Allow enabling two-phase option via replication protocol.

Extend the replication command CREATE_REPLICATION_SLOT to support the
TWO_PHASE option. This will allow decoding commands like PREPARE
TRANSACTION, COMMIT PREPARED and ROLLBACK PREPARED for slots created with
this option. The decoding of the transaction happens at prepare command.

This patch also adds support of two-phase in pg_recvlogical via a new
option --two-phase.

This option will also be used by future patches that allow streaming of
transactions at prepare time for built-in logical replication. With this,
the out-of-core logical replication solutions can enable replication of
two-phase transactions via replication protocol.

Author: Ajin Cherian
Reviewed-By: Jeff Davis, Vignesh C, Amit Kapila
Discussion:
https://postgr.es/m/02DA5F5E-CECE-4D9C-8B4B-418077E2C010@postgrespro.ru
https://postgr.es/m/64b9f783c6e125f18f88fbc0c0234e34e71d8639.camel@j-davis.com

1 files changed, 17 insertions, 2 deletions

diff --git a/src/bin/pg_basebackup/pg_recvlogical.c b/src/bin/pg_basebackup/pg_recvlogical.c
index 5efec160e88..76bd153fac2 100644
--- a/src/bin/pg_basebackup/pg_recvlogical.c
+++ b/src/bin/pg_basebackup/pg_recvlogical.c
@@ -35,6 +35,7 @@
 /* Global Options */
 static char *outfile = NULL;
 static int	verbose = 0;
+static bool two_phase = false;
 static int	noloop = 0;
 static int	standby_message_timeout = 10 * 1000;	/* 10 sec = default */
 static int	fsync_interval = 10 * 1000; /* 10 sec = default */
@@ -93,6 +94,7 @@ usage(void)
 	printf(_("  -s, --status-interval=SECS\n"
 			 "                         time between status packets sent to server (default: %d)\n"), (standby_message_timeout / 1000));
 	printf(_("  -S, --slot=SLOTNAME    name of the logical replication slot\n"));
+	printf(_("  -t, --two-phase        enable two-phase decoding when creating a slot\n"));
 	printf(_("  -v, --verbose          output verbose messages\n"));
 	printf(_("  -V, --version          output version information, then exit\n"));
 	printf(_("  -?, --help             show this help, then exit\n"));
@@ -678,6 +680,7 @@ main(int argc, char **argv)
 		{"fsync-interval", required_argument, NULL, 'F'},
 		{"no-loop", no_argument, NULL, 'n'},
 		{"verbose", no_argument, NULL, 'v'},
+		{"two-phase", no_argument, NULL, 't'},
 		{"version", no_argument, NULL, 'V'},
 		{"help", no_argument, NULL, '?'},
 /* connection options */
@@ -726,7 +729,7 @@ main(int argc, char **argv)
 		}
 	}
 
-	while ((c = getopt_long(argc, argv, "E:f:F:nvd:h:p:U:wWI:o:P:s:S:",
+	while ((c = getopt_long(argc, argv, "E:f:F:nvtd:h:p:U:wWI:o:P:s:S:",
 							long_options, &option_index)) != -1)
 	{
 		switch (c)
@@ -749,6 +752,9 @@ main(int argc, char **argv)
 			case 'v':
 				verbose++;
 				break;
+			case 't':
+				two_phase = true;
+				break;
 /* connection options */
 			case 'd':
 				dbname = pg_strdup(optarg);
@@ -920,6 +926,15 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
+	if (two_phase && !do_create_slot)
+	{
+		pg_log_error("--two-phase may only be specified with --create-slot");
+		fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
+				progname);
+		exit(1);
+	}
+
+
 #ifndef WIN32
 	pqsignal(SIGINT, sigint_handler);
 	pqsignal(SIGHUP, sighup_handler);
@@ -976,7 +991,7 @@ main(int argc, char **argv)
 			pg_log_info("creating replication slot \"%s\"", replication_slot);
 
 		if (!CreateReplicationSlot(conn, replication_slot, plugin, false,
-								   false, false, slot_exists_ok))
+								   false, false, slot_exists_ok, two_phase))
 			exit(1);
 		startpos = InvalidXLogRecPtr;
 	}