Le 27/10/2016 à 14:14, Karl O. Pinc a écrit :
> On Thu, 27 Oct 2016 11:07:43 +0200
> Christoph Berg <m...@debian.org> wrote:
>
>> Re: Karl O. Pinc 2016-10-27 <20161026222513.74cd3...@slate.meme.com>
>>> But what if current_logfile contains only a single line? What
>>> sort of file format does the logfile have? If you don't know
>>> you can't process the logfile content.
>>>
>>> When there's multiple lines in current_logfile your script might
>>> be looking for a logfile in a particular format. How is the
>>> script supposed to know the file format of each logfile listed?
>> My idea here would be to always write out two lines, the first for
>> stderr, the second for csvlog, and leave the unused one empty. That's
>> easy to parse from shell scripts.
> That'd work.
I don't think we have to store two lines when just one of the log format
is enabled. If you grep for csvlog in the file and it is not present you
will just know that csvlog is not enabled. If the log format is present
but without the path I think it adds useless information.
The current v8 of the patch only register "format<space>path" for the
enabled log destination, the description of the current_logfiles file
have been change to:
"
A file recording the current log file(s) used by the syslogger and its
log format, stderr or csvlog. Each line of the file is a space separated
list of two elements: the log format and the full path to the log file
including the value of log_directory. The log format must be present in
log_destination to be listed in the file. This file is present only when
logging_collector is activated.
"
The file have been renamed current_logfile*s*
> Agreed. I can't see adding any more meta-information other than
> file format.
>
> I'm partial to "format <space> path" over just line number, because
> it's more explicit. Either way works.
This is the format used. Ex:
~$ cat /usr/local/postgresql/data/current_logfile
stderr pg_log/postgresql-2016-10-27_185100.log
csvlog pg_log/postgresql-2016-10-27_185100.csv
> Your comment makes me wonder if pg_current_logfile(), without
> arguments, should instead be "SHOW current_logfile;".
>
> I think not, but have no rationale. Could this be a good idea?
>
-1, SHOW is used to display run-time parameters values in our case this
is log_destination + log_directory + log_filename. current_logfile is a
filename not a parameter name.
Thanks again for your reviews.
--
Gilles Darold
Consultant PostgreSQL
http://dalibo.com - http://dalibo.org
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2e64cc4..bdae4c6 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15442,6 +15442,18 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
<entry>configuration load time</entry>
</row>
+ <entry><literal><function>pg_current_logfile()</function></literal></entry>
+ <entry><type>text</type></entry>
+ <entry>primary log file name in use by the logging collector</entry>
+ </row>
+
+ <row>
+ <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+ <entry><type>text</type></entry>
+ <entry>log file name, of log in the requested format, in use by the
+ logging collector</entry>
+ </row>
+
<row>
<entry><literal><function>pg_my_temp_schema()</function></literal></entry>
<entry><type>oid</type></entry>
@@ -15660,6 +15672,29 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
the time when the postmaster process re-read the configuration files.)
</para>
+ <indexterm>
+ <primary>pg_current_logile</primary>
+ </indexterm>
+
+ <para>
+ <function>pg_current_logfile</function> returns, as <type>text</type>,
+ the path of either the csv or stderr log file currently in use by the
+ logging collector. This is a path including the
+ <xref linkend="guc-log-directory"> directory and the log file name.
+ Log collection must be active or the return value
+ is <literal>NULL</literal>. When multiple logfiles exist, each in a
+ different format, <function>pg_current_logfile</function> called
+ without arguments returns the path of the file having the first format
+ found in the ordered
+ list: <systemitem>stderr</>, <systemitem>csvlog</>.
+ <literal>NULL</literal> is returned when no log file has any of these
+ formats. To request a specific file format supply,
+ as <type>text</type>, either <systemitem>csvlog</>
+ or <systemitem>stderr</> as the value of the optional parameter. The
+ return value is <literal>NULL</literal> when the log format requested
+ is not a configured <xref linkend="guc-log-destination">.
