From c3fe108c025e4a080315562d4c15ecbe3f00405e Mon Sep 17 00:00:00 2001 From: Fujii Masao Date: Mon, 20 Jul 2020 13:30:18 +0900 Subject: Rename wal_keep_segments to wal_keep_size. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit max_slot_wal_keep_size that was added in v13 and wal_keep_segments are the GUC parameters to specify how much WAL files to retain for the standby servers. While max_slot_wal_keep_size accepts the number of bytes of WAL files, wal_keep_segments accepts the number of WAL files. This difference of setting units between those similar parameters could be confusing to users. To alleviate this situation, this commit renames wal_keep_segments to wal_keep_size, and make users specify the WAL size in it instead of the number of WAL files. There was also the idea to rename max_slot_wal_keep_size to max_slot_wal_keep_segments, in the discussion. But we have been moving away from measuring in segments, for example, checkpoint_segments was replaced by max_wal_size. So we concluded to rename wal_keep_segments to wal_keep_size. Back-patch to v13 where max_slot_wal_keep_size was added. Author: Fujii Masao Reviewed-by: Álvaro Herrera, Kyotaro Horiguchi, David Steele Discussion: https://postgr.es/m/574b4ea3-e0f9-b175-ead2-ebea7faea855@oss.nttdata.com --- src/backend/access/transam/xlog.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) (limited to 'src/backend/access/transam/xlog.c') diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 0a97b1d37fb..184c6672f3b 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -88,7 +88,7 @@ extern uint32 bootstrap_data_checksum_version; /* User-settable parameters */ int max_wal_size_mb = 1024; /* 1 GB */ int min_wal_size_mb = 80; /* 80 MB */ -int wal_keep_segments = 0; +int wal_keep_size_mb = 0; int XLOGbuffers = -1; int XLogArchiveTimeout = 0; int XLogArchiveMode = ARCHIVE_MODE_OFF; @@ -9525,7 +9525,7 @@ GetWALAvailability(XLogRecPtr targetLSN) /* * Calculate the oldest segment currently reserved by all slots, - * considering wal_keep_segments and max_slot_wal_keep_size. Initialize + * considering wal_keep_size and max_slot_wal_keep_size. Initialize * oldestSlotSeg to the current segment. */ currpos = GetXLogWriteRecPtr(); @@ -9576,9 +9576,9 @@ GetWALAvailability(XLogRecPtr targetLSN) /* * Retreat *logSegNo to the last segment that we need to retain because of - * either wal_keep_segments or replication slots. + * either wal_keep_size or replication slots. * - * This is calculated by subtracting wal_keep_segments from the given xlog + * This is calculated by subtracting wal_keep_size from the given xlog * location, recptr and by making sure that that result is below the * requirement of replication slots. For the latter criterion we do consider * the effects of max_slot_wal_keep_size: reserve at most that much space back @@ -9616,14 +9616,20 @@ KeepLogSeg(XLogRecPtr recptr, XLogSegNo *logSegNo) } } - /* but, keep at least wal_keep_segments if that's set */ - if (wal_keep_segments > 0 && currSegNo - segno < wal_keep_segments) + /* but, keep at least wal_keep_size if that's set */ + if (wal_keep_size_mb > 0) { - /* avoid underflow, don't go below 1 */ - if (currSegNo <= wal_keep_segments) - segno = 1; - else - segno = currSegNo - wal_keep_segments; + uint64 keep_segs; + + keep_segs = ConvertToXSegs(wal_keep_size_mb, wal_segment_size); + if (currSegNo - segno < keep_segs) + { + /* avoid underflow, don't go below 1 */ + if (currSegNo <= keep_segs) + segno = 1; + else + segno = currSegNo - keep_segs; + } } /* don't delete WAL segments newer than the calculated segment */ @@ -11328,7 +11334,7 @@ do_pg_stop_backup(char *labelfile, bool waitforarchive, TimeLineID *stoptli_p) * If archiving is enabled, wait for all the required WAL files to be * archived before returning. If archiving isn't enabled, the required WAL * needs to be transported via streaming replication (hopefully with - * wal_keep_segments set high enough), or some more exotic mechanism like + * wal_keep_size set high enough), or some more exotic mechanism like * polling and copying files from pg_wal with script. We have no knowledge * of those mechanisms, so it's up to the user to ensure that he gets all * the required WAL. -- cgit v1.2.3