@@ -87,6 +87,7 @@ static int checkpoint_timeout(void);
8787static void add_pgdata_files (parray * files ,const char * root );
8888static void write_backup_file_list (parray * files ,const char * root );
8989static void wait_wal_lsn (XLogRecPtr lsn );
90+ static void wait_replica_wal_lsn (XLogRecPtr lsn ,bool is_start_backup );
9091static void make_pagemap_from_ptrack (parray * files );
9192static void StreamLog (void * arg );
9293
@@ -610,18 +611,22 @@ pg_start_backup(const char *label, bool smooth, pgBackup *backup)
610611const char * params [2 ];
611612uint32 xlogid ;
612613uint32 xrecoff ;
614+ PGconn * conn ;
613615
614616params [0 ]= label ;
615617
618+ /* For replica we call pg_start_backup() on master */
619+ conn = (from_replica ) ?master_conn :backup_conn ;
620+
616621/* 2nd argument is 'fast'*/
617622params [1 ]= smooth ?"false" :"true" ;
618623if (!exclusive_backup )
619- res = pgut_execute (backup_conn ,
624+ res = pgut_execute (conn ,
620625"SELECT pg_start_backup($1, $2, false)" ,
6216262 ,
622627params );
623628else
624- res = pgut_execute (backup_conn ,
629+ res = pgut_execute (conn ,
625630"SELECT pg_start_backup($1, $2)" ,
6266312 ,
627632params );
@@ -635,14 +640,6 @@ pg_start_backup(const char *label, bool smooth, pgBackup *backup)
635640
636641PQclear (res );
637642
638- /*
639- * Switch to a new WAL segment. It is necessary to get archived WAL
640- * segment, which includes start LSN of current backup.
641- *
642- * Do not switch for standby node and if backup is stream.
643- */
644- if (!from_replica && !stream_wal )
645- pg_switch_wal (backup_conn );
646643if (!stream_wal )
647644/*
648645 * Do not wait start_lsn for stream backup.
@@ -910,6 +907,66 @@ wait_wal_lsn(XLogRecPtr lsn)
910907}
911908}
912909
910+ /*
911+ * Wait for target 'lsn' on replica instance.
912+ */
913+ static void
914+ wait_replica_wal_lsn (XLogRecPtr lsn ,bool is_start_backup )
915+ {
916+ uint32 try_count = 0 ;
917+
918+ Assert (from_replica );
919+
920+ while (true)
921+ {
922+ PGresult * res ;
923+ uint32 xlogid ;
924+ uint32 xrecoff ;
925+ XLogRecPtr replica_lsn ;
926+
927+ /*
928+ * For lsn from pg_start_backup() we need it to be replayed on replica's
929+ * data.
930+ */
931+ if (is_start_backup )
932+ res = pgut_execute (backup_conn ,"SELECT pg_last_xlog_replay_location()" ,
933+ 0 ,NULL );
934+ /*
935+ * For lsn from pg_stop_backup() we need it only to be received by
936+ * replica and fsync()'ed on WAL segment.
937+ */
938+ else
939+ res = pgut_execute (backup_conn ,"SELECT pg_last_xlog_receive_location()" ,
940+ 0 ,NULL );
941+
942+ /* Extract timeline and LSN from result */
943+ XLogDataFromLSN (PQgetvalue (res ,0 ,0 ),& xlogid ,& xrecoff );
944+ /* Calculate LSN */
945+ replica_lsn = (XLogRecPtr ) ((uint64 )xlogid <<32 ) |xrecoff ;
946+ PQclear (res );
947+
948+ /* target lsn was replicated */
949+ if (replica_lsn >=lsn )
950+ break ;
951+
952+ sleep (1 );
953+ if (interrupted )
954+ elog (ERROR ,"Interrupted during waiting for target LSN" );
955+ try_count ++ ;
956+
957+ /* Inform user if target lsn is absent in first attempt */
958+ if (try_count == 1 )
959+ elog (INFO ,"Wait for target LSN %X/%X to be received by replica" ,
960+ (uint32 ) (lsn >>32 ), (uint32 )lsn );
961+
962+ if (replica_timeout > 0 && try_count > replica_timeout )
963+ elog (ERROR ,"Target LSN %X/%X could not be recevied by replica "
964+ "in %d seconds" ,
965+ (uint32 ) (lsn >>32 ), (uint32 )lsn ,
966+ replica_timeout );
967+ }
968+ }
969+
913970/*
914971 * Notify end of backup to PostgreSQL server.
915972 */
