182 lines
7.5 KiB
Plaintext
182 lines
7.5 KiB
Plaintext
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flush status;
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set query_cache_type=DEMAND;
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set global query_cache_size= 1024*768;
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drop table if exists t1;
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create table t1 (a varchar(100));
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insert into t1 values ('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'),('bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb');
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Activate debug hook and attempt to retrieve the statement from the cache.
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set session debug='+d,wait_in_query_cache_insert';
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select SQL_CACHE * from t1;;
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On a second connection; clear the query cache.
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show status like 'Qcache_queries_in_cache';
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Variable_name Value
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Qcache_queries_in_cache 1
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set global query_cache_size= 0;
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Signal the debug hook to release the lock.
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select id from information_schema.processlist where state='wait_in_query_cache_insert' into @thread_id;
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kill query @thread_id;
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Show query cache status.
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show status like 'Qcache_queries_in_cache';
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Variable_name Value
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Qcache_queries_in_cache 0
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set global query_cache_size= 0;
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use test;
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drop table t1;
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SET @old_concurrent_insert= @@GLOBAL.concurrent_insert;
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SET @old_query_cache_size= @@GLOBAL.query_cache_size;
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DROP TABLE IF EXISTS t1, t2;
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CREATE TABLE t1 (a INT);
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CREATE TABLE t2 (a INT);
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INSERT INTO t1 VALUES (1),(2),(3);
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SET GLOBAL concurrent_insert= 1;
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SET GLOBAL query_cache_size= 1024*512;
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SET GLOBAL query_cache_type= ON;
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# Switch to connection con1
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SET SESSION debug='+d,wait_after_query_cache_invalidate';
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# Send concurrent insert, will wait in the query cache table invalidate
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INSERT INTO t1 VALUES (4);
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# Switch to connection default
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# Wait for concurrent insert to reach the debug point
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# Switch to connection con2
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# Send SELECT that shouldn't be cached
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SELECT * FROM t1;
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a
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1
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2
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3
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# Switch to connection default
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# Notify the concurrent insert to proceed
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SELECT ID FROM INFORMATION_SCHEMA.PROCESSLIST
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WHERE STATE = 'wait_after_query_cache_invalidate' INTO @thread_id;
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KILL QUERY @thread_id;
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# Switch to connection con1
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# Gather insert result
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SHOW STATUS LIKE "Qcache_queries_in_cache";
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Variable_name Value
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Qcache_queries_in_cache 0
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# Test that it's cacheable
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SELECT * FROM t1;
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a
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1
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2
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3
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4
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SHOW STATUS LIKE "Qcache_queries_in_cache";
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Variable_name Value
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Qcache_queries_in_cache 1
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# Disconnect
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# Restore defaults
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RESET QUERY CACHE;
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DROP TABLE t1,t2;
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SET GLOBAL concurrent_insert= DEFAULT;
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SET GLOBAL query_cache_size= DEFAULT;
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SET GLOBAL query_cache_type= DEFAULT;
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#
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# Bug43758 Query cache can lock up threads in 'freeing items' state
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#
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FLUSH STATUS;
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SET GLOBAL query_cache_type=DEMAND;
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SET GLOBAL query_cache_size= 1024*768;
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DROP TABLE IF EXISTS t1,t2,t3,t4,t5;
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CREATE TABLE t1 (a VARCHAR(100));
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CREATE TABLE t2 (a VARCHAR(100));
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CREATE TABLE t3 (a VARCHAR(100));
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CREATE TABLE t4 (a VARCHAR(100));
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CREATE TABLE t5 (a VARCHAR(100));
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INSERT INTO t1 VALUES ('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'),('bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb');
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INSERT INTO t2 VALUES ('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'),('bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb');
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INSERT INTO t3 VALUES ('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'),('bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb');
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INSERT INTO t4 VALUES ('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'),('bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb');
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INSERT INTO t5 VALUES ('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'),('bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb');
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=================================== Connection thd1
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**
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** Load Query Cache with a result set and one table.
