Thread: serverlog rotation/functions
The attached patch includes serverlog rotation with minimal shared
memory usage as discussed and functions to access it.
Regards,
Andreas
Index: doc/src/sgml/func.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql-server/doc/src/sgml/func.sgml,v
retrieving revision 1.211
diff -u -r1.211 func.sgml
--- doc/src/sgml/func.sgml 25 Jun 2004 17:20:21 -0000 1.211
+++ doc/src/sgml/func.sgml 28 Jun 2004 10:35:09 -0000
@@ -7430,6 +7430,80 @@
</para>
<indexterm zone="functions-misc">
+ <primary>pg_logfile_get</primary>
+ </indexterm>
+ <indexterm zone="functions-misc">
+ <primary>pg_logfile_length</primary>
+ </indexterm>
+ <indexterm zone="functions-misc">
+ <primary>pg_logfile_name</primary>
+ </indexterm>
+ <indexterm zone="functions-misc">
+ <primary>pg_logfile_rotate</primary>
+ </indexterm>
+ <para>
+ The functions shown in <xref linkend="functions-misc-logfile">
+ deal with the server log file if configured with log_destination
+ <quote>file</quote>.
+ </para>
+
+ <table id="functions-misc-logfile">
+ <title>Server Logfile Functions</title>
+ <tgroup cols="3">
+ <thead>
+ <row><entry>Name</entry> <entry>Return Type</entry> <entry>Description</entry></row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry><literal><function>pg_logfile_get</function>(<parameter>size_int4</parameter>,
+ <parameter>offset_int4</parameter>,<parameter>filename_text</parameter>)</literal></entry>
+ <entry><type>cstring</type></entry>
+ <entry>get a part of the current server log file</entry>
+ </row>
+ <row>
+ <entry><literal><function>pg_logfile_length</function>(<paramater>filename_text</parameter>)</literal></entry>
+ <entry><type>int4</type></entry>
+ <entry>return the current length of the server log file</entry>
+ </row>
+ <row>
+ <entry><literal><function>pg_logfile_rotate</function>()</literal></entry>
+ <entry><type>cstring</type></entry>
+ <entry>rotates the server log file and returns the new log file
+ name</entry>
+ </row>
+ <row>
+ <entry><literal><function>pg_logfile_name</function>()</literal></entry>
+ <entry><type>cstring</type></entry>
+ <entry>returns the current server log file name</entry>
+ </row>
+ <row>
+ <entry><literal><function>pg_logfile_rotate</function>()</literal></entry>
+ <entry><type>cstring</type></entry>
+ <entry>rotates the server log file and returns the previous log file
+ name</entry>
+ </row>
+ </tbody>
+</tgroup>
+</table>
+<para>
+The <function>pg_logfile_get</function> function will return the
+ contents of the current server log file, limited by the size
+ parameter. If size is NULL, a server internal limit (currently
+ 50000) is applied. The position parameter specifies the
+ starting position of the server log chunk to be returned. A
+ positive number or 0 will be counted from the start of the file,
+ a negative number from the end; if NULL, -size is assumed
+ (i.e. the tail of the log file).
+</para>
+<para>
+Both <function>pg_logfile_get</function> and
+ <function>pg_logfile_length</function> have a filename
+ parameter which may specify the logfile to examine or the
+ current logfile if NULL.
+</para>
+
+ <indexterm zone="functions-misc">
<primary>pg_cancel_backend</primary>
</indexterm>
Index: doc/src/sgml/runtime.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql-server/doc/src/sgml/runtime.sgml,v
retrieving revision 1.268
diff -u -r1.268 runtime.sgml
--- doc/src/sgml/runtime.sgml 27 Jun 2004 22:58:19 -0000 1.268
+++ doc/src/sgml/runtime.sgml 28 Jun 2004 10:35:19 -0000
@@ -1721,14 +1721,25 @@
<listitem>
<para>
<productname>PostgreSQL</productname> supports several methods
- for loggning, including <systemitem>stderr</systemitem> and
- <systemitem>syslog</systemitem>. On Windows,
- <systemitem>eventlog</systemitem> is also supported. Set this
+ for logging, including <systemitem>stderr</systemitem>,
+ <systemitem>file></systemitem> and <systemitem>syslog</systemitem>.
+ On Windows, <systemitem>eventlog</systemitem> is also supported. Set this
option to a list of desired log destinations separated by a
comma. The default is to log to <systemitem>stderr</systemitem>
only. This option must be set at server start.
</para>
</listitem>
+ </varlistentry>
+
+ <varlistentry id="guc-syslog-facility" xreflabel="log_filename">
+ <term><varname>log_filename</varname> (<type>string</type>)</term>
+ <listitem>
+ <para>
+ This option sets the target filename for the log destination
+ <quote>file</quote> option. It may be specified as absolute
+ path or relative to the <application>cluster directory</application>.
+ </para>
+ </listitem>
</varlistentry>
<varlistentry id="guc-syslog-facility" xreflabel="syslog_facility">
Index: src/backend/postmaster/postmaster.c
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/postmaster/postmaster.c,v
retrieving revision 1.405
diff -u -r1.405 postmaster.c
--- src/backend/postmaster/postmaster.c 24 Jun 2004 21:02:55 -0000 1.405
+++ src/backend/postmaster/postmaster.c 28 Jun 2004 10:35:26 -0000
@@ -729,6 +729,11 @@
reset_shared(PostPortNumber);
/*
+ * Opens alternate log file
+ */
+ LogFileInit();
+
+ /*
* Estimate number of openable files. This must happen after setting
* up semaphores, because on some platforms semaphores count as open
* files.
Index: src/backend/utils/adt/misc.c
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/adt/misc.c,v
retrieving revision 1.34
diff -u -r1.34 misc.c
--- src/backend/utils/adt/misc.c 2 Jun 2004 21:29:29 -0000 1.34
+++ src/backend/utils/adt/misc.c 28 Jun 2004 10:35:33 -0000
@@ -103,3 +103,138 @@
{
PG_RETURN_INT32(pg_signal_backend(PG_GETARG_INT32(0),SIGINT));
}
+
+
+
+
+extern FILE *logfile; // in elog.c
+#define MAXLOGFILECHUNK 50000
+
+static char *absClusterPath(text *arg)
+{
+ char *filename;
+
+ if (is_absolute_path(VARDATA(arg)))
+ filename=VARDATA(arg);
+ else
+ {
+ filename = palloc(strlen(DataDir)+VARSIZE(arg)+2);
+ sprintf(filename, "%s/%s", DataDir, VARDATA(arg));
+ }
+ return filename;
+}
+
+
+Datum pg_logfile_get(PG_FUNCTION_ARGS)
+{
+ size_t size=MAXLOGFILECHUNK;
+ char *buf=0;
+ size_t nbytes;
+ FILE *f;
+
+ if (!PG_ARGISNULL(0))
+ size = PG_GETARG_INT32(0);
+ if (size > MAXLOGFILECHUNK)
+ {
+ size = MAXLOGFILECHUNK;
+ ereport(WARNING,
+ (errcode(ERRCODE_OUT_OF_MEMORY),
+ errmsg("Maximum size is %d.", size)));
+ }
+
+ if (PG_ARGISNULL(2))
+ f = logfile;
+ else
+ {
+ /* explicitely named logfile */
+ char *filename = absClusterPath(PG_GETARG_TEXT_P(2));
+ f = fopen(filename, "r");
+ if (!f)
+ {
+ ereport(WARNING,
+ (errcode_for_file_access(),
+ errmsg("file not found %s", filename)));
+ PG_RETURN_NULL();
+ }
+ }
+
+ if (f)
+ {
+
+ if (PG_ARGISNULL(1))
+ fseek(f, -size, SEEK_END);
+ else
+ {
+ long pos = PG_GETARG_INT32(1);
+ if (pos >= 0)
+ fseek(f, pos, SEEK_SET);
+ else
+ fseek(f, pos, SEEK_END);
+ }
+ buf = palloc(size+1);
+ nbytes = fread(buf, 1, size, f);
+ buf[nbytes] = 0;
+
+ fseek(f, 0, SEEK_END);
+
+ if (!PG_ARGISNULL(2))
+ fclose(f);
+ }
+
+ if (buf)
+ PG_RETURN_CSTRING(buf);
+ else
+ PG_RETURN_NULL();
+}
+
+
+Datum pg_logfile_length(PG_FUNCTION_ARGS)
+{
+ if (PG_ARGISNULL(0))
+ {
+ if (logfile)
+ {
+ fflush(logfile);
+ PG_RETURN_INT32(ftell(logfile));
+ }
+ }
+ else
+ {
+ struct stat fst;
+ fst.st_size=0;
+ stat(absClusterPath(PG_GETARG_TEXT_P(0)), &fst);
+
+ PG_RETURN_INT32(fst.st_size);
+ }
+ PG_RETURN_INT32(0);
+}
+
+
+Datum pg_logfile_name(PG_FUNCTION_ARGS)
+{
+ char *filename=LogFileName();
+ if (filename)
+ {
+ if (strncmp(filename, DataDir, strlen(DataDir)))
+ PG_RETURN_CSTRING(filename);
+ else
+ PG_RETURN_CSTRING(filename+strlen(DataDir)+1);
+ }
+ PG_RETURN_NULL();
+}
+
+
+Datum pg_logfile_rotate(PG_FUNCTION_ARGS)
+{
+ char *renamedFile = LogFileRotate();
+
+ if (renamedFile)
+ {
+ if (strncmp(renamedFile, DataDir, strlen(DataDir)))
+ PG_RETURN_CSTRING(renamedFile);
+ else
+ PG_RETURN_CSTRING(renamedFile+strlen(DataDir)+1);
+ }
+ else
+ PG_RETURN_NULL();
+}
Index: src/backend/utils/error/elog.c
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/error/elog.c,v
retrieving revision 1.142
diff -u -r1.142 elog.c
--- src/backend/utils/error/elog.c 24 Jun 2004 21:03:13 -0000 1.142
+++ src/backend/utils/error/elog.c 28 Jun 2004 10:35:36 -0000
@@ -63,7 +63,6 @@
#include "utils/memutils.h"
#include "utils/guc.h"
-
/* Global variables */
ErrorContextCallback *error_context_stack = NULL;
@@ -71,9 +70,18 @@
PGErrorVerbosity Log_error_verbosity = PGERROR_VERBOSE;
char *Log_line_prefix = NULL; /* format for extra log line info */
unsigned int Log_destination = LOG_DESTINATION_STDERR;
+char *Log_filename = NULL;
bool in_fatal_exit = false;
+FILE *logfile = NULL; /* the logfile we're writing to */
+static char logfileName[MAXPGPATH]; /* current filename */
+static long logfileVersion=0; /* logfile version this backend is currently using */
+
+static FILE *globalLogfileNameFH = NULL; /* this file contains the current logfile name */
+static long *globalLogfileVersion = NULL; /* logfile version the backend should be using (shared mem) */
+
+
#ifdef HAVE_SYSLOG
char *Syslog_facility; /* openlog() parameters */
char *Syslog_ident;
@@ -140,6 +148,11 @@
static const char *error_severity(int elevel);
static void append_with_tabs(StringInfo buf, const char *str);
+static char *logfile_newname(void);
+static void logfile_reopen(void);
+static char *logfile_readname(void);
+static bool logfile_writename(char *fn);
+
/*
* errstart --- begin an error-reporting cycle
@@ -931,11 +944,216 @@
/*
* And let errfinish() finish up.
