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help / color / mirror / Atom feedFrom: Gyan Sreejith <[email protected]>
To: vignesh C <[email protected]>
Cc: Amit Kapila <[email protected]>
Cc: Euler Taveira <[email protected]>
Cc: [email protected] <[email protected]>
Cc: [email protected] <[email protected]>
Cc: Peter Smith <[email protected]>
Subject: Re: [Proposal] Adding Log File Capability to pg_createsubscriber
Date: Sun, 8 Feb 2026 21:08:15 -0500
Message-ID: <CAEqnbaUbVgGMXBNFbk=sqFJT=_TkAUYGYsFHJKFw5K492M_B=A@mail.gmail.com> (raw)
In-Reply-To: <CALDaNm17ujrJ2xHyz6r81WAiFUs38RcT8D5ebdxssASpGko0HA@mail.gmail.com>
References: <CAEqnbaUthOQARV1dscGvB_EsqC-YfxiM6rWkVDHc+G+f4oSUHw@mail.gmail.com>
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<CALDaNm17ujrJ2xHyz6r81WAiFUs38RcT8D5ebdxssASpGko0HA@mail.gmail.com>
I was able to make the first two changes that you suggested. However, I was
not able to get the test to run with one of the existing replica servers. I
have attached the patch for the first two changes.
Thank you!
Regards,
Gyan
On Wed, Feb 4, 2026 at 4:44 AM vignesh C <[email protected]> wrote:
> On Mon, 2 Feb 2026 at 04:35, Gyan Sreejith <[email protected]>
> wrote:
> >
> > Thank you!
> >
> > I have made the suggested changes. In addition, I added a wrapper for
> pg_fatal to write to the file and then do everything that pg_fatal would do.
> > I have attached the patch.
>
> Few comments:
> 1) Can we change the macro names:
> INFO -> pg_log_info
> INFO_HINT -> pg_log_info_hint
> DEBUG -> pg_log_debug
> FATAL -> pg_fatal
>
> if required do an #undef and call pg_log_generic in the else similar
> to how it is done in pg_backup_utils.h
>
> +#define INFO(...) do{\
> + if (internal_log_file_fp != NULL) \
> + internal_log_file_write(__VA_ARGS__); \
> + else \
> + pg_log_info(__VA_ARGS__);\
> +} while(0)
> +
> +#define INFO_HINT(...) do{\
> + if (internal_log_file_fp != NULL) \
> + internal_log_file_write(__VA_ARGS__); \
> + else \
> + pg_log_info_hint(__VA_ARGS__);\
> +} while(0)
> +
> +#define DEBUG(...) do{\
> + if (internal_log_file_fp != NULL) \
> + internal_log_file_write(__VA_ARGS__); \
> + else \
> + pg_log_debug(__VA_ARGS__);\
> +} while(0)
> +
> +#define FATAL(...) do{\
> + if (internal_log_file_fp != NULL) \
> + internal_log_file_write(__VA_ARGS__); \
> + pg_fatal(__VA_ARGS__); /* call pg_fatal after writing to logs */ \
> +} while(0)
>
> 2) You can keep the variabled in case 'l' handling to keep the scope
> accordingly:
> + char timestamp[128];
> + struct timeval tval;
> + time_t now;
>
> 3) Instead of creating a new standby and running with -l option, can
> you run it with -l for one of the existing tests:
> +$node_p->backup('backup_3');
> +
> +# Set up node R as a logical replica node
> +my $node_r = PostgreSQL::Test::Cluster->new('node_r');
> +$node_r->init_from_backup($node_p, 'backup_3', has_streaming => 1);
> +$node_r->append_conf(
> + 'postgresql.conf', qq[
> +primary_conninfo = '$pconnstr dbname=postgres'
> +hot_standby_feedback = on
> +]);
> +$node_r->set_standby_mode();
> +
> +# Test that --logdir works for pg_createsubscriber
> +command_ok(
> + [
> + 'pg_createsubscriber',
> + '--verbose',
> + '--pgdata' => $node_r->data_dir,
> + '--publisher-server' => $pconnstr,
> + '--database' => 'postgres',
> + '--logdir' => $logdir,
> + ],
> + 'check for log file creation for pg_createSubscriber');
> +
> +# Check that the log files were created
> +my @server_log_files = glob "$logdir/pg_createsubscriber_server_*.log";
> +is( scalar(@server_log_files), 1, "
> + pg_createsubscriber_server.log file was created");
> +my @internal_log_files = glob
> "$logdir/pg_createsubscriber_internal_*.log";
> +is( scalar(@internal_log_files), 1, "
> + pg_createsubscriber_internal.log file was created");
>
> Regards,
> Vignesh
>
Attachments:
[application/x-patch] v5-0001-Add-a-new-argument-l-logdir-to-pg_createsubscribe.patch (13.6K, 3-v5-0001-Add-a-new-argument-l-logdir-to-pg_createsubscribe.patch)
download | inline diff:
From 8f3237b07d72eb4443e025c381ff5ae7221a4141 Mon Sep 17 00:00:00 2001
From: Gyan Sreejith <[email protected]>
Date: Sun, 8 Feb 2026 20:57:07 -0500
Subject: [PATCH v5] Add a new argument -l <logdir> to pg_createsubscriber.
