At 10:02 AM 4/10/2009, Joseph Weinstein wrote:
>Hi Rick! What are you asking the statement to do
>when you set fetch size to a negative number? How
>are you verifying what result sets are doing?
>thanks,
>Joe Weinstein
Ooops, nevermind, I see in the MySQL docs that
MIN_VALUE will be taken by that driver to
always fetch only one row at a time. This is
a non-JDBC-standard MySQL-specific functionality/
value, so it would require some new JPA code
I think. I see in SQLBuffer.java that there is
a check:
if (fetch.getFetchBatchSize() > 0)
stmnt.setFetchSize(fetch.getFetchBatchSize());
so for now, it seems that you cannot just set your
fetch size to MIN_INT and get it passed to the
statement.
HTH,
Joe
>At 09:54 AM 4/10/2009, Rick Curtis wrote:
>
>>Yesterday I was looking into large result sets and it appears that they don't
>>work as implemented/documented(?). I did some googling around [1] and found a
>>number of posts talking about how setFetchSize isn't being honored, some
>>dating back as far as 2002. The MySQL docs [2] states "When using versions of
>>the JDBC driver earlier than 3.2.1, and connected to server versions earlier
>>than 5.0.3, the setFetchSize() method has no effect, other than to toggle
>>result set streaming as described above.". The doc outlines some additional
>>instructions on how to create a statement that is going to allow a streaming
>>result set. After moving to a newer JDBC driver, I wrote a simple test using
>>JDBC and it does work properly. Below is a snippet of the code [3] that I
>>used to test this with JDBC, but I wasn't able to figure out how to make
>>OpenJPA do the same.
>>
>>Any thoughts/suggestions?
>>
>>[1] Google "mysql jdbc setFetchSize"
>>[2]http://dev.mysql.com/doc/refman/5.0/en/connector-j-reference-implementation-notes.html
>>[3]
>>stmt =
>>conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,java.sql.ResultSet.CONCUR_READ_ONLY);
>>stmt.setFetchSize(Integer.MIN_VALUE);
>>--
>>View this message in context:
>>http://n2.nabble.com/Large-result-set-problem-on-MySQL-tp2617152p2617152.html
>>Sent from the OpenJPA Developers mailing list archive at Nabble.com.
>>
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