*/
+
errfinish(0);
}
/*
+ * Initialize shared mem for logfile rotation
+ */
+
+void
+LogFileInit(void)
+{
+ if (!globalLogfileVersion && Log_filename && (Log_destination & LOG_DESTINATION_FILE))
+ {
+ char buffer[MAXPGPATH];
+ char *fn = logfile_newname();
+ if (fn)
+ {
+ /* create file for logfilename distribution and write initial filename */
+ snprintf(buffer, sizeof(buffer), "%s/global/pglogfile.name", DataDir);
+
+ globalLogfileNameFH = fopen(buffer, "w+");
+ if (!globalLogfileNameFH)
+ ereport(FATAL,
+ (errcode_for_file_access(),
+ errmsg("Logfile distribution file %s couldn't be opened.", buffer)));
+
+ if (!logfile_writename(fn))
+ return;
+
+ /* allocate logfile version shared memory segment for rotation signaling */
+ globalLogfileVersion = ShmemAlloc(sizeof(long));
+ if (!globalLogfileVersion)
+ {
+ ereport(FATAL,
+ (errcode(ERRCODE_OUT_OF_MEMORY),
+ errmsg("Out of shared memory")));
+ return;
+ }
+
+ *globalLogfileVersion = 0;
+
+
+ /* open logfile after we successfully initialized */
+ logfile_reopen();
+ pfree(fn);
+ }
+ }
+}
+
+
+/*
+ * Rotate log file
+ */
+char *
+LogFileRotate(void)
+{
+ char *filename;
+ char *oldFilename;
+
+ if (!globalLogfileVersion || !logfileName || !(Log_destination & LOG_DESTINATION_FILE))
+ return NULL;
+
+ filename = logfile_newname();
+ if (!filename)
+ return NULL;
+
+ if (!strcmp(filename, logfileName))
+ {
+ ereport(ERROR,
+ (errcode(ERRCODE_CONFIG_FILE_ERROR),
+ errmsg("Log_filename not suitable for rotation.")));
+ return NULL;
+ }
+
+ oldFilename = pstrdup(logfileName);
+
+ if (logfile_writename(filename))
+ {
+ *globalLogfileVersion++;
+
+ ereport(NOTICE,
+ (errcode(ERRCODE_WARNING),
+ errmsg("Opened new log file %s; previous logfile %s", filename, oldFilename)));
+
+ return oldFilename;
+ }
+
+ return NULL;
+}
+
+
+/*
+ * return current log file name
+ */
+char*
+LogFileName(void)
+{
+ if (logfileName)
+ return pstrdup(logfileName);
+ return NULL;
+}
+
+
+/*
+ * creates a new logfile name using current timestamp information
+ */
+static char*
+logfile_newname()
+{
+ char *filetemplate;
+ char *filename;
+ pg_time_t now = time(NULL);
+
+ if (is_absolute_path(Log_filename))
+ filetemplate = pstrdup(Log_filename);
+ else
+ {
+ filetemplate = palloc(strlen(DataDir) + strlen(Log_filename) + 2);
+ sprintf(filetemplate, "%s/%s", DataDir, Log_filename);
+ }
+ filename = palloc(MAXPGPATH);
+ pg_strftime(filename, MAXPGPATH, filetemplate, pg_localtime(&now));
+
+ pfree(filetemplate);
+
+ return filename;
+}
+
+
+/*
+ * return current global logfile name
+ */
+static char*
+logfile_readname(void)
+{
+ if (globalLogfileNameFH)
+ {
+ char *fn=palloc(MAXPGPATH);
+
+ fseek(globalLogfileNameFH, 0, SEEK_SET);
+ if (fread(fn, 1, MAXPGPATH, globalLogfileNameFH) != MAXPGPATH)
+ ereport(FATAL,
+ (errcode_for_file_access(),
+ errmsg("Logfile distribution file couldn't be read.")));
+
+ fn[MAXPGPATH-1]=0; /* in case file was corrupted, making sure we're not longer than MAXPGPATH */
+
+ return fn;
+ }
+ return NULL;
+}
+
+
+/*
+ * write global logfile name
+ */
+static bool
+logfile_writename(char *fn)
+{
+ char buffer[MAXPGPATH];
+ memset(buffer, 0, sizeof(buffer));
+ strcpy(buffer, fn);
+
+ fseek(globalLogfileNameFH, 0, SEEK_SET);
+ if (fwrite(buffer, 1, sizeof(buffer), globalLogfileNameFH) != MAXPGPATH)
+ {
+ ereport(FATAL,
+ (errcode_for_file_access(),
+ errmsg("Logfile distribution file couldn't be written.")));
+ return false;
+ }
+
+ return true;
+}
+
+
+/*
+ * reopen log file.
+ */
+static void
+logfile_reopen(void)
+{
+ if (logfile)
+ {
+ fclose(logfile);
+ logfile = NULL;
+ }
+
+ if ((Log_destination & LOG_DESTINATION_FILE) && globalLogfileVersion && globalLogfileNameFH)
+ {
+ char *fn=logfile_readname();
+ logfileVersion = *globalLogfileVersion;
+ if (fn)
+ {
+ logfile = fopen(fn, "a+");
+
+ if (!logfile)
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("failed to open log file %s", fn)));
+
+ strcpy(logfileName, fn);
+ pfree(fn);
+ }
+ }
+}
+
+
+/*
* Initialization of error output file
*/
void
@@ -1455,6 +1673,24 @@
if ((Log_destination & LOG_DESTINATION_STDERR) || whereToSendOutput == Debug)
{
fprintf(stderr, "%s", buf.data);
+ }
+
+ /* Write to file, if enabled */
+ if (logfile && (Log_destination & LOG_DESTINATION_FILE))
+ {
+ /* check if logfile changed */
+ if (globalLogfileVersion && *globalLogfileVersion != logfileVersion)
+ {
+ logfileVersion = *globalLogfileVersion;
+ logfile_reopen();
+ }
+
+ if (logfile)
+ {
+ fseek(logfile, 0, SEEK_END);
+ fprintf(logfile, "%s", buf.data);
+ fflush(logfile);
+ }
}
pfree(buf.data);
Index: src/backend/utils/misc/guc.c
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/misc/guc.c,v
retrieving revision 1.211
diff -u -r1.211 guc.c
--- src/backend/utils/misc/guc.c 11 Jun 2004 03:54:54 -0000 1.211
+++ src/backend/utils/misc/guc.c 28 Jun 2004 10:35:45 -0000
@@ -76,6 +76,8 @@
static const char *assign_log_destination(const char *value,
bool doit, GucSource source);
+extern char *Log_filename;
+
#ifdef HAVE_SYSLOG
extern char *Syslog_facility;
extern char *Syslog_ident;
@@ -1644,13 +1646,23 @@
{
{"log_destination", PGC_POSTMASTER, LOGGING_WHERE,
gettext_noop("Sets the target for log output."),
- gettext_noop("Valid values are combinations of stderr, syslog "
+ gettext_noop("Valid values are combinations of stderr, file, syslog "
"and eventlog, depending on platform."),
GUC_LIST_INPUT | GUC_REPORT
},
&log_destination_string,
"stderr", assign_log_destination, NULL
},
+ {
+ {"log_filename", PGC_POSTMASTER, LOGGING_WHERE,
+ gettext_noop("Sets the target filename for log output."),
+ gettext_noop("May be specified as relative to the cluster directory "
+ "or as absolute path."),
+ GUC_LIST_INPUT | GUC_REPORT
+ },
+ &Log_filename,
+ "postgresql.log.%Y-%m-%d_%H%M%S", NULL, NULL
+ },
#ifdef HAVE_SYSLOG
{
@@ -4779,6 +4791,8 @@
if (pg_strcasecmp(tok,"stderr") == 0)
newlogdest |= LOG_DESTINATION_STDERR;
+ else if (pg_strcasecmp(tok,"file") == 0)
+ newlogdest |= LOG_DESTINATION_FILE;
#ifdef HAVE_SYSLOG
else if (pg_strcasecmp(tok,"syslog") == 0)
newlogdest |= LOG_DESTINATION_SYSLOG;
Index: src/backend/utils/misc/postgresql.conf.sample
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/misc/postgresql.conf.sample,v
retrieving revision 1.113
diff -u -r1.113 postgresql.conf.sample
--- src/backend/utils/misc/postgresql.conf.sample 7 Apr 2004 05:05:50 -0000 1.113
+++ src/backend/utils/misc/postgresql.conf.sample 28 Jun 2004 10:35:45 -0000
@@ -147,9 +147,12 @@
# - Where to Log -
-#log_destination = 'stderr' # Valid values are combinations of stderr,
+#log_destination = 'stderr' # Valid values are combinations of stderr, file,
# syslog and eventlog, depending on
# platform.
+#log_filename = 'postgresql.log.%Y-%m-%d_%H%M%S' # filename if
+ # 'file' log_destination is used.
+
#syslog_facility = 'LOCAL0'
#syslog_ident = 'postgres'
Index: src/include/catalog/pg_proc.h
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/include/catalog/pg_proc.h,v
retrieving revision 1.339
diff -u -r1.339 pg_proc.h
--- src/include/catalog/pg_proc.h 25 Jun 2004 17:20:28 -0000 1.339
+++ src/include/catalog/pg_proc.h 28 Jun 2004 10:36:00 -0000
@@ -3595,6 +3595,18 @@
DATA(insert OID = 2243 ( bit_or PGNSP PGUID 12 t f f f i 1 1560 "1560" _null_
aggregate_dummy- _null_));
DESCR("bitwise-or bit aggregate");
+DATA(insert OID = 2546( int2array_int2vector_eq PGNSP PGUID 12 f f t f i 2 16 "1005 22" _null_
int2array_int2vector_eq- _null_ ));
+DESCR("int2array int2vector equal");
+
+DATA(insert OID = 2550( pg_logfile_get PGNSP PGUID 12 f f f f v 3 2275 "23 23 25" _null_
pg_logfile_get- _null_ ));
+DESCR("return log file contents");
+DATA(insert OID = 2551( pg_logfile_length PGNSP PGUID 12 f f f f v 1 23 "25" _null_ pg_logfile_length -
_null_));
+DESCR("name of log file");
+DATA(insert OID = 2552( pg_logfile_name PGNSP PGUID 12 f f f f v 0 2275 "" _null_ pg_logfile_name -
_null_));
+DESCR("length of log file");
+DATA(insert OID = 2553( pg_logfile_rotate PGNSP PGUID 12 f f f f v 0 2275 "" _null_ pg_logfile_rotate -
_null_));
+DESCR("rotate log file");
+
/*
* Symbolic values for provolatile column: these indicate whether the result
* of a function is dependent *only* on the values of its explicit arguments,
Index: src/include/utils/builtins.h
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/include/utils/builtins.h,v
retrieving revision 1.244
diff -u -r1.244 builtins.h
--- src/include/utils/builtins.h 25 Jun 2004 17:20:29 -0000 1.244
+++ src/include/utils/builtins.h 28 Jun 2004 10:36:03 -0000
@@ -356,6 +356,10 @@
extern Datum current_database(PG_FUNCTION_ARGS);
extern Datum pg_terminate_backend(PG_FUNCTION_ARGS);
extern Datum pg_cancel_backend(PG_FUNCTION_ARGS);
+extern Datum pg_logfile_get(PG_FUNCTION_ARGS);
+extern Datum pg_logfile_length(PG_FUNCTION_ARGS);
+extern Datum pg_logfile_name(PG_FUNCTION_ARGS);
+extern Datum pg_logfile_rotate(PG_FUNCTION_ARGS);
/* not_in.c */
extern Datum int4notin(PG_FUNCTION_ARGS);
Index: src/include/utils/elog.h
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/include/utils/elog.h,v
retrieving revision 1.69
diff -u -r1.69 elog.h
--- src/include/utils/elog.h 24 Jun 2004 21:03:42 -0000 1.69
+++ src/include/utils/elog.h 28 Jun 2004 10:36:04 -0000
@@ -182,9 +182,13 @@
#define LOG_DESTINATION_STDERR 1
#define LOG_DESTINATION_SYSLOG 2
#define LOG_DESTINATION_EVENTLOG 4
+#define LOG_DESTINATION_FILE 8
/* Other exported functions */
extern void DebugFileOpen(void);
+extern void LogFileInit(void);
+extern char *LogFileRotate(void);
+extern char *LogFileName(void);
/*
* Write errors to stderr (or by equal means when stderr is
Andreas Pflug <pgadmin@pse-consulting.de> writes:
> The attached patch includes serverlog rotation with minimal shared
> memory usage as discussed and functions to access it.
This patch is still unsafe and unworkable. Why would you make the
mechanism dependent on shared memory *and* an intermediate data file
*and* an inherited file handle to access that data file? The inherited
handle is subject to race conditions (because you've got different
processes fseeking the same file descriptor with no interlocking) and
I don't really see that it's buying anything anyway. If you stored the
value of time(NULL) to use in shared memory, you'd not need the data
file because every process could compute the correct logfile name for
itself.
An issue that doesn't matter a whole lot on Unix, but I think would
matter on Windows, is that with the patch as given a process will not
reopen the log file until it's got something to write there. Non-chatty
processes could easily hold open the old log file indefinitely. It
might be a good idea to force the log file to be reopened at SIGHUP,
and for the "rotate" command to do such a SIGHUP.
Overall though, I still quite fail to see the point of doing it this
way compared to piping the postmaster's stderr into something that can
rotate log files. The fundamental objection to this whole feature is
that it can only capture elog output, which is not everything of
interest. (For example, dynamic linker failures will usually be
reported to stderr, a behavior that we cannot override.)
regards, tom lane
Tom Lane wrote: >Andreas Pflug <pgadmin@pse-consulting.de> writes: > > >>The attached patch includes serverlog rotation with minimal shared >>memory usage as discussed and functions to access it. >> >> > >This patch is still unsafe and unworkable. Why would you make the >mechanism dependent on shared memory *and* an intermediate data file >*and* an inherited file handle to access that data file? The inherited >handle is subject to race conditions (because you've got different >processes fseeking the same file descriptor with no interlocking) and >I don't really see that it's buying anything anyway. If you stored the >value of time(NULL) to use in shared memory, you'd not need the data >file because every process could compute the correct logfile name for >itself. > > 'k, the timestamp may be used as a flag to reopen too, probably better than that filehandle stuff. I can rewrite that. >An issue that doesn't matter a whole lot on Unix, but I think would >matter on Windows, is that with the patch as given a process will not >reopen the log file until it's got something to write there. Non-chatty >processes could easily hold open the old log file indefinitely. It >might be a good idea to force the log file to be reopened at SIGHUP, >and for the "rotate" command to do such a SIGHUP. > > Why do you expect problems on win32 here? I intentionally did *not* tie this to a SIGHUP, which I consider to be quite an expensive signal for this case, to reopen a file that is (hopefully) rarely used. Imagine 100 backends, SIGHUPping every minute or so. But certainly a backend could check for the logfile to be current when SIGHUP is received. >Overall though, I still quite fail to see the point of doing it this >way compared to piping the postmaster's stderr into something that can >rotate log files. The fundamental objection to this whole feature is >that it can only capture elog output, which is not everything of >interest. (For example, dynamic linker failures will usually be >reported to stderr, a behavior that we cannot override.) > > If this "something" is tightly coupled to the postmaster, and can be retrieved over a database connection, fine. The restriction about messages going to stderr are valid for log_destination syslog too, so the new log_destination=file is no regression. What would you use on win32? Piping stderr isn't really popular there, and eventlog is shared between all apps (that's probably the reason why M$ uses an own log infrastructure for MSSQL). Regards, Andreas
Updated version.
