP" TITLE="Server Configuration" HREF="runtime-config.html"><LINK REL="PREVIOUS" TITLE="Query Planning" HREF="runtime-config-query.html"><LINK REL="NEXT" TITLE="Run-time Statistics" HREF="runtime-config-statistics.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="stylesheet.css"><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"><META NAME="creation" CONTENT="2017-11-06T22:43:11"></HEAD ><BODY CLASS="SECT1" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="5" ALIGN="center" VALIGN="bottom" ><A HREF="index.html" >PostgreSQL 9.2.24 Documentation</A ></TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A TITLE="Query Planning" HREF="runtime-config-query.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="runtime-config.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" >Chapter 18. Server Configuration</TD ><TD WIDTH="20%" ALIGN="right" VALIGN="top" ><A TITLE="Run-time Statistics" HREF="runtime-config-statistics.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="RUNTIME-CONFIG-LOGGING" >18.8. Error Reporting and Logging</A ></H1 ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="RUNTIME-CONFIG-LOGGING-WHERE" >18.8.1. Where To Log</A ></H2 ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><A NAME="GUC-LOG-DESTINATION" ></A ><TT CLASS="VARNAME" >log_destination</TT > (<TT CLASS="TYPE" >string</TT >)</DT ><DD ><P > <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > supports several methods for logging server messages, including <SPAN CLASS="SYSTEMITEM" >stderr</SPAN >, <SPAN CLASS="SYSTEMITEM" >csvlog</SPAN > and <SPAN CLASS="SYSTEMITEM" >syslog</SPAN >. On Windows, <SPAN CLASS="SYSTEMITEM" >eventlog</SPAN > is also supported. Set this parameter to a list of desired log destinations separated by commas. The default is to log to <SPAN CLASS="SYSTEMITEM" >stderr</SPAN > only. This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. </P ><P > If <SPAN CLASS="SYSTEMITEM" >csvlog</SPAN > is included in <TT CLASS="VARNAME" >log_destination</TT >, log entries are output in <SPAN CLASS="QUOTE" >"comma separated value"</SPAN > (<ACRONYM CLASS="ACRONYM" >CSV</ACRONYM >) format, which is convenient for loading logs into programs. See <A HREF="runtime-config-logging.html#RUNTIME-CONFIG-LOGGING-CSVLOG" >Section 18.8.4</A > for details. <A HREF="runtime-config-logging.html#GUC-LOGGING-COLLECTOR" >logging_collector</A > must be enabled to generate CSV-format log output. </P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B > On most Unix systems, you will need to alter the configuration of your system's <SPAN CLASS="APPLICATION" >syslog</SPAN > daemon in order to make use of the <SPAN CLASS="SYSTEMITEM" >syslog</SPAN > option for <TT CLASS="VARNAME" >log_destination</TT >. <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > can log to <SPAN CLASS="APPLICATION" >syslog</SPAN > facilities <TT CLASS="LITERAL" >LOCAL0</TT > through <TT CLASS="LITERAL" >LOCAL7</TT > (see <A HREF="runtime-config-logging.html#GUC-SYSLOG-FACILITY" >syslog_facility</A >), but the default <SPAN CLASS="APPLICATION" >syslog</SPAN > configuration on most platforms will discard all such messages. You will need to add something like: </P><PRE CLASS="PROGRAMLISTING" >local0.* /var/log/postgresql</PRE ><P> to the <SPAN CLASS="APPLICATION" >syslog</SPAN > daemon's configuration file to make it work. </P ><P > On Windows, when you use the <TT CLASS="LITERAL" >eventlog</TT > option for <TT CLASS="VARNAME" >log_destination</TT >, you should register an event source and its library with the operating system so that the Windows Event Viewer can display event log messages cleanly. See <A HREF="event-log-registration.html" >Section 17.11</A > for details. </P ></BLOCKQUOTE ></DIV ></DD ><DT ><A NAME="GUC-LOGGING-COLLECTOR" ></A ><TT CLASS="VARNAME" >logging_collector</TT > (<TT CLASS="TYPE" >boolean</TT >)</DT ><DD ><P > This parameter enables the <I CLASS="FIRSTTERM" >logging collector</I >, which is a background process that captures log messages sent to <SPAN CLASS="SYSTEMITEM" >stderr</SPAN > and redirects them into log files. This approach is often more useful than logging to <SPAN CLASS="APPLICATION" >syslog</SPAN >, since some types of messages might not appear in <SPAN CLASS="APPLICATION" >syslog</SPAN > output. (One common example is dynamic-linker failure messages; another is error messages produced by scripts such as <TT CLASS="VARNAME" >archive_command</TT >.) This parameter can only be set at server start. </P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B > It is possible to log to <SPAN CLASS="SYSTEMITEM" >stderr</SPAN > without using the logging collector; the log messages will just go to wherever the server's <SPAN CLASS="SYSTEMITEM" >stderr</SPAN > is directed. However, that method is only suitable for low log volumes, since it provides no convenient way to rotate log