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**
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SELECT SQL_CACHE * FROM t1;
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a
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aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
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bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
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*************************************************************************
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** We want to accomplish the following state:
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** - Query cache status: TABLE_FLUSH_IN_PROGRESS
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** - THD1: invalidate_table_internal (iterating query blocks)
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** - THD2: query_cache_insert (cond_wait)
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** - THD3: query_cache_insert (cond_wait)
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** - No thread should be holding the structure_guard_mutex.
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**
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** First step is to place a DELETE-statement on the debug hook just
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** before the mutex lock in invalidate_table_internal.
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** This will allow new result sets to be written into the QC.
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**
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SET SESSION debug='+d,wait_in_query_cache_invalidate1';
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SET SESSION debug='+d,wait_in_query_cache_invalidate2';
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DELETE FROM t1 WHERE a like '%a%';;
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=================================== Connection default
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** Assert that the expect process status is obtained.
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**
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=================================== Connection thd2
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** On THD2: Insert a result into the cache. This attempt will be blocked
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** because of a debug hook placed just before the mutex lock after which
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** the first part of the result set is written.
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SET SESSION debug='+d,wait_in_query_cache_insert';
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SELECT SQL_CACHE * FROM t2 UNION SELECT * FROM t3;
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=================================== Connection thd3
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** On THD3: Insert another result into the cache and block on the same
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** debug hook.
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SET SESSION debug='+d,wait_in_query_cache_insert';
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SELECT SQL_CACHE * FROM t4 UNION SELECT * FROM t5;;
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=================================== Connection default
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** Assert that the two SELECT-stmt threads to reach the hook.
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**
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**
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** Signal the DELETE thread, THD1, to continue. It will enter the mutex
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** lock and set query cache status to TABLE_FLUSH_IN_PROGRESS and then
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** unlock the mutex before stopping on the next debug hook.
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SELECT SQL_NO_CACHE id FROM information_schema.processlist WHERE state='wait_in_query_cache_invalidate1' LIMIT 1 INTO @flush_thread_id;
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KILL QUERY @flush_thread_id;
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** Assert that we reach the next debug hook.
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**
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** Signal the remaining debug hooks blocking THD2 and THD3.
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** The threads will grab the guard mutex enter the wait condition and
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** and finally release the mutex. The threads will continue to wait
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** until a broadcast signal reaches them causing both threads to
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** come alive and check the condition.
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SELECT SQL_NO_CACHE id FROM information_schema.processlist WHERE state='wait_in_query_cache_insert' ORDER BY id ASC LIMIT 1 INTO @thread_id;
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KILL QUERY @thread_id;
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SELECT SQL_NO_CACHE id FROM information_schema.processlist WHERE state='wait_in_query_cache_insert' ORDER BY id DESC LIMIT 1 INTO @thread_id;
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KILL QUERY @thread_id;
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**
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** Finally signal the DELETE statement on THD1 one last time.
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** The stmt will complete the query cache invalidation and return
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** cache status to NO_FLUSH_IN_PROGRESS. On the status change
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** One signal will be sent to the thread group waiting for executing
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** invalidations and a broadcast signal will be sent to the thread
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** group holding result set writers.
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SELECT SQL_NO_CACHE id FROM information_schema.processlist WHERE state='wait_in_query_cache_invalidate2' LIMIT 1 INTO @flush_thread_id;
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KILL QUERY @flush_thread_id;
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**
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*************************************************************************
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** No tables should be locked
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=================================== Connection thd2
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a
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aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
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bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
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DELETE FROM t1;
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DELETE FROM t2;
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DELETE FROM t3;
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=================================== Connection thd3
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a
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aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
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bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
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DELETE FROM t4;
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DELETE FROM t5;
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=================================== Connection thd1
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** Done.
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SET GLOBAL query_cache_size= 0;
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# Restore defaults
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RESET QUERY CACHE;
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FLUSH STATUS;
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DROP TABLE t1,t2,t3,t4,t5;
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SET GLOBAL query_cache_size= DEFAULT;
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SET GLOBAL query_cache_type= DEFAULT;
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