Enabling the option to write messages to log files in the specified directory.
A new directory is created if required, and two new logfiles (with timestamps in their names) are added to the directory:
1. pg_createsubscriber_server_timestamp.log - captures messages related to starting and stopping the standby server.
2. pg_createsubscriber_internal_timestamp.log - captures internal diagnostic output from pg_createsubscriber.
For example, if we specify -l abc as an argument, and if the timestamp on running it is 2026-01-19-20-43-17.204240, a directory abc is created if it doesn't exist already, and the directory will contain the two log files pg_createsubscriber_server_2026-01-19-20-43-17.204240.log and pg_createsubscriber_internal_2026-01-19-20-43-17.204240.log
---
doc/src/sgml/ref/pg_createsubscriber.sgml | 22 +++
src/bin/pg_basebackup/pg_createsubscriber.c | 162 +++++++++++++++++-
.../t/040_pg_createsubscriber.pl | 36 +++-
3 files changed, 215 insertions(+), 5 deletions(-)
diff --git a/doc/src/sgml/ref/pg_createsubscriber.sgml b/doc/src/sgml/ref/pg_createsubscriber.sgml
index cf45ff3573d..8cb70403931 100644
--- a/doc/src/sgml/ref/pg_createsubscriber.sgml
+++ b/doc/src/sgml/ref/pg_createsubscriber.sgml
@@ -136,6 +136,28 @@ PostgreSQL documentation
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>-l <replaceable class="parameter">directory</replaceable></option></term>
+ <term><option>--logdir=<replaceable class="parameter">directory</replaceable></option></term>
+ <listitem>
+ <para>
+ Specify the name of the log directory. A new directory is created with this name if it does not exist. The following two log files will be created with a umask of 077 so that access is disallowed to other users by default. The timestamp that is added to the name will indicate the time at which pg_createsubscriber was run.
+ <itemizedlist>
+ <listitem>
+ <para>
+ pg_createsubscriber_server_timestamp.log which captures logs related to stopping and starting the standby server,
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ pg_createsubscriber_internal_timestamp.log which captures internal diagnostic output (validations, checks, etc.)
+ </para>
+ </listitem>
+ </itemizedlist>
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><option>-n</option></term>
<term><option>--dry-run</option></term>
diff --git a/src/bin/pg_basebackup/pg_createsubscriber.c b/src/bin/pg_basebackup/pg_createsubscriber.c
index 2bc84505aab..598cb07a1bf 100644
--- a/src/bin/pg_basebackup/pg_createsubscriber.c
+++ b/src/bin/pg_basebackup/pg_createsubscriber.c
@@ -49,10 +49,48 @@
#define INCLUDED_CONF_FILE "pg_createsubscriber.conf"
#define INCLUDED_CONF_FILE_DISABLED INCLUDED_CONF_FILE ".disabled"
+#define SERVER_LOG_FILE_NAME "pg_createsubscriber_server"
+#define INTERNAL_LOG_FILE_NAME "pg_createsubscriber_internal"
+
+#undef pg_log_info
+#define pg_log_info(...) do{\
+ if (internal_log_file_fp != NULL) \
+ internal_log_file_write(__VA_ARGS__); \
+ else \
+ pg_log_generic(PG_LOG_INFO,PG_LOG_PRIMARY,__VA_ARGS__);\
+} while(0)
+
+#undef pg_log_info_hint
+#define pg_log_info_hint(...) do{\
+ if (internal_log_file_fp != NULL) \
+ internal_log_file_write(__VA_ARGS__); \
+ else \
+ pg_log_generic(PG_LOG_INFO, PG_LOG_HINT, __VA_ARGS__);\
+} while(0)
+
+#undef pg_log_debug
+#define pg_log_debug(...) do{\
+ if (internal_log_file_fp != NULL) \
+ internal_log_file_write(__VA_ARGS__); \
+ else \
+ if (unlikely(__pg_log_level <= PG_LOG_DEBUG)) \
+ pg_log_generic(PG_LOG_DEBUG, PG_LOG_PRIMARY, __VA_ARGS__); \
