Recovery from compressed PriLog entry - connect_cdc_sqdata

A compressed prilog entry in the IMS RECON represents a gap of one of more SLDS that IMS considers that it no longer needs. However, the IMS Log Capture does need to process these gapped SLDS in order to ensure that no changed data is lost.

Background:

In the event IMS Log Capture encounters a compressed prilog entry, it will detect that there is a gap in the SLDS and it will stop.

Recovery from this condition involves specification of the --log keyword in the SQDPARM DD of the previously described IMS Log Reader Capture JCL:

Syntax

//SQDPARMS DD *
 /home/sqdata/imscdc1/IMSCDC1.cab
 --log <ims_ssid>:<data_set_name>[:[0x]<start_lsn>][:[0x]<stop_lsn>][:]
 ...
 --log <ims_ssid>:<data_set_name>[:[0x]<start_lsn>][:[0x]<stop_lsn>][:]
 --continue

Keyword and Parameter Descriptions

Keyword	Descriptions
<ims_ssid>	Required, IMS Sub System ID.
<data_set_name>	Required, SLDS dataset name.
<start_lsn>	Optional since normally the entire dataset that has gone missing from the RECON would be processed. It is intended for unique situations where you need to process only a portion of a log.
<stop_lsn>	Optional since normally the entire dataset that has gone missing from the RECON would be processed. It is intended for unique situations where you need to process only a portion of a log.
--continue	Optional keyword. If not specified, capture will stop after processing the last --log statement.

Note:

If multiple --log statements are specified, they must be entered in the correct order, based on the date/time values in the SLDS dataset name.
The --log statement cannot span multiple lines. If you need to include start_lsn and/or stop_lsn, where the length of the statement would exceed 80 characters, you should adjust your SQDPARM dataset to be variable blocked (i.e. RECFM=VB,LRECL=255).
To continue processing from the RECON following the --log SLDS, specify --continue in the SQDPARMS command line. If it is not specified, capture will stop after processing the last --log statement.

Example

The Log Reader Capture detects the Compressed Prilog situation from a gap in the SLDS and has stopped. The recommended steps for recovering the situation:

Obtain a recon listing and locate the Compressed Prilog entry.
The listing identifies six "gapped" SLDS beginning with SLDS dataset DFSD10.SLDSP.IVP1.D18304.T1106552.VF4.
Verify that capture processed the SLDS dataset listed before the Compressed Prilog entry. This will be the case If capture stopped by itself on the Compressed Prilog entry. However, if for some reason, it did not process this SLDS or any before it, you will need to include these SLDS in the restart.
Switch the OLDS to create a new SLDS entry after the Compressed Prilog entry if one does not already exist.
In the SQDPARM DD, specify a --log statement for each SLDS in the "gap" (i.e. those between the last SLDS processed by capture and the first SLDS after the Compressed Prilog entry).

To continue capture after processing the gapped SLDS, the --continue statement was specified.

The following JCL snippet example tells capture to start processing with SLDS dataset

 DFSD10.SLDSP.IVP1.D18304.T1106552.VF4, then process five (5) other "gapped" SLDS, then continue processing using the SLDS/OLDS from the IMS Recon.
//SQDPARM DD *
<ims_capture_cab>
--log IVP1:DFSD10.SLDSP.IVP1.D18304.T1106552.VF4
--log IVP1:DFSD10.SLDSP.IVP1.D18304.T1109542.VC9
--log IVP1:DFSD10.SLDSP.IVP1.D18304.T1110026.V68
--log ivp1:DFSD10.SLDSP.IVP1.D18304.T1110144.V48
--log ivp1:DFSD10.SLDSP.IVP1.D18304.T1111113.VF5
--log iVp1:DFSD10.SLDSP.IVP1.D18304.T1117415.VCA
--continue

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Connect CDC (SQData) Troubleshooting