On Thu, Oct 2, 2014 at 12:44 AM, Andres Freund <and...@2ndquadrant.com>
wrote:
> I pushed the first part.
>
Thanks. Attached is a rebased version of patch 2, implementing the actual
feature. One thing I noticed with more testing is that if --create is used
and that the destination folder does not exist, pg_receivexlog was creating
the slot, and left with an error. This does not look user-friendly so I
changed the logic a bit to check for the destination folder before creating
any slot. This results in a bit of refactoring, but this way behavior is
more intuitive.
Regards,
--
Michael
From e3ee4b918b8122d414c03207fdd50f2472dc292e Mon Sep 17 00:00:00 2001
From: Michael Paquier <mich...@otacoo.com>
Date: Mon, 1 Sep 2014 20:53:45 +0900
Subject: [PATCH] Support for replslot creation and drop in pg_receivexlog
Using the new actions --create and --drop that are similarly present
in pg_recvlogical, a user can respectively create and drop a replication
slot that can be used afterwards when fetching WALs.
---
doc/src/sgml/ref/pg_receivexlog.sgml | 29 +++++++
src/bin/pg_basebackup/pg_receivexlog.c | 154 +++++++++++++++++++++++++++++----
2 files changed, 168 insertions(+), 15 deletions(-)
diff --git a/doc/src/sgml/ref/pg_receivexlog.sgml b/doc/src/sgml/ref/pg_receivexlog.sgml
index 5916b8f..69aa0af 100644
--- a/doc/src/sgml/ref/pg_receivexlog.sgml
+++ b/doc/src/sgml/ref/pg_receivexlog.sgml
@@ -72,6 +72,35 @@ PostgreSQL documentation
<title>Options</title>
<para>
+ <application>pg_receivexlog</application> can run in one of two following
+ modes, which control physical replication slot:
+
+ <variablelist>
+
+ <varlistentry>
+ <term><option>--create</option></term>
+ <listitem>
+ <para>
+ Create a new physical replication slot with the name specified in
+ <option>--slot</option>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>--drop</option></term>
+ <listitem>
+ <para>
+ Drop the replication slot with the name specified in
+ <option>--slot</option>, then exit.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ </para>
+
+ <para>
The following command-line options control the location and format of the
output.
diff --git a/src/bin/pg_basebackup/pg_receivexlog.c b/src/bin/pg_basebackup/pg_receivexlog.c
index 171cf43..8c4f752 100644
--- a/src/bin/pg_basebackup/pg_receivexlog.c
+++ b/src/bin/pg_basebackup/pg_receivexlog.c
@@ -38,11 +38,15 @@ static int noloop = 0;
static int standby_message_timeout = 10 * 1000; /* 10 sec = default */
static int fsync_interval = 0; /* 0 = default */
static volatile bool time_to_abort = false;
+static bool do_create_slot = false;
+static bool do_drop_slot = false;
static void usage(void);
+static DIR* get_destination_dir(char *dest_folder);
+static void close_destination_dir(DIR *dest_dir, char *dest_folder);
static XLogRecPtr FindStreamingStart(uint32 *tli);
-static void StreamLog();
+static void StreamLog(void);
static bool stop_streaming(XLogRecPtr segendpos, uint32 timeline,
bool segment_finished);
@@ -78,6 +82,9 @@ usage(void)
printf(_(" -w, --no-password never prompt for password\n"));
printf(_(" -W, --password force password prompt (should happen automatically)\n"));
printf(_(" -S, --slot=SLOTNAME replication slot to use\n"));
+ printf(_("\nOptional actions:\n"));
+ printf(_(" --create create a new replication slot (for the slot's name see --slot)\n"));
+ printf(_(" --drop drop the replication slot (for the slot's name see --slot)\n"));
printf(_("\nReport bugs to <pgsql-b...@postgresql.org>.\n"));
}
@@ -118,6 +125,44 @@ stop_streaming(XLogRecPtr xlogpos, uint32 timeline, bool segment_finished)
return false;
}
+
+/*
+ * Get destination directory.
+ */
+static DIR*
+get_destination_dir(char *dest_folder)
+{
+ DIR *dir;
+
+ Assert(dest_folder != NULL);
+ dir = opendir(dest_folder);
+ if (dir == NULL)
+ {
+ fprintf(stderr, _("%s: could not open directory \"%s\": %s\n"),
+ progname, basedir, strerror(errno));
+ disconnect_and_exit(1);
+ }
+
+ return dir;
+}
+
+
+/*
+ * Close existing directory.
