RECOVER QMGR(TUNE READAHEAD ON)
IBM Data Replication's Q and SQL news.
ReplPerformanceTeam 270005S618 Tags:  q_replication performance db2 replication mq 7,251 Views
A new WebSphere MQ enhancement may give Q Replication a significant throughput boost in those situations where you have either (1) workload spikes that increase replication latency or (2) changed data that has built up in queues because of the temporary unavailability of a target database. The new feature is tailored for the sequential access of messages and causes MQ to read messages into the MQ buffer before the messages are needed. This method lets both the Q Apply program and MQ channel agents pull messages from memory instead of disk.
Why is this possible? When the number of messages overruns the buffer pool allocation for the queue, messages are spilled to disk and must then be retrieved from disk when needed. With the read-ahead enhancement, messages can be in memory. In addition to greatly improving throughput in these situations, the enhancement lowers overall replication latency. This new MQ feature also benefits performance at the source transmission queue.
In our test, we achieved the 55 percent increase in rows per second processed by Q Apply on a DB2 for z/OS Version 9 non-data sharing system with Q Replication Version 10.1 and WebSphere MQ Version 7. The average message size for the test was 50K. We have observed significantly higher improvements in replication throughput with smaller messages, for example 10K. Your throughput numbers could be noticeably different from these because replication performance can be heavily influenced by environment, row lengths, replication configuration, and more.
For more information, see the text for APAR PM63802.
The buffer pool read ahead enhancement is available starting with WebSphere MQ V7 APAR PM63802. You can enable the function by issuing the following MQSC command:
You can add the read ahead function to both the source and target queue managers for optimal performance. No changes are required to your Q Replication environment to take advantage of this feature.
DavidT 120000JC6D Tags:  oracle data_replication mq infosphere_warehouse db2 datastage q_replication event_publishing 1 Comment 11,963 Views
Note: The products in this article have been superceded in some cases and the license terms of the replacement products might be different.
DavidT 120000JC6D Tags:  licensing q_replication warehouse mq wmq what_do_i_need mqseries infosphere webspheremq db2 1 Comment 11,470 Views
This post is the answer to one of the FAQs found in
Yes, a limited-use copy of WebSphere MQ comes with all products that license use of Q Replication. "Limited-use" of MQ simply means that you can only use this copy of MQ with Q Replication. However, some products allow a few other things, too. For example, most DB2 LUW and InfoSphere Warehouse editions bundle MQ because DB2 LUW has a several integration points with MQ, not just Q Replication.
Do you have to use the bundled copy of MQ? No. If you already have a fully licensed copy of MQ, Q Replication will work with that. The one thing to remember is that a best practice is to have dedicated queue managers for Q Replication. In other words, create new ones, don't use queue managers that have other work going through them.
For UNIX and Windows, do you have to install the WebSphere MQ server software on the same system as where Q Replication is installed? No. The MQ server software can be installed on a different system and queue managers created there. Q Replication will access those queue mangers through MQ client software installed on the same system as Q Replication. However, for optimal performance, queue managers should be co-located on the same system(s) as Q Replication. For those of you who want an example of what's allowed, here's one :)
For z/OS, are there any special considerations? Yes, but only for how you order the bundled copy that comes with a z/OS product. See the last heading of this post for ordering information.
How do you verify everything I just said about licensing? :) Check the IBM license information documents. They are the official and final word about what you're entitled to. In fact, what they say overrides anything anyone says in a blog :) You can find IBM license information documents on ibm.com by using IBM's search interface:
Simply enter the product name and date, then follow the on-screen instructions. To read the MQ related terms, search for the string 'MQ'. Here are links to two license information documents that tend to be of interest to people:
You may want to use a date range to limit the results returned.
Ordering Considerations for z/OS
If you plan to use the copy of MQ that comes with InfoSphere Replication Server v10 for z/OS, please note that Replication Server is in Shopz's DB2 zone and the bundled WebSphere MQ is in Shopz's MVS zone. For example, Shopz will show something like the following in the DBS DB2 group/zone:
Shopz will show something like the following for MQ in the MVS group/zone: