RE: MCH2804 Message and Access Path Size

Jonathan,

I don't have the answer to your questions, but I will point out that IBM recommends using the *1TB for
all access paths as there are advantages (performance?) other than just being able to have a bigger
access path.

HTH,

Charles Wilt
--
Software Engineer
CINTAS Corporation - IT 92B
513.701.1307

wiltc@xxxxxxxxxx

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-
bounces@xxxxxxxxxxxx] On Behalf Of Jonathan Mason
Sent: Wednesday, April 30, 2008 7:34 AM
To: midrange-l@xxxxxxxxxxxx
Subject: MCH2804 Message and Access Path Size

Hi List

We had a process crash last night with an MCH2804 error message against
a logical file. After checking the lists I found that this was due to
the access path reaching the maximum 4 GB size.

The physical file had 210,598,846 records in it, and the decision was
taken to purge the file rather than change the maximum size to 1
TeraByte. 3-4 hours in to the purge the job was cancelled by an
operator to free up a job queue for overnight processing. The result
was that 7,141,840 records were removed and the access path size was
freed up by 14,680,064 bytes.

Today, however, the same process has crashed and the access path is back
up to 4 GB. Only 90,548 records have been written to the physical.

The key for the access path is 9 bytes, and I was expecting there to be
space for approx 1 million entries (allowing for pointers or suchlike)
in the access path. Does anybody know why there would be significantly
less? By my calculations it looks like each entry in the access path is
taking 162 bytes.

Also, would running a RGZPFM after the purge free up any space in the
access path? The fact it's "PFM" makes me think no, but I'm just
wondering if it removes any allocated space from the access path too.

Any ideas, suggestions, advice or sympathy will be gratefully welcome.

Thanks

Jonathan

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