Problem with using C3P0-0.9.1.jar package: apparent deadlock !!! Creating emergency threads for unassigned pending tasks!

Tomcat is running well. The boss said the server is down. Hurry and check it out...

It is still running, but an error is reported ......

A little problem. Restart tomcat. So... restart...

The problem of C3P0-0.9.1.jar package appeared:

16:15:57. 500 [COM. mchange. v2.c3p0. c3p0registry]-[info] initializing c3p0-0.9.1 [built 16-January-2007 14:46:42; debug? True; trace: 10] <br/> 16:15:57. 640 [COM. mchange. v2.c3p0. impl. abstractpoolbackeddatasource]-[info] initializing c3p0 pool... com. mchange. v2.c3p0. poolbackeddatasource @ 6e6ed172 [connectionpooldatasource-> COM. mchange. v2.c3p0. wrapperconnectionpooldatasource @ 68581fed [acquireincrement-> 3, acquireretryattempts-> 30, acquireretrydelay-> 1000, autocommitonclose-> false, automatictesttab Le-> null, breakafteracquirefailure-> false, checkouttimeout-> 0, connectioncustomizerclassname-> null, connectiontesterclassname-> COM. mchange. v2.c3p0. impl. defaultconnectiontester, debugunreturnedconnectionstacktraces-> false, factoryclasslocation-> null, Token-> false, identitytoken-> token | 9bb04a, idleconnectiontestperiod-> 0, initialpoolsiz E-> 20, latency-> 0, maxconnectionage-> 0, maxidletime-> 5000, maxidletimeexcessconnections-> 0, maxpoolsize-> 50, maxstatements-> 100, maxstatementsperconnection-> 0, minpoolsize-> 20, nesteddatasource-> COM. mchange. v2.c3p0. drivermanagerdatasource @ 96b27bd3 [description-> null, driverclass-> null, factoryclasslocation-> null, identitytoken-> 1bqc2na8gw1f1seoboglg | 1 5a6bd5, jdbcurl-> JDBC: oracle: thin: @ 172.7.19.70: 1521: orcl, properties-> {user = ******, password = ******, autocommit = false, release_mode = auto}], preferredtestquery-> null, propertycycle-> 0, testconnectiononcheckin-> false, testconnectiononcheckout-> false, allow-> 0, allow-> false; useroverrides :{}], datasourcename-> null, factoryclassloca Tion-> null, identitytoken-> 1bqc2na8gw1f1seoboglg | 730333, numhelperthreads-> 3] <br/> 16:16:17. 640 [COM. mchange. v2.async. threadpoolasynchronousrunner]-[warn] COM. mchange. v2.async. threadpoolasynchronousrunner $ deadlockdetector @ 689af4 -- apparent deadlock !!! Creating emergency threads for unassigned pending tasks! <Br/> 16:16:17. 640 [COM. mchange. v2.async. threadpoolasynchronousrunner]-[warn] com. mchange. v2.async. Handler $ deadlockdetector @ 689af4 -- apparent deadlock !!! Complete status: <br/> managed threads: 3 <br/> active threads: 3 <br/> active tasks: <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 13c6c41 (COM. mchange. v2.async. threadpoolasynchronousrunner $ poolthread-#0) <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 1e74f39 (COM. mchange. v2.async. threadpoolasynchronousrunner $ poolthread-#1) <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 1023cad (COM. mchange. v2.async. threadpoolasynchronousrunner $ poolthread-#2) <br/> pending tasks: <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 1dd8a94 <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 1b51005 <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 2ec051 <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 15422a8 <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ af4653 <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 1321f9b <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 1b8ffe1 <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ a738be <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 7e7592 <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 58d3e2 <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 1be9a9b <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 985ae9 <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 7890f2 <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 17418ba <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 10379d4 <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 1336fab <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask @ 1e85079 <br/> pool thread stack traces: <br/> thread [COM. mchange. v2.async. threadpoolasynchronousrunner $ poolthread-#0, 5, main] <br/> java.net. plainsocketimpl. socketconnect (native method) <br/> java.net. plainsocketimpl. doconnect (plainsocketimpl. java: 333) <br/> java.net. plainsocketimpl. connecttoaddress (plainsocketimpl. java: 195) <br/> java.net. plainsocketimpl. connect (plainsocketimpl. java: 182) <br/> java.net. sockssocketimpl. connect (sockssocketimpl. java: 366) <br/> java.net. socket. connect (socket. java: 525) <br/> java.net. socket. connect (socket. java: 475) <br/> java.net. socket. <init> (socket. java: 372) <br/> java.net. socket. <init> (socket. java: 186) <br/> oracle.net. NT. tcpntadapter. connect (unknown source) <br/> oracle.net. NT. connoption. connect (unknown source) <br/> oracle.net.nt.connstrategy.exe cute (unknown source) <br/> oracle.net. resolver. addrresolution. resolveandexecute (unknown source) <br/> oracle.net. NS. nsprotocol. establishconnection (unknown source) <br/> oracle.net. NS. nsprotocol. connect (unknown source) <br/> oracle. JDBC. driver. t4cconnection. connect (t4cconnection. java: 843) <br/> oracle. JDBC. driver. t4cconnection. logon (t4cconnection. java: 267) <br/> oracle. JDBC. driver. physicalconnection. <init> (physicalconnection. java: 413) <br/> oracle. JDBC. driver. t4cconnection. <init> (t4cconnection. java: 164) <br/> oracle. JDBC. driver. t4cdriverextension. getconnection (t4cdriverextension. java: 34) <br/> oracle. JDBC. driver. oracledriver. connect (oracledriver. java: 752) <br/> COM. mchange. v2.c3p0. drivermanagerdatasource. getconnection (drivermanagerdatasource. java: 135) <br/> COM. mchange. v2.c3p0. wrapperconnectionpooldatasource. getpooledconnection (wrapperconnectionpooldatasource. java: 182) <br/> COM. mchange. v2.c3p0. wrapperconnectionpooldatasource. getpooledconnection (wrapperconnectionpooldatasource. java: 171) <br/> COM. mchange. v2.c3p0. impl. c3p0pooledconnectionpool $ 1pooledconnectionresourcepoolmanager. acquireresource (c3p0pooledconnectionpool. java: 137) <br/> COM. mchange. v2.resourcepool. basicresourcepool. doacquire (basicresourcepool. java: 1014) <br/> COM. mchange. v2.resourcepool. basicresourcepool. access $800 (basicresourcepool. java: 32) <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask. run (basicresourcepool. java: 1810) <br/> COM. mchange. v2.async. threadpoolasynchronousrunner $ poolthread. run (threadpoolasynchronousrunner. java: 547) <br/> thread [COM. mchange. v2.async. threadpoolasynchronousrunner $ poolthread-#1, 5, main] <br/> java.net. plainsocketimpl. socketconnect (native method) <br/> java.net. plainsocketimpl. doconnect (plainsocketimpl. java: 333) <br/> java.net. plainsocketimpl. connecttoaddress (plainsocketimpl. java: 195) <br/> java.net. plainsocketimpl. connect (plainsocketimpl. java: 182) <br/> java.net. sockssocketimpl. connect (sockssocketimpl. java: 366) <br/> java.net. socket. connect (socket. java: 525) <br/> java.net. socket. connect (socket. java: 475) <br/> java.net. socket. <init> (socket. java: 372) <br/> java.net. socket. <init> (socket. java: 186) <br/> oracle.net. NT. tcpntadapter. connect (unknown source) <br/> oracle.net. NT. connoption. connect (unknown source) <br/> oracle.net.nt.connstrategy.exe cute (unknown source) <br/> oracle.net. resolver. addrresolution. resolveandexecute (unknown source) <br/> oracle.net. NS. nsprotocol. establishconnection (unknown source) <br/> oracle.net. NS. nsprotocol. connect (unknown source) <br/> oracle. JDBC. driver. t4cconnection. connect (t4cconnection. java: 843) <br/> oracle. JDBC. driver. t4cconnection. logon (t4cconnection. java: 267) <br/> oracle. JDBC. driver. physicalconnection. <init> (physicalconnection. java: 413) <br/> oracle. JDBC. driver. t4cconnection. <init> (t4cconnection. java: 164) <br/> oracle. JDBC. driver. t4cdriverextension. getconnection (t4cdriverextension. java: 