Re: An ancient mystery
Date: Sat, 22 Nov 2008 10:02:43 -0600
Here is a thought.
May be some implicit data conversion is happening? For example, assuming the query involves bind values, passing a number type instead of character type can lead to "unexpected" behavior. The table has possibly grown large enough that you are able to feel the "pain" now.
On Thu, Nov 20, 2008 at 9:05 PM, Dennis Williams < oracledba.williams_at_gmail.com> wrote:
> The situation:
> Oracle 18.104.22.168 database on Solaris 8 (soon to be upgraded to 10g)
> Rule-based Optimizer
> A query which has run for years using an indexed access to a very large
> table (maybe 100 million rows)
> suddenly decides to use a full-table scan, shutting down a critical
> business process.
> Then after several hours, it switches back to using the index.
> All concerned claim that nothing changed before or after.
> Needless to say the business users are nervous. They think maybe the
> database grew beyond some limit.
> Can anyone think of an explanation?
> Dennis Williams