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Rick Shaw edited comment on CASSANDRA-3244 at 9/23/11 2:04 PM:
---------------------------------------------------------------
Creating a {{Statement}} every time you need one is unnecessary but not
illegal. The assumption is the {{Statement}} is closed when Spring is done,
which should be just fine. The problem is the list in {{Connection}} _should_
be a list of open {{Statements}}. The implication being that closing a
{{Statement}} removes itself from that list. Unfortunately this is not being
done.
The list is necessary. But it needs to be maintained by {{Statement}} because
only it knows when it is asked to close.
As a note this has nothing to do with pooling. The JDBC driver pooling
({{PooledConnection}}) will handle the issues around {{Statement}} creation and
does not engage the physical {{Connection}} so the connection can be reused
because none of that state is placed at the physical level and is therefore
reusable without closing it.
Thanks for catching this bug. I'll create a fix for this.
was (Author: ardot):
Creating a {{Statement}} every time you need one is unnecessary but not
illegal. The assumption is the {{Statement}} is closed when Spring is done,
which should be just fine. The problem is the list in {{Connection}} _should_
be a list of open {{Statements}}. The implecation being that closing a
{{Statement}} removes itself from that list. Unfortunately this is not being
done.
The list is necessary. But it needs to be maintained by {{Statement}} because
only it knows when it is asked to close.
As a note this has nothing to do with pooling. The JDBC driver pooling
({{PooledConnection}}) will handle the issues around {{Statement}} creation and
does not engage the physical {{Connection}} so the connection can be reused
because none of that state is placed at the physical level and is therefore
reusable without closing it.
Thanks for catching this bug. I'll create a fix for this.
> JDBC CassandraConnection may lead to memory leak when used in a pool
> --------------------------------------------------------------------
>
> Key: CASSANDRA-3244
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3244
> Project: Cassandra
> Issue Type: Improvement
> Components: Drivers
> Affects Versions: 1.0.0
> Reporter: Patricio Echague
> Priority: Minor
>
> I may be wrong here but I noticed that the implementations of
> CassandraConnection#createStatement() and
> CassandraConnection#prepareStatement() keep(cache) the created
> Statement/PrepareStatement internally in a List.
> They list is freed up only during CassandraConnection.close() which makes me
> think that, if the connection object is used in a pool implementation, it
> will lead to a memory leak as it will hold every single statement that is
> used to interact with the DB until the connection gets closed.
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