Only timestamp of fresh logfile in shared mem, with sanity checks.
On SIGHUP, timestamp is checked if rotation was issued, as well as
changed log_filename setting from postgresql.conf.
Regards,
Andreas
Index: src/backend/postmaster/postmaster.c
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/postmaster/postmaster.c,v
retrieving revision 1.405
diff -u -r1.405 postmaster.c
--- src/backend/postmaster/postmaster.c 24 Jun 2004 21:02:55 -0000 1.405
+++ src/backend/postmaster/postmaster.c 6 Jul 2004 22:12:22 -0000
@@ -729,6 +729,11 @@
reset_shared(PostPortNumber);
/*
+ * Opens alternate log file
+ */
+ LogFileInit();
+
+ /*
* Estimate number of openable files. This must happen after setting
* up semaphores, because on some platforms semaphores count as open
* files.
Index: src/backend/utils/adt/misc.c
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/adt/misc.c,v
retrieving revision 1.35
diff -u -r1.35 misc.c
--- src/backend/utils/adt/misc.c 2 Jul 2004 18:59:22 -0000 1.35
+++ src/backend/utils/adt/misc.c 6 Jul 2004 22:12:34 -0000
@@ -202,3 +202,137 @@
FreeDir(fctx->dirdesc);
SRF_RETURN_DONE(funcctx);
}
+
+
+extern FILE *logfile; // in elog.c
+#define MAXLOGFILECHUNK 50000
+
+static char *absClusterPath(text *arg)
+{
+ char *filename;
+
+ if (is_absolute_path(VARDATA(arg)))
+ filename=VARDATA(arg);
+ else
+ {
+ filename = palloc(strlen(DataDir)+VARSIZE(arg)+2);
+ sprintf(filename, "%s/%s", DataDir, VARDATA(arg));
+ }
+ return filename;
+}
+
+
+Datum pg_logfile_get(PG_FUNCTION_ARGS)
+{
+ size_t size=MAXLOGFILECHUNK;
+ char *buf=0;
+ size_t nbytes;
+ FILE *f;
+
+ if (!PG_ARGISNULL(0))
+ size = PG_GETARG_INT32(0);
+ if (size > MAXLOGFILECHUNK)
+ {
+ size = MAXLOGFILECHUNK;
+ ereport(WARNING,
+ (errcode(ERRCODE_OUT_OF_MEMORY),
+ errmsg("Maximum size is %d.", size)));
+ }
+
+ if (PG_ARGISNULL(2))
+ f = logfile;
+ else
+ {
+ /* explicitely named logfile */
+ char *filename = absClusterPath(PG_GETARG_TEXT_P(2));
+ f = fopen(filename, "r");
+ if (!f)
+ {
+ ereport(WARNING,
+ (errcode_for_file_access(),
+ errmsg("file not found %s", filename)));
+ PG_RETURN_NULL();
+ }
+ }
+
+ if (f)
+ {
+
+ if (PG_ARGISNULL(1))
+ fseek(f, -size, SEEK_END);
+ else
+ {
+ long pos = PG_GETARG_INT32(1);
+ if (pos >= 0)
+ fseek(f, pos, SEEK_SET);
+ else
+ fseek(f, pos, SEEK_END);
+ }
+ buf = palloc(size+1);
+ nbytes = fread(buf, 1, size, f);
+ buf[nbytes] = 0;
+
+ fseek(f, 0, SEEK_END);
+
+ if (!PG_ARGISNULL(2))
+ fclose(f);
+ }
+
+ if (buf)
+ PG_RETURN_CSTRING(buf);
+ else
+ PG_RETURN_NULL();
+}
+
+
+Datum pg_logfile_length(PG_FUNCTION_ARGS)
+{
+ if (PG_ARGISNULL(0))
+ {
+ if (logfile)
+ {
+ fflush(logfile);
+ PG_RETURN_INT32(ftell(logfile));
+ }
+ }
+ else
+ {
+ struct stat fst;
+ fst.st_size=0;
+ stat(absClusterPath(PG_GETARG_TEXT_P(0)), &fst);
+
+ PG_RETURN_INT32(fst.st_size);
+ }
+ PG_RETURN_INT32(0);
+}
+
+
+Datum pg_logfile_name(PG_FUNCTION_ARGS)
+{
+ char *filename=LogFileName();
+ if (filename)
+ {
+ if (strncmp(filename, DataDir, strlen(DataDir)))
+ PG_RETURN_CSTRING(filename);
+ else
+ PG_RETURN_CSTRING(filename+strlen(DataDir)+1);
+ }
+ PG_RETURN_NULL();
+}
+
+
+Datum pg_logfile_rotate(PG_FUNCTION_ARGS)
+{
+ char *renamedFile = LogFileRotate();
+
+ if (renamedFile)
+ {
+ if (strncmp(renamedFile, DataDir, strlen(DataDir)))
+ PG_RETURN_CSTRING(renamedFile);
+ else
+ PG_RETURN_CSTRING(renamedFile+strlen(DataDir)+1);
+ }
+ else
+ PG_RETURN_NULL();
+}
+
Index: src/backend/utils/error/elog.c
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/error/elog.c,v
retrieving revision 1.142
diff -u -r1.142 elog.c
--- src/backend/utils/error/elog.c 24 Jun 2004 21:03:13 -0000 1.142
+++ src/backend/utils/error/elog.c 6 Jul 2004 22:12:37 -0000
@@ -63,7 +63,6 @@
#include "utils/memutils.h"
#include "utils/guc.h"
-
/* Global variables */
ErrorContextCallback *error_context_stack = NULL;
@@ -71,9 +70,17 @@
PGErrorVerbosity Log_error_verbosity = PGERROR_VERBOSE;
char *Log_line_prefix = NULL; /* format for extra log line info */
unsigned int Log_destination = LOG_DESTINATION_STDERR;
+char *Log_filename = NULL;
bool in_fatal_exit = false;
+FILE *logfile = NULL; /* the logfile we're writing to */
+static char logfileName[MAXPGPATH]; /* current filename */
+static pg_time_t logfileTimestamp=0; /* logfile version this backend is currently using */
+
+static pg_time_t *globalLogfileTimestamp = NULL; /* logfile version the backend should be using (shared mem) */
+
+
#ifdef HAVE_SYSLOG
char *Syslog_facility; /* openlog() parameters */
char *Syslog_ident;
@@ -140,6 +147,9 @@
static const char *error_severity(int elevel);
static void append_with_tabs(StringInfo buf, const char *str);
+static char *logfile_getname(pg_time_t timestamp);
+static void logfile_reopen(void);
+
/*
* errstart --- begin an error-reporting cycle
@@ -931,11 +941,181 @@
/*
* And let errfinish() finish up.
*/
+
errfinish(0);
}
/*
+ * Initialize shared mem for logfile rotation
+ */
+
+void
+LogFileInit(void)
+{
+ if (!globalLogfileTimestamp && Log_filename && (Log_destination & LOG_DESTINATION_FILE))
+ {
+ /* allocate logfile version shared memory segment for rotation signaling */
+ globalLogfileTimestamp = ShmemAlloc(sizeof(pg_time_t));
+ if (!globalLogfileTimestamp)
+ {
+ ereport(FATAL,
+ (errcode(ERRCODE_OUT_OF_MEMORY),
+ errmsg("Out of shared memory")));
+ return;
+ }
+
+ *globalLogfileTimestamp = time(NULL);
+
+ /* open logfile after we successfully initialized */
+ logfile_reopen();
+ }
+}
+
+
+/*
+ * Rotate log file
+ */
+char *
+LogFileRotate(void)
+{
+ char *filename;
+ char *oldFilename;
+ pg_time_t now;
+
+ if (!globalLogfileTimestamp || !logfileName || !(Log_destination & LOG_DESTINATION_FILE))
+ return NULL;
+
+ now = time(NULL);
+
+ filename = logfile_getname(now);
+ if (!filename)
+ return NULL;
+
+ if (!strcmp(filename, logfileName))
+ {
+ ereport(ERROR,
+ (errcode(ERRCODE_CONFIG_FILE_ERROR),
+ errmsg("Log_filename not suitable for rotation.")));
+ return NULL;
+ }
+
+ oldFilename = pstrdup(logfileName);
+ *globalLogfileTimestamp = now;
+
+ ereport(NOTICE,
+ (errcode(ERRCODE_WARNING),
+ errmsg("Opened new log file %s; previous logfile %s", filename, oldFilename)));
+
+ return oldFilename;
+}
+
+
+/*
+ * return current log file name
+ */
+char*
+LogFileName(void)
+{
+ if (logfileName)
+ return pstrdup(logfileName);
+ return NULL;
+}
+
+
+/*
+ * check if logfile has to be reopened
+ * if called from ProcessConfigFile after SIGHUP, also check for filename template change
+ */
+void LogFileCheckReopen(bool fromSIGHUP)
+{
+ if (globalLogfileTimestamp)
+ {
+ if (*globalLogfileTimestamp != logfileTimestamp)
+ {
+ /* sanity check: if it's in the future, shmem probably corrupted */
+ pg_time_t now=time(NULL);
+ if (*globalLogfileTimestamp > now)
+ *globalLogfileTimestamp = now;
+
+ logfile_reopen();
+ }
+ else if (fromSIGHUP)
+ {
+ char *filename = logfile_getname(logfileTimestamp);
+ if (filename && strcmp(filename, logfileName))
+ {
+ /* template for logfile was changed */
+ logfile_reopen();
+ pfree(filename);
+ }
+ }
+ }
+}
+
+
+/*
+ * creates logfile name using timestamp information
+ */
+static char*
+logfile_getname(pg_time_t timestamp)
+{
+ char *filetemplate;
+ char *filename;
+
+ if (is_absolute_path(Log_filename))
+ filetemplate = pstrdup(Log_filename);
+ else
+ {
+ filetemplate = palloc(strlen(DataDir) + strlen(Log_filename) + 2);
+ sprintf(filetemplate, "%s/%s", DataDir, Log_filename);
+ }
+ filename = palloc(MAXPGPATH);
+ pg_strftime(filename, MAXPGPATH, filetemplate, pg_localtime(×tamp));
+
+ pfree(filetemplate);
+
+ return filename;
+}
+
+
+/*
+ * reopen log file.
+ */
+static void
+logfile_reopen(void)
+{
+ if (logfile)
+ {
+ fclose(logfile);
+ logfile = NULL;
+ }
+
+ if ((Log_destination & LOG_DESTINATION_FILE) && globalLogfileTimestamp)
+ {
+ char *fn;
+
+ logfileTimestamp = *globalLogfileTimestamp;
+
+ fn=logfile_getname(logfileTimestamp);
+
+ if (fn)
+ {
+ logfile = fopen(fn, "a+");
+
+ if (!logfile)
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("failed to open log file %s", fn)));
+
+ strcpy(logfileName, fn);
+ pfree(fn);
+ }
+ }
+}
+
+
+/*
* Initialization of error output file
*/
void
@@ -1455,6 +1635,20 @@
if ((Log_destination & LOG_DESTINATION_STDERR) || whereToSendOutput == Debug)
{
fprintf(stderr, "%s", buf.data);
+ }
+
+ /* Write to file, if enabled */
+ if (logfile && (Log_destination & LOG_DESTINATION_FILE))
+ {
+ /* check if logfile changed */
+ LogFileCheckReopen(false);
+
+ if (logfile)
+ {
+ fseek(logfile, 0, SEEK_END);
+ fprintf(logfile, "%s", buf.data);
+ fflush(logfile);
+ }
}
pfree(buf.data);
Index: src/backend/utils/misc/guc-file.l
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/misc/guc-file.l,v
retrieving revision 1.22
diff -u -r1.22 guc-file.l
--- src/backend/utils/misc/guc-file.l 26 May 2004 15:07:38 -0000 1.22
+++ src/backend/utils/misc/guc-file.l 6 Jul 2004 22:12:38 -0000
@@ -276,6 +276,9 @@
set_config_option(item->name, item->value, context,
PGC_S_FILE, false, true);
+ if (context == PGC_SIGHUP)
+ LogFileCheckReopen(true);
+
cleanup_exit:
free_name_value_list(head);
return;
Index: src/backend/utils/misc/guc.c
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/misc/guc.c,v
retrieving revision 1.213
diff -u -r1.213 guc.c
--- src/backend/utils/misc/guc.c 5 Jul 2004 23:14:14 -0000 1.213
+++ src/backend/utils/misc/guc.c 6 Jul 2004 22:12:46 -0000
@@ -76,6 +76,8 @@
static const char *assign_log_destination(const char *value,
bool doit, GucSource source);
+extern char *Log_filename;
+
#ifdef HAVE_SYSLOG
extern char *Syslog_facility;
extern char *Syslog_ident;
@@ -1606,13 +1608,23 @@
{
{"log_destination", PGC_POSTMASTER, LOGGING_WHERE,
gettext_noop("Sets the target for log output."),
- gettext_noop("Valid values are combinations of stderr, syslog "
+ gettext_noop("Valid values are combinations of stderr, file, syslog "
"and eventlog, depending on platform."),
GUC_LIST_INPUT
},
&log_destination_string,
"stderr", assign_log_destination, NULL
},
+ {
+ {"log_filename", PGC_SIGHUP, LOGGING_WHERE,
+ gettext_noop("Sets the target filename for log output."),
+ gettext_noop("May be specified as relative to the cluster directory "
+ "or as absolute path."),
+ GUC_LIST_INPUT | GUC_REPORT
+ },
+ &Log_filename,
+ "postgresql.log.%Y-%m-%d_%H%M%S", NULL, NULL
+ },
#ifdef HAVE_SYSLOG
{
@@ -5033,6 +5045,8 @@
if (pg_strcasecmp(tok,"stderr") == 0)
newlogdest |= LOG_DESTINATION_STDERR;
+ else if (pg_strcasecmp(tok,"file") == 0)
+ newlogdest |= LOG_DESTINATION_FILE;
#ifdef HAVE_SYSLOG
else if (pg_strcasecmp(tok,"syslog") == 0)
newlogdest |= LOG_DESTINATION_SYSLOG;
Index: src/backend/utils/misc/postgresql.conf.sample
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/misc/postgresql.conf.sample,v
retrieving revision 1.113
diff -u -r1.113 postgresql.conf.sample
--- src/backend/utils/misc/postgresql.conf.sample 7 Apr 2004 05:05:50 -0000 1.113
+++ src/backend/utils/misc/postgresql.conf.sample 6 Jul 2004 22:12:47 -0000
@@ -147,9 +147,12 @@
# - Where to Log -
-#log_destination = 'stderr' # Valid values are combinations of stderr,
+#log_destination = 'stderr' # Valid values are combinations of stderr, file,
# syslog and eventlog, depending on
# platform.
+#log_filename = 'postgresql.log.%Y-%m-%d_%H%M%S' # filename if
+ # 'file' log_destination is used.
