Le 11/12/2016 à 04:38, Karl O. Pinc a écrit :
> On Sat, 10 Dec 2016 19:41:21 -0600
> "Karl O. Pinc" <k...@meme.com> wrote:
>
>> On Fri, 9 Dec 2016 23:36:12 -0600
>> "Karl O. Pinc" <k...@meme.com> wrote:
>>
>>> Instead I propose (code I have not actually executed):
>>> ...
>>> char lbuffer[MAXPGPATH];
>>> char *log_format = lbuffer;
>>> ...
>>>
>>> /* extract log format and log file path from the line */
>>> log_filepath = strchr(lbuffer, ' '); /* lbuffer == log_format
>>> */ *log_filepath = '\0'; /* terminate log_format */
>>> log_filepath++; /* start of file path */
>>> log_filepath[strcspn(log_filepath, "\n")] = '\0';
>> Er, I guess I prefer the more paranoid, just because who knows
>> what might have manged to somehow write the file that's read
>> into lbuffer:
>>
>> ...
>> char lbuffer[MAXPGPATH];
>> char *log_format = lbuffer;
>> ...
>>
>> /* extract log format and log file path from the line */
>> if (log_filepath = strchr(lbuffer, ' ')) /* lbuffer == log_format
>> */ *log_filepath = '\0'; /* terminate log_format */
>> log_filepath++; /* start of file path */
>> log_filepath[strcspn(log_filepath, "\n")] = '\0';
> *sigh*
>
>
> ...
> char lbuffer[MAXPGPATH];
> char *log_format = lbuffer;
> ...
>
> /* extract log format and log file path from the line */
> /* lbuffer == log_format, they share storage */
> if (log_filepath = strchr(lbuffer, ' '))
> *log_filepath = '\0'; /* terminate log_format */
> else
> {
> /* Unknown format, no space. Return NULL to caller. */
> lbuffer[0] = '\0';
> break;
> }
> log_filepath++; /* start of file path */
> log_filepath[strcspn(log_filepath, "\n")] = '\0';
>
Applied in last version of the patch v18 as well as removing of an
unused variable.
--
Gilles Darold
Consultant PostgreSQL
http://dalibo.com - http://dalibo.org
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 0fc4e57..871efec 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4169,6 +4169,14 @@ SELECT * FROM parent WHERE key = 2400;
<primary>server log</primary>
</indexterm>
+ <para>
+ When logs are written to the file-system their paths, names, and
+ types are recorded in
+ the <xref linkend="storage-pgdata-current-logfiles"> file. This provides
+ a convenient way to find and access log content without establishing a
+ database connection.
+ </para>
+
<sect2 id="runtime-config-logging-where">
<title>Where To Log</title>
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index eca98df..20de903 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15444,6 +15444,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
</row>
<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>
<entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15661,6 +15674,39 @@ 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>
+
+ <indexterm>
+ <primary>Logging</primary>
+ <secondary>pg_current_logfile function</secondary>
+ </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">.
+
+ <function>pg_current_logfiles</function> reflects the content of the
+ <xref linkend="storage-pgdata-current-logfiles"> file. All caveats
+ regards <filename>current_logfiles</filename> content are applicable
+ to <function>pg_current_logfiles</function>' return value.
+ </para>
+
<indexterm>
<primary>pg_my_temp_schema</primary>
</indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 5c52824..3b003f5 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -60,6 +60,81 @@ Item
<entry>Subdirectory containing per-database subdirectories</entry>
</row>
+<row id="storage-pgdata-current-logfiles" xreflabel="current_logfiles">
+ <entry>
+ <indexterm>
+ <primary><filename>current_logfiles</filename></primary>
+ </indexterm>
+ <indexterm>
+ <primary>Logging</primary>
+ <secondary><filename>current_logfiles</filename> file</secondary>
+ </indexterm>
+ <filename>current_logfiles</>
+ </entry>
+ <entry>
+ <para>
+ A file recording the log file(s) currently written to by the syslogger
+ and the file's log formats, <systemitem>stderr</>
+ or <systemitem>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
+ <filename>current_logfiles</filename>.
+ </para>
+
+ <note>
+ <indexterm>
+ <primary><application>pg_ctl</application></primary>
+ <secondary>and <filename>current_logfiles</filename></secondary>
+ </indexterm>
+ <indexterm>
+ <primary><filename>stderr</filename></primary>
+ <secondary>and <filename>current_logfiles</filename></secondary>
+ </indexterm>
+ <indexterm>
+ <primary>log_destination configuration parameter</primary>
+ <secondary>and <filename>current_logfiles</filename></secondary>
+ </indexterm>
+
+ <para>
+ Although logs directed to <filename>stderr</filename> may be written
+ to the filesystem, when the writing of <filename>stderr</filename> is
+ managed outside of the <productname>PostgreSQL</productname> database
+ server the location of such files in the filesystem is not reflected in
+ the content of <filename>current_logfiles</filename>. One such case is
+ when the <application>pg_ctl</application> command is used to start
+ the <command>postgres</command> database server, capture
+ the <filename>stderr</filename> output of the server, and direct it to a
+ file.
+ </para>
+
+ <para>
+ There are other notable situations related
+ to <filename>stderr</filename> logging.
+ Non-<productname>PostgreSQL</productname> log sources, such as 3rd party
+ libraries, which deliver error messages directly
+ to <filename>stderr</filename> are always logged
+ by <productname>PostgreSQL</productname>
+ to <filename>stderr</filename>. <Filename>Stderr</Filename> is also the
+ destination for any incomplete log messages produced by
+ <productname>PostgreSQL</productname>. When
+ <systemitem>stderr</systemitem> is not in
+ <xref linkend="guc-log-destination">,
+ <filename>current_logfiles</filename> does not not contain the name of the
+ file where these sorts of log messages are written.
+ </para>
+ </note>
+
+ <para>
+ The <filename>current_logfiles</filename> file
+ is present only when <xref linkend="guc-logging-collector"> is
+ activated and when at least one of <systemitem>stderr</> or
+ <systemitem>csvlog</> value is present in
+ <xref linkend="guc-log-destination">.
+ </para>
+ </entry>
+</row>
+
<row>
<entry><filename>global</></entry>
<entry>Subdirectory containing cluster-wide tables, such as
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..06859bf 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 update_metainfo_datafile(void);
/*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
rotation_disabled = false;
rotation_requested = true;
}
+
+ /*
+ * Force rewriting last log filename when reloading configuration,
+ * even if rotation_requested is false, log_destination may have
+ * been changed and we don't want to wait the next file rotation.
+ */
+ update_metainfo_datafile();
}
if (Log_RotationAge > 0 && !rotation_disabled)
@@ -511,10 +519,15 @@ int
SysLogger_Start(void)
{
pid_t sysloggerPid;
- char *filename;
if (!Logging_collector)
+ {
+ /* Logging collector is not enabled. We don't know where messages are
+ * logged. Remove outdated file holding the current log filenames.
+ */
+ unlink(LOG_METAINFO_DATAFILE);
return 0;
+ }
/*
* If first time through, create the pipe which will receive stderr
@@ -570,11 +583,13 @@ SysLogger_Start(void)
* a time-based rotation.
*/
first_syslogger_file_time = time(NULL);
- filename = logfile_getname(first_syslogger_file_time, NULL);
+ last_file_name = logfile_getname(first_syslogger_file_time, NULL);
+
+ syslogFile = logfile_open(last_file_name, "a", false);
- syslogFile = logfile_open(filename, "a", false);
+ update_metainfo_datafile();
- pfree(filename);
+ pfree(last_file_name);
#ifdef EXEC_BACKEND
switch ((sysloggerPid = syslogger_forkexec()))
@@ -1098,6 +1113,8 @@ open_csvlogfile(void)
pfree(last_csv_file_name);
last_csv_file_name = filename;
+
+ update_metainfo_datafile();
}
/*
@@ -1151,9 +1168,11 @@ static void
logfile_rotate(bool time_based_rotation, int size_rotation_for)
{
char *filename;
- char *csvfilename = NULL;
+ char *csvfilename;
pg_time_t fntime;
FILE *fh;
+ bool rotate_csvlog;
+ bool rotate_stderr;
rotation_requested = false;
@@ -1166,9 +1185,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
fntime = next_rotation_time;
else
fntime = time(NULL);
- filename = logfile_getname(fntime, NULL);
- if (csvlogFile != NULL)
- csvfilename = logfile_getname(fntime, ".csv");
/*
* Decide whether to overwrite or append. We can overwrite if (a)
@@ -1178,8 +1194,12 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
*
* Note: last_file_name should never be NULL here, but if it is, append.
