Re: how 8.1.7.4 calculates the # of 'library cache' latch children ?

alberto.dellera_at_bigfoot.com (Alberto Dell'Era) wrote in message news:<f4ed41c5.0311250712.4124d566_at_posting.google.com>...
> Does anybody know how the number of 'library cache' latches are
> determined by the 8.1.7.4 kernel ?
>
> Yesterday we had 11 children and today we have 17 of them, after
> (1) upping the shared_pool dimension from 150M to 400M
> (2) increasing cpu_count from 10 to 14

Look in the server reference manual. It says, "If there is heavy contention for latches, change the value of LOG_SIMULTANEOUS_COPIES to twice the number of CPUs you have. Do not change the value of CPU_COUNT."
>
> Which one (or other) caused the birth of the 6=17-11 children ?
>
> This is very relevant to us since a f#@%ing third-party applications
> overparses millions of statements (no bind variables, parse
> once-execute once ...) and, until they solve the problem (in 2020AD I
> guess), i would like to limit the damage by at least increasing that
> number.
>

Please post your latch contention information like v$latch_misses so we can advise you correctly.

Also see http://www.ixora.com.au/scripts/latches.htm

jg

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