c3p0 apparent deadlock / creating emergency threads
Posted by: Thomas Jajeh
Date: July 07, 2010 05:54AM

Hi Guys,

Exact errormessage is:

com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@7030f9f0 -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks! [com.mchange.v2.async.ThreadPoolAsynchronousRunner]


i found this thread here in this forum.. but it doenst seem to have a solution for the issue:
https://forum.hibernate.org/viewtopic.php?t=947246&highlight=apparent+deadlock+c3p0

I am still getting the errors under high load. Every few hours hour server is bringing up this error message. we are using:

hibernate-core-3.3.1.GA.jar
hibernate-c3p0-3.3.1.GA.jar
hibernate-3.2.6.ga.jar
c3p0-0.9.1.2.jar

i tried already to set max_statements to 0 and to a very high number 30.000 (because its only DB server - so it can take all the RAM)... both didnt work. any solutions on that?


my hibernate.properties look like this:
jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://***/***?useUnicode=true&characterEncoding=UTF-8
jdbc.username=***
jdbc.password=***

hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
hibernate.show_sql=false
hibernate.connection.charSet=utf8
hibernate.update.mode=update

hibernate.c3p0.minPoolSize=5
hibernate.c3p0.maxPoolSize=400
hibernate.c3p0.timeout=1000
hibernate.c3p0.max_statement=300

hibernate.cache.provider_class=org.hibernate.cache.EhCacheProvider
hibernate.cache.region_prefix=hibernate
hibernate.cache.use_second_level_cache=true
hibernate.cache.use_query_cache=true




My my.cfn looks like this:
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock

[mysqld_safe]
socket = /var/run/mysqld/mysqld.sock
nice = 0

[mysqld]
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
language = /usr/share/mysql/english
skip-external-locking

bind-address = 127.0.0.1

key_buffer = 16M
max_allowed_packet = 16M
thread_stack = 128K
thread_cache_size = 8
myisam-recover = BACKUP
max_connections = 30000
table_cache = 64
query_cache_limit = 1M
query_cache_size = 16M
log_slow_queries = /var/log/mysql/mysql-slow.log
long_query_time = 2

expire_logs_days = 10
max_binlog_size = 100M

[mysqldump]
quick
quote-names
max_allowed_packet = 16M

[isamchk]
key_buffer = 16M

!includedir /etc/mysql/conf.d/




Can anybody help?

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c3p0 apparent deadlock / creating emergency threads
July 07, 2010 05:54AM


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