Re: SQL query never ends

This sort of behavior often indicates some kind of unsafe concurrent
usage of the JDBC Connection.  Is this running in a multi-threaded
environment?  If so, are there measures in place to ensure that only one
thread uses the connection at a time?

It would also be useful if you could do a thread dump while it's hanging
and send a stack trace of the affected thread.

-- Mark

On Wed, 2006-08-09 at 10:21 +0000, James Im wrote:
> I'm experimenting a random problem on my PC. Sometimes a sql query
> executed with Statement never returns. The code is blocked at a line
> like this one:
>
> rs = stmt.executeQuery("select true");
>
> The query is not important: it fails with any type of query, at random,
> even with the one above.
>
> I never get an exception.
>
> Now the logs. I've enable logging at the database level and I have set
> "statement_timeout = 3000". I have searched for the query in
> postgresql's log but I cannot find the query which is blocking in my
> java code so I guess that it means that the query never reached postgresql.
>
> I've enabled jdbc logging with "loglevel=2" and this is what I get:
>
> simple execute,
> handler=org.postgresql.jdbc2.AbstractJdbc2Statement$StatementResultHandler@996cca,
> maxRows=0, fetchSize=0, flags=17
> FE=> Parse(stmt=null,query="i've remove the select query",oids={})
> FE=> Bind(stmt=null,portal=null)
> FE=> Describe(portal=null)
> FE=> Execute(portal=null,limit=0)
> FE=> Sync
>
> .. and nothing else. No "<=BE ..." follow the " FE=> Sync" log entry.
>
>
> I've also tried to put "stmt.setQueryTimeout(3);" but it doesn't seem to
> do anything.
>
> I'm using postgresql 8.1.4 on Windows 2000 Pro SP4 and the driver      is
> "8.1-407 JDBC 3". I'm also using java 1.5.0_06-b05.
>
>
> I guess that there is a bug in the driver. If I'm wrong, please tell me
> how to solve it. If I'm right, could you try to fix it?
>
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