Jeff:
it would help to have some specific information about your file - such as -
what is the split/merge type?
The ECL FILE.STAT command (in ECLTYPE U mode) provides necessary details -
including average record sizes and std deviation, etc.
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Jeff Butera
<[EMAIL PROTECTED]
e.edu> To
Sent by: [email protected]
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Subject
[U2] Unidata Dynamic files
07/05/2007 07:44
AM
Please respond to
[EMAIL PROTECTED]
er.u2ug.org
hpux, unidata 7.1.8
More in my quest to understand dynamic files in Unidata. I understand
that split and merge load are not universal constants and many file
factors affect the optimal values for them. What I don't understand is
why you'd want a split load of something like 20 in any circumstance.
Perhaps it's my misunderstanding of split load, but I take it to mean that
when a group reaches 20% full, it will split it into two different groups.
Of course, I'm dealing with a headache of a dynamic file that just isn't
happy. In short, it's got about 33,000,000 records, each in under 512 in
size with purely integer keys. I can create a dynamic file with hash type
0, modulo around 3,000,000 and block size 1024 which looks good at the
start: it's got 3 dat segments and 1 small ovr segment.
When I copy records from the original to the new dynamic file and get
somewhere around 20,000,000 records, it start creating ovr segments lie
crazy. I end up with 4 dat segments and 5 ovr segments.
When I run guide on resulting file, it's taking up about 9Gig on disk, but
only contains about 1.1Gig of data. I've tried split/merge loads of 20/10
and 60/40 with similar results.
Hence, I'm trying to determine why it's splitting like mad even thought
it's mostly empty. With the purely integer (sequential) keys, it's got a
nice even distribution in keys. I can avoid the overflow by creating
with a rediculously large modulo (eg: 10,000,000) but again, I get a file
that's 80% empty in the end.
Anyadvice appreciated.
Jeff Butera, Ph.D.
Administrative Systems
Hampshire College
[EMAIL PROTECTED]
413-559-5556
"Daddy - did you lose your mind?"
Catherine Butera
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