CQS structure cold start

Common Queue Server (CQS) cold starts both a primary structure and its overflow structure if the primary structure is empty and both of the structure recovery data sets are empty.

During a structure cold start, CQS deletes:

The overflow structure
All the log records in the log stream for the structure

To cold start a structure, you must:

Procedure

Shut down any CQS systems that are connected to the structure.
For example, issue the following command, where cqs_name is the CQS subsystem name.
```
P cqs_name
```
The response will be shown as follows:
```
CQS0021I CQS SHUTDOWN COMPLETE
CQS0101I CQS CLEANUP SUCCESSFUL
```
Delete the primary and overflow structures on the coupling facility.
For example, issue the following command, where structure_name is the structure name.
```
SETXCF FORCE,STRUCTURE,STRNAME=structure_name
```
The response will be shown as follows:
```
IXC353I THE SETXCF FORCE REQUEST FOR STRUCTURE
structure_name WAS COMPLETED:        
STRUCTURE WAS DELETED              
```
Scratch both structure recovery data sets (SRDS 1 and 2).
For example, use the Access Method Services program IDCAMS to scratch the data sets.
Reallocate both structure recovery data sets (SRDS 1 and 2).
For example, use the Access Method Services program IDCAMS to reallocate the data sets.
Restart a CQS. CQS initialization will reallocate the structure.
For example, use the CQS startup procedure.

Verify that the structure is empty.

For example,

Issue the following z/OS® command, where structure_name is the structure name.
```
D XCF,STR,STRNAME=structure_name
```

The response for the z/OS command will be shown as follows:

...
STORAGE INCREMENT SIZE: 256 K                              
ENTRIES:  IN-USE:          3 TOTAL:       4238,   0% FULL  
ELEMENTS: IN-USE:          3 TOTAL:       4238,   0% FULL  
EMCS:     IN-USE:          0 TOTAL:       6634,   0% FULL  
...

When structure cold start completes, CQS automatically performs cold start restart processing.