DLITRACE

DLITRACE

To trigger the IMS DLITRACE facility, you must allocate two ddnames in your JCL or CLIST.

Allocate ddname DFSVSAMP to a partitioned dataset or sequential file with record length 80 and load the VSAM buffer pool size information into this dataset or file. (You should first find out whether your site has a pre-defined set of buffer pools.) The following is a sample allocation
```
//DFSVSAMP DD DSN=highlvl.DFSVSAMP(BUFPOOL),DISP=SHR
```
where:
highlvl
Is the high-level qualifier for your VSAM buffer pool dataset.
This allocation indicates that member BUFPOOL in the DFSVSAMP dataset contains the VSAM buffer pool size information. For example:
```
8192,21                   /* 21 BUFFERS OF SIZE 8192
4096,21                   /*
2048,21                   /*
1024,30                   /*
512,21                    /*
IOBF=(2048,4,Y,Y)         /*
IOBF=(6144,4,Y,Y)         /* IO BUFFERS OF THIS SIZE
IOBF=(8192,4,Y,Y)         /*
OPTION,VSAMFIX=(BFR,IOB)
```
To turn on the trace, add the following line to the end of the VSAM buffer pool information
```
DLITRACE DDNAME=ddname 
```
where:
ddname
Is any ddname. Allocate this ddname to SYSOUT or to a file with LRECL 80. The trace output is sent to the file or SYSOUT class you allocate. If you allocate the trace to a file, keep in mind that trace output can be voluminous.
Suppose you choose the ddname DDTRACE by adding this line to your VSAM buffer pool file:
```
DLITRACE DDNAME=DDTRACE
```
To send the trace output to SYSOUT, include the following allocation in your JCL:
```
//DDTRACE   DD  SYSOUT=*
```

Note:

This trace facility is valid for DLI or batch mode (see Environments). To trace BMP mode, the operator must issue a command from the MVS console to start a PSB trace.
You must allocate the ddnames in the address space that actually issues the DL/I calls, either the XMI server address space or the FOCUS address space, depending on your environment (see Environments).

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