On Jun 29, 15:22, uunet!st.com!deepu.madan wrote:
> ...
>
> 1. How does the 24x7 shops, hopefully doing moderate to extensive INSERTs and
>    DELETEs, reclaiming the disk space ? I know modifying the tables is the
>    answer but it becomes all the more difficult in a 24x7 environment and if
the
>    database is big.

I dunno.  Probably by being not quite 24x7.  In those rare situations
where absolutely no table downtime is acceptable, ever, I could imagine
tricks like keeping a couple alternating transaction tables and one
history (archive, whatever) table backing them.  etc.  I think most
24x7 shops can find a little downtime somewhere to modify those big
tables.  Little tables of course can be modified on the fly when not
actually in use.

>
> 2. What are the various utilities, tracepoints that once can use for
performance
>    tuning and how ?

This is a big subject.  There is no single answer aside from maybe
"hire a consultant".  (Not an ad, I am not in the consulting business.)
Start with ipm for hot-query watching and log file watching.  Use
SET QEP and friends (SET TRACE POINT QE90, SET OPTIMIZEONLY) for
tuning individual queries.  Trace points QS501 and DM420 will help you
check out the REPEATED query pool and the dmf cache respectively.
Don't expect big gains from server tuning.  The big gains come from
query tuning ie algorithmic (and data) tuning.


>
> 3. Ingres locks require some memory - It is stated in the manuals but can
>    someone please tell me how much memory do these locks take up ? Because I
>    would like to increase number of maxlocks to an optimal number.
>

I'm not sure of the exact number.  I am tempted to reply "locks don't
take enough memory to worry about.  Configure what you need and forget
about it".  I think you can figure very very very roughly 100 bytes per
lock including associated lock lists, etc.

Which maxlocks are you planning on tuning?  max locks in the system or
the SET MAXLOCKS= parameter which is something entirely different and
has no relation to memory?


-- 
Karl Schendel            Phone: (412) 963-8844
Telesis Computer Corp      Fax: (412) 963-1373
wiz@telesis.com

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