Re: Index degree changed on all indexes to cpu_count on

From: Sriram Kumar <>
Date: Thu, 24 Jan 2013 17:24:00 +0530
Message-ID: <>

Hi Fred,
Thats a tough one. how long this problem has been there?. if it has happened quite recently , could possibly restore few rman backups in chronological order a test environment and see when this got changed and then narrow down to any events that happened around that time. alternatively look at the last ddl time of the indexes. could have possibly been a result of alter index <> parallel <> then there could be a clue on the last ddl time. hope your site is not one of those does a periodic index rebuilds which would have over written the date on which the alter index <> paralllel was used.

hope this helps.

best regards

sriram kumar

On Thu, Jan 24, 2013 at 3:57 PM, Fred Tilly <> wrote:

> Hi All,
> We have a customer who recently started complaining about performance of
> our application which had been running smoothly for several years. On
> looking at some AWR reports the top wait was 'PX Deq Credit: send blkd'
> We looked at the explain plans and could see that parallel query was now
> being used where it had not been before.
> On examining the database all indexes on all schemas including sys had
> there degree set to 8, which also just happens to be the cpu_count for the
> server.
> On looking at other customer environments also on the index
> degree was set to 1.
> The DBA who manages the server has no idea how the indexes all got changed
> to a degree of 8 and it is not something we had seen before.
> The database was originally and had been upgraded to
> sometime ago.
> Anyone got any ideas.
> Thanks
> Fred
> --

Received on Thu Jan 24 2013 - 12:54:00 CET

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