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Home -> Community -> Mailing Lists -> Oracle-L -> Re: snapshots
Dennis,
I would think since the snap$ table has the rowid value that when a delete needs to be performed it would delete using the rowid.
James
--- Dennis Taylor <ismgr_at_pctc.com> wrote:
> At 10:06 AM 1/12/01 -0800, you wrote:
> >hi list
> >
> >would any refresh of a snapshot fire a query
> against the base table?
> >
> > i think its supposed to go against the mlog$ table
> of the base table. we
> >have a situation where there is a poor-performing
> query that is fired at
> >exact intervals accessing the base table and no
> application seems to be
> >firing it?
>
> The mlog$ table only contains a couple of fields,
> one of which is the ROWID
> of the affected record, and another is the dml
> operation (insert, delete,
> update). I'd assume that the snapshot update uses
> this info to go get the
> affected record (unless it's a delete) from the base
> table.
>
> This is weird when you think of it. It implies that
> the snapshot process is
> able to get "old" information, i.e. the record from
> before the delete, so
> that it can grab the PK info. Or am I missing
> something?
>
>
> Dennis Taylor
> --------------------------------
> Save the plankton - nuke the whales!
>
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> Author: Dennis Taylor
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