Writing log messages to syslog caters to ancient syslog implementations
in two ways:
- sequence numbers
- line splitting
While these are arguably reasonable defaults, I would like a way to turn
them off, because they get in the way of doing more interesting things
with syslog (e.g., logging somewhere that is not just a text file).
So I propose the two attached patches that introduce new configuration
Boolean parameters syslog_sequence_numbers and syslog_split_lines that
can toggle these behaviors.
From e6a17750956e3e6950683bad397a74adb30f30a2 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Fri, 26 Feb 2016 22:34:30 -0500
Subject: [PATCH 1/2] Add syslog_sequence_numbers parameter
---
doc/src/sgml/config.sgml | 28 +++++++++++++++++++++++++++
src/backend/utils/error/elog.c | 12 ++++++++++--
src/backend/utils/misc/guc.c | 10 ++++++++++
src/backend/utils/misc/postgresql.conf.sample | 1 +
src/include/utils/elog.h | 1 +
5 files changed, 50 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index a09ceb2..0d1ae4b 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4218,6 +4218,34 @@ <title>Where To Log</title>
</listitem>
</varlistentry>
+ <varlistentry id="guc-syslog-sequence-numbers" xreflabel="syslog_sequence_numbers">
+ <term><varname>syslog_sequence_numbers</varname> (<type>boolean</type>)
+ <indexterm>
+ <primary><varname>syslog_sequence_numbers</> configuration parameter</primary>
+ </indexterm>
+ </term>
+
+ <listitem>
+ <para>
+ When logging to <application>syslog</application> and this is on (the
+ default), then each message will be prefixed by an increasing
+ sequence number (such as <literal>[2]</literal>). This circumvents
+ the <quote>--- last message repeated N times ---</quote> suppression
+ that many syslog implementations perform by default. In more modern
+ syslog implementations, repeat message suppression can be configured
+ (for example, <literal>$RepeatedMsgReduction</literal>
+ in <productname>rsyslog</productname>), so this might not be
+ necessary. Also, you could turn this off if you actually want to
+ suppress repeated messages.
+ </para>
+
+ <para>
+ This parameter can only be set in the <filename>postgresql.conf</>
+ file or on the server command line.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-event-source" xreflabel="event_source">
<term><varname>event_source</varname> (<type>string</type>)
<indexterm>
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 9005b26..0bc96b4 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -106,6 +106,7 @@ int Log_error_verbosity = PGERROR_VERBOSE;
char *Log_line_prefix = NULL; /* format for extra log line info */
int Log_destination = LOG_DESTINATION_STDERR;
char *Log_destination_string = NULL;
+bool syslog_sequence_numbers = true;
#ifdef HAVE_SYSLOG
@@ -2008,7 +2009,11 @@ write_syslog(int level, const char *line)
chunk_nr++;
- syslog(level, "[%lu-%d] %s", seq, chunk_nr, buf);
+ if (syslog_sequence_numbers)
+ syslog(level, "[%lu-%d] %s", seq, chunk_nr, buf);
+ else
+ syslog(level, "[%d] %s", chunk_nr, buf);
+
line += buflen;
len -= buflen;
}
@@ -2016,7 +2021,10 @@ write_syslog(int level, const char *line)
else
{
/* message short enough */
- syslog(level, "[%lu] %s", seq, line);
+ if (syslog_sequence_numbers)
+ syslog(level, "[%lu] %s", seq, line);
+ else
+ syslog(level, "%s", line);
}
}
#endif /* HAVE_SYSLOG */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index ea5a09a..bc8faa9 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -1632,6 +1632,16 @@ static struct config_bool ConfigureNamesBool[] =
NULL, NULL, NULL
},
+ {
+ {"syslog_sequence_numbers", PGC_SIGHUP, LOGGING_WHERE,
+ gettext_noop("Add sequence number to syslog messags to avoid duplicate suppression."),
+ NULL
+ },
+ &syslog_sequence_numbers,
+ true,
+ NULL, NULL, NULL
+ },
+
/* End-of-list marker */
{
{NULL, 0, 0, NULL, NULL}, NULL, false, NULL, NULL, NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index ee3d378..a85ba36 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -358,6 +358,7 @@
# These are relevant when logging to syslog:
#syslog_facility = 'LOCAL0'
#syslog_ident = 'postgres'
+#syslog_sequence_numbers = true
# This is only relevant when logging to eventlog (win32):
#event_source = 'PostgreSQL'
diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h
index 326896f..bfbcf96 100644
--- a/src/include/utils/elog.h
