Le 22/03/2016 14:44, Michael Paquier a écrit :
> On Sat, Mar 12, 2016 at 12:46 AM, Gilles Darold
> <gilles.dar...@dalibo.com> wrote:
>> Here is the patch rewritten to use alternate file
>> $PGDATA/pg_log_filename to store the current log filename used by
>> syslogger. All examples used in the first mail of this thread work the
>> exact same way. If there's no other remarks, I will add the patch to the
>> next commit fest.
> Please be sure to register this patch to the next CF:
> https://commitfest.postgresql.org/10/
> Things are hot enough with 9.6, so this will only be considered in 9.7.
Thanks for the reminder, here is the v3 of the patch after a deeper
review and testing. It is now registered to the next commit fest under
the System Administration topic.
Fixes in this patch are:
- Output file have been renamed as PGDATA/pg_log_file
- Log level of the warning when logging collector is not active has been
changed to NOTICE
postgres=# select pg_current_logfile();
NOTICE: current log can not be reported, log collection is not active
pg_current_logfile
--------------------
(1 row)
- Log level for file access errors in function
store_current_log_filename() of file src/backend/postmaster/syslogger.c
has been set to WARNING, using ERROR level forced the backend to stop
with a FATAL error.
- Add information about file PGDATA/pg_log_file in storage file layout
of doc/src/sgml/storage.sgml
--
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 ae93e69..155e76b 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15158,6 +15158,11 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
(0 if not called, directly or indirectly, from inside a trigger)</entry>
</row>
+ <entry><literal><function>pg_current_logfile()</function></literal></entry>
+ <entry><type>text</type></entry>
+ <entry>current log file used by the logging collector</entry>
+ </row>
+
<row>
<entry><literal><function>session_user</function></literal></entry>
<entry><type>name</type></entry>
@@ -15365,6 +15370,16 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
<primary>pg_notification_queue_usage</primary>
</indexterm>
+ <indexterm>
+ <primary>pg_current_logfile</primary>
+ </indexterm>
+
+ <para>
+ <function>pg_current_logfile</function> returns the name of the current log
+ file used by the logging collector, as a <type>text</type>. Log collection
+ must be active.
+ </para>
+
<para>
<function>pg_listening_channels</function> returns a set of names of
asynchronous notification channels that the current session is listening
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 9b2e09e..6284d54 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -170,6 +170,13 @@ last started with</entry>
(this file is not present after server shutdown)</entry>
</row>
+<row>
+ <entry><filename>pg_log_file</></entry>
+ <entry>A file recording the current log file used by the syslogger
+ when log collection is active</entry>
+</row>
+
+
</tbody>
</tgroup>
</table>
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..c3bf672 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -145,6 +145,7 @@ 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 store_current_log_filename(char *filename);
/*
@@ -571,6 +572,9 @@ SysLogger_Start(void)
syslogFile = logfile_open(filename, "a", false);
+ /* store information about current log filename used by log collection */
+ store_current_log_filename(filename);
+
pfree(filename);
#ifdef EXEC_BACKEND
@@ -1209,6 +1213,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
fclose(syslogFile);
syslogFile = fh;
+ /* store information about current log filename used by log collection */
+ store_current_log_filename(filename);
+
/* instead of pfree'ing filename, remember it for next time */
if (last_file_name != NULL)
pfree(last_file_name);
@@ -1253,6 +1260,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
fclose(csvlogFile);
csvlogFile = fh;
+ /* store information about current log filename used by log collection */
+ store_current_log_filename(csvfilename);
+
/* instead of pfree'ing filename, remember it for next time */
if (last_csv_file_name != NULL)
pfree(last_csv_file_name);
@@ -1362,3 +1372,35 @@ sigUsr1Handler(SIGNAL_ARGS)
errno = save_errno;
}
+
+
+/*
+ * Store the name of the 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.
+ */
+static void
+store_current_log_filename(char *filename)
+{
+ FILE *fh;
+ char logpathfilename[MAXPGPATH];
+
+ snprintf(logpathfilename, sizeof(logpathfilename), "%s",
+ CURRENT_LOG_FILENAME);
+ if ((fh = fopen(logpathfilename, "w")) == NULL)
+ {
+ ereport(WARNING,
+ (errcode_for_file_access(),
+ errmsg("could not open log file \"%s\": %m",
+ logpathfilename)));
+ return;
+ }
+ if (fprintf(fh, "%s\n", filename) < 0)
+ {
+ ereport(WARNING,
+ (errcode_for_file_access(),
+ errmsg("could not write log file \"%s\": %m",
+ logpathfilename)));
+ }
+ fclose(fh);
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 4dcc5a6..fbcd1d4 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -943,3 +943,61 @@ 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 log_filename[MAXPGPATH];
+
+ if (!Logging_collector)
+ {
+ ereport(NOTICE,
+ (errmsg("current log can not be reported, log collection is not active")));
+ PG_RETURN_NULL();
+ }
+
+ /*
+ * See if current log file is present
+ */
+ 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 first line of the file to gather current log filename
+ * registered by the syslogger.
+ */
+ fgets(log_filename, sizeof(log_filename), fd);
+
+ /* Check for a read error. */
+ if (ferror(fd))
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+ /* 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)));
+
+ /* remove trailing newline */
+ if (strchr(log_filename, '\n') != NULL)
+ *strchr(log_filename, '\n') = '\0';
+
+ if (log_filename[0] == '\0')
+ 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 a595327..f0caf6f 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3125,6 +3125,8 @@ 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 = 3794 ( pg_current_logfile PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 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 9200f04..a25cd5e 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -465,4 +465,12 @@ 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 "pg_log_file"
+
#endif /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 206288d..bdc3922 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -511,6 +511,7 @@ 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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