Re: Table with 300 columns (ie > 255) : Row Chaining ?
- From: Hemant K Chitale <hkchital@xxxxxxxxxxxxxx>
- To: Christian.Antognini@xxxxxxxxxxxx
- Date: Mon, 19 Oct 2009 23:29:26 +0800
"In other words, the pieces are split and stored in "reverse order". "
I didn't know that. Also, the splilt at the 96th column was the
surprise. Why 96 ?
What if the table has 250 columns ? Then it is a single row piece
without a split ?
If so, how is 96 a split boundary when the number of columns exceeds 255 ?
Hemant K Chitale
http://hemantoracledba.blogspot.com
At 04:02 PM Monday, Christian Antognini wrote:
Hi Hemant
This is probably because the split occurs between column 95 and 96. Do a
block dump to check it... This is because the first row piece is not of
"full length". In other words, the pieces are split and stored in
"reverse order". For example, if you have a chained row that is stored
in two blocks, not only the first column is stored in a block coming
after the block containing the last row, but in addition the first piece
is smaller than the second one. Go figure why...
HTH
Chris
Troubleshooting Oracle Performance, Apress 2008
http://top.antognini.ch
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