Re: dc_sequences

From: Ravi Kulkarni <nandagokul_at_yahoo.com>
Date: Wed, 31 Dec 2003 14:44:26 -0800
Message-ID: <F001.005DB5F4.20031231144426@fatcity.com>

Ashish,

Are you using NOCACHE/ORDER for your sequences ? If so, is the cache size for your sequences default (20)? Try increasing the cache size to see if the misses reduce.
If these sequences a columns of an Index, it would affect the cache fusion latencies (hence performance) since the column is accessed from multiple nodes. Increasing cache size for sequences (with NOORDER, if feasible) can yield good results if you have -

- High "row cache lock" waits in v$system_event;
- High dlm_conflicts in v$rowcache
- High Cum_wait_time for SQ enqueue in v$enqueue_stat

HTH,
Ravi.

• Ashish Sahasrabudhe <asahasrabudhe_at_weightwatchers.com> wrote:
  > In statspack report on RAC 9.2.0.2 database, under
  > section "Dictionary Cache
  > Stats for DB"
  > there are 64.3% miss for dc_sequences. What causes
  > this?
  >
  > Thanks
  >
  

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Author: Ravi Kulkarni
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Received on Wed Dec 31 2003 - 16:44:26 CST