OraFAQ Forum: Performance Tuning » Difference between SORT_MULTIBLOCK_READ_COUNT and DB_MULTIBLOCK_READ

Home » RDBMS Server » Performance Tuning » Difference between SORT_MULTIBLOCK_READ_COUNT and DB_MULTIBLOCK_READ_COUNT

Show: Today's Messages :: Polls :: Message Navigator
E-mail to friend

Difference between SORT_MULTIBLOCK_READ_COUNT and DB_MULTIBLOCK_READ_COUNT [message #202821]

Sun, 12 November 2006 23:53

reena_ch30
Messages: 100
Registered: December 2005

Senior Member

What is the difference between SORT_MULTIBLOCK_READ_COUNT and DB_MULTIBLOCK_READ_COUNT ?

Regards,
reena

Report message to a moderator

Re: Difference between SORT_MULTIBLOCK_READ_COUNT and DB_MULTIBLOCK_READ_COUNT [message #202823 is a reply to message #202821]

Mon, 13 November 2006 00:06

Mohammad Taj
Messages: 2412
Registered: September 2006
Location: Dubai, UAE

Senior Member

HI

SORT_MULTIBLOCK_READ_COUNT
http://orafaq.com/maillist/oracle-l/2001/06/15/2276.htm

DB_MULTIBLOCK_READ_COUNT
http://orafaq.com/maillist/oracle-l/2003/05/02/0113.htm

HOPE THIS HELPS.
MOHAMMAD TAJ

Report message to a moderator

Re: Difference between SORT_MULTIBLOCK_READ_COUNT and DB_MULTIBLOCK_READ_COUNT [message #202834 is a reply to message #202821]

Mon, 13 November 2006 00:30

reena_ch30
Messages: 100
Registered: December 2005

Senior Member

It says "If the information needing to be sorted does not fit into the memory allocated to SORT_AREA_SIZE, sections of data are written to temporary
segments in the form of sorted runs. Once all the data has been partially sorted to these runs, the runs are merged by reading pieces of them (i.e. based on sort_multiblock_read_count) from the temporary segment into memory to produce the final sorted output. If SORT_AREA_SIZE is not large enough to merge all the runs at once (which is likely to be the case as it was not large enough to perform the entire sort in memory to begin with), subsets of the runs are merged in a number of merge passes."

My question is , if sort_area_size cannot merge all the runs at once, how would it do in no. of merge passes? Is the sort_area_retained_size used then?

Thanks
Reena

Report message to a moderator

Re: Difference between SORT_MULTIBLOCK_READ_COUNT and DB_MULTIBLOCK_READ_COUNT [message #203108 is a reply to message #202834]

Mon, 13 November 2006 22:40

Mohammad Taj
Messages: 2412
Registered: September 2006
Location: Dubai, UAE

Senior Member

hi reena

SORT_AREA_SIZE
http://saturn.uab.es/server.920/a96536/ch1198.htm

SORT_AREA_RETAINTED_SIZE
http://saturn.uab.es/server.920/a96536/ch1197.htm

DB_MULTIBLOCK_READ_COUNT
http://www.oracle.com/technology/oramag/oracle/05-jan/o15tech_tuning.html

If you database Shared Server configure then no need to used above first two parameter.

and for 3rd one read article by "kim".

hope this helps.
Mohammad Taj.

Report message to a moderator

Previous Topic:	Query Optimization problem...
Next Topic:	Regarding Autotrace execution Plan

Goto Forum:

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

]

Current Time: Thu May 01 21:11:04 CDT 2025