Re: Re: what's mean of "enqueue hash chains" latch?

From: biti_rainy <biti_rainy_at_itpub.net>
Date: Sun, 9 Jan 2005 12:14:42 +0800
Message-Id: <20050109041450.5AFE772C02C@turing.freelists.org>

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_at_OCN>select INDX from x$ksppi where KSPPINM = '_enqueue_hash';

      INDX

---

        82

sys_at_OCN>select KSPPSTVL from X$KSPPSV where indx = 82;

KSPPSTVL

---

177

sys_at_OCN>show parameter dml_locks

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
dml_locks                            integer     312

sys_at_OCN>show parameters enqueue_resource

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
enqueue_resources                    integer     532

sys_at_OCN>

Best regards

msn: biti_rainy_at_hotmail.com
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_at_itpub.net> 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_at_hotmail.com
  >> a dba from alibaba(china)
  >>
  >
  >----------------------------------------
  >eygle from China.
  >my site: http://www.eygle.com
  >
  >.
  

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Received on Sat Jan 08 2005 - 22:10:07 CST