+ </para>
+
<indexterm>
<primary>pg_my_temp_schema</primary>
</indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index fddb69b..6e8ae05 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -61,6 +61,17 @@ Item
</row>
<row>
+ <entry><filename>current_logfiles</></entry>
+ <entry>A file recording the current log file(s) used by the syslogger and
+ its log format, stderr or csvlog. Each line of the file is a space separated
+ list of two elements: the log format and the full path to the log file
+ including the value of <xref linkend="guc-log-directory">. The log format
+ must be present in <xref linkend="guc-log-destination"> to be listed in the
+ file. This file is present only when <xref linkend="guc-logging-collector">
+ is activated.</entry>
+</row>
+
+<row>
<entry><filename>global</></entry>
<entry>Subdirectory containing cluster-wide tables, such as
<structname>pg_database</></entry>
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..5cb44d6 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
static void set_next_rotation_time(void);
static void sigHupHandler(SIGNAL_ARGS);
static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename, char *csvfilename);
/*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
rotation_disabled = false;
rotation_requested = true;
}
+
+ /*
+ * Force rewriting last log filename when reloading configuration,
+ * log_destination and logging_collector may have been changed. Do
+ * it right now to not wait for the next file rotation.
+ */
+ logfile_writename(last_file_name, last_csv_file_name);
}
if (Log_RotationAge > 0 && !rotation_disabled)
@@ -513,8 +521,14 @@ SysLogger_Start(void)
pid_t sysloggerPid;
char *filename;
- if (!Logging_collector)
+ if (!Logging_collector) {
+ /* If logging collector is not enabled, remove current log
+ * filename as we don't know where messages are logged and
+ * information contained in this file are obsolete.
+ */
+ unlink(CURRENT_LOG_FILENAME);
return 0;
+ }
/*
* If first time through, create the pipe which will receive stderr
@@ -574,6 +588,8 @@ SysLogger_Start(void)
syslogFile = logfile_open(filename, "a", false);
+ logfile_writename(filename, NULL);
+
pfree(filename);
#ifdef EXEC_BACKEND
@@ -988,8 +1004,10 @@ write_syslogger_file(const char *buffer, int count, int destination)
int rc;
FILE *logfile;
- if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL)
+ if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL) {
open_csvlogfile();
+ logfile_writename(last_file_name, last_csv_file_name);
+ }
logfile = destination == LOG_DESTINATION_CSVLOG ? csvlogFile : syslogFile;
rc = fwrite(buffer, 1, count, logfile);
@@ -1209,6 +1227,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
return;
}
+ logfile_writename(filename, csvfilename);
+
fclose(syslogFile);
syslogFile = fh;
@@ -1220,7 +1240,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
}
/* Same as above, but for csv file. */
-
if (csvlogFile != NULL &&
(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
{
@@ -1253,6 +1272,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
return;
}
+ logfile_writename(last_file_name, csvfilename);
+
fclose(csvlogFile);
csvlogFile = fh;
@@ -1365,3 +1386,60 @@ sigUsr1Handler(SIGNAL_ARGS)
errno = save_errno;
}
+
+/*
+ * Store the name of the files where current log messages are written when
+ * log collector is enabled. Useful to find the name of the current log file
+ * when a time-based rotation is defined. Filenames are first stored into a
+ * temporary file and renamed into the final destination.
