When I come to think of it, my question was not very smart.
RDBMS can use multiblock read only to read contiguous blocks.
If the blocks are in two different extents, they're not contiguous.
Sorry for asking, hopefully the fact that it's Monday can explain my
somewhat diminished capabilities.
> -----Original Message-----
> From: K Gopalakrishnan [mailto:kaygopal_at_YAHOO.COM]
> Sent: Monday, March 17, 2003 12:42 PM
> To: Multiple recipients of list ORACLE-L
> Subject: RE: db file scattered read
>
>
> Mladen,
>
> I guess the rdbms kernel will be passing the startblock-stop block
> addresses and will be passing to the readv (or pread?) system calls.
> A single multiblock read can not read two different sets (!) of
> contiguos blocks.. Or I am thinking in the different direction??
>
>
>
>
> Best Regards,
> K Gopalakrishnan
>
>
>
>
> -----Original Message-----
> Mladen
> Sent: Monday, March 17, 2003 7:45 AM
> To: Multiple recipients of list ORACLE-L
>
>
> How can you tell that DB_FILE_MULTIBLOCK_READ will not span extents?
> I was unable to confitrm that on Metalink.
>
> > -----Original Message-----
> > From: Hemant K Chitale [mailto:hkchital_at_singnet.com.sg]
> > Sent: Monday, March 17, 2003 9:44 AM
> > To: Multiple recipients of list ORACLE-L
> > Subject: Re: db file scattered read
> >
> >
> >
> > If 14706+3 is one extent and another extent begins at 14710,
> > it will NOT read
> > 14706+8. A DB_FILE_MULTIBLOCK_READ will not span extents.
> > Hemant
> >
> > At 09:04 AM 14-03-03 -0800, you wrote:
> > >Here is a part of trace file . I am finding that oracle is
> > trying to read
> > >8 or 3 or 7 blocks at a time . But block numbers are all
> > sequential i.e.
> > >it will read 3 blocks starting from 14706 and then 8 blocks
> > starting from
> > >14710 ( 14706+3 ). Why it doesn't read 8 blcoks always it
> > multi_block_read
> > >is set to 8 ? Any Idea .
> > >Also what is ela=1 ,does it mean elapsed time is 1 sentisec ?
> > >
> > >
> > >
> > >WAIT #32: nam='db file scattered read' ela= 0 p1=4 p2=14706 p3=3
> > >WAIT #32: nam='db file scattered read' ela= 1 p1=4 p2=14710 p3=8
> > >WAIT #32: nam='db file scattered read' ela= 2 p1=4 p2=14718 p3=8
> > >WAIT #32: nam='db file scattered read' ela= 0 p1=4 p2=14727 p3=3
> > >WAIT #32: nam='db file scattered read' ela= 0 p1=4 p2=14731 p3=7
> > >WAIT #32: nam='db file scattered read' ela= 1 p1=4 p2=14739 p3=3
> > >WAIT #32: nam='db file scattered read' ela= 1 p1=4 p2=14744 p3=8
> > >WAIT #32: nam='db file scattered read' ela= 1 p1=4 p2=129784 p3=8
> > >
> > >
> > >Thanks
> > >-ak
> >
> > Hemant K Chitale
> > My personal web site is : http://hkchital.tripod.com
> >
> >
> > --
> > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > --
> > Author: Hemant K Chitale
> > INET: hkchital_at_singnet.com.sg
> >
> > 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: Gogala, Mladen
> INET: MGogala_at_oxhp.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).
>
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: K Gopalakrishnan
> INET: kaygopal_at_yahoo.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).
>
--
Please see the official ORACLE-L FAQ: http://www.orafaq.net
--
Author: Gogala, Mladen
INET: MGogala_at_oxhp.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 Mon Mar 17 2003 - 12:41:00 CST