+} while(0)
+
+#undef pg_fatal
+#define pg_fatal(...) do{\
+ if (internal_log_file_fp != NULL) \
+ internal_log_file_write(__VA_ARGS__); \
+ pg_log_generic(PG_LOG_ERROR, PG_LOG_PRIMARY, __VA_ARGS__); \
+ exit(1); \
+} while(0)
+
+
/* Command-line options */
struct CreateSubscriberOptions
{
char *config_file; /* configuration file */
+ char *log_dir; /* log directory name */
char *pub_conninfo_str; /* publisher connection string */
char *socket_dir; /* directory for Unix-domain socket, if any */
char *sub_port; /* subscriber port number */
@@ -146,6 +184,9 @@ static void drop_existing_subscription(PGconn *conn, const char *subname,
const char *dbname);
static void get_publisher_databases(struct CreateSubscriberOptions *opt,
bool dbnamespecified);
+static void
+ internal_log_file_write(const char *format,...) __attribute__((format(printf, 1, 2)));
+
#define WAIT_INTERVAL 1 /* 1 second */
@@ -167,6 +208,10 @@ static pg_prng_state prng_state;
static char *pg_ctl_path = NULL;
static char *pg_resetwal_path = NULL;
+static FILE *internal_log_file_fp = NULL; /* File ptr to log all messages to */
+static char *log_timestamp = NULL; /* Timestamp to be used in all log file
+ * names */
+
/* standby / subscriber data directory */
static char *subscriber_dir = NULL;
@@ -174,6 +219,50 @@ static bool recovery_ended = false;
static bool standby_running = false;
static bool recovery_params_set = false;
+static void
+internal_log_file_write(const char *format,...)
+{
+ if (internal_log_file_fp != NULL)
+ {
+ va_list args;
+
+ va_start(args, format);
+ vfprintf(internal_log_file_fp, format, args);
+ fprintf(internal_log_file_fp, "\n");
+ fflush(internal_log_file_fp);
+ va_end(args);
+ }
+}
+
+/*
+ * Open a new logfile with proper permissions.
+ * From src/backend/postmaster/syslogger.c
+ */
+static FILE *
+logfile_open(const char *filename, const char *mode)
+{
+ FILE *fh;
+ mode_t oumask;
+
+ oumask = umask((mode_t) ((~(S_IRUSR | S_IWUSR)) & (S_IRWXU | S_IRWXG | S_IRWXO)));
+ fh = fopen(filename, mode);
+ umask(oumask);
+
+ if (fh)
+ {
+ setvbuf(fh, NULL, PG_IOLBF, 0);
+
+#ifdef WIN32
+ /* use CRLF line endings on Windows */
+ _setmode(_fileno(fh), _O_TEXT);
+#endif
+ }
+ else
+ pg_fatal("could not open log file \"%s\": %m",
+ filename);
+
+ return fh;
+}
/*
* Clean up objects created by pg_createsubscriber.
@@ -269,6 +358,12 @@ cleanup_objects_atexit(void)
if (standby_running)
stop_standby_server(subscriber_dir);
+
+ if (internal_log_file_fp != NULL)
+ {
+ fclose(internal_log_file_fp);
+ internal_log_file_fp = NULL;
+ }
}
static void
@@ -283,6 +378,7 @@ usage(void)
" databases and databases that don't allow connections\n"));
printf(_(" -d, --database=DBNAME database in which to create a subscription\n"));
printf(_(" -D, --pgdata=DATADIR location for the subscriber data directory\n"));
+ printf(_(" -l, --logdir=LOGDIR location for the new log directory\n"));
printf(_(" -n, --dry-run dry run, just show what would be done\n"));
printf(_(" -p, --subscriber-port=PORT subscriber port number (default %s)\n"), DEFAULT_SUB_PORT);
printf(_(" -P, --publisher-server=CONNSTR publisher connection string\n"));
@@ -702,6 +798,7 @@ modify_subscriber_sysid(const struct CreateSubscriberOptions *opt)
bool crc_ok;
struct timeval tv;
+ char *out_file;
char *cmd_str;
pg_log_info("modifying system identifier of subscriber");
@@ -713,7 +810,7 @@ modify_subscriber_sysid(const struct CreateSubscriberOptions *opt)
/*
* Select a new system identifier.