+ */
+static void
+logfile_writename(char *filename, char *csvfilename)
+{
+ FILE *fh;
+ char tempfn[MAXPGPATH];
+ char logpathfilename[MAXPGPATH];
+
+ snprintf(tempfn, sizeof(tempfn), "%s",
+ CURRENT_LOG_FILENAME);
+ strcat(tempfn, ".tmp");
+ snprintf(logpathfilename, sizeof(logpathfilename), "%s",
+ CURRENT_LOG_FILENAME);
+ if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+ {
+ return;
+ }
+ if (filename && (Log_destination & LOG_DESTINATION_STDERR)) {
+ if (fprintf(fh, "stderr %s\n", filename) < 0)
+ {
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not write log file \"%s\": %m",
+ tempfn)));
+ fclose(fh);
+ return;
+ }
+ }
+
+ if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG)) {
+ if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+ {
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not write log file \"%s\": %m",
+ tempfn)));
+ fclose(fh);
+ return;
+ }
+ }
+ fclose(fh);
+
+ if (rename(tempfn, logpathfilename) != 0)
+ {
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not rename file \"%s\": %m",
+ tempfn)));
+ return;
+ }
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..06acdb2 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
#include <dirent.h>
#include <math.h>
#include <unistd.h>
+#include <sys/stat.h>
#include "access/sysattr.h"
#include "catalog/pg_authid.h"
@@ -892,3 +893,122 @@ parse_ident(PG_FUNCTION_ARGS)
PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
}
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+ FILE *fd;
+ char lbuffer[MAXPGPATH];
+ text *fmt;
+ char *logfmt;
+ struct stat stat_buf;
+ char *log_format;
+ char *log_filename;
+
+ /* The log format parameter is optional */
+ if (PG_NARGS() == 1) {
+ fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+ if (fmt != NULL) {
+ logfmt = text_to_cstring(fmt);
+ if ( (strcmp(logfmt, "stderr") != 0) &&
+ (strcmp(logfmt, "csvlog") != 0) ) {
+ ereport(ERROR,
+ (errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+ PG_RETURN_NULL();
+ }
+ }
+ } else {
+ logfmt = NULL;
+ }
+
+ if (!Logging_collector)
+ PG_RETURN_NULL();
+
+ /* Check if current log file is present */
+ if (stat(CURRENT_LOG_FILENAME, &stat_buf) != 0)
+ PG_RETURN_NULL();
+
+ fd = AllocateFile(CURRENT_LOG_FILENAME, "r");
+ if (fd == NULL)
+ {
+ if (errno != ENOENT)
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not read file \"%s\": %m",
+ CURRENT_LOG_FILENAME)));
+ PG_RETURN_NULL();
+ }
+
+ /*
+ * Read the file to gather current log filename(s) registered
+ * by the syslogger.
+ */
+ while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) {
+
+ /* Check for a read error. */
+ if (ferror(fd)) {
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+ FreeFile(fd);
+ break;
+ }
+
+ /* remove trailing newline */
+ if (strchr(lbuffer, '\n') != NULL)
+ *strchr(lbuffer, '\n') = '\0';
+
+ /* extract log format and log file path from the line */
+ log_format = strtok(lbuffer, " ");
+ if (log_format)
+ {
+ log_filename = strtok(NULL, " ");
+ if (!log_filename) {
+ ereport(ERROR,
+ (errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+ break;
+ }
+ }
+ else
+ {
+ ereport(ERROR,
+ (errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+ break;
+ }
+
+ /*
+ * When no log format is provided as argument always reports
+ * the first registered log file in CURRENT_LOG_FILENAME.
+ */
+ if (logfmt == NULL)
+ break;
+
+ /* report the entry corresponding to the requested format */
+ if (strcmp(logfmt, log_format) == 0)
+ break;
+ }
+ /* Close the current log filename file. */
+ if (FreeFile(fd))
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not close file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+
+ if (log_filename[0] == '\0')
+ PG_RETURN_NULL();
+
+ /* Return null when csvlog is requested but we have a stderr log */
+ if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+ && !(Log_destination & LOG_DESTINATION_CSVLOG) )
+ PG_RETURN_NULL();
+
+ /* Return null when stderr is requested but we have a csv log */
+ if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+ && !(Log_destination & LOG_DESTINATION_STDERR) )
+ PG_RETURN_NULL();
+
+ PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 17ec71d..78e23a6 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3179,6 +3179,8 @@ DATA(insert OID = 2621 ( pg_reload_conf PGNSP PGUID 12 1 0 0 0 f f f f t f v s
DESCR("reload configuration files");
DATA(insert OID = 2622 ( pg_rotate_logfile PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
DATA(insert OID = 2623 ( pg_stat_file PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78545da..2faefdd 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,12 @@ extern bool has_rolreplication(Oid roleid);
extern bool BackupInProgress(void);
extern void CancelBackup(void);
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file where current log messages are written when log collector is
+ * enabled. Useful to find the name of the current log file when a time-based
+ * rotation is defined.
+ */
+#define CURRENT_LOG_FILENAME "current_logfiles"
+
#endif /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..df9a1e1 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,7 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
/* oid.c */
extern Datum oidin(PG_FUNCTION_ARGS);
--
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