What is the format of column STORE_CLOCK in the CA Datacom Change Data Capture (CDC) feature and where is it derived from?

Products

• Datacom
• DATACOM - AD
• Datacom/AD
• Datacom/DB

Issue/Introduction

What is the format of column STORE_CLOCK in the Datacom Change Data Capture (CDC) feature and where is it derived from?

 

Resolution

The STORE_CLOCK value in the CDC tables is the time the log record was written to the source MUF's LXX log file. 

This value is a hardware IBM TOD (time of day) clock stamp. This is the clock the LXX depends on. 

The TOD timestamp is an 8 byte field but this STORE_CLOCK field is 10 bytes with a zero at both ends of the TOD timestamp. Bytes 1 and bytes 10 are zeros bytes 2 thru 9 are the TOD timestamp. 

 

The TIME_STAMP field is a 26 byte. 

The TIME_STAMP value in the CDC tables is an externalized clock that honors the timezone set by the system.

This timestamp is the same value you will see in the Read Rxx report columns DATE and TIME. 

This would be the same externalized clock found in an SQL date/time format. 

 

So TIME_STAMP is stored in SQL date/time format. It is not easily read in raw form. 

 

 

Sample CDC programs can be found here under Sample Programs, CA Datacom/DB

http://www.ca.com/us/support/ca-support-online/product-content/recommended-reading/technical-document-index/sample-programs-jcl-data-procedures.aspx?id=%7B19AC0890-4A58-4218-B2F5-98E851EF1D49%7D

There is also COBOL READRXX with sample COBOL program, JCL, and sample report.

Additional Information

Refer the Datacom® Core quide for information on Change Data Capture (CDC) feature