mirror of
https://github.com/MariaDB/server.git
synced 2025-01-30 18:41:56 +01:00
14685b10df
The motivation of introducing the parameter innodb_purge_rseg_truncate_frequency in mysql/mysql-server@28bbd66ea5 and mysql/mysql-server@8fc2120fed seems to have been to avoid stalls due to freeing undo log pages or truncating undo log tablespaces. In MariaDB Server, innodb_undo_log_truncate=ON should be a much lighter operation than in MySQL, because it will not involve any log checkpoint. Another source of performance stalls should be trx_purge_truncate_rseg_history(), which is shrinking the history list by freeing the undo log pages whose undo records have been purged. To alleviate that, we will introduce a purge_truncation_task that will offload this from the purge_coordinator_task. In that way, the next innodb_purge_batch_size pages may be parsed and purged while the pages from the previous batch are being freed and the history list being shrunk. The processing of innodb_undo_log_truncate=ON will still remain the responsibility of the purge_coordinator_task. purge_coordinator_state::count: Remove. We will ignore innodb_purge_rseg_truncate_frequency, and act as if it had been set to 1 (the maximum shrinking frequency). purge_coordinator_state::do_purge(): Invoke an asynchronous task purge_truncation_callback() to free the undo log pages. purge_sys_t::iterator::free_history(): Free those undo log pages that have been processed. This used to be a part of trx_purge_truncate_history(). purge_sys_t::clone_end_view(): Take a new value of purge_sys.head as a parameter, so that it will be updated while holding exclusive purge_sys.latch. This is needed for race-free access to the field in purge_truncation_callback(). Reviewed by: Vladislav Lesin
29 lines
950 B
Text
29 lines
950 B
Text
CREATE TABLE t1(id INT PRIMARY key, val VARCHAR(16000))
|
|
ENGINE=InnoDB STATS_PERSISTENT=0;
|
|
INSERT INTO t1 (id,val) SELECT 2*seq,'x' FROM seq_0_to_1023;
|
|
connect con1,localhost,root,,;
|
|
InnoDB 0 transactions not purged
|
|
START TRANSACTION WITH CONSISTENT SNAPSHOT;
|
|
connection default;
|
|
DELETE FROM t1 WHERE id=1788;
|
|
SET @saved_dbug = @@GLOBAL.debug_dbug;
|
|
SET @@GLOBAL.debug_dbug="d,enable_row_purge_del_mark_exit_sync_point";
|
|
BEGIN;
|
|
SELECT * FROM t1 WHERE id=1788 FOR UPDATE;
|
|
id val
|
|
connection con1;
|
|
COMMIT;
|
|
SET DEBUG_SYNC = 'now WAIT_FOR row_purge_del_mark_finished';
|
|
SET @@GLOBAL.debug_dbug = @saved_dbug;
|
|
connection default;
|
|
INSERT INTO t1 (id,val) VALUES (1787, REPEAT('x',2000));
|
|
connection con1;
|
|
SET innodb_lock_wait_timeout=0;
|
|
INSERT INTO t1 (id,val) VALUES (1788, 'x');
|
|
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
|
|
SELECT * FROM t1 WHERE id=1788 FOR UPDATE;
|
|
id val
|
|
disconnect con1;
|
|
connection default;
|
|
COMMIT;
|
|
DROP TABLE t1;
|