Re: Re: what's mean of "enqueue hash chains" latch?
- From: "biti_rainy" <biti_rainy@xxxxxxxxx>
- To: "eygle" <oracle.unix@xxxxxxxxx>
- Date: Sun, 9 Jan 2005 12:14:42 +0800
hi,eygle
i think the 'enqueue hash chains' looks like the 'cache buffer
chains',oracle often use * hash table + list * to manage resource.
enqueue resources would be put on the list blow some hash bucket.
so ,i am not sure whether the parallel process's locks are all put on
the same list. if they always on the same list ,you would not use
parallel insert. if not,you would increase the _enqueue_hash to a prime
number.
there is my 9i database:
sys@OCN>select INDX from x$ksppi where KSPPINM = '_enqueue_hash';
INDX
----------
82
sys@OCN>select KSPPSTVL from X$KSPPSV where indx = 82;
KSPPSTVL
----------------------------------------------------------------------------------------------------
177
sys@OCN>show parameter dml_locks
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
dml_locks integer 312
sys@OCN>show parameters enqueue_resource
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
enqueue_resources integer 532
sys@OCN>
Best regards
msn: biti_rainy@xxxxxxxxxxx
a dba from alibaba(china)
---- from the mail-----
>hello,biti_rainy;
>
>It's very helpful,I'll read it carefully.
>thanks.
>
>
>On Sat, 8 Jan 2005 22:33:58 +0800, biti_rainy <biti_rainy@xxxxxxxxx> wrote:
>> hi,eygle
>>
>> please read steve adams's oracle 8i intermal service (p41)
>> it describe more detail .
>>
>> he said :
>> if we've increased the enqueue_resources parameter, it may be necessary to
>> increase the _enqueue_hash parameter because the size of the hash table is
>> derived from the value of processes.
>>
>> you may increase the _enqueue_hash to a prime number .
>>
>> and do not use parallel insert ?
>>
>> Best regards
>>
>> msn: biti_rainy@xxxxxxxxxxx
>> a dba from alibaba(china)
>>
>
>----------------------------------------
>eygle from China.
>my site: http://www.eygle.com
>
>.
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