database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-16 06:01:02 +03:00
Code Activity

Make DROP DATABASE command generate less WAL records.

Browse Source 
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
This commit is contained in:
Fujii Masao
2019-11-21 21:10:37 +09:00
parent 30840c92ac
commit e6d8069522
3 changed files with 59 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
src/include/commands/dbcommands_xlog.h
View File

@ -32,10 +32,11 @@ typedef struct xl_dbase_create_rec
typedef struct xl_dbase_drop_rec
{
/* Records dropping of a single subdirectory incl. contents */
Oid db_id;
Oid tablespace_id;
int ntablespaces; /* number of tablespace IDs */
Oid tablespace_ids[FLEXIBLE_ARRAY_MEMBER];
} xl_dbase_drop_rec;
#define MinSizeOfDbaseDropRec offsetof(xl_dbase_drop_rec, tablespace_ids)
extern void dbase_redo(XLogReaderState *rptr);
extern void dbase_desc(StringInfo buf, XLogReaderState *rptr);