+
#syslog_facility = 'LOCAL0'
#syslog_ident = 'postgres'
Index: src/include/catalog/pg_proc.h
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/include/catalog/pg_proc.h,v
retrieving revision 1.341
diff -u -r1.341 pg_proc.h
--- src/include/catalog/pg_proc.h 2 Jul 2004 22:49:48 -0000 1.341
+++ src/include/catalog/pg_proc.h 6 Jul 2004 22:13:02 -0000
@@ -3595,6 +3595,14 @@
DATA(insert OID = 2556 ( pg_tablespace_databases PGNSP PGUID 12 f f t t s 1 26 "26" _null_ pg_tablespace_databases
-_null_));
DESCR("returns database oids in a tablespace");
+DATA(insert OID = 2557( pg_logfile_get PGNSP PGUID 12 f f f f v 3 2275 "23 23 25" _null_
pg_logfile_get- _null_ ));
+DESCR("return log file contents");
+DATA(insert OID = 2558( pg_logfile_length PGNSP PGUID 12 f f f f v 1 23 "25" _null_ pg_logfile_length -
_null_));
+DESCR("name of log file");
+DATA(insert OID = 2559( pg_logfile_name PGNSP PGUID 12 f f f f v 0 2275 "" _null_ pg_logfile_name -
_null_));
+DESCR("length of log file");
+DATA(insert OID = 2560( pg_logfile_rotate PGNSP PGUID 12 f f f f v 0 2275 "" _null_ pg_logfile_rotate -
_null_));
+DESCR("rotate log file");
/*
* Symbolic values for provolatile column: these indicate whether the result
Index: src/include/utils/builtins.h
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/include/utils/builtins.h,v
retrieving revision 1.245
diff -u -r1.245 builtins.h
--- src/include/utils/builtins.h 2 Jul 2004 18:59:25 -0000 1.245
+++ src/include/utils/builtins.h 6 Jul 2004 22:13:05 -0000
@@ -358,6 +358,11 @@
extern Datum pg_cancel_backend(PG_FUNCTION_ARGS);
extern Datum pg_tablespace_databases(PG_FUNCTION_ARGS);
+extern Datum pg_logfile_get(PG_FUNCTION_ARGS);
+extern Datum pg_logfile_length(PG_FUNCTION_ARGS);
+extern Datum pg_logfile_name(PG_FUNCTION_ARGS);
+extern Datum pg_logfile_rotate(PG_FUNCTION_ARGS);
+
/* not_in.c */
extern Datum int4notin(PG_FUNCTION_ARGS);
extern Datum oidnotin(PG_FUNCTION_ARGS);
Index: src/include/utils/elog.h
===================================================================
RCS file: /projects/cvsroot/pgsql-server/src/include/utils/elog.h,v
retrieving revision 1.69
diff -u -r1.69 elog.h
--- src/include/utils/elog.h 24 Jun 2004 21:03:42 -0000 1.69
+++ src/include/utils/elog.h 6 Jul 2004 22:13:05 -0000
@@ -182,10 +182,14 @@
#define LOG_DESTINATION_STDERR 1
#define LOG_DESTINATION_SYSLOG 2
#define LOG_DESTINATION_EVENTLOG 4
+#define LOG_DESTINATION_FILE 8
/* Other exported functions */
extern void DebugFileOpen(void);
-
+extern void LogFileInit(void);
+extern void LogFileCheckReopen(bool fromSIGHUP);
+extern char *LogFileRotate(void);
+extern char *LogFileName(void);
/*
* Write errors to stderr (or by equal means when stderr is
* not available). Used before ereport/elog can be used
How is this patch supposed to work? Do people need to modify
postgresql.conf and then sighup the postmaster? It seems more logical
for the super-user to call a server-side function. You have
pg_logfile_rotate(), but that doesn't send a sighup to the postmaster so
all the backends will reread the global log file name.
Also, what mechanism is there to prevent backends from reading the log
filename _while_ it is being modified?
Also there are no documenttion changes.
However, looking at the issue of backends all reloading their
postgresql.conf files at different times and sending output to different
files, I wonder if it would be best to create a log process and have
each backend connect to that. That way, all the logging happens in one
process.
---------------------------------------------------------------------------
Andreas Pflug wrote:
> Updated version.
>
> Only timestamp of fresh logfile in shared mem, with sanity checks.
> On SIGHUP, timestamp is checked if rotation was issued, as well as
> changed log_filename setting from postgresql.conf.
>
> Regards,
> Andreas
>
>
>
> Index: src/backend/postmaster/postmaster.c
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/backend/postmaster/postmaster.c,v
> retrieving revision 1.405
> diff -u -r1.405 postmaster.c
> --- src/backend/postmaster/postmaster.c 24 Jun 2004 21:02:55 -0000 1.405
> +++ src/backend/postmaster/postmaster.c 6 Jul 2004 22:12:22 -0000
> @@ -729,6 +729,11 @@
> reset_shared(PostPortNumber);
>
> /*
> + * Opens alternate log file
> + */
> + LogFileInit();
> +
> + /*
> * Estimate number of openable files. This must happen after setting
> * up semaphores, because on some platforms semaphores count as open
> * files.
> Index: src/backend/utils/adt/misc.c
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/adt/misc.c,v
> retrieving revision 1.35
> diff -u -r1.35 misc.c
> --- src/backend/utils/adt/misc.c 2 Jul 2004 18:59:22 -0000 1.35
> +++ src/backend/utils/adt/misc.c 6 Jul 2004 22:12:34 -0000
> @@ -202,3 +202,137 @@
> FreeDir(fctx->dirdesc);
> SRF_RETURN_DONE(funcctx);
> }
> +
> +
> +extern FILE *logfile; // in elog.c
> +#define MAXLOGFILECHUNK 50000
> +
> +static char *absClusterPath(text *arg)
> +{
> + char *filename;
> +
> + if (is_absolute_path(VARDATA(arg)))
> + filename=VARDATA(arg);
> + else
> + {
> + filename = palloc(strlen(DataDir)+VARSIZE(arg)+2);
> + sprintf(filename, "%s/%s", DataDir, VARDATA(arg));
> + }
> + return filename;
> +}
> +
> +
> +Datum pg_logfile_get(PG_FUNCTION_ARGS)
> +{
> + size_t size=MAXLOGFILECHUNK;
> + char *buf=0;
> + size_t nbytes;
> + FILE *f;
> +
> + if (!PG_ARGISNULL(0))
> + size = PG_GETARG_INT32(0);
> + if (size > MAXLOGFILECHUNK)
> + {
> + size = MAXLOGFILECHUNK;
> + ereport(WARNING,
> + (errcode(ERRCODE_OUT_OF_MEMORY),
> + errmsg("Maximum size is %d.", size)));
> + }
> +
> + if (PG_ARGISNULL(2))
> + f = logfile;
> + else
> + {
> + /* explicitely named logfile */
> + char *filename = absClusterPath(PG_GETARG_TEXT_P(2));
> + f = fopen(filename, "r");
> + if (!f)
> + {
> + ereport(WARNING,
> + (errcode_for_file_access(),
> + errmsg("file not found %s", filename)));
> + PG_RETURN_NULL();
> + }
> + }
> +
> + if (f)
> + {
> +
> + if (PG_ARGISNULL(1))
> + fseek(f, -size, SEEK_END);
> + else
> + {
> + long pos = PG_GETARG_INT32(1);
> + if (pos >= 0)
> + fseek(f, pos, SEEK_SET);
> + else
> + fseek(f, pos, SEEK_END);
> + }
> + buf = palloc(size+1);
> + nbytes = fread(buf, 1, size, f);
> + buf[nbytes] = 0;
> +
> + fseek(f, 0, SEEK_END);
> +
> + if (!PG_ARGISNULL(2))
> + fclose(f);
> + }
> +
> + if (buf)
> + PG_RETURN_CSTRING(buf);
> + else
> + PG_RETURN_NULL();
> +}
> +
> +
> +Datum pg_logfile_length(PG_FUNCTION_ARGS)
> +{
> + if (PG_ARGISNULL(0))
> + {
> + if (logfile)
> + {
> + fflush(logfile);
> + PG_RETURN_INT32(ftell(logfile));
> + }
> + }
> + else
> + {
> + struct stat fst;
> + fst.st_size=0;
> + stat(absClusterPath(PG_GETARG_TEXT_P(0)), &fst);
> +
> + PG_RETURN_INT32(fst.st_size);
> + }
> + PG_RETURN_INT32(0);
> +}
> +
> +
> +Datum pg_logfile_name(PG_FUNCTION_ARGS)
> +{
> + char *filename=LogFileName();
> + if (filename)
> + {
> + if (strncmp(filename, DataDir, strlen(DataDir)))
> + PG_RETURN_CSTRING(filename);
> + else
> + PG_RETURN_CSTRING(filename+strlen(DataDir)+1);
> + }
> + PG_RETURN_NULL();
> +}
> +
> +
> +Datum pg_logfile_rotate(PG_FUNCTION_ARGS)
> +{
> + char *renamedFile = LogFileRotate();
> +
> + if (renamedFile)
> + {
> + if (strncmp(renamedFile, DataDir, strlen(DataDir)))
> + PG_RETURN_CSTRING(renamedFile);
> + else
> + PG_RETURN_CSTRING(renamedFile+strlen(DataDir)+1);
> + }
> + else
> + PG_RETURN_NULL();
> +}
> +
> Index: src/backend/utils/error/elog.c
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/error/elog.c,v
> retrieving revision 1.142
> diff -u -r1.142 elog.c
> --- src/backend/utils/error/elog.c 24 Jun 2004 21:03:13 -0000 1.142
> +++ src/backend/utils/error/elog.c 6 Jul 2004 22:12:37 -0000
> @@ -63,7 +63,6 @@
> #include "utils/memutils.h"
> #include "utils/guc.h"
>
> -
> /* Global variables */
> ErrorContextCallback *error_context_stack = NULL;
>
> @@ -71,9 +70,17 @@
> PGErrorVerbosity Log_error_verbosity = PGERROR_VERBOSE;
> char *Log_line_prefix = NULL; /* format for extra log line info */
> unsigned int Log_destination = LOG_DESTINATION_STDERR;
> +char *Log_filename = NULL;
>
> bool in_fatal_exit = false;
>
> +FILE *logfile = NULL; /* the logfile we're writing to */
> +static char logfileName[MAXPGPATH]; /* current filename */
> +static pg_time_t logfileTimestamp=0; /* logfile version this backend is currently using */
> +
> +static pg_time_t *globalLogfileTimestamp = NULL; /* logfile version the backend should be using (shared mem) */
> +
> +
> #ifdef HAVE_SYSLOG
> char *Syslog_facility; /* openlog() parameters */
> char *Syslog_ident;
> @@ -140,6 +147,9 @@
> static const char *error_severity(int elevel);
> static void append_with_tabs(StringInfo buf, const char *str);
>
> +static char *logfile_getname(pg_time_t timestamp);
> +static void logfile_reopen(void);
> +
>
> /*
> * errstart --- begin an error-reporting cycle
> @@ -931,11 +941,181 @@
> /*
> * And let errfinish() finish up.
