Identify z/OS system LogStream to be used - connect_cdc_sqdata - Latest

Connect CDC (SQData) Change Data Capture

Product type
Software
Portfolio
Integrate
Product family
Connect
Product
Connect > Connect CDC (SQData)
Version
Latest
Language
English
Product name
Connect CDC (SQData)
Title
Connect CDC (SQData) Change Data Capture
Copyright
2024
First publish date
2000
ft:lastEdition
2024-09-05
ft:lastPublication
2024-09-05T15:00:09.754973

A new LogStream is recommended by Precisely to be processed by a new Publisher. Using the existing LogStream and Publisher used by IMS Capture requires careful consideration of potential out of sync conditions.

When CF Structures are used for the z/OS System Logstreams, the IMS Log Capture and IMS Unload components use a throttling technique to avoid offloads and keep data in the CF structure until it is Published and consumed by the downstream Engine(s). This provides better performance and more efficient use of CPU vs having the publisher retrieve data from offloaded datasets. Throttling is controlled by the specification of High and Low Offload percentages for structure utilization. It is important to size CF structures to avoid throttling if possible while at the same time to avoid offloads.

Throttling is turned on by default but can be turned off using --ptk=14. Throttling slows down the LogStream (zlog) put process used by the Capture to give publishers time to catch up and hopefully avoid offload. It's a crude control, and sometimes not very effective because It can cause capture to slow down. The Capture and Publisher don't communicate with each other to refine it. Some customers however choose to disable throttling with the PTK because they would rather have offloads occur than slow down change data capture.