From d75d8631ed2d6af730931ea7079ec7e512e61796 Mon Sep 17 00:00:00 2001 From: Monty Date: Fri, 20 Jan 2017 15:33:28 +0200 Subject: [MDEV-10570] Add Flashback support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ==== Description ==== Flashback can rollback the instances/databases/tables to an old snapshot. It's implement on Server-Level by full image format binary logs (--binlog-row-image=FULL), so it supports all engines. Currently, it’s a feature inside mysqlbinlog tool (with --flashback arguments). Because the flashback binlog events will store in the memory, you should check if there is enough memory in your machine. ==== New Arguments to mysqlbinlog ==== --flashback (-B) It will let mysqlbinlog to work on FLASHBACK mode. ==== New Arguments to mysqld ==== --flashback Setup the server to use flashback. This enables binary log in row mode and will enable extra logging for DDL's needed by flashback feature ==== Example ==== I have a table "t" in database "test", we can compare the output with "--flashback" and without. #client/mysqlbinlog /data/mysqldata_10.0/binlog/mysql-bin.000001 -vv -d test -T t --start-datetime="2013-03-27 14:54:00" > /tmp/1.sql #client/mysqlbinlog /data/mysqldata_10.0/binlog/mysql-bin.000001 -vv -d test -T t --start-datetime="2013-03-27 14:54:00" -B > /tmp/2.sql Then, importing the output flashback file (/tmp/2.log), it can flashback your database/table to the special time (--start-datetime). And if you know the exact postion, "--start-postion" is also works, mysqlbinlog will output the flashback logs that can flashback to "--start-postion" position. ==== Implement ==== 1. As we know, if binlog_format is ROW (binlog-row-image=FULL in 10.1 and later), all columns value are store in the row event, so we can get the data before mis-operation. 2. Just do following things: 2.1 Change Event Type, INSERT->DELETE, DELETE->INSERT. For example: INSERT INTO t VALUES (...) ---> DELETE FROM t WHERE ... DELETE FROM t ... ---> INSERT INTO t VALUES (...) 2.2 For Update_Event, swapping the SET part and WHERE part. For example: UPDATE t SET cols1 = vals1 WHERE cols2 = vals2 ---> UPDATE t SET cols2 = vals2 WHERE cols1 = vals1 2.3 For Multi-Rows Event, reverse the rows sequence, from the last row to the first row. For example: DELETE FROM t WHERE id=1; DELETE FROM t WHERE id=2; ...; DELETE FROM t WHERE id=n; ---> DELETE FROM t WHERE id=n; ...; DELETE FROM t WHERE id=2; DELETE FROM t WHERE id=1; 2.4 Output those events from the last one to the first one which mis-operation happened. For example: --- client/client_priv.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'client/client_priv.h') diff --git a/client/client_priv.h b/client/client_priv.h index 1d85791fa73..e96e187fb34 100644 --- a/client/client_priv.h +++ b/client/client_priv.h @@ -66,6 +66,10 @@ enum options_client OPT_MYSQLDUMP_SLAVE_APPLY, OPT_MYSQLDUMP_SLAVE_DATA, OPT_MYSQLDUMP_INCLUDE_MASTER_HOST_PORT, +#ifdef WHEN_FLASHBACK_REVIEW_READY + OPT_REVIEW, + OPT_REVIEW_DBNAME, OPT_REVIEW_TABLENAME, +#endif OPT_SLAP_CSV, OPT_SLAP_CREATE_STRING, OPT_SLAP_AUTO_GENERATE_SQL_LOAD_TYPE, OPT_SLAP_AUTO_GENERATE_WRITE_NUM, OPT_SLAP_AUTO_GENERATE_ADD_AUTO, -- cgit v1.2.1