[JDBC-56] Problem with find-connection when using agents with c3p0 connection pool

Thu, 16 May 2013 04:50:41 -0500

I use an agent to offload email processing and update a db on completion. If I use a c3p0 connection pool, I get an exception and a complaint that the connection isn't open (see stacktrace). The code works if I wrap the agent fn in a clojure.java.jdbc/with-connection and get a connection from the pool in the agent thread.

The in jdbc.clj, the find-connection (db-find-connection in HEAD) checks for an existing connection and tries to use it without checking if it's open. This causes an exception with a c3p0 connection that was acquired in another thread.

Here's the stacktrace I'm seeing (note the "You can't operate on a closed Connection!!!"):

2013-05-16 10:32:22,208 [clojure-agent-send-off-pool-7] DEBUG com.mchange.v2.sql.SqlUtils - Converting Throwable to SQLException...
java.lang.NullPointerException
	at com.mchange.v2.c3p0.impl.NewProxyConnection.prepareStatement(NewProxyConnection.java:186)
	at clojure.java.jdbc$prepare_statement.doInvoke(jdbc.clj:450)
	at clojure.lang.RestFn.invoke(RestFn.java:425)
	at clojure.lang.AFn.applyToHelper(AFn.java:163)
	at clojure.lang.RestFn.applyTo(RestFn.java:132)
	at clojure.core$apply.invoke(core.clj:621)
	at clojure.java.jdbc$with_query_results_STAR_.invoke(jdbc.clj:646)
	at clj_record.core$find_by_sql$func__3362__auto____3378.invoke(core.clj:72)
	at clj_record.core$find_by_sql.invoke(core.clj:71)
	at clj_record.core$find_records.invoke(core.clj:85)
	at clj_record.core$find_record.invoke(core.clj:91)
	at neataudio.domain.interview_participant_relationship$find_record.invoke(interview_participant_relationship.clj:18)
	at neataudio.domain.interview_participant_relationship$update_email_status.invoke(interview_participant_relationship.clj:37)
	at neataudio.controllers.participant_controller$notify$fn__5113$fn__5114$func__3362__auto____5115$fn__5116.invoke(participant_controller.clj:104)
	at clojure.java.jdbc$transaction_STAR_$fn__3162.invoke(jdbc.clj:372)
	at clojure.java.jdbc$transaction_STAR_.invoke(jdbc.clj:371)
	at neataudio.controllers.participant_controller$notify$fn__5113$fn__5114$func__3362__auto____5115.invoke(participant_controller.clj:101)
	at neataudio.controllers.participant_controller$notify$fn__5113$fn__5114.invoke(participant_controller.clj:101)
	at neataudio.controllers.participant_controller$notify$fn__5113.invoke(participant_controller.clj:101)
	at clojure.lang.AFn.applyToHelper(AFn.java:185)
	at clojure.lang.AFn.applyTo(AFn.java:151)
	at clojure.core$apply.invoke(core.clj:623)
	at clojure.core$binding_conveyor_fn$fn__4115.doInvoke(core.clj:1848)
	at clojure.lang.RestFn.applyTo(RestFn.java:146)
	at clojure.lang.Agent$Action.doRun(Agent.java:114)
	at clojure.lang.Agent$Action.run(Agent.java:163)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
	at java.lang.Thread.run(Thread.java:680)
java.sql.SQLException: You can't operate on a closed Connection!!!
	at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
	at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:65)
	at com.mchange.v2.c3p0.impl.NewProxyConnection.prepareStatement(NewProxyConnection.java:222)
	at clojure.java.jdbc$prepare_statement.doInvoke(jdbc.clj:450)
	at clojure.lang.RestFn.invoke(RestFn.java:425)
	at clojure.lang.AFn.applyToHelper(AFn.java:163)
	at clojure.lang.RestFn.applyTo(RestFn.java:132)
	at clojure.core$apply.invoke(core.clj:621)
	at clojure.java.jdbc$with_query_results_STAR_.invoke(jdbc.clj:646)
	at clj_record.core$find_by_sql$func__3362__auto____3378.invoke(core.clj:72)
	at clj_record.core$find_by_sql.invoke(core.clj:71)
	at clj_record.core$find_records.invoke(core.clj:85)
	at clj_record.core$find_record.invoke(core.clj:91)
	at neataudio.domain.interview_participant_relationship$find_record.invoke(interview_participant_relationship.clj:18)
	at neataudio.domain.interview_participant_relationship$update_email_status.invoke(interview_participant_relationship.clj:37)
	at neataudio.controllers.participant_controller$notify$fn__5113$fn__5114$func__3362__auto____5115$fn__5116.invoke(participant_controller.clj:104)
	at clojure.java.jdbc$transaction_STAR_$fn__3162.invoke(jdbc.clj:372)
	at clojure.java.jdbc$transaction_STAR_.invoke(jdbc.clj:371)
	at neataudio.controllers.participant_controller$notify$fn__5113$fn__5114$func__3362__auto____5115.invoke(participant_controller.clj:101)
	at neataudio.controllers.participant_controller$notify$fn__5113$fn__5114.invoke(participant_controller.clj:101)
	at neataudio.controllers.participant_controller$notify$fn__5113.invoke(participant_controller.clj:101)
	at clojure.lang.AFn.applyToHelper(AFn.java:185)
	at clojure.lang.AFn.applyTo(AFn.java:151)
	at clojure.core$apply.invoke(core.clj:623)
	at clojure.core$binding_conveyor_fn$fn__4115.doInvoke(core.clj:1848)
	at clojure.lang.RestFn.applyTo(RestFn.java:146)
	at clojure.lang.Agent$Action.doRun(Agent.java:114)
	at clojure.lang.Agent$Action.run(Agent.java:163)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
	at java.lang.Thread.run(Thread.java:680)
Caused by: java.lang.NullPointerException
	at com.mchange.v2.c3p0.impl.NewProxyConnection.prepareStatement(NewProxyConnection.java:186)
	... 28 more

[JDBC-1] Provide option to return SQL generated / execution stats

Sun, 8 May 2011 21:12:52 -0500

Shantanu: Provide a mechanism to show the SQL being executed (configurable, so that it can be turned off)

Sean: Good idea. Even better, a way to access statistics about the prepared statement after execution - timing etc?

Shantanu: Yes, that would be an add-on value to show how are the queries performing.

Clojure JIRA

[JDBC-56] Problem with find-connection when using agents with c3p0 connection pool

[JDBC-1] Provide option to return SQL generated / execution stats