Re: MySQL + Iterated/Streamed Query

Yeah, had to deal with this before. While there's no API to directly access the Statement (I think we should introduce it just in case), there is an alternative: add "useCursorFetch=true" URL parameter and use "ObjectSelect.statementFetchSize(..)".

Andrus


> On Mar 14, 2020, at 5:31 PM, Michael Gentry <[email protected]> wrote:
> 
> I'm trying to do an iterated query (using the 4.1 RC) against MySQL and it
> appears that the MySQL JDBC driver loads everything into memory first
> instead of streaming results.  This results in memory-related exceptions
> for larger results.
> 
> From searching, it appears that the MySQL JDBC driver needs the following
> hint to stream results:
> 
> statement =
> connection.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,
> java.sql.ResultSet.CONCUR_READ_ONLY);
> statement.setFetchSize(Integer.MIN_VALUE);
> 
> Is there an easy way to get the iterated query to provide that hint when
> getting a connection?  I've not found a way yet.  Best I've found so far is
> to swap out a whole slew of classes to change the DataSource that's
> actually returned.
> 
> Thanks,
> 
> mrg