> */
> +
> errfinish(0);
> }
>
>
> /*
> + * Initialize shared mem for logfile rotation
> + */
> +
> +void
> +LogFileInit(void)
> +{
> + if (!globalLogfileTimestamp && Log_filename && (Log_destination & LOG_DESTINATION_FILE))
> + {
> + /* allocate logfile version shared memory segment for rotation signaling */
> + globalLogfileTimestamp = ShmemAlloc(sizeof(pg_time_t));
> + if (!globalLogfileTimestamp)
> + {
> + ereport(FATAL,
> + (errcode(ERRCODE_OUT_OF_MEMORY),
> + errmsg("Out of shared memory")));
> + return;
> + }
> +
> + *globalLogfileTimestamp = time(NULL);
> +
> + /* open logfile after we successfully initialized */
> + logfile_reopen();
> + }
> +}
> +
> +
> +/*
> + * Rotate log file
> + */
> +char *
> +LogFileRotate(void)
> +{
> + char *filename;
> + char *oldFilename;
> + pg_time_t now;
> +
> + if (!globalLogfileTimestamp || !logfileName || !(Log_destination & LOG_DESTINATION_FILE))
> + return NULL;
> +
> + now = time(NULL);
> +
> + filename = logfile_getname(now);
> + if (!filename)
> + return NULL;
> +
> + if (!strcmp(filename, logfileName))
> + {
> + ereport(ERROR,
> + (errcode(ERRCODE_CONFIG_FILE_ERROR),
> + errmsg("Log_filename not suitable for rotation.")));
> + return NULL;
> + }
> +
> + oldFilename = pstrdup(logfileName);
> + *globalLogfileTimestamp = now;
> +
> + ereport(NOTICE,
> + (errcode(ERRCODE_WARNING),
> + errmsg("Opened new log file %s; previous logfile %s", filename, oldFilename)));
> +
> + return oldFilename;
> +}
> +
> +
> +/*
> + * return current log file name
> + */
> +char*
> +LogFileName(void)
> +{
> + if (logfileName)
> + return pstrdup(logfileName);
> + return NULL;
> +}
> +
> +
> +/*
> + * check if logfile has to be reopened
> + * if called from ProcessConfigFile after SIGHUP, also check for filename template change
> + */
> +void LogFileCheckReopen(bool fromSIGHUP)
> +{
> + if (globalLogfileTimestamp)
> + {
> + if (*globalLogfileTimestamp != logfileTimestamp)
> + {
> + /* sanity check: if it's in the future, shmem probably corrupted */
> + pg_time_t now=time(NULL);
> + if (*globalLogfileTimestamp > now)
> + *globalLogfileTimestamp = now;
> +
> + logfile_reopen();
> + }
> + else if (fromSIGHUP)
> + {
> + char *filename = logfile_getname(logfileTimestamp);
> + if (filename && strcmp(filename, logfileName))
> + {
> + /* template for logfile was changed */
> + logfile_reopen();
> + pfree(filename);
> + }
> + }
> + }
> +}
> +
> +
> +/*
> + * creates logfile name using timestamp information
> + */
> +static char*
> +logfile_getname(pg_time_t timestamp)
> +{
> + char *filetemplate;
> + char *filename;
> +
> + if (is_absolute_path(Log_filename))
> + filetemplate = pstrdup(Log_filename);
> + else
> + {
> + filetemplate = palloc(strlen(DataDir) + strlen(Log_filename) + 2);
> + sprintf(filetemplate, "%s/%s", DataDir, Log_filename);
> + }
> + filename = palloc(MAXPGPATH);
> + pg_strftime(filename, MAXPGPATH, filetemplate, pg_localtime(×tamp));
> +
> + pfree(filetemplate);
> +
> + return filename;
> +}
> +
> +
> +/*
> + * reopen log file.
> + */
> +static void
> +logfile_reopen(void)
> +{
> + if (logfile)
> + {
> + fclose(logfile);
> + logfile = NULL;
> + }
> +
> + if ((Log_destination & LOG_DESTINATION_FILE) && globalLogfileTimestamp)
> + {
> + char *fn;
> +
> + logfileTimestamp = *globalLogfileTimestamp;
> +
> + fn=logfile_getname(logfileTimestamp);
> +
> + if (fn)
> + {
> + logfile = fopen(fn, "a+");
> +
> + if (!logfile)
> + ereport(ERROR,
> + (errcode_for_file_access(),
> + errmsg("failed to open log file %s", fn)));
> +
> + strcpy(logfileName, fn);
> + pfree(fn);
> + }
> + }
> +}
> +
> +
> +/*
> * Initialization of error output file
> */
> void
> @@ -1455,6 +1635,20 @@
> if ((Log_destination & LOG_DESTINATION_STDERR) || whereToSendOutput == Debug)
> {
> fprintf(stderr, "%s", buf.data);
> + }
> +
> + /* Write to file, if enabled */
> + if (logfile && (Log_destination & LOG_DESTINATION_FILE))
> + {
> + /* check if logfile changed */
> + LogFileCheckReopen(false);
> +
> + if (logfile)
> + {
> + fseek(logfile, 0, SEEK_END);
> + fprintf(logfile, "%s", buf.data);
> + fflush(logfile);
> + }
> }
>
> pfree(buf.data);
> Index: src/backend/utils/misc/guc-file.l
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/misc/guc-file.l,v
> retrieving revision 1.22
> diff -u -r1.22 guc-file.l
> --- src/backend/utils/misc/guc-file.l 26 May 2004 15:07:38 -0000 1.22
> +++ src/backend/utils/misc/guc-file.l 6 Jul 2004 22:12:38 -0000
> @@ -276,6 +276,9 @@
> set_config_option(item->name, item->value, context,
> PGC_S_FILE, false, true);
>
> + if (context == PGC_SIGHUP)
> + LogFileCheckReopen(true);
> +
> cleanup_exit:
> free_name_value_list(head);
> return;
> Index: src/backend/utils/misc/guc.c
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/misc/guc.c,v
> retrieving revision 1.213
> diff -u -r1.213 guc.c
> --- src/backend/utils/misc/guc.c 5 Jul 2004 23:14:14 -0000 1.213
> +++ src/backend/utils/misc/guc.c 6 Jul 2004 22:12:46 -0000
> @@ -76,6 +76,8 @@
> static const char *assign_log_destination(const char *value,
> bool doit, GucSource source);
>
> +extern char *Log_filename;
> +
> #ifdef HAVE_SYSLOG
> extern char *Syslog_facility;
> extern char *Syslog_ident;
> @@ -1606,13 +1608,23 @@
> {
> {"log_destination", PGC_POSTMASTER, LOGGING_WHERE,
> gettext_noop("Sets the target for log output."),
> - gettext_noop("Valid values are combinations of stderr, syslog "
> + gettext_noop("Valid values are combinations of stderr, file, syslog "
> "and eventlog, depending on platform."),
> GUC_LIST_INPUT
> },
> &log_destination_string,
> "stderr", assign_log_destination, NULL
> },
> + {
> + {"log_filename", PGC_SIGHUP, LOGGING_WHERE,
> + gettext_noop("Sets the target filename for log output."),
> + gettext_noop("May be specified as relative to the cluster directory "
> + "or as absolute path."),
> + GUC_LIST_INPUT | GUC_REPORT
> + },
> + &Log_filename,
> + "postgresql.log.%Y-%m-%d_%H%M%S", NULL, NULL
> + },
>
> #ifdef HAVE_SYSLOG
> {
> @@ -5033,6 +5045,8 @@
>
> if (pg_strcasecmp(tok,"stderr") == 0)
> newlogdest |= LOG_DESTINATION_STDERR;
> + else if (pg_strcasecmp(tok,"file") == 0)
> + newlogdest |= LOG_DESTINATION_FILE;
> #ifdef HAVE_SYSLOG
> else if (pg_strcasecmp(tok,"syslog") == 0)
> newlogdest |= LOG_DESTINATION_SYSLOG;
> Index: src/backend/utils/misc/postgresql.conf.sample
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/misc/postgresql.conf.sample,v
> retrieving revision 1.113
> diff -u -r1.113 postgresql.conf.sample
> --- src/backend/utils/misc/postgresql.conf.sample 7 Apr 2004 05:05:50 -0000 1.113
> +++ src/backend/utils/misc/postgresql.conf.sample 6 Jul 2004 22:12:47 -0000
> @@ -147,9 +147,12 @@
>
> # - Where to Log -
>
> -#log_destination = 'stderr' # Valid values are combinations of stderr,
> +#log_destination = 'stderr' # Valid values are combinations of stderr, file,
> # syslog and eventlog, depending on
> # platform.
> +#log_filename = 'postgresql.log.%Y-%m-%d_%H%M%S' # filename if
> + # 'file' log_destination is used.
> +
> #syslog_facility = 'LOCAL0'
> #syslog_ident = 'postgres'
>
> Index: src/include/catalog/pg_proc.h
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/include/catalog/pg_proc.h,v
> retrieving revision 1.341
> diff -u -r1.341 pg_proc.h
> --- src/include/catalog/pg_proc.h 2 Jul 2004 22:49:48 -0000 1.341
> +++ src/include/catalog/pg_proc.h 6 Jul 2004 22:13:02 -0000
> @@ -3595,6 +3595,14 @@
> DATA(insert OID = 2556 ( pg_tablespace_databases PGNSP PGUID 12 f f t t s 1 26 "26" _null_
pg_tablespace_databases- _null_));
> DESCR("returns database oids in a tablespace");
>
> +DATA(insert OID = 2557( pg_logfile_get PGNSP PGUID 12 f f f f v 3 2275 "23 23 25" _null_
pg_logfile_get- _null_ ));
> +DESCR("return log file contents");
> +DATA(insert OID = 2558( pg_logfile_length PGNSP PGUID 12 f f f f v 1 23 "25" _null_ pg_logfile_length
-_null_ ));
> +DESCR("name of log file");
> +DATA(insert OID = 2559( pg_logfile_name PGNSP PGUID 12 f f f f v 0 2275 "" _null_ pg_logfile_name -
_null_));
> +DESCR("length of log file");
> +DATA(insert OID = 2560( pg_logfile_rotate PGNSP PGUID 12 f f f f v 0 2275 "" _null_ pg_logfile_rotate
-_null_ ));
> +DESCR("rotate log file");
>
> /*
> * Symbolic values for provolatile column: these indicate whether the result
> Index: src/include/utils/builtins.h
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/include/utils/builtins.h,v
> retrieving revision 1.245
> diff -u -r1.245 builtins.h
> --- src/include/utils/builtins.h 2 Jul 2004 18:59:25 -0000 1.245
> +++ src/include/utils/builtins.h 6 Jul 2004 22:13:05 -0000
> @@ -358,6 +358,11 @@
> extern Datum pg_cancel_backend(PG_FUNCTION_ARGS);
> extern Datum pg_tablespace_databases(PG_FUNCTION_ARGS);
>
> +extern Datum pg_logfile_get(PG_FUNCTION_ARGS);
> +extern Datum pg_logfile_length(PG_FUNCTION_ARGS);
> +extern Datum pg_logfile_name(PG_FUNCTION_ARGS);
> +extern Datum pg_logfile_rotate(PG_FUNCTION_ARGS);
> +
> /* not_in.c */
> extern Datum int4notin(PG_FUNCTION_ARGS);
> extern Datum oidnotin(PG_FUNCTION_ARGS);
> Index: src/include/utils/elog.h
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/include/utils/elog.h,v
> retrieving revision 1.69
> diff -u -r1.69 elog.h
> --- src/include/utils/elog.h 24 Jun 2004 21:03:42 -0000 1.69
> +++ src/include/utils/elog.h 6 Jul 2004 22:13:05 -0000
> @@ -182,10 +182,14 @@
> #define LOG_DESTINATION_STDERR 1
> #define LOG_DESTINATION_SYSLOG 2
> #define LOG_DESTINATION_EVENTLOG 4
> +#define LOG_DESTINATION_FILE 8
>
> /* Other exported functions */
> extern void DebugFileOpen(void);
> -
> +extern void LogFileInit(void);
> +extern void LogFileCheckReopen(bool fromSIGHUP);
> +extern char *LogFileRotate(void);
> +extern char *LogFileName(void);
> /*
> * Write errors to stderr (or by equal means when stderr is
> * not available). Used before ereport/elog can be used
--
Bruce Momjian | http://candle.pha.pa.us
pgman@candle.pha.pa.us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> However, looking at the issue of backends all reloading their
> postgresql.conf files at different times and sending output to different
> files, I wonder if it would be best to create a log process and have
> each backend connect to that. That way, all the logging happens in one
> process.
That was something that bothered me too. I think in the patch as given,
the GUC parameter determining the logfile name would have to be
PGC_POSTMASTER, ie, you could not change it on the fly because the
backends wouldn't all switch together. There may be some finer-grain
timing issues as well.