+++ b/src/include/utils/elog.h
@@ -396,6 +396,7 @@ extern int Log_error_verbosity;
extern char *Log_line_prefix;
extern int Log_destination;
extern char *Log_destination_string;
+extern bool syslog_sequence_numbers;
/* Log destination bitmap */
#define LOG_DESTINATION_STDERR 1
--
2.7.2
From 72ea7dc222f41ab8246c0aa080d1c1adaf78f4c7 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Fri, 26 Feb 2016 22:37:15 -0500
Subject: [PATCH 2/2] Add syslog_split_lines parameter
---
doc/src/sgml/config.sgml | 33 +++++++++++++++++++++++++++
src/backend/utils/error/elog.c | 3 ++-
src/backend/utils/misc/guc.c | 10 ++++++++
src/backend/utils/misc/postgresql.conf.sample | 1 +
src/include/utils/elog.h | 1 +
5 files changed, 47 insertions(+), 1 deletion(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 0d1ae4b..eb12cc5 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4246,6 +4246,39 @@ <title>Where To Log</title>
</listitem>
</varlistentry>
+ <varlistentry id="guc-syslog-split-lines" xreflabel="syslog_split_lines">
+ <term><varname>syslog_split_lines</varname> (<type>boolean</type>)
+ <indexterm>
+ <primary><varname>syslog_split_lines</> configuration parameter</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ When logging to <application>syslog</> is enabled, this parameter
+ determines how messages are delivered to syslog. When on (the
+ default), messages are split by lines, and long lines are split so
+ that they will fit into 1024 bytes, which is a typical size limit for
+ traditional syslog implementations. When off, PostgreSQL server log
+ messages are delivered to the syslog service as is, and it is up to
+ the syslog service to cope with the potentially bulky messages.
+ </para>
+
+ <para>
+ If syslog is ultimately logging to a text file, then the effect will
+ be the same either way, and it is best to leave the setting on, since
+ most syslog implementations either cannot handle large messages or
+ would need to be specially configured to handle them. But if syslog
+ is ultimately writing into some other medium, it might be necessary or
+ more useful to keep messages logically together.
+ </para>
+
+ <para>
+ This parameter can only be set in the <filename>postgresql.conf</>
+ file or on the server command line.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-event-source" xreflabel="event_source">
<term><varname>event_source</varname> (<type>string</type>)
<indexterm>
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 0bc96b4..8c999a7 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -107,6 +107,7 @@ char *Log_line_prefix = NULL; /* format for extra log line info */
int Log_destination = LOG_DESTINATION_STDERR;
char *Log_destination_string = NULL;
bool syslog_sequence_numbers = true;
+bool syslog_split_lines = true;
#ifdef HAVE_SYSLOG
@@ -1956,7 +1957,7 @@ write_syslog(int level, const char *line)
*/
len = strlen(line);
nlpos = strchr(line, '\n');
- if (len > PG_SYSLOG_LIMIT || nlpos != NULL)
+ if (syslog_split_lines && (len > PG_SYSLOG_LIMIT || nlpos != NULL))
{
int chunk_nr = 0;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index bc8faa9..f5e071d 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -1642,6 +1642,16 @@ static struct config_bool ConfigureNamesBool[] =
NULL, NULL, NULL
},
+ {
+ {"syslog_split_lines", PGC_SIGHUP, LOGGING_WHERE,
+ gettext_noop("Split messages sent to syslog."),
+ NULL
+ },
+ &syslog_split_lines,
+ true,
+ NULL, NULL, NULL
+ },
+
/* End-of-list marker */
{
{NULL, 0, 0, NULL, NULL}, NULL, false, NULL, NULL, NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index a85ba36..89fd8f7 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -359,6 +359,7 @@
#syslog_facility = 'LOCAL0'
#syslog_ident = 'postgres'
#syslog_sequence_numbers = true
+#syslog_split_lines = on
# This is only relevant when logging to eventlog (win32):
#event_source = 'PostgreSQL'
diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h
index bfbcf96..4ab6356 100644
--- a/src/include/utils/elog.h
+++ b/src/include/utils/elog.h
@@ -397,6 +397,7 @@ extern char *Log_line_prefix;
extern int Log_destination;
extern char *Log_destination_string;
extern bool syslog_sequence_numbers;
+extern bool syslog_split_lines;
/* Log destination bitmap */
#define LOG_DESTINATION_STDERR 1
--
2.7.2
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