34) <br/> oracle. JDBC. driver. oracledriver. connect (oracledriver. java: 752) <br/> COM. mchange. v2.c3p0. drivermanagerdatasource. getconnection (drivermanagerdatasource. java: 135) <br/> COM. mchange. v2.c3p0. wrapperconnectionpooldatasource. getpooledconnection (wrapperconnectionpooldatasource. java: 182) <br/> COM. mchange. v2.c3p0. wrapperconnectionpooldatasource. getpooledconnection (wrapperconnectionpooldatasource. java: 171) <br/> COM. mchange. v2.c3p0. impl. c3p0pooledconnectionpool $ 1pooledconnectionresourcepoolmanager. acquireresource (c3p0pooledconnectionpool. java: 137) <br/> COM. mchange. v2.resourcepool. basicresourcepool. doacquire (basicresourcepool. java: 1014) <br/> COM. mchange. v2.resourcepool. basicresourcepool. access $800 (basicresourcepool. java: 32) <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask. run (basicresourcepool. java: 1810) <br/> COM. mchange. v2.async. threadpoolasynchronousrunner $ poolthread. run (threadpoolasynchronousrunner. java: 547) <br/> thread [COM. mchange. v2.async. threadpoolasynchronousrunner $ poolthread-#2, 5, main] <br/> java.net. plainsocketimpl. socketconnect (native method) <br/> java.net. plainsocketimpl. doconnect (plainsocketimpl. java: 333) <br/> java.net. plainsocketimpl. connecttoaddress (plainsocketimpl. java: 195) <br/> java.net. plainsocketimpl. connect (plainsocketimpl. java: 182) <br/> java.net. sockssocketimpl. connect (sockssocketimpl. java: 366) <br/> java.net. socket. connect (socket. java: 525) <br/> java.net. socket. connect (socket. java: 475) <br/> java.net. socket. <init> (socket. java: 372) <br/> java.net. socket. <init> (socket. java: 186) <br/> oracle.net. NT. tcpntadapter. connect (unknown source) <br/> oracle.net. NT. connoption. connect (unknown source) <br/> oracle.net.nt.connstrategy.exe cute (unknown source) <br/> oracle.net. resolver. addrresolution. resolveandexecute (unknown source) <br/> oracle.net. NS. nsprotocol. establishconnection (unknown source) <br/> oracle.net. NS. nsprotocol. connect (unknown source) <br/> oracle. JDBC. driver. t4cconnection. connect (t4cconnection. java: 843) <br/> oracle. JDBC. driver. t4cconnection. logon (t4cconnection. java: 267) <br/> oracle. JDBC. driver. physicalconnection. <init> (physicalconnection. java: 413) <br/> oracle. JDBC. driver. t4cconnection. <init> (t4cconnection. java: 164) <br/> oracle. JDBC. driver. t4cdriverextension. getconnection (t4cdriverextension. java: 34) <br/> oracle. JDBC. driver. oracledriver. connect (oracledriver. java: 752) <br/> COM. mchange. v2.c3p0. drivermanagerdatasource. getconnection (drivermanagerdatasource. java: 135) <br/> COM. mchange. v2.c3p0. wrapperconnectionpooldatasource. getpooledconnection (wrapperconnectionpooldatasource. java: 182) <br/> COM. mchange. v2.c3p0. wrapperconnectionpooldatasource. getpooledconnection (wrapperconnectionpooldatasource. java: 171) <br/> COM. mchange. v2.c3p0. impl. c3p0pooledconnectionpool $ 1pooledconnectionresourcepoolmanager. acquireresource (c3p0pooledconnectionpool. java: 137) <br/> COM. mchange. v2.resourcepool. basicresourcepool. doacquire (basicresourcepool. java: 1014) <br/> COM. mchange. v2.resourcepool. basicresourcepool. access $800 (basicresourcepool. java: 32) <br/> COM. mchange. v2.resourcepool. basicresourcepool $ acquiretask. run (basicresourcepool. java: 1810) <br/> COM. mchange. v2.async. threadpoolasynchronousrunner $ poolthread. run (threadpoolasynchronousrunner. java: 547) </P> <p>

 

Reference relatively full calculation: http://japi.iteye.com/blog/243702

In the SSH project, set hibernate. c3p0. max_statements in hibernate. properties to 0 and restart tomcat.

 

This c3p0 bug exists and persists. The author seems powerless now and hopes someone can break through this bottleneck.

 

Another concern is that the original hibernate. c3p0. max_statements is 100. One of the uneasiness factors that become early after being changed to 0 is that the page cannot be accessed. This problem hasn't occurred yet. What if so? Why?