[Mondrian] RE: Time out waiting for Idle object UPDATE

Julian Hyde jhyde at pentaho.com
Fri Jan 1 15:54:18 EST 2010


> Benny Chow wrote:
>
> Have you ever ran into issues with Mondrian not closing its JDBC
connection?
> This is the first time I have seen Mondrian exhaust its connection pool.


 

Mondrian is very good at returning connections to the pool under all
circumstances -- regardless whether SQL statements succeed or fail. So a
'connection leak' is unlikely. But nothing is impossible.
 
One case that it would use a lot of open connections is if the statements
are still running and you are not using a connection pool. (Mondrian
sometimes adds a connection pool anyway. See PoolNeeded in
RolapConnectionProperties.)
 
If you are using a JDBC connection pool, the pool will hold a number of
connections open (depending on how you configure the pool). If you say tell
it to keep 30 connections open and the database (or some lower-level pool)
is only good for say 20, then the system will hang when you open connection
#21. I've seen this in the field.
 
Cc mondrian dev because someone else may have seen this issue.
 
Julian
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