+ */
+static void
+close_destination_dir(DIR *dest_dir, char *dest_folder)
+{
+ Assert(dest_dir != NULL && dest_folder != NULL);
+ if (closedir(dest_dir))
+ {
+ fprintf(stderr, _("%s: could not close directory \"%s\": %s\n"),
+ progname, dest_folder, strerror(errno));
+ disconnect_and_exit(1);
+ }
+}
+
+
/*
* Determine starting location for streaming, based on any existing xlog
* segments in the directory. We start at the end of the last one that is
@@ -134,13 +179,7 @@ FindStreamingStart(uint32 *tli)
uint32 high_tli = 0;
bool high_ispartial = false;
- dir = opendir(basedir);
- if (dir == NULL)
- {
- fprintf(stderr, _("%s: could not open directory \"%s\": %s\n"),
- progname, basedir, strerror(errno));
- disconnect_and_exit(1);
- }
+ dir = get_destination_dir(basedir);
while (errno = 0, (dirent = readdir(dir)) != NULL)
{
@@ -219,12 +258,7 @@ FindStreamingStart(uint32 *tli)
disconnect_and_exit(1);
}
- if (closedir(dir))
- {
- fprintf(stderr, _("%s: could not close directory \"%s\": %s\n"),
- progname, basedir, strerror(errno));
- disconnect_and_exit(1);
- }
+ close_destination_dir(dir, basedir);
if (high_segno > 0)
{
@@ -344,11 +378,15 @@ main(int argc, char **argv)
{"status-interval", required_argument, NULL, 's'},
{"slot", required_argument, NULL, 'S'},
{"verbose", no_argument, NULL, 'v'},
+/* action */
+ {"create", no_argument, NULL, 1},
+ {"drop", no_argument, NULL, 2},
{NULL, 0, NULL, 0}
};
int c;
int option_index;
+ char *db_name;
progname = get_progname(argv[0]);
set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pg_receivexlog"));
@@ -427,6 +465,13 @@ main(int argc, char **argv)
case 'v':
verbose++;
break;
+/* action */
+ case 1:
+ do_create_slot = true;
+ break;
+ case 2:
+ do_drop_slot = true;
+ break;
default:
/*
@@ -451,10 +496,26 @@ main(int argc, char **argv)
exit(1);
}
+ if (replication_slot == NULL && (do_drop_slot || do_create_slot))
+ {
+ fprintf(stderr, _("%s: replication slot needed with action --create or --drop\n"), progname);
+ fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
+ progname);
+ exit(1);
+ }
+
+ if (do_drop_slot && do_create_slot)
+ {
+ fprintf(stderr, _("%s: cannot use --create together with --drop\n"), progname);
+ fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
+ progname);
+ exit(1);
+ }
+
/*
* Required arguments
*/
- if (basedir == NULL)
+ if (basedir == NULL && !do_drop_slot)
{
fprintf(stderr, _("%s: no target directory specified\n"), progname);
fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
@@ -462,10 +523,73 @@ main(int argc, char **argv)
exit(1);
}
+ /*
+ * Check existence of destination folder.
+ */
+ if (!do_drop_slot)
+ {
+ DIR *dir = get_destination_dir(basedir);
+ close_destination_dir(dir, basedir);
+ }
+
#ifndef WIN32
pqsignal(SIGINT, sigint_handler);
#endif
+ /*
+ * Obtain a connection before doing anything.
+ */
+ conn = GetConnection();
+ if (!conn)
+ /* error message already written in GetConnection() */
+ exit(1);
+
+ /*
+ * Run IDENTIFY_SYSTEM so we can get the timeline and current xlog
+ * position.
+ */
+ if (!RunIdentifySystem(conn, NULL, NULL, NULL, &db_name))
+ disconnect_and_exit(1);
+
+ /*
+ * Check that there is a database associated with connection, none
+ * should be defined in this context.
+ */
+ if (db_name)
+ {
+ fprintf(stderr,
+ _("%s: database defined for replication connection \"%s\"\n"),
+ progname, replication_slot);
+ disconnect_and_exit(1);
+ }
+
+ /*
+ * Drop a replication slot.
+ */
+ if (do_drop_slot)
+ {
+ if (verbose)
+ fprintf(stderr,
+ _("%s: dropping replication slot \"%s\"\n"),
+ progname, replication_slot);
+
+ if (!DropReplicationSlot(conn, replication_slot))
+ disconnect_and_exit(1);
+ disconnect_and_exit(0);
+ }
+
+ /* Create a replication slot */
+ if (do_create_slot)
+ {
+ if (verbose)
+ fprintf(stderr,
+ _("%s: creating replication slot \"%s\"\n"),
+ progname, replication_slot);
+
+ if (!CreateReplicationSlot(conn, replication_slot, NULL, NULL, true))
+ disconnect_and_exit(1);
+ }
+
while (true)
{
StreamLog();
--
2.1.1
--
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