On the whole I think that capturing all the backends' stderr via a pipe
and doing the file rotation in a single downstream process is a *much*
cleaner solution. However, I've been saying that right along and
haven't been listened to...
regards, tom lane
Bruce Momjian wrote: > How is this patch supposed to work? Do people need to modify > postgresql.conf and then sighup the postmaster? It seems more logical > for the super-user to call a server-side function. I assume calling pg_logfile_rotate() to be the standard way. calling pg_logfile_rotate will increment the internal logfile timestamp, so each backend's next write to the logfile will lead to a reopen. On the other hand, if nothing is to be logged, nothing happens in the backends. > You have > pg_logfile_rotate(), but that doesn't send a sighup to the postmaster so > all the backends will reread the global log file name. As long as there's no SIGHUP, the logfile name template will not change, so each backend can calculate the logfile's name from the timestamp. In case a SIGHUP *is* issued, the template might have changed, so despite an unchanged timestamp the filename to create might be different. Additionally, SIGHUP will force all backends to check for current logfile name, and close/reopen if their internal timestamp isn't up-to-date with the common timestamp. > > Also, what mechanism is there to prevent backends from reading the log > filename _while_ it is being modified? I don't understand your concern. There's no place where the name is stored, only the GUC log_filename which is actually the template, and the timestamp (probably accessed atomically by the processor). > > Also there are no documenttion changes. Hm, seems I missed this in this posting; the previous had it. I'll repost it. > > However, looking at the issue of backends all reloading their > postgresql.conf files at different times and sending output to different > files, We might have a fraction of a second in practice, when a SIGHUP was issued to reread postgresql.conf, with a log_filename change, and a backend still writing its log to the "old" log because GUC reread is deferred for queries that started before SIGHUP. I don't really see a problem with that. I wonder if it would be best to create a log process and have > each backend connect to that. That way, all the logging happens in one > process. <sigh> All I wanted was displaying the serverlog </sigh> While this might be ultimately the best solution (we even might find a way to catch stderr without interrupting further stderr piping), currently this doesn't seem to be the right moment. We'd have several inter process issues (and more with win32), which probably need some discussion. OTOH, if the current implementation is replaced by a log process later, the api interface probably would stay the same. Regards, Andreas
Tom Lane wrote: > > That was something that bothered me too. I think in the patch as given, > the GUC parameter determining the logfile name would have to be > PGC_POSTMASTER, ie, you could not change it on the fly because the > backends wouldn't all switch together. In my original posting it was PGC_POSTMASTER, I changed it recently after I added rotation handling in ProcessConfigFile. If you think this is critical, we can revert it. Regards, Andreas
Tom Lane wrote: > Bruce Momjian <pgman@candle.pha.pa.us> writes: > > However, looking at the issue of backends all reloading their > > postgresql.conf files at different times and sending output to different > > files, I wonder if it would be best to create a log process and have > > each backend connect to that. That way, all the logging happens in one > > process. > > That was something that bothered me too. I think in the patch as given, > the GUC parameter determining the logfile name would have to be > PGC_POSTMASTER, ie, you could not change it on the fly because the > backends wouldn't all switch together. There may be some finer-grain > timing issues as well. > > On the whole I think that capturing all the backends' stderr via a pipe > and doing the file rotation in a single downstream process is a *much* > cleaner solution. However, I've been saying that right along and > haven't been listened to... I saw Andreas demonstrating the viewing of server log files from pgadmin at Germany Linuxtag, and it certainly was impressive. However, for heavy, general usage, I don't think this patch is going to work. Probably the big thing this program was trying to solve was for the server to know the output file name, even with log file rotation, and I don't see a pipe and 'rotatelogs' process really addressing this. It was also interesting to do the log rotate as a database call. The only idea I have is for the postmaster to close its stderror the create a pipe to roatelogs and someone send all messages into there, and pass the file name from postgresql.conf to that rotatelogs program. Crazy, I know, but that is the best I can think of. We would then need a use some API to read the log files, and find the valid numbered log files. We could also control log file rotations via signals to the log process. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073
Andreas Pflug wrote: > Bruce Momjian wrote: > > How is this patch supposed to work? Do people need to modify > > postgresql.conf and then sighup the postmaster? It seems more logical > > for the super-user to call a server-side function. > > I assume calling pg_logfile_rotate() to be the standard way. calling > pg_logfile_rotate will increment the internal logfile timestamp, so each > backend's next write to the logfile will lead to a reopen. On the other > hand, if nothing is to be logged, nothing happens in the backends. Oh, I remember now. You had explained it in a previous email. Only the timestamp is saved in global memory (not the name). Each backend, before writing, checks the global and reopens if needed. I see the LogFileCheckReopen() call in elog.c now, and that is the key to the whole thing. Sorry I got confused. One question, you open the logfile in a+ (append/read). Isn't "a" alone correct? > > You have > > pg_logfile_rotate(), but that doesn't send a sighup to the postmaster so > > all the backends will reread the global log file name. > > > As long as there's no SIGHUP, the logfile name template will not change, > so each backend can calculate the logfile's name from the timestamp. In > case a SIGHUP *is* issued, the template might have changed, so despite > an unchanged timestamp the filename to create might be different. > Additionally, SIGHUP will force all backends to check for current > logfile name, and close/reopen if their internal timestamp isn't > up-to-date with the common timestamp. Sounds good. I get it now. > > > > Also, what mechanism is there to prevent backends from reading the log > > filename _while_ it is being modified? > > I don't understand your concern. There's no place where the name is > stored, only the GUC log_filename which is actually the template, and > the timestamp (probably accessed atomically by the processor). > > > > Also there are no documenttion changes. > > Hm, seems I missed this in this posting; the previous had it. I'll > repost it. > > > > > However, looking at the issue of backends all reloading their > > postgresql.conf files at different times and sending output to different > > files, > > We might have a fraction of a second in practice, when a SIGHUP was > issued to reread postgresql.conf, with a log_filename change, and a > backend still writing its log to the "old" log because GUC reread is > deferred for queries that started before SIGHUP. I don't really see a > problem with that. You are right. Each backend reads the postgresql.conf file itself so there is not a real problem except for backends that are delayed rereading. I don't see that as a huge problem because if you change the postgresql.conf to log to a different file location (file name aleady changes with reload call to be current time), you should expect a delay. The rotate is pretty fast. > While this might be ultimately the best solution (we even might find a > way to catch stderr without interrupting further stderr piping), > currently this doesn't seem to be the right moment. We'd have several > inter process issues (and more with win32), which probably need some > discussion. > OTOH, if the current implementation is replaced by a log process later, > the api interface probably would stay the same. OK, I withdraw my concerns. It looks quite interesting (with docs you already have). -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> I saw Andreas demonstrating the viewing of server log files from pgadmin
> at Germany Linuxtag, and it certainly was impressive. However, for
> heavy, general usage, I don't think this patch is going to work.
That's my gut feeling as well.
> Probably the big thing this program was trying to solve was for the
> server to know the output file name, even with log file rotation, and I
> don't see a pipe and 'rotatelogs' process really addressing this.
It could be done. Given the infrastructure we have now, it's possible
to imagine the log capture process being a child of the postmaster that
can respond to GUC SIGHUPs (or forget that and just freeze the file name
pattern at PGC_POSTMASTER time, which isn't really that big a drawback).
You'd need the postmaster to create the pipe and then re-point its own
stdout and stderr at it, but that's doable on Unixen at least (I'm less
sure about Windows).
If the file names are timestamp-driven in any sane fashion then it's
easy enough to tell which is newest, so I don't think there is really a
need for shared memory communication between the log capture program and
the backends that want to grab some of the data. Just legislate that
the naming convention must generate names that sort ASCII-wise into
time order.
In this scenario the log capture process has robustness requirements
similar to the postmaster --- you really DO NOT want it to die, ever.
So the KISS principle applies. That means keep it away from shared
memory and try to minimize the number of signals it has to handle.
(This might be a good reason for treating all its config variables
as PGC_POSTMASTER; then it does not need to respond to SIGHUP.)
> It was also interesting to do the log rotate as a database call.
That struck me as not only useless but the deliberately hard way to do
it. To use that in the real world, you'd have to set up a cron job to
trigger the rotation, which means a lot of infrastructure and privilege;
whereas ISTM the point of this feature was to avoid both. The log
capture process should just do its own rotation on a pre-configured
time-interval basis, and/or maximum-file-size basis. I see zero value
added in having it respond to external signals.
I would like to have something like this in 7.5, but it's got to be
designed right. The patch as structured just feels all wrong to me...
> The only idea I have is for the postmaster to close its stderror the
> create a pipe to roatelogs and someone send all messages into there, and
> pass the file name from postgresql.conf to that rotatelogs program.
Right, pretty much the same thing I'm thinking.
regards, tom lane
Now that I understand Andreas's patch, and the way he is using shared memory to store only the timestamp, and how he checks shared memory on every elog call, I no longer see problems with his method. --------------------------------------------------------------------------- Tom Lane wrote: > Bruce Momjian <pgman@candle.pha.pa.us> writes: > > I saw Andreas demonstrating the viewing of server log files from pgadmin > > at Germany Linuxtag, and it certainly was impressive. However, for > > heavy, general usage, I don't think this patch is going to work. > > That's my gut feeling as well. > > > Probably the big thing this program was trying to solve was for the > > server to know the output file name, even with log file rotation, and I > > don't see a pipe and 'rotatelogs' process really addressing this. > > It could be done. Given the infrastructure we have now, it's possible > to imagine the log capture process being a child of the postmaster that > can respond to GUC SIGHUPs (or forget that and just freeze the file name > pattern at PGC_POSTMASTER time, which isn't really that big a drawback). > You'd need the postmaster to create the pipe and then re-point its own > stdout and stderr at it, but that's doable on Unixen at least (I'm less > sure about Windows). > > If the file names are timestamp-driven in any sane fashion then it's > easy enough to tell which is newest, so I don't think there is really a > need for shared memory communication between the log capture program and > the backends that want to grab some of the data. Just legislate that > the naming convention must generate names that sort ASCII-wise into > time order. > > In this scenario the log capture process has robustness requirements > similar to the postmaster --- you really DO NOT want it to die, ever. > So the KISS principle applies. That means keep it away from shared > memory and try to minimize the number of signals it has to handle. > (This might be a good reason for treating all its config variables > as PGC_POSTMASTER; then it does not need to respond to SIGHUP.) > > > It was also interesting to do the log rotate as a database call. > > That struck me as not only useless but the deliberately hard way to do > it. To use that in the real world, you'd have to set up a cron job to > trigger the rotation, which means a lot of infrastructure and privilege; > whereas ISTM the point of this feature was to avoid both. The log > capture process should just do its own rotation on a pre-configured > time-interval basis, and/or maximum-file-size basis. I see zero value > added in having it respond to external signals. > > I would like to have something like this in 7.5, but it's got to be > designed right. The patch as structured just feels all wrong to me... > > > > The only idea I have is for the postmaster to close its stderror the > > create a pipe to roatelogs and someone send all messages into there, and > > pass the file name from postgresql.conf to that rotatelogs program. > > Right, pretty much the same thing I'm thinking. > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 6: Have you searched our list archives? > > http://archives.postgresql.org > -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Now that I understand Andreas's patch, and the way he is using shared
> memory to store only the timestamp, and how he checks shared memory on
> every elog call, I no longer see problems with his method.
The fundamentally unfixable problem with his method is that it can only
capture elog output, not stderr output from libraries that we don't
control (the dynamic linker being the biggest case, but there are
others).
I do not have any faith in the method as regards to switchover
reliability or message synchronization, either. I'm prepared to
grant that those might be only minor problems ... but I don't really see
why we should put up with doubts in this area. When you want to look at
a server log, it's because you are trying to debug a problem. The very
last thing you need is any niggling doubts about whether what you are
reading is the truth.
Finally, I simply do not trust *any* dependency on shared memory in this
connection. Again, I'm sure it works great in the normal case, but the
normal case is not what you need a server log for.
regards, tom lane
> > Probably the big thing this program was trying to solve was for the > > server to know the output file name, even with log file > rotation, and > > I don't see a pipe and 'rotatelogs' process really addressing this. > > It could be done. Given the infrastructure we have now, it's > possible to imagine the log capture process being a child of > the postmaster that can respond to GUC SIGHUPs (or forget > that and just freeze the file name pattern at PGC_POSTMASTER > time, which isn't really that big a drawback). > You'd need the postmaster to create the pipe and then > re-point its own stdout and stderr at it, but that's doable > on Unixen at least (I'm less sure about Windows). Given the issues we've had with stdout/stderr on mingw, I'm not convinced it will work there. But I'm not convinced it won't work either :-) What would be the portable way to do it on *nix - I could always run some tests on w32. Just "stderr = mynewpipe;" is a bit too simplistic, right? The other option would be to go with a syslog-style implementation, which you write explicitly to over a socket. But that won't address your concern below (from other mail). > The fundamentally unfixable problem with his method is that > it can only capture elog output, not stderr output from > libraries that we don't control (the dynamic linker being the > biggest case, but there are others). How common are these issues really? Just getting to the normal backend output would probably be a big win in most sitations, wouldn't it? In the case these libraries put out information, we get an elog() call *as well*, don't we? Then you could easily redirect stderr somewhere on the server, while still processing "ordinary elog output" through the log manager. //Magnus
"Magnus Hagander" <mha@sollentuna.net> writes:
>> You'd need the postmaster to create the pipe and then
>> re-point its own stdout and stderr at it, but that's doable
>> on Unixen at least (I'm less sure about Windows).
> Given the issues we've had with stdout/stderr on mingw, I'm not
> convinced it will work there. But I'm not convinced it won't work either
> :-) What would be the portable way to do it on *nix - I could always run
> some tests on w32. Just "stderr = mynewpipe;" is a bit too simplistic,
> right?
Given that you have a pipe, I'd do something like
fclose(stderr);
stderr = fdopen(dup(p[0]), "a");
or possibly just
close(2);
d = dup(p[0]);
Assert(d == 2);
which would substitute the pipe into descriptor 2 without touching the
state of the user-level stderr file. This has the advantage that you
don't have to assume you can assign to the stderr macro. (If you do do
it the first way, you'd probably need an additional call to force the
buffering mode back to linebuffered or unbuffered.)
