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| author | Fujii Masao <fujii@postgresql.org> | 2019-11-21 21:10:37 +0900 |
|---|---|---|
| committer | Fujii Masao <fujii@postgresql.org> | 2019-11-21 21:10:37 +0900 |
| commit | e6d8069522c8bde8239dd1fedfb4984efa4b3a1a (patch) | |
| tree | b0d38edfd892bdd52f3086616c36d1bce5d350ab /src/backend/access/rmgrdesc/dbasedesc.c | |
| parent | 30840c92ac0c4073fb7bc8222317630571b8cf25 (diff) | |
| download | postgresql-e6d8069522c8bde8239dd1fedfb4984efa4b3a1a.tar.gz postgresql-e6d8069522c8bde8239dd1fedfb4984efa4b3a1a.zip | |
Make DROP DATABASE command generate less WAL records.
Previously DROP DATABASE generated as many XLOG_DBASE_DROP WAL records
as the number of tablespaces that the database to drop uses. This caused
the scans of shared_buffers as many times as the number of the tablespaces
during recovery because WAL replay of one XLOG_DBASE_DROP record needs
that full scan. This could make the recovery time longer especially
when shared_buffers is large.
This commit changes DROP DATABASE so that it generates only one
XLOG_DBASE_DROP record, and registers the information of all the tablespaces
into it. Then, WAL replay of XLOG_DBASE_DROP record needs full scan of
shared_buffers only once, and which may improve the recovery performance.
Author: Fujii Masao
Reviewed-by: Kirk Jamison, Simon Riggs
Discussion: https://postgr.es/m/CAHGQGwF8YwNH0ZaL+2wjZPkj+ji9UhC+Z4ScnG97WKtVY5L9iw@mail.gmail.com
Diffstat (limited to 'src/backend/access/rmgrdesc/dbasedesc.c')
| -rw-r--r-- | src/backend/access/rmgrdesc/dbasedesc.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/src/backend/access/rmgrdesc/dbasedesc.c b/src/backend/access/rmgrdesc/dbasedesc.c index c7d60ce10d6..d08c5758729 100644 --- a/src/backend/access/rmgrdesc/dbasedesc.c +++ b/src/backend/access/rmgrdesc/dbasedesc.c @@ -35,9 +35,12 @@ dbase_desc(StringInfo buf, XLogReaderState *record) else if (info == XLOG_DBASE_DROP) { xl_dbase_drop_rec *xlrec = (xl_dbase_drop_rec *) rec; + int i; - appendStringInfo(buf, "dir %u/%u", - xlrec->tablespace_id, xlrec->db_id); + appendStringInfo(buf, "dir"); + for (i = 0; i < xlrec->ntablespaces; i++) + appendStringInfo(buf, " %u/%u", + xlrec->tablespace_ids[i], xlrec->db_id); } } |