Re: 10046 trace: 'latch free' then 'db file seq. read' waits

From: joel garry <joel-garry_at_home.com>
Date: 15 Jun 2006 11:41:15 -0700
Message-ID: <1150396875.829859.314350@h76g2000cwa.googlegroups.com>

Spendius wrote:

>

> What I CAN'T understand is why Oracle starts to display
> very quickly, then stays blocked for about 2 mn only to
> finish displaying the 10 last rows... (when i say I get the
> same behaviour everyday that means every day -and
> even every 5 minutes- the result set differs and gets
> bigger every hour as these tables incur many inserts/updates
> all the time)

Perhaps you deleted many rows and then have a few, so it has to scan over a lot of empty blocks in the index, just the same few are way at the end since the new ones are reusing the empty space? Have you rebuilt this index lately?

Conversely, maybe you have the same number of very hot blocks that are the last few that the scan needs, and everybody is fighting to get them to see the data in their own consistent way?

Just random thoughts.

jg

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Received on Thu Jun 15 2006 - 13:41:15 CDT