Мы столкнулись с ЯВНОЙ ТУПИЧНОЙ БЛОКИРОВКОЙ при использовании c3p0 0.9.5.1 (последняя версия c3p0). Ниже приведена конфигурация пула соединений, которую мы используем.
p:driverClass="${app.jdbc.driverClassReplica}"
p:jdbcUrl="jdbc:mysql://database,database/dbname"
p:acquireIncrement="5"
p:idleConnectionTestPeriod="300"
p:maxPoolSize="100"
p:maxStatements="2000"
p:minPoolSize="10"
p:maxIdleTime="1800"
p:maxConnectionAge="3600"
p:maxIdleTimeExcessConnections="20"
p:numHelperThreads="15"
p:preferredTestQuery="SELECT 1"/>
и следующие журналы
ThreadPoolAsynchronousRunner:743---- com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@70f6e5f5 -- A
PPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks! #]
2015-06-20 11:36:15 WARN ThreadPoolAsynchronousRunner:759---- com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@70f6e5f5 -- A
PPARENT DEADLOCK!!! Complete Status:
Managed Threads: 15
Active Threads: 15
Active Tasks:
Каждая активная задача выглядит как
com.mchange.v2.c3p0.stmt.GooGooStatementCache$StatementDestructionManager$1UncheckedStatementCloseTask@4ec69595
on thread: C3P0PooledConnectionPoolManager[identityToken->z8kflt9a33udv812q4fqf|60dffe1d]-HelperThread-#6
Незавершенные задачи:
com.mchange.v2.c3p0.stmt.GooGooStatementCache$StatementDestructionManager$1UncheckedStatementCloseTask@2b131ea8
com.mchange.v2.c3p0.stmt.GooGooStatementCache$StatementDestructionManager$1UncheckedStatementCloseTask@7441bdaf
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@80c67ca
com.mchange.v2.c3p0.stmt.GooGooStatementCache$StatementDestructionManager$1UncheckedStatementCloseTask@667202e6
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@471c7e95
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@1fba8cac
com.mchange.v2.c3p0.stmt.GooGooStatementCache$StatementDestructionManager$1UncheckedStatementCloseTask@1069807a
com.mchange.v2.c3p0.stmt.GooGooStatementCache$StatementDestructionManager$1UncheckedStatementCloseTask@7e71d200
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@62923eda
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@6f5c8cc4
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@251dd0fa
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@4882e01f
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@848386a
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@3d6fbb65
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@72780365
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@25271699
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@293ca9dd
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@4db40151
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@64c294b1
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@22b02425
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@5a150aed
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@1b807bcf
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@10406124
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@72a98ad1
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@58d8da26
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@2a013697
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@35a7090c
com.mchange.v2.c3p0.stmt.GooGooStatementCache$StatementDestructionManager$1UncheckedStatementCloseTask@69430e58
com.mchange.v2.c3p0.stmt.GooGooStatementCache$StatementDestructionManager$1UncheckedStatementCloseTask@3162e965
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@54c8ff37
com.mchange.v2.c3p0.stmt.GooGooStatementCache$StatementDestructionManager$1UncheckedStatementCloseTask@57eb9f5d
Трассировки стека потоков пула: все 15 потоков выглядят следующим образом
Thread[C3P0PooledConnectionPoolManager[identityToken->z8kflt9a33udv812q4fqf|60dffe1d]-HelperThread-#6,5,main]
com.mysql.jdbc.StatementImpl.close(StatementImpl.java:575)
com.mchange.v1.db.sql.StatementUtils.attemptClose(StatementUtils.java:53)
com.mchange.v2.c3p0.stmt.GooGooStatementCache$StatementDestructionManager$1UncheckedStatementCloseTask.run(GooGooStatementCache.java:938)
Всякий раз, когда это происходит, db перестает отвечать на запросы на некоторое время, а количество подключений увеличивается до db. Это проблема с c3p0 ?? Поможет ли переход на другой пул jdbc, такой как hikaricp или boncecp?
