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Home -> Community -> Mailing Lists -> Oracle-L -> RE: (looong) PCTFREE, PCTUSED and ASSM
I believe it's direct read from files in parallel execution, nothing gets
read from cache.
Cached blocks for the table get flushed to files before the direct read.
Regards,
Waleed
-----Original Message-----
Sent: Wednesday, November 12, 2003 7:10 AM
To: Multiple recipients of list ORACLE-L
Yep, the situation can get bad for parallel execution, especially if blocks
read aren't cached...
But for serial FTS I haven't seen such a problem, I did even a test to
verify it on 9.2.0.4, and did see behaviour as I expected - all blocks were
scanned using multiblock reads and rows were returned in order the contents
of them were found, instead of pointers.
Tanel.
> Actually row migration is a big problem for FTS also(whether serially or
> using PQ).
> You end up waiting for too many "db file sequential read" single block
reads
> instead of
> MBRC in (direct path read, db file scattered read)
>
> Regards,
>
> Waleed
>
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Tanel Poder INET: tanel.poder.003_at_mail.ee Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- 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). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Khedr, Waleed INET: Waleed.Khedr_at_FMR.COM Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- 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 Wed Nov 12 2003 - 08:34:40 CST
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