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Row Chaining problem [message #343378] Wed, 27 August 2008 02:03 Go to next message
sudhir1582
Messages: 17
Registered: December 2007
Junior Member
Hi

I'm facing the problem of row chaining in some of the tables. where in database DB_BLOCK_SIZE=8192 and oracle version is 10g

Can any one tell me how to eliminate the row chaining problem permanently from the tables , without recreating the database with higher db_block_size.

Thank& Regards
Sudhir

Re: Row Chaining problem [message #343416 is a reply to message #343378] Wed, 27 August 2008 04:29 Go to previous message
JRowbottom
Messages: 5933
Registered: June 2006
Location: Sunny North Yorkshire, ho...
Senior Member
Do you mean row-chaining, or row migration?

If you insert a row that is larger than the block size, then it will be inserted across a series of blocks. This is Row-Chaining.
If your row is larger than the block, then it will happen, and there's nothing you can do about it

If you have an application where you update rows that were created a while ago, and increase the amount of data in that row such that it takes up more space than the block has free, then the row gets moved to a new block. This is row migration.

You can minimise this problem in manual tablespaces by setting the PCTFREE and PCTUSED to leave enough free space in a block to hold the average length of a row. (Documentation)
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