files. Also, on some platforms not using the logging collector can result in lost or garbled log output, because multiple processes writing concurrently to the same log file can overwrite each other's output. </P ></BLOCKQUOTE ></DIV ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B > The logging collector is designed to never lose messages. This means that in case of extremely high load, server processes could be blocked while trying to send additional log messages when the collector has fallen behind. In contrast, <SPAN CLASS="APPLICATION" >syslog</SPAN > prefers to drop messages if it cannot write them, which means it may fail to log some messages in such cases but it will not block the rest of the system. </P ></BLOCKQUOTE ></DIV ></DD ><DT ><A NAME="GUC-LOG-DIRECTORY" ></A ><TT CLASS="VARNAME" >log_directory</TT > (<TT CLASS="TYPE" >string</TT >)</DT ><DD ><P > When <TT CLASS="VARNAME" >logging_collector</TT > is enabled, this parameter determines the directory in which log files will be created. It can be specified as an absolute path, or relative to the cluster data directory. This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. The default is <TT CLASS="LITERAL" >pg_log</TT >. </P ></DD ><DT ><A NAME="GUC-LOG-FILENAME" ></A ><TT CLASS="VARNAME" >log_filename</TT > (<TT CLASS="TYPE" >string</TT >)</DT ><DD ><P > When <TT CLASS="VARNAME" >logging_collector</TT > is enabled, this parameter sets the file names of the created log files. The value is treated as a <SPAN CLASS="SYSTEMITEM" >strftime</SPAN > pattern, so <TT CLASS="LITERAL" >%</TT >-escapes can be used to specify time-varying file names. (Note that if there are any time-zone-dependent <TT CLASS="LITERAL" >%</TT >-escapes, the computation is done in the zone specified by <A HREF="runtime-config-logging.html#GUC-LOG-TIMEZONE" >log_timezone</A >.) The supported <TT CLASS="LITERAL" >%</TT >-escapes are similar to those listed in the Open Group's <A HREF="http://pubs.opengroup.org/onlinepubs/009695399/functions/strftime.html" TARGET="_top" >strftime </A > specification. Note that the system's <SPAN CLASS="SYSTEMITEM" >strftime</SPAN > is not used directly, so platform-specific (nonstandard) extensions do not work. The default is <TT CLASS="LITERAL" >postgresql-%Y-%m-%d_%H%M%S.log</TT >. </P ><P > If you specify a file name without escapes, you should plan to use a log rotation utility to avoid eventually filling the entire disk. In releases prior to 8.4, if no <TT CLASS="LITERAL" >%</TT > escapes were present, <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > would append the epoch of the new log file's creation time, but this is no longer the case. </P ><P > If CSV-format output is enabled in <TT CLASS="VARNAME" >log_destination</TT >, <TT CLASS="LITERAL" >.csv</TT > will be appended to the timestamped log file name to create the file name for CSV-format output. (If <TT CLASS="VARNAME" >log_filename</TT > ends in <TT CLASS="LITERAL" >.log</TT >, the suffix is replaced instead.) </P ><P > This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. </P ></DD ><DT ><A NAME="GUC-LOG-FILE-MODE" ></A ><TT CLASS="VARNAME" >log_file_mode</TT > (<TT CLASS="TYPE" >integer</TT >)</DT ><DD ><P > On Unix systems this parameter sets the permissions for log files when <TT CLASS="VARNAME" >logging_collector</TT > is enabled. (On Microsoft Windows this parameter is ignored.) The parameter value is expected to be a numeric mode specified in the format accepted by the <CODE CLASS="FUNCTION" >chmod</CODE > and <CODE CLASS="FUNCTION" >umask</CODE > system calls. (To use the customary octal format the number must start with a <TT CLASS="LITERAL" >0</TT > (zero).) </P ><P > The default permissions are <TT CLASS="LITERAL" >0600</TT >, meaning only the server owner can read or write the log files. The other commonly useful setting is <TT CLASS="LITERAL" >0640</TT >, allowing members of the owner's group to read the files. Note however that to make use of such a setting, you'll need to alter <A HREF="runtime-config-logging.html#GUC-LOG-DIRECTORY" >log_directory</A > to store the files somewhere outside the cluster data directory. In any case, it's unwise to make the log files world-readable, since they might contain sensitive data. </P ><P > This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. </P ></DD ><DT ><A NAME="GUC-LOG-ROTATION-AGE" ></A ><TT CLASS="VARNAME" >log_rotation_age</TT > (<TT CLASS="TYPE" >integer</TT >)</DT ><DD ><P > When <TT CLASS="VARNAME" >logging_collector</TT > is enabled, this parameter determines the maximum lifetime of an individual log file. After this many minutes have elapsed, a new log file will be created. Set to zero to disable time-based creation of new log files. This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. </P ></DD ><DT ><A NAME="GUC-LOG-ROTATION-SIZE" ></A ><TT CLASS="VARNAME" >log_rotation_size</TT > (<TT CLASS="TYPE" >integer</TT >)</DT ><DD ><P > When <TT CLASS="VARNAME" >logging_collector</TT > is enabled, this parameter determines the maximum size of an individual log file. After this many kilobytes have been emitted into a log file, a new log file will be created. Set to zero to disable size-based creation of new log files. This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. </P ></DD ><DT ><A NAME="GUC-LOG-TRUNCATE-ON-ROTATION" ></A ><TT CLASS="VARNAME" >log_truncate_on_rotation</TT > (<TT CLASS="TYPE" >boolean</TT >)</DT ><DD ><P > When <TT CLASS="VARNAME" >logging_collector</TT > is enabled, this parameter will cause <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > to truncate (overwrite), rather than append to, any existing log file of the same name. However, truncation will occur only when a new file is being opened due to time-based rotation, not during server startup or size-based rotation. When off, pre-existing files will be appended to in all cases. For example, using this setting in combination with a <TT CLASS="VARNAME" >log_filename</TT > like <TT CLASS="LITERAL" >postgresql-%H.log</TT > would result in generating twenty-four hourly log files and then cyclically overwriting them. This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. </P ><P > Example: To keep 7 days of logs, one log file per day named <TT CLASS="LITERAL" >server_log.Mon</TT >, <TT CLASS="LITERAL" >server_log.Tue</TT >, etc, and automatically overwrite last week's log with this week's log, set <TT CLASS="VARNAME" >log_filename</TT > to <TT CLASS="LITERAL" >server_log.%a</TT >, <TT CLASS="VARNAME" >log_truncate_on_rotation</TT > to <TT CLASS="LITERAL" >on</TT >, and <TT CLASS="VARNAME" >log_rotation_age</TT > to <TT CLASS="LITERAL" >1440</TT >. </P ><P > Example: To keep 24 hours of logs, one log file per hour, but also rotate sooner if the log file size exceeds 1GB, set <TT CLASS="VARNAME" >log_filename</TT > to <TT CLASS="LITERAL" >server_log.%H%M</TT >, <TT CLASS="VARNAME" >log_truncate_on_rotation</TT > to <TT CLASS="LITERAL" >on</TT >, <TT CLASS="VARNAME" >log_rotation_age</TT > to <TT CLASS="LITERAL" >60</TT >, and <TT CLASS="VARNAME" >log_rotation_size</TT > to <TT CLASS="LITERAL" >1000000</TT >. Including <TT CLASS="LITERAL" >%M</TT > in <TT CLASS="VARNAME" >log_filename</TT > allows any size-driven rotations that might occur to select a file name different from the hour's initial file name. </P ></DD ><DT ><A NAME="GUC-SYSLOG-FACILITY" ></A ><TT CLASS="VARNAME" >syslog_facility</TT > (<TT CLASS="TYPE" >enum</TT >)</DT ><DD ><P > When logging to <SPAN CLASS="APPLICATION" >syslog</SPAN > is enabled, this parameter determines the <SPAN CLASS="APPLICATION" >syslog</SPAN > <SPAN CLASS="QUOTE" >"facility"</SPAN > to be used. You can choose from <TT CLASS="LITERAL" >LOCAL0</TT >, <TT CLASS="LITERAL" >LOCAL1</TT >, <TT CLASS="LITERAL" >LOCAL2</TT >, <TT CLASS="LITERAL" >LOCAL3</TT >, <TT CLASS="LITERAL" >LOCAL4</TT >, <TT CLASS="LITERAL" >LOCAL5</TT >, <TT CLASS="LITERAL" >LOCAL6</TT >, <TT CLASS="LITERAL" >LOCAL7</TT >; the default is <TT CLASS="LITERAL" >LOCAL0</TT >. See also the documentation of your system's <SPAN CLASS="APPLICATION" >syslog</SPAN > daemon. This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. </P ></DD ><DT ><A NAME="GUC-SYSLOG-IDENT" ></A ><TT CLASS="VARNAME" >syslog_ident</TT > (<TT CLASS="TYPE" >string</TT >)</DT ><DD ><P > When logging to <SPAN CLASS="APPLICATION" >syslog</SPAN > is enabled, this parameter determines the program name used to identify <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > messages in <SPAN CLASS="APPLICATION" >syslog</SPAN > logs. The default is <TT CLASS="LITERAL" >postgres</TT >. This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. </P ></DD ><DT ><A NAME="GUC-EVENT-SOURCE" ></A ><TT CLASS="VARNAME" >event_source</TT > (<TT CLASS="TYPE" >string</TT >)</DT ><DD ><P > When logging to <SPAN CLASS="APPLICATION" >event log</SPAN > is enabled, this parameter determines the program name used to identify <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > messages in the log. The default is <TT CLASS="LITERAL" >PostgreSQL</TT >. This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. </P ></DD ></DL ></DIV ></DIV ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="RUNTIME-CONFIG-LOGGING-WHEN" >18.8.2. When To Log</A ></H2 ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><A NAME="GUC-CLIENT-MIN-MESSAGES" ></A ><TT CLASS="VARNAME" >client_min_messages</TT > (<TT CLASS="TYPE" >enum</TT >)</DT ><DD ><P > Controls which message levels are sent to the client. Valid values are <TT CLASS="LITERAL" >DEBUG5</TT >, <TT CLASS="LITERAL" >DEBUG4</TT >, <TT CLASS="LITERAL" >DEBUG3</TT >, <TT CLASS="LITERAL" >DEBUG2</TT >, <TT CLASS="LITERAL" >DEBUG1</TT >, <TT CLASS="LITERAL" >LOG</TT >, <TT