From 499c9b1266395c5e4c22bd7b2cbdb7f5a64ea4fa Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Sat, 18 Sep 2021 10:42:13 +0900 Subject: [PATCH] Improve some check logic in pg_receivewal The following things are improved: - Fetch the system identifier from the source server before any WAL streaming loop. This triggers extra checks to make sure that pg_receivewal is still connected to a server with the same system ID with a correct timeline. - Switch umask() (for file creation mode mask) and RetrieveWalSegSize() (to fetch the size of WAL segments) a bit later before the initial stream attempt. If the connection was done with a database, pg_receivewal would fail but those commands were still executed, which was a waste. The slot creation and drop are now done before retrieving the segment size. Author: Bharath Rupireddy Reviewed-by: Ronan Dunklau, Michael Paquier Discussion: https://postgr.es/m/CALj2ACX00YYeyBfoi55Cy=NrP-FcfMgiYYx1qRUEib3yjCVoaA@mail.gmail.com --- src/bin/pg_basebackup/pg_receivewal.c | 33 +++++++++++++++------------ 1 file changed, 18 insertions(+), 15 deletions(-) diff --git a/src/bin/pg_basebackup/pg_receivewal.c b/src/bin/pg_basebackup/pg_receivewal.c index 9d1843728d..d5140a79fe 100644 --- a/src/bin/pg_basebackup/pg_receivewal.c +++ b/src/bin/pg_basebackup/pg_receivewal.c @@ -372,6 +372,7 @@ StreamLog(void) XLogRecPtr serverpos; TimeLineID servertli; StreamCtl stream; + char *sysidentifier; MemSet(&stream, 0, sizeof(stream)); @@ -399,7 +400,7 @@ StreamLog(void) * at the same time, necessary if not valid data can be found in the * existing output directory. */ - if (!RunIdentifySystem(conn, NULL, &servertli, &serverpos, NULL)) + if (!RunIdentifySystem(conn, &sysidentifier, &servertli, &serverpos, NULL)) exit(1); /* @@ -435,6 +436,7 @@ StreamLog(void) stream.do_sync); stream.partial_suffix = ".partial"; stream.replication_slot = replication_slot; + stream.sysidentifier = sysidentifier; ReceiveXlogStream(conn, &stream); @@ -449,6 +451,7 @@ StreamLog(void) FreeWalDirectoryMethod(); pg_free(stream.walmethod); + pg_free(stream.sysidentifier); } /* @@ -687,20 +690,6 @@ main(int argc, char **argv) if (!RunIdentifySystem(conn, NULL, NULL, NULL, &db_name)) exit(1); - /* - * Set umask so that directories/files are created with the same - * permissions as directories/files in the source data directory. - * - * pg_mode_mask is set to owner-only by default and then updated in - * GetConnection() where we get the mode from the server-side with - * RetrieveDataDirCreatePerm() and then call SetDataDirectoryCreatePerm(). - */ - umask(pg_mode_mask); - - /* determine remote server's xlog segment size */ - if (!RetrieveWalSegSize(conn)) - exit(1); - /* * Check that there is a database associated with connection, none should * be defined in this context. @@ -712,6 +701,16 @@ main(int argc, char **argv) exit(1); } + /* + * Set umask so that directories/files are created with the same + * permissions as directories/files in the source data directory. + * + * pg_mode_mask is set to owner-only by default and then updated in + * GetConnection() where we get the mode from the server-side with + * RetrieveDataDirCreatePerm() and then call SetDataDirectoryCreatePerm(). + */ + umask(pg_mode_mask); + /* * Drop a replication slot. */ @@ -737,6 +736,10 @@ main(int argc, char **argv) exit(0); } + /* determine remote server's xlog segment size */ + if (!RetrieveWalSegSize(conn)) + exit(1); + /* * Don't close the connection here so that subsequent StreamLog() can * reuse it. -- 2.39.5