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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
43 lines
1.1 KiB
Text
43 lines
1.1 KiB
Text
--source include/have_innodb.inc
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--source include/have_sequence.inc
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--source include/have_debug.inc
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--source include/have_debug_sync.inc
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CREATE TABLE t1(id INT PRIMARY key, val VARCHAR(16000))
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ENGINE=InnoDB STATS_PERSISTENT=0;
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INSERT INTO t1 (id,val) SELECT 2*seq,'x' FROM seq_0_to_1023;
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connect(con1,localhost,root,,);
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source include/wait_all_purged.inc;
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# Prevent purge.
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START TRANSACTION WITH CONSISTENT SNAPSHOT;
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connection default;
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DELETE FROM t1 WHERE id=1788;
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SET @saved_dbug = @@GLOBAL.debug_dbug;
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SET @@GLOBAL.debug_dbug="d,enable_row_purge_del_mark_exit_sync_point";
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BEGIN;
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# This will return no result, but should acquire a gap lock.
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SELECT * FROM t1 WHERE id=1788 FOR UPDATE;
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connection con1;
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COMMIT;
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SET DEBUG_SYNC = 'now WAIT_FOR row_purge_del_mark_finished';
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SET @@GLOBAL.debug_dbug = @saved_dbug;
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connection default;
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INSERT INTO t1 (id,val) VALUES (1787, REPEAT('x',2000));
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connection con1;
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SET innodb_lock_wait_timeout=0;
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--error ER_LOCK_WAIT_TIMEOUT
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INSERT INTO t1 (id,val) VALUES (1788, 'x');
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SELECT * FROM t1 WHERE id=1788 FOR UPDATE;
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disconnect con1;
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connection default;
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COMMIT;
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DROP TABLE t1;
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