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Problem: ======= There are two issues that are addressed in this patch: 1) SHOW BINARY LOGS uses caching to store the binary logs that exist in the log directory; however, if new events are written to the logs, the caching strategy is unaware. This is okay for users, as it is okay for SHOW to return slightly old data. The test, however, can result in inconsistent data. It runs two connections concurrently, where one shows the logs, and the other adds a new file. The output of SHOW BINARY LOGS then depends on when the cache is built, with respect to the time that the second connection rotates the logs. 2) There is a race condition between RESET MASTER and SHOW BINARY LOGS. More specifically, where they both need the binary log lock to begin, SHOW BINARY LOGS only needs the lock to build its cache. If RESET MASTER is issued after SHOW BINARY LOGS has built its cache and before it has returned the results, the presented data may be incorrect. Solution: ======== 1) As it is okay for users to see stale data, to make the test consistent, use DEBUG_SYNC to force the race condition (problem 2) to make SHOW BINARY LOGS build a cache before RESET MASTER is called. Then, use additional logic from the next part of the solution to rebuild the cache. 2) Use an Atomic_counter to keep track of the number of times RESET MASTER has been called. If the value of the counter changes after building the cache, the cache should be rebuilt and the analysis should be restarted. Reviewed By: ============ Andrei Elkin: <andrei.elkin@mariadb.com>
29 lines
821 B
Text
29 lines
821 B
Text
--source include/have_debug.inc
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--source include/have_debug_sync.inc
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# mere to limit it run rate
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--source include/have_binlog_format_row.inc
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connect(con1,localhost,root,,);
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FLUSH LOGS;
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FLUSH LOGS;
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FLUSH LOGS;
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# This forced synchronization pattern ensures con1 will execute its retry
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# path. More specifically, con1 should see that the cache of log files it
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# creates during SHOW BINARY LOGS becomes invalidated after con2 completes
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# RESET MASTER.
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SET DEBUG_SYNC= "at_after_lock_index SIGNAL con1_ready WAIT_FOR con1_go";
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--send SHOW BINARY LOGS
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connect(con2,localhost,root,,);
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SET DEBUG_SYNC= "now WAIT_FOR con1_ready";
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RESET MASTER;
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FLUSH LOGS;
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SET DEBUG_SYNC= "now SIGNAL con1_go";
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--connection con1
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--echo # The correct result must consists of two records
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--replace_column 2 #
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--reap
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SET debug_sync = 'reset';
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