*
- * XXX this code was extracted from BootStrapXLOG().
+ * XXX this code was extracted from BootStrapXpg_log_info().
*/
gettimeofday(&tv, NULL);
cf->system_identifier = ((uint64) tv.tv_sec) << 32;
@@ -735,8 +832,14 @@ modify_subscriber_sysid(const struct CreateSubscriberOptions *opt)
else
pg_log_info("running pg_resetwal on the subscriber");
- cmd_str = psprintf("\"%s\" -D \"%s\" > \"%s\"", pg_resetwal_path,
- subscriber_dir, DEVNULL);
+
+ if (opt->log_dir != NULL)
+ out_file = psprintf("%s/%s_%s.log", opt->log_dir, SERVER_LOG_FILE_NAME, log_timestamp);
+ else
+ out_file = DEVNULL;
+
+ cmd_str = psprintf("\"%s\" -D \"%s\" >> \"%s\"", pg_resetwal_path,
+ subscriber_dir, out_file);
pg_log_debug("pg_resetwal command is: %s", cmd_str);
@@ -1650,6 +1753,11 @@ start_standby_server(const struct CreateSubscriberOptions *opt, bool restricted_
if (restrict_logical_worker)
appendPQExpBufferStr(pg_ctl_cmd, " -o \"-c max_logical_replication_workers=0\"");
+ if (opt->log_dir != NULL)
+ {
+ appendPQExpBuffer(pg_ctl_cmd, " -l %s/%s_%s.log", opt->log_dir, SERVER_LOG_FILE_NAME, log_timestamp);
+ }
+
pg_log_debug("pg_ctl command is: %s", pg_ctl_cmd->data);
rc = system(pg_ctl_cmd->data);
pg_ctl_status(pg_ctl_cmd->data, rc);
@@ -2181,6 +2289,7 @@ main(int argc, char **argv)
{"all", no_argument, NULL, 'a'},
{"database", required_argument, NULL, 'd'},
{"pgdata", required_argument, NULL, 'D'},
+ {"logdir", required_argument, NULL, 'l'},
{"dry-run", no_argument, NULL, 'n'},
{"subscriber-port", required_argument, NULL, 'p'},
{"publisher-server", required_argument, NULL, 'P'},
@@ -2215,6 +2324,7 @@ main(int argc, char **argv)
char *consistent_lsn;
char pidfile[MAXPGPATH];
+ char *internal_log_file;
pg_logging_init(argv[0]);
pg_logging_set_level(PG_LOG_WARNING);
@@ -2239,6 +2349,7 @@ main(int argc, char **argv)
/* Default settings */
subscriber_dir = NULL;
opt.config_file = NULL;
+ opt.log_dir = NULL;
opt.pub_conninfo_str = NULL;
opt.socket_dir = NULL;
opt.sub_port = DEFAULT_SUB_PORT;
@@ -2267,7 +2378,7 @@ main(int argc, char **argv)
get_restricted_token();
- while ((c = getopt_long(argc, argv, "ad:D:np:P:s:t:TU:v",
+ while ((c = getopt_long(argc, argv, "ad:D:l:np:P:s:t:TU:v",
long_options, &option_index)) != -1)
{
switch (c)
@@ -2288,6 +2399,46 @@ main(int argc, char **argv)
subscriber_dir = pg_strdup(optarg);
canonicalize_path(subscriber_dir);
break;
+ case 'l':
+ {
+ char timestamp[128];
+ struct timeval tval;
+ time_t now;
+ struct tm tmbuf;
+
+ gettimeofday(&tval, NULL);
+ now = tval.tv_sec;
+ strftime(timestamp, sizeof(timestamp), "%Y-%m-%d-%H-%M-%S", localtime_r(&now, &tmbuf));
+ /* append microseconds */
+ snprintf(timestamp + strlen(timestamp), sizeof(timestamp) - strlen(timestamp),
+ ".%06u", (unsigned int) (tval.tv_usec));
+ log_timestamp = pg_strdup(timestamp);
+
+ opt.log_dir = pg_strdup(optarg);
+ canonicalize_path(opt.log_dir);
+
+ if (stat(opt.log_dir, &statbuf) != 0)
+ {
+ if (errno == ENOENT)
+ {
+ if (mkdir(opt.log_dir, S_IRWXU) == 0)
+ pg_log_info("log directory created");
+ else if (errno == EACCES)
