Friday, 28 May 2010

Encyclopaedia Performance

A few customers have asked us for information on improving performance on both the Gen host ency and client/server ency. Rather than try and write out a definitive list of things to look for, I thought it would be useful (and less onerous) to provide occasional posts on this subject.

If you have any ideas or experiences that you would like to share, then please add comments to the postings, or if you prefer, e-mail them and they can be included in a new post.

The areas that will be considered in this section include encyclopaedia server performance, reducing contention, working practices and other factors that affect the overall performance of the encyclopaedia.

To start things off:

1) Model size rather than overall ency size has a big impact on performance. Smaller models perform much better than larger ones for the same function, i.e. downloading the same subset from a small model will be much faster than a large model. The speed is roughly proportional to the model size.

2) Encourage 'right sizing' subsets and working practices that are efficient, like only generating changed objects rather than all action blocks in a load module.

1) Use the support client and check the Object Cache setting. The default is far too low. We have ours set to 500,000

2) Database i/o has a major impact on performance. Does your DBMS have enough memory for caching? Oracle likes a lot!

Have you implemented DB2 type 2 indices for the encyclopaedia? Originally (many years ago now) these were not available for DB2, so if you have an old encyclopaedia, you may not have converted the indices to type 2. This can have a big impact on contention. Type 1 indices are not supported from DB2 v8 onwards, so if you are on v8, then this will have been taken care of.

Monday, 10 May 2010

Gen r8 z/OS Libraries for Batch

Gen r8.0 introduces support for operations libraries on z/OS (zLIBs). These are DLL load modules that contain one or more action blocks. The zLIB load module contains the DB2 language interface module and this is environment specific, for example DSNCLI is required for CICS, DFHLI000 for IMS and DSNELI for batch.

Therefore, as with standalone dynamic action blocks, a separate version of the zLIB is required for each operating environment, typically one for on-line and server environments and one for batch. This is also true for dynamically linked RI triggers since these are implemented as DLL load modules.

With 'normal' dynamic action blocks, separate on-line and batch versions are created by installing an on-line or batch load module that uses the dynamic action block. This requires the on-line and batch load modules to reside in different business systems and each business system must have a separate load library so that the on-line and batch versions of the dynamic action block are linked into different libraries.

In contrast, zLIBs and dynamic RI load modules are installed as separate load modules rather than as part of a normal load module. At present with Gen r8.0 you cannot specify whether you want to install the zLIB for on-line or batch and hence you cannot create a batch version of the zLIB.

We have developed a solution for this dilemma with GuardIEn 8.0, which has support for linking both on-line and batch versions of zLIBs and RI DLL load modules. CA plan to address this limitation with a service pack for Gen r8.0.

Tuesday, 4 May 2010

Beyond Compare

As a tools developer for CA Gen, the fact that we also develop our tools with CA Gen has meant that we tend to 'build not buy'. In other words, when we find the need for some additional tools support as part of our own Gen development projects, we enhance our own tools. This approach then leads to extra functionality in the products that is almost always useful to our customers as well.

However there are certain 3rd party tools and utilities that we have purchased runtime licences for instead of building ourselves. Examples include the diagramming OCX that we have used for creating the Object Structure, Life-Cycle and Model Architecture diagrams in GuardIEn, the ftp/sftp utilities and the file compare tool.

For the file compare tool, we have used the freely distributable WinDiff tool with the option for customers to replace this with their own favourite product. However Windiff is a fairly basic tool, and some time ago we replaced this for internal use with Beyond Compare 3 (BC3).

We like BC3 so much, that for the 8.0 release of our products, we have purchased additional licences to be able to distribute BC3 to our customers as well.