Le 08/12/2016 à 00:52, Robert Haas a écrit :
> On Tue, Dec 6, 2016 at 6:11 PM, Gilles Darold <gilles.dar...@dalibo.com>
> wrote:
>> It seems that all fixes have been included in this patch.
> Yikes. This patch has certainly had a lot of review, but it has lots
> of basic inconsistencies with PostgreSQL coding style, which one would
> think somebody would have noticed by now, and there are multiple
> places where the logic seems to do in a complicated way something that
> could be done significantly more simply. I don't have any objection
> to the basic idea of this patch, but it's got to look and feel like
> the surrounding PostgreSQL code. And not be unnecessarily
> complicated.
>
> Detailed comments below:
>
> The SGML doesn't match the surrounding style - for example, <para>
> typically appears on a line by itself.
Fixed.
> + if (!Logging_collector) {
>
> Formatting.
Fixed.
> rm_log_metainfo() could be merged into logfile_writename(), since
> they're always called in conjunction and in the same pattern. The
> function is poorly named; it should be something like
> update_metainfo_datafile().
Merge and logfile_writename() function renamed as suggested.
> + if (errno == ENFILE || errno == EMFILE)
> + ereport(LOG,
> + (errmsg("system is too busy to write logfile meta
> info, %s will be updated on next rotation (or use SIGHUP to retry)",
> LOG_METAINFO_DATAFILE)));
>
> This seems like a totally unprincipled reaction to a purely arbitrary
> subset of errors. EMFILE or ENFILE doesn't represent a general "too
> busy" condition, and logfile_open() has already logged the real error.
Removed.
> + snprintf(tempfn, sizeof(tempfn), "%s.tmp", LOG_METAINFO_DATAFILE);
>
> You don't really need to use snprintf() here. You could #define
> LOG_METAINFO_DATAFILE_TMP LOG_METAINFO_DATAFILE ".tmp" and compute
> this at compile time instead of runtime.
Done and added to syslogger.h
> + 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;
> + }
>
> Formatting. This is unlike PostgreSQL style in multiple ways,
> including cuddled braces, extra parentheses and spaces, and use of
> braces around a single-line block. Also, this could be written in a
> much less contorted way, like:
>
> 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(...);
> }
Applied.
> Also, the ereport() needs an errcode(), not just an errmsg().
> Otherwise it defaults to ERRCODE_INTERNAL_ERROR, which is not correct.
Add errcode(ERRCODE_INVALID_PARAMETER_VALUE) to the ereport call.
> + /* Check if current log file is present */
> + if (stat(LOG_METAINFO_DATAFILE, &stat_buf) != 0)
> + PG_RETURN_NULL();
>
> Useless test. The code that follows catches this case anyway and
> handles it the same way. Which is good, because this has an inherent
> race condition. The previous if (!Logging_collector) test sems fairly
> useless too; unless there's a bug in your syslogger.c code, the file
> won't exist anyway, so we'll return NULL for that reason with no extra
> code needed here.
That's right, both test have been removed.
> + /*
> + * Read the file to gather current log filename(s) registered
> + * by the syslogger.
> + */
>
> Whitespace isn't right.
>
> + while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) {
> + char log_format[10];
> + int i = 0, space_pos = 0;
> +
> + /* Check for a read error. */
> + if (ferror(fd)) {
>
> More coding style issues.
>
> + ereport(ERROR,
> + (errcode_for_file_access(),
> + errmsg("could not read file \"%s\": %m",
> LOG_METAINFO_DATAFILE)));
> + FreeFile(fd);
> + break;
>
> ereport(ERROR) doesn't return, so the code that follows is pointless.
All issues above are fixed.
> + if (strchr(lbuffer, '\n') != NULL)
> + *strchr(lbuffer, '\n') = '\0';
>
> Probably worth adding a local variable instead of doing this twice.
> Local variables are cheap, and the code would be more readable.
Removed
> + if ((space_pos == 0) && (isspace(lbuffer[i]) != 0))
>
> Too many parentheses. Also, I think the whole loop in which this is
> contained could be eliminated entirely. Just search for the first ' '
> character with strchr(); you don't need to are about isspace() because
> you know the code that writes this file uses ' ' specifically.
> Overwrite it with '\0'. And then use a pointer to lbuffer for the log
> format and a pointer to lbuffer + strchr_result + 1 for the pathname.
Rewritten, not exactly the way you describe but like this:
/* extract log format and log file path from the line */
log_filepath = strchr(lbuffer, ' ');
log_filepath++;
lbuffer[log_filepath-lbuffer-1] = '\0';
log_format = lbuffer;
*strchr(log_filepath, '\n') = '\0';
it was possible to not use the additional log_format variable and just
keep the log format information in lbuffer, then use it the next code,
but I have kept the log_format variable for readability.
> + if ((space_pos != (int)strlen("stderr")) &&
> + (space_pos != (int)strlen("csvlog")))
> + {
> + ereport(ERROR,
> + (errmsg("unexpected line format in file %s",
> LOG_METAINFO_DATAFILE)));
> + break;
> + }
>
> I think this is pointless. Validating the length of the log format
> but not the content seems kind of silly, and why do either? The only
> way it's going to do the wrong thing is if the file contents are
> corrupt, and that should only happen if we have a bug. Which we
> probably won't, and if we do we'll fix it and then we won't, and this
> will just be deadweight -- and one more thing to update if we ever add
> support for another log format.
Removed.
> + /* 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();
>
> Seems complicated. Instead, you could declare char *result = NULL.
> When you find the row you're looking for, set result and break out of
> the loop. Then here you can just do if (result == NULL)
> PG_RETURN_NULL() and this complexity goes away.
Fixed.
> +/* 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"
>
> syslogger.h seems more appropriate. miscadmin.h is quite widely
> included and it would be better not to bloat it with things that
> aren't widely needed. It makes sense to use it for widely-used stuff
> that has no other obvious home, but since this is clearly a creature
> of the syslogger, it could logically go in syslogger.h.
Moved to syslogger.h
> This might not be exhaustive but I think fixing these things would get
> us much closer to a committable patch.
I have also run the code through pgindent as Tom suggest to fix all
pending coding style issues. I've just change on line from pgindent
work to prevent git apply to complain about a space in tabulation
issue. I don't know which is the best, let things like pgindent want to
write it or prevent git to complain. Attached is the v17 of the patch.
Thanks a lot for this synthetic review.
Regards
--
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..de23296 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 +893,107 @@ 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;
+ struct stat stat_buf;
+ char *log_filepath;
+ char *log_format;
+
+ /* 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 */
+ log_filepath = strchr(lbuffer, ' ');
+ log_filepath++;
+ lbuffer[log_filepath-lbuffer-1] = '\0';
+ log_format = lbuffer;
+ *strchr(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);
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