+ pg_fatal("permission denied trying to create log directory \"%s\": %m", opt.log_dir);
+ else
+ pg_fatal("could not create log directory \"%s\": %m", opt.log_dir);
+ }
+ else if (errno == EACCES)
+ pg_fatal("permission denied trying to access directory \"%s\": %m", opt.log_dir);
+ else
+ pg_fatal("could not access directory \"%s\": %m", opt.log_dir);
+ }
+ internal_log_file = psprintf("%s/%s_%s.log", opt.log_dir, INTERNAL_LOG_FILE_NAME, log_timestamp);
+ if ((internal_log_file_fp = logfile_open(internal_log_file, "a")) == NULL)
+ pg_fatal("could not open log file \"%s\": %m", internal_log_file);
+
+ break;
+ }
case 'n':
dry_run = true;
break;
@@ -2621,5 +2772,8 @@ main(int argc, char **argv)
pg_log_info("Done!");
+ if (internal_log_file_fp != NULL)
+ fclose(internal_log_file_fp);
+
return 0;
}
diff --git a/src/bin/pg_basebackup/t/040_pg_createsubscriber.pl b/src/bin/pg_basebackup/t/040_pg_createsubscriber.pl
index 0c27fca7bb7..cdb12623b3b 100644
--- a/src/bin/pg_basebackup/t/040_pg_createsubscriber.pl
+++ b/src/bin/pg_basebackup/t/040_pg_createsubscriber.pl
@@ -13,7 +13,8 @@ program_help_ok('pg_createsubscriber');
program_version_ok('pg_createsubscriber');
program_options_handling_ok('pg_createsubscriber');
-my $datadir = PostgreSQL::Test::Utils::tempdir;
+my $datadir = PostgreSQL::Test::Utils::tempdir + "/datadir";
+my $logdir = PostgreSQL::Test::Utils::tempdir + "/logdir";
# Generate a database with a name made of a range of ASCII characters.
# Extracted from 002_pg_upgrade.pl.
@@ -629,10 +630,43 @@ command_ok(
# not being tracked, something that is set within $node->start().
system_log('pg_ctl', 'stop', '--pgdata', $node_k->data_dir);
+$node_p->backup('backup_3');
+
+# Set up node R as a logical replica node
+my $node_r = PostgreSQL::Test::Cluster->new('node_r');
+$node_r->init_from_backup($node_p, 'backup_3', has_streaming => 1);
+$node_r->append_conf(
+ 'postgresql.conf', qq[
+primary_conninfo = '$pconnstr dbname=postgres'
+hot_standby_feedback = on
+]);
+$node_r->set_standby_mode();
+
+# Test that --logdir works for pg_createsubscriber
+command_ok(
+ [
+ 'pg_createsubscriber',
+ '--verbose',
+ '--pgdata' => $node_r->data_dir,
+ '--publisher-server' => $pconnstr,
+ '--database' => 'postgres',
+ '--logdir' => $logdir,
+ ],
+ 'check for log file creation for pg_createSubscriber');
+
+# Check that the log files were created
+my @server_log_files = glob "$logdir/pg_createsubscriber_server_*.log";
+is( scalar(@server_log_files), 1, "
+ pg_createsubscriber_server.log file was created");
+my @internal_log_files = glob "$logdir/pg_createsubscriber_internal_*.log";
+is( scalar(@internal_log_files), 1, "
+ pg_createsubscriber_internal.log file was created");
+
# clean up
$node_p->teardown_node;
$node_s->teardown_node;
$node_t->teardown_node;
$node_f->teardown_node;
+$node_r->teardown_node;
done_testing();
--
2.43.0
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Subject: Re: [Proposal] Adding Log File Capability to pg_createsubscriber
In-Reply-To: <CAEqnbaUbVgGMXBNFbk=sqFJT=_TkAUYGYsFHJKFw5K492M_B=A@mail.gmail.com>
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