CLASS="LITERAL" >NOTICE</TT >, <TT CLASS="LITERAL" >WARNING</TT >, <TT CLASS="LITERAL" >ERROR</TT >, <TT CLASS="LITERAL" >FATAL</TT >, and <TT CLASS="LITERAL" >PANIC</TT >. Each level includes all the levels that follow it. The later the level, the fewer messages are sent. The default is <TT CLASS="LITERAL" >NOTICE</TT >. Note that <TT CLASS="LITERAL" >LOG</TT > has a different rank here than in <TT CLASS="VARNAME" >log_min_messages</TT >. </P ></DD ><DT ><A NAME="GUC-LOG-MIN-MESSAGES" ></A ><TT CLASS="VARNAME" >log_min_messages</TT > (<TT CLASS="TYPE" >enum</TT >)</DT ><DD ><P > Controls which message levels are written to the server log. Valid values are <TT CLASS="LITERAL" >DEBUG5</TT >, <TT CLASS="LITERAL" >DEBUG4</TT >, <TT CLASS="LITERAL" >DEBUG3</TT >, <TT CLASS="LITERAL" >DEBUG2</TT >, <TT CLASS="LITERAL" >DEBUG1</TT >, <TT CLASS="LITERAL" >INFO</TT >, <TT CLASS="LITERAL" >NOTICE</TT >, <TT CLASS="LITERAL" >WARNING</TT >, <TT CLASS="LITERAL" >ERROR</TT >, <TT CLASS="LITERAL" >LOG</TT >, <TT CLASS="LITERAL" >FATAL</TT >, and <TT CLASS="LITERAL" >PANIC</TT >. Each level includes all the levels that follow it. The later the level, the fewer messages are sent to the log. The default is <TT CLASS="LITERAL" >WARNING</TT >. Note that <TT CLASS="LITERAL" >LOG</TT > has a different rank here than in <TT CLASS="VARNAME" >client_min_messages</TT >. Only superusers can change this setting. </P ></DD ><DT ><A NAME="GUC-LOG-MIN-ERROR-STATEMENT" ></A ><TT CLASS="VARNAME" >log_min_error_statement</TT > (<TT CLASS="TYPE" >enum</TT >)</DT ><DD ><P > Controls which SQL statements that cause an error condition are recorded in the server log. The current SQL statement is included in the log entry for any message of the specified severity or higher. Valid values are <TT CLASS="LITERAL" >DEBUG5</TT >, <TT CLASS="LITERAL" >DEBUG4</TT >, <TT CLASS="LITERAL" >DEBUG3</TT >, <TT CLASS="LITERAL" >DEBUG2</TT >, <TT CLASS="LITERAL" >DEBUG1</TT >, <TT CLASS="LITERAL" >INFO</TT >, <TT CLASS="LITERAL" >NOTICE</TT >, <TT CLASS="LITERAL" >WARNING</TT >, <TT CLASS="LITERAL" >ERROR</TT >, <TT CLASS="LITERAL" >LOG</TT >, <TT CLASS="LITERAL" >FATAL</TT >, and <TT CLASS="LITERAL" >PANIC</TT >. The default is <TT CLASS="LITERAL" >ERROR</TT >, which means statements causing errors, log messages, fatal errors, or panics will be logged. To effectively turn off logging of failing statements, set this parameter to <TT CLASS="LITERAL" >PANIC</TT >. Only superusers can change this setting. </P ></DD ><DT ><A NAME="GUC-LOG-MIN-DURATION-STATEMENT" ></A ><TT CLASS="VARNAME" >log_min_duration_statement</TT > (<TT CLASS="TYPE" >integer</TT >)</DT ><DD ><P > 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 <TT CLASS="LITERAL" >250ms</TT > 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. </P ><P > For clients using extended query protocol, durations of the Parse, Bind, and Execute steps are logged independently. </P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B > When using this option together with <A HREF="runtime-config-logging.html#GUC-LOG-STATEMENT" >log_statement</A >, the text of statements that are logged because of <TT CLASS="VARNAME" >log_statement</TT > will not be repeated in the duration log message. If you are not using <SPAN CLASS="APPLICATION" >syslog</SPAN >, it is recommended that you log the PID or session ID using <A HREF="runtime-config-logging.html#GUC-LOG-LINE-PREFIX" >log_line_prefix</A > so that you can link the statement message to the later duration message using the process ID or session ID. </P ></BLOCKQUOTE ></DIV ></DD ></DL ></DIV ><P > <A HREF="runtime-config-logging.html#RUNTIME-CONFIG-SEVERITY-LEVELS" >Table 18-1</A > explains the message severity levels used by <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN >. If logging output is sent to <SPAN CLASS="SYSTEMITEM" >syslog</SPAN > or Windows' <SPAN CLASS="SYSTEMITEM" >eventlog</SPAN >, the severity levels are translated as shown in the table. </P ><DIV CLASS="TABLE" ><A NAME="RUNTIME-CONFIG-SEVERITY-LEVELS" ></A ><P ><B >Table 18-1. Message Severity Levels</B ></P ><TABLE BORDER="1" CLASS="CALSTABLE" ><COL><COL><COL><COL><THEAD ><TR ><TH >Severity</TH ><TH >Usage</TH ><TH ><SPAN CLASS="SYSTEMITEM" >syslog</SPAN ></TH ><TH ><SPAN CLASS="SYSTEMITEM" >eventlog</SPAN ></TH ></TR ></THEAD ><TBODY ><TR ><TD ><TT CLASS="LITERAL" >DEBUG1..DEBUG5</TT ></TD ><TD >Provides successively-more-detailed information for use by developers.</TD ><TD ><TT CLASS="LITERAL" >DEBUG</TT ></TD ><TD ><TT CLASS="LITERAL" >INFORMATION</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >INFO</TT ></TD ><TD >Provides information implicitly requested by the user, e.g., output from <TT CLASS="COMMAND" >VACUUM VERBOSE</TT >.</TD ><TD ><TT CLASS="LITERAL" >INFO</TT ></TD ><TD ><TT CLASS="LITERAL" >INFORMATION</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >NOTICE</TT ></TD ><TD >Provides information that might be helpful to users, e.g., notice of truncation of long identifiers.