Re: Help: Reducing Extents
Posted in 1997
Chad,
after increasing the NEXTSIZE in systables (don't worry too much about
the first extent, it'll tend to be coalesced pretty well unless you have
a lot of fragmented tables in the same dbspace).
two methods not mentioned are:
1. use onunload/onload - it's waaaay faster than dbexport/dbimport, but
takes more disk or tape space and you can't edit the schema before
onload....
2. use "alter fragment on table <tablename> init in <dbspacename>" - I
really like this one because it requires only knowledge of the tablename
and where you want it to go. The clustered index oriented strategies
require you to look up stuff for each table that has little to do with
the job at hand. Alter fragment is much simpler.....
Anyway, you have advice out the keister now, let us know how it goes....
Greg
p.s. >5 extents isn't necessarily a performance killer, if you have
enough memory to keep your read hit ratio high (> 99ish percent), you
won't be able to tell the difference between 3 extents and 30 extents.
You are at a point it's probably worthwhile to clean up a little. I
try to organize it so I only have to reorganize things a couple of times
a year.
Chad Laity wrote:
snip....
> How do I reduce the number of extents to improve performance??
>
> Thanks,
> Chad Laity
> chad_laity@arrowintl.com
> wick@fast.net
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