MQSeries.net :: View topic - Streaming data from MQMessage object to MF DB2

72dolfan · Posted: Tue Feb 09, 2010 9:17 pm Post subject:

Hi All,

I have a Web App running on Shared WAS 7.0 servers that pulls messages form a queue using Java MQ API and stores the header and message in DB2 on z/OS via a Stored Procedure call. Some of these messages are rather large (36 MB) and have cuased Out Of Memory issues ont he server.

We get the message from the queue into a MQMessage object. We also create a object inmemory called stpBean which holds the MQ Header info and message text. So to get the message into the stpBean, we use the following statement;

stpBean.setMsgString(mqMessage.readStringOfCharLength(mqMessage.getDataLength()));

The stpBean object is passed in the STP to a z/OS program to handle the inserts. To do that, we create a callable statement and set the parameters (parm 39 is the message data).

public void setParameterValues(CallableStatement cs, STPBean stpBean) throws SQLException{
cs.setString(1, stpBean.getCalltype());
cs.setString(2, stpBean.getRetCode());
cs.setString(3, stpBean.getRetMessage());
cs.setBigDecimal(4, stpBean.getSqlCode());
cs.setString(5, stpBean.getUniqueId());
cs.setBigDecimal(6, stpBean.getMsgNumber());
cs.setString(7, stpBean.getQueueName());
cs.setString(8, stpBean.getQueueManagerName());
cs.setString(9, stpBean.getCurrentDate());
cs.setString(10, stpBean.getStrucID());
cs.setBigDecimal(11, stpBean.getStrucVersion());
cs.setBigDecimal(12, stpBean.getReportMsg());
cs.setBigDecimal(13, stpBean.getMessageType());
cs.setBigDecimal(14, stpBean.getMessageExpiryTm());
cs.setBigDecimal(15, stpBean.getFeedback());
cs.setBigDecimal(16,stpBean.getEncoding());
cs.setBigDecimal(17, stpBean.getCharacterSet());
cs.setString(18, stpBean.getFormat());
cs.setBigDecimal(19, stpBean.getPriority());
cs.setBigDecimal(20, stpBean.getPersistence());
cs.setString(21, stpBean.getMessageId());
cs.setString(22, stpBean.getCorrelationId());
cs.setBigDecimal(23, stpBean.getBackoutCount());
cs.setString(24, stpBean.getReplyToQueueName());
cs.setString(25, stpBean.getReplyToQueueManagerName());
cs.setString(26, stpBean.getUserId());
cs.setString(27, stpBean.getAccountingToken());
cs.setString(28, stpBean.getApplicationIdData());
cs.setBigDecimal(29, stpBean.getPutApplicationType());
cs.setString(30, stpBean.getPutApplicationName());
cs.setString(31, stpBean.getPutDate());
cs.setString(32, stpBean.getPutTime());
cs.setString(33, stpBean.getApplicationOriginData());
cs.setString(34, stpBean.getGroupId());
cs.setBigDecimal(35, stpBean.getMessageSequenceNumber());
cs.setBigDecimal(36, stpBean.getMessageOffset());
cs.setBigDecimal(37, stpBean.getMessageFlags());
cs.setBigDecimal(38, stpBean.getOriginalLength());
cs.setObject(39, stpBean.getMsgString().getBytes(), Types.BLOB);

What I'd like to do is eliminate the need to store the large message in the stpBean object and use streaming instead to avoid the need for three chunks of contiguous memory (MQMessage, stpBean, & that created in the setObject(39) above.

I've been looking at ByteArrayOutputStream as a possiblity, but after creating the output stream;

ByteArrayOutputStream os = new ByteArrayOutputStream();

I'm not sure how to write the stream instead of

stpBean.setMsgString(mqMessage.readStringOfCharLength(mqMessage.getDataLength()));

Once that is done, I plan to use setBinaryStream inside the setObject on parameter 39 above, but I'm not certain how to do that either.

Anyone out there know how to write the outputstream and then code the setBinaryStream?

Thanks!