</TD ><TD ><TT CLASS="LITERAL" >NOTICE</TT ></TD ><TD ><TT CLASS="LITERAL" >INFORMATION</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >WARNING</TT ></TD ><TD >Provides warnings of likely problems, e.g., <TT CLASS="COMMAND" >COMMIT</TT > outside a transaction block.</TD ><TD ><TT CLASS="LITERAL" >NOTICE</TT ></TD ><TD ><TT CLASS="LITERAL" >WARNING</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >ERROR</TT ></TD ><TD >Reports an error that caused the current command to abort.</TD ><TD ><TT CLASS="LITERAL" >WARNING</TT ></TD ><TD ><TT CLASS="LITERAL" >ERROR</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >LOG</TT ></TD ><TD >Reports information of interest to administrators, e.g., checkpoint activity.</TD ><TD ><TT CLASS="LITERAL" >INFO</TT ></TD ><TD ><TT CLASS="LITERAL" >INFORMATION</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >FATAL</TT ></TD ><TD >Reports an error that caused the current session to abort.</TD ><TD ><TT CLASS="LITERAL" >ERR</TT ></TD ><TD ><TT CLASS="LITERAL" >ERROR</TT ></TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >PANIC</TT ></TD ><TD >Reports an error that caused all database sessions to abort.</TD ><TD ><TT CLASS="LITERAL" >CRIT</TT ></TD ><TD ><TT CLASS="LITERAL" >ERROR</TT ></TD ></TR ></TBODY ></TABLE ></DIV ></DIV ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="RUNTIME-CONFIG-LOGGING-WHAT" >18.8.3. What To Log</A ></H2 ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><A NAME="GUC-APPLICATION-NAME" ></A ><TT CLASS="VARNAME" >application_name</TT > (<TT CLASS="TYPE" >string</TT >)</DT ><DD ><P > The <TT CLASS="VARNAME" >application_name</TT > can be any string of less than <TT CLASS="SYMBOL" >NAMEDATALEN</TT > characters (64 characters in a standard build). It is typically set by an application upon connection to the server. The name will be displayed in the <TT CLASS="STRUCTNAME" >pg_stat_activity</TT > view and included in CSV log entries. It can also be included in regular log entries via the <A HREF="runtime-config-logging.html#GUC-LOG-LINE-PREFIX" >log_line_prefix</A > parameter. Only printable ASCII characters may be used in the <TT CLASS="VARNAME" >application_name</TT > value. Other characters will be replaced with question marks (<TT CLASS="LITERAL" >?</TT >). </P ></DD ><DT ><TT CLASS="VARNAME" >debug_print_parse</TT > (<TT CLASS="TYPE" >boolean</TT >)<BR><TT CLASS="VARNAME" >debug_print_rewritten</TT > (<TT CLASS="TYPE" >boolean</TT >)<BR><TT CLASS="VARNAME" >debug_print_plan</TT > (<TT CLASS="TYPE" >boolean</TT >)</DT ><DD ><P > These parameters enable various debugging output to be emitted. When set, they print the resulting parse tree, the query rewriter output, or the execution plan for each executed query. These messages are emitted at <TT CLASS="LITERAL" >LOG</TT > message level, so by default they will appear in the server log but will not be sent to the client. You can change that by adjusting <A HREF="runtime-config-logging.html#GUC-CLIENT-MIN-MESSAGES" >client_min_messages</A > and/or <A HREF="runtime-config-logging.html#GUC-LOG-MIN-MESSAGES" >log_min_messages</A >. These parameters are off by default. </P ></DD ><DT ><TT CLASS="VARNAME" >debug_pretty_print</TT > (<TT CLASS="TYPE" >boolean</TT >)</DT ><DD ><P > When set, <TT CLASS="VARNAME" >debug_pretty_print</TT > indents the messages produced by <TT CLASS="VARNAME" >debug_print_parse</TT >, <TT CLASS="VARNAME" >debug_print_rewritten</TT >, or <TT CLASS="VARNAME" >debug_print_plan</TT >. This results in more readable but much longer output than the <SPAN CLASS="QUOTE" >"compact"</SPAN > format used when it is off. It is on by default. </P ></DD ><DT ><A NAME="GUC-LOG-CHECKPOINTS" ></A ><TT CLASS="VARNAME" >log_checkpoints</TT > (<TT CLASS="TYPE" >boolean</TT >)</DT ><DD ><P > Causes checkpoints and restartpoints to be logged in the server log. Some statistics are included in the log messages, including the number of buffers written and the time spent writing them. This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. The default is off. </P ></DD ><DT ><A NAME="GUC-LOG-CONNECTIONS" ></A ><TT CLASS="VARNAME" >log_connections</TT > (<TT CLASS="TYPE" >boolean</TT >)</DT ><DD ><P > Causes each attempted connection to the server to be logged, as well as successful completion of client authentication. This parameter cannot be changed after session start. The default is off. </P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B > Some client programs, like <SPAN CLASS="APPLICATION" >psql</SPAN >, attempt to connect twice while determining if a password is required, so duplicate <SPAN CLASS="QUOTE" >"connection received"</SPAN > messages do not necessarily indicate a problem. </P ></BLOCKQUOTE ></DIV ></DD ><DT ><A