*/
- if (time_based_rotation || (size_rotation_for & LOG_DESTINATION_STDERR))
+ rotate_stderr = time_based_rotation ||
+ (size_rotation_for & LOG_DESTINATION_STDERR);
+ if (rotate_stderr)
{
+ filename = logfile_getname(fntime, NULL);
+
if (Log_truncate_on_rotation && time_based_rotation &&
last_file_name != NULL &&
strcmp(filename, last_file_name) != 0)
@@ -1202,10 +1222,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
rotation_disabled = true;
}
- if (filename)
- pfree(filename);
- if (csvfilename)
- pfree(csvfilename);
+ pfree(filename);
return;
}
@@ -1216,14 +1233,16 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
if (last_file_name != NULL)
pfree(last_file_name);
last_file_name = filename;
- filename = NULL;
}
/* Same as above, but for csv file. */
-
- if (csvlogFile != NULL &&
- (time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
+ rotate_csvlog = csvlogFile != NULL &&
+ (time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG));
+ if (rotate_csvlog)
{
+ if (csvlogFile != NULL)
+ csvfilename = logfile_getname(fntime, ".csv");
+
if (Log_truncate_on_rotation && time_based_rotation &&
last_csv_file_name != NULL &&
strcmp(csvfilename, last_csv_file_name) != 0)
@@ -1246,10 +1265,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
rotation_disabled = true;
}
- if (filename)
- pfree(filename);
- if (csvfilename)
- pfree(csvfilename);
+ pfree(csvfilename);
return;
}
@@ -1260,13 +1276,10 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
if (last_csv_file_name != NULL)
pfree(last_csv_file_name);
last_csv_file_name = csvfilename;
- csvfilename = NULL;
}
- if (filename)
- pfree(filename);
- if (csvfilename)
- pfree(csvfilename);
+ if (rotate_stderr || rotate_csvlog)
+ update_metainfo_datafile();
set_next_rotation_time();
}
@@ -1365,3 +1378,62 @@ sigUsr1Handler(SIGNAL_ARGS)
errno = save_errno;
}
+
+/*
+ * Store the name of the file(s) where the log collector, when enabled, writes
+ * log messages. Useful for finding the name(s) of the current log file(s)
+ * when there is time-based logfile rotation. Filenames are stored in a
+ * temporary file and renamed into the final destination for atomicity.
+ */
+static void
+update_metainfo_datafile()
+{
+ FILE *fh;
+
+ if (!(Log_destination & LOG_DESTINATION_STDERR)
+ && !(Log_destination & LOG_DESTINATION_CSVLOG))
+ {
+ unlink(LOG_METAINFO_DATAFILE);
+ return;
+ }
+
+ if ((fh = logfile_open(LOG_METAINFO_DATAFILE_TMP, "w", true)) == NULL)
+ return;
+
+ if (last_file_name && (Log_destination & LOG_DESTINATION_STDERR))
+ {
+ if (fprintf(fh, "stderr %s\n", last_file_name) < 0)
+ {
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not write stderr log file path \"%s\": %m",
+ LOG_METAINFO_DATAFILE_TMP)));
+ fclose(fh);
+ return;
+ }
+ }
+
+ if (last_csv_file_name && (Log_destination & LOG_DESTINATION_CSVLOG))
+ {
+ if (fprintf(fh, "csvlog %s\n", last_csv_file_name) < 0)
+ {
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not write csvlog log file path \"%s\": %m",
+ LOG_METAINFO_DATAFILE_TMP)));
+ fclose(fh);
+ return;
+ }
+ }
+ fclose(fh);
+
+ if (rename(LOG_METAINFO_DATAFILE_TMP, LOG_METAINFO_DATAFILE) != 0)
+ {
+ ereport(LOG,
+ (errcode_for_file_access(),
+ errmsg("could not rename file \"%s\": %m",
+ LOG_METAINFO_DATAFILE_TMP)));
+ return;
+ }
+
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..c275e66 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 +893,114 @@ 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];
+ char *logfmt;
+ char *log_filepath;
+ char *log_format = lbuffer;
+
+ /* The log format parameter is optional */
+ if (PG_NARGS() == 0 || PG_ARGISNULL(0))
+ logfmt = NULL;
+ else
+ {
+ logfmt = text_to_cstring(PG_GETARG_TEXT_PP(0));