I don't have a problem with #ifdef'ing this part if something slightly
different is needed on Windows, though.
>> The fundamentally unfixable problem with his method is that
>> it can only capture elog output, not stderr output from
>> libraries that we don't control (the dynamic linker being the
>> biggest case, but there are others).
> How common are these issues really?
Exceedingly. I've lost count of the number of times we've needed to
look at the stderr output of someone's dynamic linker because we had
no other way to debug a problem with loading a shared library. I'm
really not going to accept a "logging" solution that can't handle it.
(And yes, this is one of the big complaints against our syslog
implementation.)
regards, tom lane
I wrote:
> close(2);
> d = dup(p[0]);
> Assert(d == 2);
Having re-read the pipe(2) man page, of course that should be
d = dup(p[1]);
since it's the writing end of the pipe you want to plug stderr into.
BTW, if it wasn't clear: I'd do the same pushup for stdout too,
just in case. I'm not sure there is any output to stdout left in the
backend, but I wouldn't swear there is not, either.
regards, tom lane
We could make the same adjustments when opening a new log file rather than pipe, no? --------------------------------------------------------------------------- Tom Lane wrote: > I wrote: > > close(2); > > d = dup(p[0]); > > Assert(d == 2); > > Having re-read the pipe(2) man page, of course that should be > d = dup(p[1]); > since it's the writing end of the pipe you want to plug stderr into. > > BTW, if it wasn't clear: I'd do the same pushup for stdout too, > just in case. I'm not sure there is any output to stdout left in the > backend, but I wouldn't swear there is not, either. > > regards, tom lane > -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073
Tom Lane wrote: > That struck me as not only useless but the deliberately hard way to do > it. To use that in the real world, you'd have to set up a cron job to > trigger the rotation, Still on my radar... which means a lot of infrastructure and privilege; > whereas ISTM the point of this feature was to avoid both. ... I was thinking about putting this into the pg_autovacuum process. The log > capture process should just do its own rotation on a pre-configured > time-interval basis, and/or maximum-file-size basis. Yup. I see zero value > added in having it respond to external signals. I see >0 value. I like to truncate my logfile before doing some complicated stuff, to have a handy file for debugging purposes. Regards, Andreas
Bruce Momjian wrote:
>
> Also there are no documenttion changes.
Here are the missing docs, freshly created against cvs.
Regards,
Andreas
Index: func.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql-server/doc/src/sgml/func.sgml,v
retrieving revision 1.214
diff -u -r1.214 func.sgml
--- func.sgml 12 Jul 2004 20:23:47 -0000 1.214
+++ func.sgml 14 Jul 2004 19:08:16 -0000
@@ -7455,6 +7455,80 @@
</para>
<indexterm zone="functions-misc">
+ <primary>pg_logfile_get</primary>
+ </indexterm>
+ <indexterm zone="functions-misc">
+ <primary>pg_logfile_length</primary>
+ </indexterm>
+ <indexterm zone="functions-misc">
+ <primary>pg_logfile_name</primary>
+ </indexterm>
+ <indexterm zone="functions-misc">
+ <primary>pg_logfile_rotate</primary>
+ </indexterm>
+ <para>
+ The functions shown in <xref linkend="functions-misc-logfile">
+ deal with the server log file if configured with log_destination
+ <quote>file</quote>.
+ </para>
+
+ <table id="functions-misc-logfile">
+ <title>Server Logfile Functions</title>
+ <tgroup cols="3">
+ <thead>
+ <row><entry>Name</entry> <entry>Return Type</entry> <entry>Description</entry></row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry><literal><function>pg_logfile_get</function>(<parameter>size_int4</parameter>,
+ <parameter>offset_int4</parameter>,<parameter>filename_text</parameter>)</literal></entry>
+ <entry><type>cstring</type></entry>
+ <entry>get a part of the current server log file</entry>
+ </row>
+ <row>
+ <entry><literal><function>pg_logfile_length</function>(<paramater>filename_text</parameter>)</literal></entry>
+ <entry><type>int4</type></entry>
+ <entry>return the current length of the server log file</entry>
+ </row>
+ <row>
+ <entry><literal><function>pg_logfile_rotate</function>()</literal></entry>
+ <entry><type>cstring</type></entry>
+ <entry>rotates the server log file and returns the new log file
+ name</entry>
+ </row>
+ <row>
+ <entry><literal><function>pg_logfile_name</function>()</literal></entry>
+ <entry><type>cstring</type></entry>
+ <entry>returns the current server log file name</entry>
+ </row>
+ <row>
+ <entry><literal><function>pg_logfile_rotate</function>()</literal></entry>
+ <entry><type>cstring</type></entry>
+ <entry>rotates the server log file and returns the previous log file
+ name</entry>
+ </row>
+ </tbody>
+</tgroup>
+</table>
+<para>
+The <function>pg_logfile_get</function> function will return the
+ contents of the current server log file, limited by the size
+ parameter. If size is NULL, a server internal limit (currently
+ 50000) is applied. The position parameter specifies the
+ starting position of the server log chunk to be returned. A
+ positive number or 0 will be counted from the start of the file,
+ a negative number from the end; if NULL, -size is assumed
+ (i.e. the tail of the log file).
+</para>
+<para>
+Both <function>pg_logfile_get</function> and
+ <function>pg_logfile_length</function> have a filename
+ parameter which may specify the logfile to examine or the
+ current logfile if NULL.
+</para>
+
+ <indexterm zone="functions-misc">
<primary>pg_cancel_backend</primary>
</indexterm>
Index: runtime.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql-server/doc/src/sgml/runtime.sgml,v
retrieving revision 1.269
diff -u -r1.269 runtime.sgml
--- runtime.sgml 11 Jul 2004 00:18:40 -0000 1.269
+++ runtime.sgml 14 Jul 2004 19:08:26 -0000
@@ -1769,9 +1769,9 @@
<listitem>
<para>
<productname>PostgreSQL</productname> supports several methods
- for loggning, including <systemitem>stderr</systemitem> and
- <systemitem>syslog</systemitem>. On Windows,
- <systemitem>eventlog</systemitem> is also supported. Set this
+ for logging, including <systemitem>stderr</systemitem>,
+ <systemitem>file></systemitem> and <systemitem>syslog</systemitem>.
+ On Windows, <systemitem>eventlog</systemitem> is also supported. Set this
option to a list of desired log destinations separated by a
comma. The default is to log to <systemitem>stderr</systemitem>
only. This option must be set at server start.
@@ -1779,6 +1779,17 @@
</listitem>
</varlistentry>
+ <varlistentry id="guc-syslog-facility" xreflabel="log_filename">
+ <term><varname>log_filename</varname> (<type>string</type>)</term>
+ <listitem>
+ <para>
+ This option sets the target filename for the log destination
+ <quote>file</quote> option. It may be specified as absolute
+ path or relative to the <application>cluster directory</application>.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-syslog-facility" xreflabel="syslog_facility">
<term><varname>syslog_facility</varname> (<type>string</type>)</term>
<listitem>
Path withdrawn by author.
---------------------------------------------------------------------------
Andreas Pflug wrote:
> Updated version.
>
> Only timestamp of fresh logfile in shared mem, with sanity checks.
> On SIGHUP, timestamp is checked if rotation was issued, as well as
> changed log_filename setting from postgresql.conf.
>
> Regards,
> Andreas
>
>
>
> Index: src/backend/postmaster/postmaster.c
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/backend/postmaster/postmaster.c,v
> retrieving revision 1.405
> diff -u -r1.405 postmaster.c
> --- src/backend/postmaster/postmaster.c 24 Jun 2004 21:02:55 -0000 1.405
> +++ src/backend/postmaster/postmaster.c 6 Jul 2004 22:12:22 -0000
> @@ -729,6 +729,11 @@
> reset_shared(PostPortNumber);
>
> /*
> + * Opens alternate log file
> + */
> + LogFileInit();
> +
> + /*
> * Estimate number of openable files. This must happen after setting
> * up semaphores, because on some platforms semaphores count as open
> * files.
> Index: src/backend/utils/adt/misc.c
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/adt/misc.c,v
> retrieving revision 1.35
> diff -u -r1.35 misc.c
> --- src/backend/utils/adt/misc.c 2 Jul 2004 18:59:22 -0000 1.35
> +++ src/backend/utils/adt/misc.c 6 Jul 2004 22:12:34 -0000
> @@ -202,3 +202,137 @@
> FreeDir(fctx->dirdesc);
> SRF_RETURN_DONE(funcctx);
> }
> +
> +
> +extern FILE *logfile; // in elog.c
> +#define MAXLOGFILECHUNK 50000
> +
> +static char *absClusterPath(text *arg)
> +{
> + char *filename;
> +
> + if (is_absolute_path(VARDATA(arg)))
> + filename=VARDATA(arg);
> + else
> + {
> + filename = palloc(strlen(DataDir)+VARSIZE(arg)+2);
> + sprintf(filename, "%s/%s", DataDir, VARDATA(arg));
> + }
> + return filename;
> +}
> +
> +
> +Datum pg_logfile_get(PG_FUNCTION_ARGS)
> +{
> + size_t size=MAXLOGFILECHUNK;
> + char *buf=0;
> + size_t nbytes;
> + FILE *f;
> +
> + if (!PG_ARGISNULL(0))
> + size = PG_GETARG_INT32(0);
> + if (size > MAXLOGFILECHUNK)
> + {
> + size = MAXLOGFILECHUNK;
> + ereport(WARNING,
> + (errcode(ERRCODE_OUT_OF_MEMORY),
> + errmsg("Maximum size is %d.", size)));
> + }
> +
> + if (PG_ARGISNULL(2))
> + f = logfile;
> + else
> + {
> + /* explicitely named logfile */
> + char *filename = absClusterPath(PG_GETARG_TEXT_P(2));
> + f = fopen(filename, "r");
> + if (!f)
> + {
> + ereport(WARNING,
> + (errcode_for_file_access(),
> + errmsg("file not found %s", filename)));
> + PG_RETURN_NULL();
> + }
> + }
> +
> + if (f)
> + {
> +
> + if (PG_ARGISNULL(1))
> + fseek(f, -size, SEEK_END);
> + else
> + {
> + long pos = PG_GETARG_INT32(1);
> + if (pos >= 0)
> + fseek(f, pos, SEEK_SET);
> + else
> + fseek(f, pos, SEEK_END);
> + }
> + buf = palloc(size+1);
> + nbytes = fread(buf, 1, size, f);
> + buf[nbytes] = 0;
> +
> + fseek(f, 0, SEEK_END);
> +
> + if (!PG_ARGISNULL(2))
> + fclose(f);
> + }
> +
> + if (buf)
> + PG_RETURN_CSTRING(buf);
> + else
> + PG_RETURN_NULL();
> +}
> +
> +
> +Datum pg_logfile_length(PG_FUNCTION_ARGS)
> +{
> + if (PG_ARGISNULL(0))
> + {
> + if (logfile)
> + {
> + fflush(logfile);
> + PG_RETURN_INT32(ftell(logfile));
> + }
> + }
> + else
> + {
> + struct stat fst;
> + fst.st_size=0;
> + stat(absClusterPath(PG_GETARG_TEXT_P(0)), &fst);
> +
> + PG_RETURN_INT32(fst.st_size);
> + }
> + PG_RETURN_INT32(0);
> +}
> +
> +
> +Datum pg_logfile_name(PG_FUNCTION_ARGS)
> +{
> + char *filename=LogFileName();
> + if (filename)
> + {
> + if (strncmp(filename, DataDir, strlen(DataDir)))
> + PG_RETURN_CSTRING(filename);
> + else
> + PG_RETURN_CSTRING(filename+strlen(DataDir)+1);
> + }
> + PG_RETURN_NULL();
> +}
> +
> +
> +Datum pg_logfile_rotate(PG_FUNCTION_ARGS)
> +{
> + char *renamedFile = LogFileRotate();
> +
> + if (renamedFile)
> + {
> + if (strncmp(renamedFile, DataDir, strlen(DataDir)))
> + PG_RETURN_CSTRING(renamedFile);
> + else
> + PG_RETURN_CSTRING(renamedFile+strlen(DataDir)+1);
> + }
> + else
> + PG_RETURN_NULL();
> +}
> +
> Index: src/backend/utils/error/elog.c
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/error/elog.c,v
> retrieving revision 1.142
> diff -u -r1.142 elog.c
> --- src/backend/utils/error/elog.c 24 Jun 2004 21:03:13 -0000 1.142
> +++ src/backend/utils/error/elog.c 6 Jul 2004 22:12:37 -0000
> @@ -63,7 +63,6 @@
> #include "utils/memutils.h"
> #include "utils/guc.h"
>
> -
> /* Global variables */
> ErrorContextCallback *error_context_stack = NULL;
>
> @@ -71,9 +70,17 @@
> PGErrorVerbosity Log_error_verbosity = PGERROR_VERBOSE;
> char *Log_line_prefix = NULL; /* format for extra log line info */
> unsigned int Log_destination = LOG_DESTINATION_STDERR;
> +char *Log_filename = NULL;
>
> bool in_fatal_exit = false;
>
> +FILE *logfile = NULL; /* the logfile we're writing to */
> +static char logfileName[MAXPGPATH]; /* current filename */
> +static pg_time_t logfileTimestamp=0; /* logfile version this backend is currently using */
> +
> +static pg_time_t *globalLogfileTimestamp = NULL; /* logfile version the backend should be using (shared mem) */
> +
> +
> #ifdef HAVE_SYSLOG
> char *Syslog_facility; /* openlog() parameters */
> char *Syslog_ident;
> @@ -140,6 +147,9 @@
> static const char *error_severity(int elevel);
> static void append_with_tabs(StringInfo buf, const char *str);
>
> +static char *logfile_getname(pg_time_t timestamp);
> +static void logfile_reopen(void);
> +
>
> /*
> * errstart --- begin an error-reporting cycle
> @@ -931,11 +941,181 @@
> /*
> * And let errfinish() finish up.