NAME="GUC-LOG-DISCONNECTIONS" ></A ><TT CLASS="VARNAME" >log_disconnections</TT > (<TT CLASS="TYPE" >boolean</TT >)</DT ><DD ><P > This outputs a line in the server log similar to <TT CLASS="VARNAME" >log_connections</TT > but at session termination, and includes the duration of the session. This is off by default. This parameter cannot be changed after session start. </P ></DD ><DT ><A NAME="GUC-LOG-DURATION" ></A ><TT CLASS="VARNAME" >log_duration</TT > (<TT CLASS="TYPE" >boolean</TT >)</DT ><DD ><P > Causes the duration of every completed statement to be logged. The default is <TT CLASS="LITERAL" >off</TT >. Only superusers can change this setting. </P ><P > For clients using extended query protocol, durations of the Parse, Bind, and Execute steps are logged independently. </P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B > The difference between setting this option and setting <A HREF="runtime-config-logging.html#GUC-LOG-MIN-DURATION-STATEMENT" >log_min_duration_statement</A > to zero is that exceeding <TT CLASS="VARNAME" >log_min_duration_statement</TT > forces the text of the query to be logged, but this option doesn't. Thus, if <TT CLASS="VARNAME" >log_duration</TT > is <TT CLASS="LITERAL" >on</TT > and <TT CLASS="VARNAME" >log_min_duration_statement</TT > has a positive value, all durations are logged but the query text is included only for statements exceeding the threshold. This behavior can be useful for gathering statistics in high-load installations. </P ></BLOCKQUOTE ></DIV ></DD ><DT ><A NAME="GUC-LOG-ERROR-VERBOSITY" ></A ><TT CLASS="VARNAME" >log_error_verbosity</TT > (<TT CLASS="TYPE" >enum</TT >)</DT ><DD ><P > Controls the amount of detail written in the server log for each message that is logged. Valid values are <TT CLASS="LITERAL" >TERSE</TT >, <TT CLASS="LITERAL" >DEFAULT</TT >, and <TT CLASS="LITERAL" >VERBOSE</TT >, each adding more fields to displayed messages. <TT CLASS="LITERAL" >TERSE</TT > excludes the logging of <TT CLASS="LITERAL" >DETAIL</TT >, <TT CLASS="LITERAL" >HINT</TT >, <TT CLASS="LITERAL" >QUERY</TT >, and <TT CLASS="LITERAL" >CONTEXT</TT > error information. <TT CLASS="LITERAL" >VERBOSE</TT > output includes the <TT CLASS="SYMBOL" >SQLSTATE</TT > error code (see also <A HREF="errcodes-appendix.html" >Appendix A</A >) and the source code file name, function name, and line number that generated the error. Only superusers can change this setting. </P ></DD ><DT ><A NAME="GUC-LOG-HOSTNAME" ></A ><TT CLASS="VARNAME" >log_hostname</TT > (<TT CLASS="TYPE" >boolean</TT >)</DT ><DD ><P > By default, connection log messages only show the IP address of the connecting host. Turning this parameter on causes logging of the host name as well. Note that depending on your host name resolution setup this might impose a non-negligible performance penalty. This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. </P ></DD ><DT ><A NAME="GUC-LOG-LINE-PREFIX" ></A ><TT CLASS="VARNAME" >log_line_prefix</TT > (<TT CLASS="TYPE" >string</TT >)</DT ><DD ><P > This is a <CODE CLASS="FUNCTION" >printf</CODE >-style string that is output at the beginning of each log line. <TT CLASS="LITERAL" >%</TT > characters begin <SPAN CLASS="QUOTE" >"escape sequences"</SPAN > that are replaced with status information as outlined below. Unrecognized escapes are ignored. Other characters are copied straight to the log line. Some escapes are only recognized by session processes, and are ignored by background processes such as the main server process. This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. The default is an empty string. <DIV CLASS="INFORMALTABLE" ><P ></P ><A NAME="AEN29710" ></A ><TABLE BORDER="1" CLASS="CALSTABLE" ><COL><COL><COL><THEAD ><TR ><TH >Escape</TH ><TH >Effect</TH ><TH >Session only</TH ></TR ></THEAD ><TBODY ><TR ><TD ><TT CLASS="LITERAL" >%a</TT ></TD ><TD >Application name</TD ><TD >yes</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%u</TT ></TD ><TD >User name</TD ><TD >yes</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%d</TT ></TD ><TD >Database name</TD ><TD >yes</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%r</TT ></TD ><TD >Remote host name or IP address, and remote port</TD ><TD >yes</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%h</TT ></TD ><TD >Remote host name or IP address</TD ><TD >yes</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%p</TT ></TD ><TD >Process ID</TD ><TD >no</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%t</TT ></TD ><TD >Time stamp without milliseconds</TD ><TD >no</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%m</TT ></TD ><TD >Time stamp with milliseconds</TD ><TD >no</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%i</TT ></TD ><TD >Command tag: type of session's current command</TD ><TD >yes</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%e</TT ></TD ><TD >SQLSTATE error code</TD ><TD >no</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%c</TT ></TD ><TD >Session ID: see below</TD ><TD >no</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%l</TT ></TD ><TD >Number of the log line for each session or process, starting at 1</TD ><TD >no</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%s</TT ></TD ><TD >Process start time stamp</TD ><TD >no</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%v</TT ></TD ><TD >Virtual transaction ID (backendID/localXID)</TD ><TD >no</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%x</TT ></TD ><TD >Transaction ID (0 if none is assigned)</TD ><TD >no</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%q</TT ></TD ><TD >Produces no output, but tells non-session processes to stop at this point in the string; ignored by session processes</TD ><TD >no</TD ></TR ><TR ><TD ><TT CLASS="LITERAL" >%%</TT ></TD ><TD >Literal <TT CLASS="LITERAL" >%</TT ></TD ><TD >no</TD ></TR ></TBODY ></TABLE ><P ></P ></DIV > The <TT CLASS="LITERAL" >%c</TT > escape prints a quasi-unique session identifier, 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 <TT CLASS="LITERAL" >%c</TT > can also be used as a space saving way of printing those items. For example, to generate the session identifier from <TT CLASS="LITERAL" >pg_stat_activity</TT >, use this query: </P><PRE CLASS="PROGRAMLISTING" >SELECT to_hex(EXTRACT(EPOCH FROM backend_start)::integer) || '.' || to_hex(pid) FROM pg_stat_activity;</PRE ><P> </P ><DIV CLASS="TIP" ><BLOCKQUOTE CLASS="TIP" ><P ><B >Tip: </B > If you set a nonempty value for <TT CLASS="VARNAME" >log_line_prefix</TT >, you should usually make its last character be a space, to provide visual separation from the rest of the log line. A punctuation character can be used too. </P ></BLOCKQUOTE ></DIV ><DIV CLASS="TIP" ><BLOCKQUOTE CLASS="TIP" ><P ><B >Tip: </B > <SPAN CLASS="APPLICATION" >Syslog</SPAN > produces its own time stamp and process ID information, so you probably do not want to include those escapes if you are logging to <SPAN CLASS="APPLICATION" >syslog</SPAN >. </P ></BLOCKQUOTE ></DIV ></DD ><DT ><A NAME="GUC-LOG-LOCK-WAITS" ></A ><TT CLASS="VARNAME" >log_lock_waits</TT > (<TT CLASS="TYPE" >boolean</TT >)</DT ><DD ><P > Controls whether a log message is produced when a session waits longer than <A HREF="runtime-config-locks.html#GUC-DEADLOCK-TIMEOUT" >deadlock_timeout</A > to acquire a lock. This is useful in determining if lock waits are causing poor performance. The default is <TT CLASS="LITERAL" >off</TT >. Only superusers can change this setting. </P ></DD ><DT ><A NAME="GUC-LOG-STATEMENT" ></A ><TT CLASS="VARNAME" >log_statement</TT > (<TT CLASS="TYPE" >enum</TT >)</DT ><DD ><P > Controls which SQL statements are logged. Valid values are <TT CLASS="LITERAL" >none</TT > (off), <TT CLASS="LITERAL" >ddl</TT >, <TT CLASS="LITERAL" >mod</TT >, and <TT CLASS="LITERAL" >all</TT > (all statements). <TT CLASS="LITERAL" >ddl</TT > logs all data definition statements, such as <TT CLASS="COMMAND" >CREATE</TT >, <TT CLASS="COMMAND" >ALTER</TT >, and <TT CLASS="COMMAND" >DROP</TT > statements. <TT CLASS="LITERAL" >mod</TT > logs all <TT CLASS="LITERAL" >ddl</TT > statements, plus data-modifying statements such as <TT CLASS="COMMAND" >INSERT</TT >, <TT CLASS="COMMAND" >UPDATE</TT >, <TT CLASS="COMMAND" >DELETE</TT >, <TT CLASS="COMMAND" >TRUNCATE</TT >, and <TT CLASS="COMMAND" >COPY FROM</TT >. <TT CLASS="COMMAND" >PREPARE</TT >, <TT CLASS="COMMAND" >EXECUTE</TT >, and <TT CLASS="COMMAND" >EXPLAIN ANALYZE</TT > 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). </P ><P > The default is <TT CLASS="LITERAL" >none</TT >. Only superusers can change this setting. </P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B > Statements that contain simple syntax errors are not logged even by the <TT CLASS="VARNAME" >log_statement</TT > = <TT CLASS="LITERAL" >all</TT > setting, because the log message is emitted only after basic parsing has been done to determine the statement type. In the case of extended query protocol, this setting likewise does not log statements that fail before the Execute phase (i.e., during parse analysis or planning). Set <TT CLASS="VARNAME" >log_min_error_statement</TT > to <TT CLASS="LITERAL" >ERROR</TT > (or lower) to log such statements. </P ></BLOCKQUOTE ></DIV ></DD ><DT ><A NAME="GUC-LOG-TEMP-FILES" ></A ><TT CLASS="VARNAME" >log_temp_files</TT > (<TT CLASS="TYPE" >integer</TT >)</DT ><DD ><P > Controls logging of temporary file names and sizes. Temporary files can be created for sorts, hashes, and temporary query results. A log entry is made for each temporary file when it is deleted. A value of zero logs all temporary file information, while positive values log only files whose size is greater than or equal to the specified number of