+ if (strcmp(logfmt, "stderr") != 0 && strcmp(logfmt, "csvlog") != 0)
+ {
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("log format not supported, possible values are stderr or csvlog")));
+ PG_RETURN_NULL();
+ }
+ }
+
+ fd = AllocateFile(LOG_METAINFO_DATAFILE, "r");
+ if (fd == NULL)
+ {
+ if (errno != ENOENT)
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not read file \"%s\": %m",
+ LOG_METAINFO_DATAFILE)));
+ 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))
+ {
+ FreeFile(fd);
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not read file \"%s\": %m",
+ LOG_METAINFO_DATAFILE)));
+ }
+
+ /*
+ * extract log format and log file path from the line
+ * lbuffer == log_format, they share storage
+ */
+ if (log_filepath = strchr(lbuffer, ' '))
+ *log_filepath = '\0';
+ else
+ {
+ /* Unknown format, no space. Return NULL to caller. */
+ lbuffer[0] = '\0';
+ break;
+ }
+ log_filepath++;
+ log_filepath[strcspn(log_filepath, "\n")] = '\0';
+
+ /*
+ * When no log format is provided as argument always reports
+ * the first registered log file in LOG_METAINFO_DATAFILE.
+ */
+ 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",
+ LOG_METAINFO_DATAFILE)));
+
+ if (lbuffer[0] == '\0')
+ PG_RETURN_NULL();
+
+ /* Recheck requested log format against the one extracted from the file */
+ if (logfmt != NULL && (log_format == NULL ||
+ strcmp(logfmt, log_format) != 0))
+ PG_RETURN_NULL();
+
+ PG_RETURN_TEXT_P(cstring_to_text(log_filepath));
+}
+
+/*
+ * Report current log file used by log collector (1 argument version)
+ *
+ * note: this wrapper is necessary to pass the sanity check in opr_sanity,
+ * which checks that all built-in functions that share the implementing C
+ * function take the same number of arguments
+ */
+Datum
+pg_current_logfile_1arg(PG_FUNCTION_ARGS)
+{
+ return pg_current_logfile(fcinfo);
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 96e77ec..bec5bbb 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3183,6 +3183,10 @@ 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 0 0 25 "" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
+DATA(insert OID = 3801 ( 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_1arg _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 999440f..db8c3f7 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,5 +466,4 @@ extern bool has_rolreplication(Oid roleid);
/* in access/transam/xlog.c */
extern bool BackupInProgress(void);
extern void CancelBackup(void);
-
#endif /* MISCADMIN_H */
diff --git a/src/include/postmaster/syslogger.h b/src/include/postmaster/syslogger.h
index 66c2111..1de4d6e 100644
--- a/src/include/postmaster/syslogger.h
+++ b/src/include/postmaster/syslogger.h
@@ -87,4 +87,15 @@ extern void write_syslogger_file(const char *buffer, int count, int dest);
extern void SysLoggerMain(int argc, char *argv[]) pg_attribute_noreturn();
#endif
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file holding the paths, names, and types of the files where current
+ * log messages are written, when the log collector is enabled. Useful
+ * outside of Postgres when finding the name of the current log file in the
+ * case of time-based log rotation.
+ */
+#define LOG_METAINFO_DATAFILE "current_logfiles"
+#define LOG_METAINFO_DATAFILE_TMP LOG_METAINFO_DATAFILE ".tmp"
+
+
#endif /* _SYSLOGGER_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 7ed1623..838d977 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,8 @@ 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);
+extern Datum pg_current_logfile_1arg(PG_FUNCTION_ARGS);
/* oid.c */
extern Datum oidin(PG_FUNCTION_ARGS);
--
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