> */
> +
> errfinish(0);
> }
>
>
> /*
> + * Initialize shared mem for logfile rotation
> + */
> +
> +void
> +LogFileInit(void)
> +{
> + if (!globalLogfileTimestamp && Log_filename && (Log_destination & LOG_DESTINATION_FILE))
> + {
> + /* allocate logfile version shared memory segment for rotation signaling */
> + globalLogfileTimestamp = ShmemAlloc(sizeof(pg_time_t));
> + if (!globalLogfileTimestamp)
> + {
> + ereport(FATAL,
> + (errcode(ERRCODE_OUT_OF_MEMORY),
> + errmsg("Out of shared memory")));
> + return;
> + }
> +
> + *globalLogfileTimestamp = time(NULL);
> +
> + /* open logfile after we successfully initialized */
> + logfile_reopen();
> + }
> +}
> +
> +
> +/*
> + * Rotate log file
> + */
> +char *
> +LogFileRotate(void)
> +{
> + char *filename;
> + char *oldFilename;
> + pg_time_t now;
> +
> + if (!globalLogfileTimestamp || !logfileName || !(Log_destination & LOG_DESTINATION_FILE))
> + return NULL;
> +
> + now = time(NULL);
> +
> + filename = logfile_getname(now);
> + if (!filename)
> + return NULL;
> +
> + if (!strcmp(filename, logfileName))
> + {
> + ereport(ERROR,
> + (errcode(ERRCODE_CONFIG_FILE_ERROR),
> + errmsg("Log_filename not suitable for rotation.")));
> + return NULL;
> + }
> +
> + oldFilename = pstrdup(logfileName);
> + *globalLogfileTimestamp = now;
> +
> + ereport(NOTICE,
> + (errcode(ERRCODE_WARNING),
> + errmsg("Opened new log file %s; previous logfile %s", filename, oldFilename)));
> +
> + return oldFilename;
> +}
> +
> +
> +/*
> + * return current log file name
> + */
> +char*
> +LogFileName(void)
> +{
> + if (logfileName)
> + return pstrdup(logfileName);
> + return NULL;
> +}
> +
> +
> +/*
> + * check if logfile has to be reopened
> + * if called from ProcessConfigFile after SIGHUP, also check for filename template change
> + */
> +void LogFileCheckReopen(bool fromSIGHUP)
> +{
> + if (globalLogfileTimestamp)
> + {
> + if (*globalLogfileTimestamp != logfileTimestamp)
> + {
> + /* sanity check: if it's in the future, shmem probably corrupted */
> + pg_time_t now=time(NULL);
> + if (*globalLogfileTimestamp > now)
> + *globalLogfileTimestamp = now;
> +
> + logfile_reopen();
> + }
> + else if (fromSIGHUP)
> + {
> + char *filename = logfile_getname(logfileTimestamp);
> + if (filename && strcmp(filename, logfileName))
> + {
> + /* template for logfile was changed */
> + logfile_reopen();
> + pfree(filename);
> + }
> + }
> + }
> +}
> +
> +
> +/*
> + * creates logfile name using timestamp information
> + */
> +static char*
> +logfile_getname(pg_time_t timestamp)
> +{
> + char *filetemplate;
> + char *filename;
> +
> + if (is_absolute_path(Log_filename))
> + filetemplate = pstrdup(Log_filename);
> + else
> + {
> + filetemplate = palloc(strlen(DataDir) + strlen(Log_filename) + 2);
> + sprintf(filetemplate, "%s/%s", DataDir, Log_filename);
> + }
> + filename = palloc(MAXPGPATH);
> + pg_strftime(filename, MAXPGPATH, filetemplate, pg_localtime(×tamp));
> +
> + pfree(filetemplate);
> +
> + return filename;
> +}
> +
> +
> +/*
> + * reopen log file.
> + */
> +static void
> +logfile_reopen(void)
> +{
> + if (logfile)
> + {
> + fclose(logfile);
> + logfile = NULL;
> + }
> +
> + if ((Log_destination & LOG_DESTINATION_FILE) && globalLogfileTimestamp)
> + {
> + char *fn;
> +
> + logfileTimestamp = *globalLogfileTimestamp;
> +
> + fn=logfile_getname(logfileTimestamp);
> +
> + if (fn)
> + {
> + logfile = fopen(fn, "a+");
> +
> + if (!logfile)
> + ereport(ERROR,
> + (errcode_for_file_access(),
> + errmsg("failed to open log file %s", fn)));
> +
> + strcpy(logfileName, fn);
> + pfree(fn);
> + }
> + }
> +}
> +
> +
> +/*
> * Initialization of error output file
> */
> void
> @@ -1455,6 +1635,20 @@
> if ((Log_destination & LOG_DESTINATION_STDERR) || whereToSendOutput == Debug)
> {
> fprintf(stderr, "%s", buf.data);
> + }
> +
> + /* Write to file, if enabled */
> + if (logfile && (Log_destination & LOG_DESTINATION_FILE))
> + {
> + /* check if logfile changed */
> + LogFileCheckReopen(false);
> +
> + if (logfile)
> + {
> + fseek(logfile, 0, SEEK_END);
> + fprintf(logfile, "%s", buf.data);
> + fflush(logfile);
> + }
> }
>
> pfree(buf.data);
> Index: src/backend/utils/misc/guc-file.l
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/misc/guc-file.l,v
> retrieving revision 1.22
> diff -u -r1.22 guc-file.l
> --- src/backend/utils/misc/guc-file.l 26 May 2004 15:07:38 -0000 1.22
> +++ src/backend/utils/misc/guc-file.l 6 Jul 2004 22:12:38 -0000
> @@ -276,6 +276,9 @@
> set_config_option(item->name, item->value, context,
> PGC_S_FILE, false, true);
>
> + if (context == PGC_SIGHUP)
> + LogFileCheckReopen(true);
> +
> cleanup_exit:
> free_name_value_list(head);
> return;
> Index: src/backend/utils/misc/guc.c
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/misc/guc.c,v
> retrieving revision 1.213
> diff -u -r1.213 guc.c
> --- src/backend/utils/misc/guc.c 5 Jul 2004 23:14:14 -0000 1.213
> +++ src/backend/utils/misc/guc.c 6 Jul 2004 22:12:46 -0000
> @@ -76,6 +76,8 @@
> static const char *assign_log_destination(const char *value,
> bool doit, GucSource source);
>
> +extern char *Log_filename;
> +
> #ifdef HAVE_SYSLOG
> extern char *Syslog_facility;
> extern char *Syslog_ident;
> @@ -1606,13 +1608,23 @@
> {
> {"log_destination", PGC_POSTMASTER, LOGGING_WHERE,
> gettext_noop("Sets the target for log output."),
> - gettext_noop("Valid values are combinations of stderr, syslog "
> + gettext_noop("Valid values are combinations of stderr, file, syslog "
> "and eventlog, depending on platform."),
> GUC_LIST_INPUT
> },
> &log_destination_string,
> "stderr", assign_log_destination, NULL
> },
> + {
> + {"log_filename", PGC_SIGHUP, LOGGING_WHERE,
> + gettext_noop("Sets the target filename for log output."),
> + gettext_noop("May be specified as relative to the cluster directory "
> + "or as absolute path."),
> + GUC_LIST_INPUT | GUC_REPORT
> + },
> + &Log_filename,
> + "postgresql.log.%Y-%m-%d_%H%M%S", NULL, NULL
> + },
>
> #ifdef HAVE_SYSLOG
> {
> @@ -5033,6 +5045,8 @@
>
> if (pg_strcasecmp(tok,"stderr") == 0)
> newlogdest |= LOG_DESTINATION_STDERR;
> + else if (pg_strcasecmp(tok,"file") == 0)
> + newlogdest |= LOG_DESTINATION_FILE;
> #ifdef HAVE_SYSLOG
> else if (pg_strcasecmp(tok,"syslog") == 0)
> newlogdest |= LOG_DESTINATION_SYSLOG;
> Index: src/backend/utils/misc/postgresql.conf.sample
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/backend/utils/misc/postgresql.conf.sample,v
> retrieving revision 1.113
> diff -u -r1.113 postgresql.conf.sample
> --- src/backend/utils/misc/postgresql.conf.sample 7 Apr 2004 05:05:50 -0000 1.113
> +++ src/backend/utils/misc/postgresql.conf.sample 6 Jul 2004 22:12:47 -0000
> @@ -147,9 +147,12 @@
>
> # - Where to Log -
>
> -#log_destination = 'stderr' # Valid values are combinations of stderr,
> +#log_destination = 'stderr' # Valid values are combinations of stderr, file,
> # syslog and eventlog, depending on
> # platform.
> +#log_filename = 'postgresql.log.%Y-%m-%d_%H%M%S' # filename if
> + # 'file' log_destination is used.
> +
> #syslog_facility = 'LOCAL0'
> #syslog_ident = 'postgres'
>
> Index: src/include/catalog/pg_proc.h
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/include/catalog/pg_proc.h,v
> retrieving revision 1.341
> diff -u -r1.341 pg_proc.h
> --- src/include/catalog/pg_proc.h 2 Jul 2004 22:49:48 -0000 1.341
> +++ src/include/catalog/pg_proc.h 6 Jul 2004 22:13:02 -0000
> @@ -3595,6 +3595,14 @@
> DATA(insert OID = 2556 ( pg_tablespace_databases PGNSP PGUID 12 f f t t s 1 26 "26" _null_
pg_tablespace_databases- _null_));
> DESCR("returns database oids in a tablespace");
>
> +DATA(insert OID = 2557( pg_logfile_get PGNSP PGUID 12 f f f f v 3 2275 "23 23 25" _null_
pg_logfile_get- _null_ ));
> +DESCR("return log file contents");
> +DATA(insert OID = 2558( pg_logfile_length PGNSP PGUID 12 f f f f v 1 23 "25" _null_ pg_logfile_length
-_null_ ));
> +DESCR("name of log file");
> +DATA(insert OID = 2559( pg_logfile_name PGNSP PGUID 12 f f f f v 0 2275 "" _null_ pg_logfile_name -
_null_));
> +DESCR("length of log file");
> +DATA(insert OID = 2560( pg_logfile_rotate PGNSP PGUID 12 f f f f v 0 2275 "" _null_ pg_logfile_rotate
-_null_ ));
> +DESCR("rotate log file");
>
> /*
> * Symbolic values for provolatile column: these indicate whether the result
> Index: src/include/utils/builtins.h
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/include/utils/builtins.h,v
> retrieving revision 1.245
> diff -u -r1.245 builtins.h
> --- src/include/utils/builtins.h 2 Jul 2004 18:59:25 -0000 1.245
> +++ src/include/utils/builtins.h 6 Jul 2004 22:13:05 -0000
> @@ -358,6 +358,11 @@
> extern Datum pg_cancel_backend(PG_FUNCTION_ARGS);
> extern Datum pg_tablespace_databases(PG_FUNCTION_ARGS);
>
> +extern Datum pg_logfile_get(PG_FUNCTION_ARGS);
> +extern Datum pg_logfile_length(PG_FUNCTION_ARGS);
> +extern Datum pg_logfile_name(PG_FUNCTION_ARGS);
> +extern Datum pg_logfile_rotate(PG_FUNCTION_ARGS);
> +
> /* not_in.c */
> extern Datum int4notin(PG_FUNCTION_ARGS);
> extern Datum oidnotin(PG_FUNCTION_ARGS);
> Index: src/include/utils/elog.h
> ===================================================================
> RCS file: /projects/cvsroot/pgsql-server/src/include/utils/elog.h,v
> retrieving revision 1.69
> diff -u -r1.69 elog.h
> --- src/include/utils/elog.h 24 Jun 2004 21:03:42 -0000 1.69
> +++ src/include/utils/elog.h 6 Jul 2004 22:13:05 -0000
> @@ -182,10 +182,14 @@
> #define LOG_DESTINATION_STDERR 1
> #define LOG_DESTINATION_SYSLOG 2
> #define LOG_DESTINATION_EVENTLOG 4
> +#define LOG_DESTINATION_FILE 8
>
> /* Other exported functions */
> extern void DebugFileOpen(void);
> -
> +extern void LogFileInit(void);
> +extern void LogFileCheckReopen(bool fromSIGHUP);
> +extern char *LogFileRotate(void);
> +extern char *LogFileName(void);
> /*
> * Write errors to stderr (or by equal means when stderr is
> * not available). Used before ereport/elog can be used
--
Bruce Momjian | http://candle.pha.pa.us
pgman@candle.pha.pa.us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073