| Difference in DML operations on Table and Global temp table [message #411014] |
Wed, 01 July 2009 08:32  |
vikram1780
Messages: 162
Registered: January 2007
Location: Bangalore |
Senior Member |
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Hi,
Could there be any difference in performance on Normal table and Global temp table in respect to DML operations.
Example;
Inserting 6 M records.
Insert into table..........
same no of records
Insert into Global_temp_table
Thanks in advance
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| Re: Difference in DML operations on Table and Global temp table [message #411496 is a reply to message #411267] |
Sat, 04 July 2009 06:02  |
smartin
Messages: 1803
Registered: March 2005
Location: Jacksonville, Florida |
Senior Member |
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| Kevin Meade wrote on Thu, 02 July 2009 22:47 | I wonder if there are situations where using a GTT would actually be slower?
Kevin
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Maybe disk or freespace contention within the TEMP tablespace?
Interesting question; my assumption of course is that GTT is faster, at worst, but that there are relatively few situations in which it can be used.
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| Re: Difference in DML operations on Table and Global temp table [message #411505 is a reply to message #411350] |
Sat, 04 July 2009 07:41 |
rleishman
Messages: 3190
Registered: October 2005
Location: Melbourne, Australia |
Senior Member |
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| JRowbottom wrote on Fri, 03 July 2009 18:12 | | Quote: | ...and it bypasses buffer cache.
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Does it?
I've never heard that - do you have any more details?
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I don't have any actual facts, just speculation and wild assumptions - but logically what COULD it do with the buffer cache?
The Buffer Cache contains SHARED blocks read from disk and blocks to be written back to disk. Data in a GTT is not shareable; although it may be written to disk, it is only done as part of memory management - not permanent storage.
Or - to be more precise - the Buffer Cache is part of the SGA - GTT data is part of the PGA.
Ross Leishman
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