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Will Deleting rows from Table improve Performance? [message #201466] Sat, 04 November 2006 12:43 Go to next message
kumarsz
Messages: 180
Registered: March 2005
Location: canada
Senior Member
Hi,
i am using oracle 9.2.0.6.0 on Linux

one of our table has millions of rows

If i delete some of the rows from table will i get performance benefit or ONLy truncating will improve performance as it will reset High Water Mark and queries while (FTS) scans till High Water Mark only

above query is for tow scenarios
1) accessing table via index (no FTS)
2) accessing table without index


Thanks and REgards,
Pratap

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Re: Will Deleting rows from Table improve Performance? [message #201469 is a reply to message #201466] Sat, 04 November 2006 13:35 Go to previous messageGo to next message
Littlefoot
Messages: 21823
Registered: June 2005
Location: Croatia, Europe
Senior Member
Account Moderator
If you truncate the table, query that selects from that table will run at light speed because it will be empty Smile

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Re: Will Deleting rows from Table improve Performance? [message #201471 is a reply to message #201466] Sat, 04 November 2006 14:12 Go to previous message
kimant
Messages: 201
Registered: August 2006
Location: Denmark
Senior Member
If You delete, the query using index should get the benefit.
Depending how much You delete, it might benefit from a rebuild of the index too.

Why do You not try it out?

Just CTAS to make a copy of Your many million rows table, create the index etc.....

Br
Kim

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