Joined: 20 Oct 2006 Posts: 6968 Location: porcelain throne
IS there any relation for parameter BUFNO in jcl and number of record read from a sequential file in a job?
No. The number of records read by a STEP (since BUFNO is a DD parameter; DD parms are part of a STEP, not a JOB) depends upon what the STEP does. The BUFNO parm indicates - number of blocks read during a physical I/O.
for performance point of view is there any standards to be followed for coding BUFNO in realtion with sequention file content(number of records)
Standards are set by sites. Have no idea what your site standards are. Since buffers are usually allocated below the 16M line, and sites have standards concerning how much lower memory can be allocated to a JOB, you need to learn about your site standards.
Now, if your question is: 'are there things that need to be taken into consideration when determining the BUFNO value with respect to performance' - yes. A buffer contains a block. If you allocate enough buffers to load the complete file in memory, the physical I/O performed with the first read will load everything; subsequent reads will effectively be repositioning of record pointers in memory.
You also need to take into consideration, what else occurs during this STEP.
your question is so general that it will only elicit general answers.