At 20:52 -0500 on 04/03/2009, Spencer, Mike wrote about Re: CA and CI splits:
CI and CA splits are no longer an issue from a performance
perspective. Yes, there is some degradation during the split, but
with today's technology of DASD, the hit cannot be truly measured.
What you want to understand is not the individual splits, but the
frequency of the splits.
Michael Spencer
BMC Software
There is a performance hit (to some extent) to read a file with
splits as opposed to reading the same data from the file if it had
been recreated to eliminate the splits due to you needing to read
more (and shorter) blocks.
OTOH: Once the CIs with update activity have been split, there will
be free space for added records (and existent records whose size is
increased thus requiring a CI split since the new block is over the
CI size). You need to look at not only how often there is a split but
where the splits are occurring. If they are evenly spread over the
file you can live with it (or reorganize the file once and define
free space at define time so that there will be a lessened need to
additional splits). The problem occurs when the splits are
concentrated in a narrow area of the file when you keep getting split
after split due to record insertions into that area.
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