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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
85 lines
2.4 KiB
Plaintext
85 lines
2.4 KiB
Plaintext
--source include/have_innodb.inc
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--source include/have_sequence.inc
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SET @saved_include_delete_marked = @@GLOBAL.innodb_stats_include_delete_marked;
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SET GLOBAL innodb_stats_include_delete_marked = ON;
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SET @saved_traditional = @@GLOBAL.innodb_stats_traditional;
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SET GLOBAL innodb_stats_traditional=false;
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SET @saved_modified_counter = @@GLOBAL.innodb_stats_modified_counter;
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SET GLOBAL innodb_stats_modified_counter=1;
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CREATE TABLE t1 (id SERIAL, val INT UNSIGNED NOT NULL, KEY(val))
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ENGINE=INNODB STATS_PERSISTENT=1,STATS_AUTO_RECALC=1;
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CREATE TABLE t2 LIKE t1;
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INSERT INTO t1 (val) SELECT 4 FROM seq_1_to_16;
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ANALYZE TABLE t1;
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connect(con1, localhost, root,,);
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START TRANSACTION;
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DELETE FROM t1;
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send SELECT COUNT(*) FROM t1;
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connection default;
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--echo # With innodb_stats_include_delete_marked=ON,
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--echo # DELETE must not affect statistics before COMMIT.
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EXPLAIN SELECT * FROM t1 WHERE val=4;
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connection con1;
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reap;
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ROLLBACK;
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SELECT COUNT(*) FROM t1;
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EXPLAIN SELECT * FROM t1 WHERE val=4;
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BEGIN;
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DELETE FROM t1;
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COMMIT;
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SELECT COUNT(*) FROM t1;
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connection default;
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BEGIN;
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INSERT INTO t2 (val) SELECT 4 FROM seq_1_to_16;
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--echo # The INSERT will show up before COMMIT.
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EXPLAIN SELECT * FROM t2 WHERE val=4;
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SELECT COUNT(*) FROM t2;
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--echo # The ROLLBACK of the INSERT must affect the statistics.
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ROLLBACK;
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SELECT COUNT(*) FROM t2;
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connection con1;
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EXPLAIN SELECT * FROM t2 WHERE val=4;
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--source include/wait_all_purged.inc
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--echo # After COMMIT and purge, the DELETE must show up.
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EXPLAIN SELECT * FROM t1 WHERE val=4;
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SET GLOBAL innodb_stats_include_delete_marked = OFF;
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BEGIN;
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INSERT INTO t1 (val) SELECT 4 FROM seq_1_to_16;
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EXPLAIN SELECT * FROM t1 WHERE val=4;
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ROLLBACK;
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EXPLAIN SELECT * FROM t1 WHERE val=4;
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BEGIN;
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INSERT INTO t1 (val) SELECT 4 FROM seq_1_to_16;
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COMMIT;
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EXPLAIN SELECT * FROM t1 WHERE val=4;
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BEGIN;
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DELETE FROM t1;
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SELECT COUNT(*) FROM t1;
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--echo # With innodb_stats_include_delete_marked=OFF,
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--echo # DELETE must affect statistics even before COMMIT.
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--echo # However, if there was a WHERE condition,
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--echo # ha_innobase::records_in_range() would count the delete-marked records.
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EXPLAIN SELECT * FROM t1;
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ROLLBACK;
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EXPLAIN SELECT * FROM t1;
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SELECT COUNT(*) FROM t1;
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disconnect con1;
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connection default;
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DROP TABLE t1,t2;
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SET GLOBAL innodb_stats_include_delete_marked = @saved_include_delete_marked;
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SET GLOBAL innodb_stats_traditional = @saved_traditional;
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SET GLOBAL innodb_stats_modified_counter = @saved_modified_counter;
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