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Home -> Community -> Mailing Lists -> Oracle-L -> Re: insert nologging parallel/noparallel and archiving
sorry, meant insert as select, not insert as append
--- Jack Silvey <jack_silvey_at_yahoo.com> wrote:
> Gene,
>
> This sounds right.
>
> Standard insert as append does freelist block
> checking
> and generates redo. Parallel DML generates minimial
> redo, just for the new temp segments being created,
> not for the datablock updates. This is one reason it
> is so fast.
>
> Index changes are always logged, even in PDML and
> append modes.
>
> One way to consider would be to alter indexes to
> unusable and rebuild with nologging and compute
> statistics clauses. This way, your load is fast, you
> generate minimal redo, and your indexes are
> balanaced
> and have good stats afterwards.
>
> A space consideration with PDML and dictionary
> managed
> tablespaces - each PQ process in your PDML is going
> to
> have its own extent. This extent will begin life
> with
> a size=initial, but will have the empty space
> trimmed
> off at the end of the write, leaving an odd size
> extent. Since you are doing PDML, you might have
> these
> extents close together, and when the trim occurs, it
> will leave odd sized holes in between and throw off
> your space managment strategy. I don't believe that
> LMT tablespaces have this issue.
>
> hth,
>
> jack
>
>
> --- Gurelei <gurelei_at_yahoo.com> wrote:
> > Hi all.
> >
> > I've been trying to copy a 20mil rows table
> between
> > two databases via insert as select statement. I
> > have dropped all the indices and ran in nologging
> > mode
> > with hints forcing parallel execution of both
> ISERT
> > and SELECT. While checking the archive directory I
> > have noticed that the archives have been created
> > every
> > 2 minutes. I have cancelled the load and noticed
> > that
> > I forgot to alter system enable parallel dml so in
> > effect the load was going in sequential mode. Then
> I
> > reran my script having added the alter system
> > statement and there we no archive created while it
> > ran.
> > So it looks like even without the indices a
> > sequential
> > insert as select nologging still creates the
> > archives
> > wihle the parallel - doesn't. Does it sound right?
> > If
> > so, why. I thought the nollogging and with no
> > indices
> > shouldn't produce any log info regardless of the
> > mode.
> >
> > TIA
> >
> > Gene
> >
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> > Author: Gurelei
> > INET: gurelei_at_yahoo.com
> >
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-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Jack Silvey INET: jack_silvey_at_yahoo.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Fri Jul 05 2002 - 15:03:25 CDT