kilobytes. The default setting is -1, which disables such logging. Only superusers can change this setting. </P ></DD ><DT ><A NAME="GUC-LOG-TIMEZONE" ></A ><TT CLASS="VARNAME" >log_timezone</TT > (<TT CLASS="TYPE" >string</TT >)</DT ><DD ><P > Sets the time zone used for timestamps written in the server log. Unlike <A HREF="runtime-config-client.html#GUC-TIMEZONE" >TimeZone</A >, this value is cluster-wide, so that all sessions will report timestamps consistently. The built-in default is <TT CLASS="LITERAL" >GMT</TT >, but that is typically overridden in <TT CLASS="FILENAME" >postgresql.conf</TT >; <SPAN CLASS="APPLICATION" >initdb</SPAN > will install a setting there corresponding to its system environment. See <A HREF="datatype-datetime.html#DATATYPE-TIMEZONES" >Section 8.5.3</A > for more information. This parameter can only be set in the <TT CLASS="FILENAME" >postgresql.conf</TT > file or on the server command line. </P ></DD ></DL ></DIV ></DIV ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="RUNTIME-CONFIG-LOGGING-CSVLOG" >18.8.4. Using CSV-Format Log Output</A ></H2 ><P > Including <TT CLASS="LITERAL" >csvlog</TT > in the <TT CLASS="VARNAME" >log_destination</TT > list provides a convenient way to import log files into a database table. This option emits log lines in comma-separated-values (<ACRONYM CLASS="ACRONYM" >CSV</ACRONYM >) format, with these columns: time stamp with milliseconds, user name, database name, process ID, client host:port number, session ID, per-session line number, command tag, session start time, virtual transaction ID, regular transaction ID, error severity, SQLSTATE code, error message, error message detail, hint, internal query that led to the error (if any), character count of the error position therein, error context, user query that led to the error (if any and enabled by <TT CLASS="VARNAME" >log_min_error_statement</TT >), character count of the error position therein, location of the error in the PostgreSQL source code (if <TT CLASS="VARNAME" >log_error_verbosity</TT > is set to <TT CLASS="LITERAL" >verbose</TT >), and application name. Here is a sample table definition for storing CSV-format log output: </P><PRE CLASS="PROGRAMLISTING" >CREATE TABLE postgres_log ( log_time timestamp(3) with time zone, user_name text, database_name text, process_id integer, connection_from text, session_id text, session_line_num bigint, command_tag text, session_start_time timestamp with time zone, virtual_transaction_id text, transaction_id bigint, error_severity text, sql_state_code text, message text, detail text, hint text, internal_query text, internal_query_pos integer, context text, query text, query_pos integer, location text, application_name text, PRIMARY KEY (session_id, session_line_num) );</PRE ><P> </P ><P > To import a log file into this table, use the <TT CLASS="COMMAND" >COPY FROM</TT > command: </P><PRE CLASS="PROGRAMLISTING" >COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;</PRE ><P> </P ><P > There are a few things you need to do to simplify importing CSV log files: <P ></P ></P><OL TYPE="1" ><LI ><P > Set <TT CLASS="VARNAME" >log_filename</TT > and <TT CLASS="VARNAME" >log_rotation_age</TT > to provide a consistent, predictable naming scheme for your log files. This lets you predict what the file name will be and know when an individual log file is complete and therefore ready to be imported. </P ></LI ><LI ><P > Set <TT CLASS="VARNAME" >log_rotation_size</TT > to 0 to disable size-based log rotation, as it makes the log file name difficult to predict. </P ></LI ><LI ><P > Set <TT CLASS="VARNAME" >log_truncate_on_rotation</TT > to <TT CLASS="LITERAL" >on</TT > so that old log data isn't mixed with the new in the same file. </P ></LI ><LI ><P > The table definition above includes a primary key specification. This is useful to protect against accidentally importing the same information twice. The <TT CLASS="COMMAND" >COPY</TT > command commits all of the data it imports at one time, so any error will cause the entire import to fail. If you import a partial log file and later import the file again when it is complete, the primary key violation will cause the import to fail. Wait until the log is complete and closed before importing. This procedure will also protect against accidentally importing a partial line that hasn't been completely written, which would also cause <TT CLASS="COMMAND" >COPY</TT > to fail. </P ></LI ></OL ><P> </P ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="runtime-config-query.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="runtime-config-statistics.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Query Planning</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="runtime-config.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Run-time Statistics</TD ></TR ></TABLE ></DIV ></BODY ></HTML >