Re: Import performance.

Also (if you don't want to build indexes afterward from scratch), before you do the initial export, set parallel degree on your largest tables to something other than 1 ( try 4 or 6 for starters, depending on how large the table ).

This will cause parallel index builds during the import on those tables with degree >1.

-Kevin
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Douglas Dunyan wrote in message <36343928.3F9E900E_at_hotmail.com>...
>On large imports, I found that turning off archive mode will save the
>most time.
>
>Here's the trick, if you have the luxury.
>
>We run everything redundant, including disks. Before attempting the
>import, put in a third shadow set, and turn off archiving. When done
>with the import, do a normal shutdown, and break the 3rd shadow set
>(you can use that for cold backup!) and then turn archive mode back
>on....
>
>With large imports, most of the performance hit is i/o due to archive
>mode.
>
>Doug
>
>
>Linda Montgomery wrote:
>>
>> There are several changes we make to increase import speeds. Here is our
little
>> checklist of things to check/change before a big import. Afterwards we
put
>> everything back like it was.
>> 1. Make sure redo logs are large enough & that there are enough groups.
Try to
>> keep log switches at least 3 minutes or more apart. We have been
increasing
>> logfile size to 30M minumum ( a size that worked for our environment) if
>> smaller than that in production.
>> 2. Place each logfile on a seperate drive (or ping pong between drives)
to
>> eliminate contention.
>> 3. Set db writers = # of disk drives * 2
>> 4. Set init.ora parameter checkpoint_process = true
>> 5. Verify log_simultaneous_copies is corret for the # of processors, or
remove
>> parameter if on a single cpu machine.
>> 6. Check for adequete rollback & temp tablespace sizes & that their
initial &
>> next extent will allow them to grow to the maximum value.
>> 7.Be sure to use commit=y for large tables
>> 8. Increase size of init.ora parameter log_buffer to 1,024,000
>>
>> Linda
>> montgolh_at_jmu.edu
>>
>> MotoX wrote:
>>
>> > Correct, only EXPORT supports DIRECT.
>> >
>> > And remember to take a *backup* after recreation of the indexes, unless
you
>> > want to go through the whole procedure again should you suffer media
>> > failure...
>> >
>> > MotoX.
>> >
>> > Murali Kazhipurath wrote in message <362d879c.0_at_blushng.jps.net>...
>> > >From what I have understood, DIRECT PATH only works with EXPORT. Here
are a
>> > >few tips:
>> > >
>> > >1. Drop all Indexes.
>> > >2. Import without indexes using the option indexes=n.
>> > >3. Rebuild indexes using the UNRECOVERABLE option.
>> > >
>> > >Hope this helps.
>> > >
>> > >Murali
>> > >murali_at_jps.net
>> > >
>> > >
>> > >xsun1913_at_my-dejanews.com wrote in message
>> > ><70ilit$2j0$1_at_nnrp1.dejanews.com>...
>> > >>In article <01bdf5d0$fabc77a0$5feaabc3_at_ken-bailey>,
>> > >> "Ken Bailey" <Ken.Bailey_at_BLAENAU_GWENT.btinternet.com> wrote:
>> > >>> Can anyone give me any guidelines on improving import performace (
>> > >>> parameters etc) ?
>> > >>>
>> > >>>
>> > >>
>> > >>Use DIRECT PATH when running import; Set buffer to a large number.
>> > >>
>> > >>
>> > >>Xuening Sun
>> > >>
>> > >>
>> > >>
>> > >>-----------== Posted via Deja News, The Discussion Network
==----------
>> > >>http://www.dejanews.com/ Search, Read, Discuss, or Start Your
Own
>> > >
>> > >
Received on Mon Oct 26 1998 - 16:42:01 CST