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Re: Big table joining [message #597205 is a reply to message #597203] |
Tue, 01 October 2013 10:15 |
cookiemonster
Messages: 13943 Registered: September 2008 Location: Rainy Manchester
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Senior Member |
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because oracle has decided it would be less efficient to use the pk than do a full table scan.
Since you are doing select * oracle still has to go to the actual t2 table to get the data so going back and forth from the index is just unnecessary overhead.
EDIT: typo
[Updated on: Tue, 01 October 2013 10:15] Report message to a moderator
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Re: Big table joining [message #597206 is a reply to message #597205] |
Tue, 01 October 2013 10:19 |
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BlackSwan
Messages: 26766 Registered: January 2009 Location: SoCal
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Senior Member |
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>Why the big tables are not using index
how many rows must exist to have any table be labeled as "big"
some, many, most folks would NOT consider table with fewer than 50,000 rows to be "big".
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