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The CPU Costing Model: A Few Thoughts Part I
In the coming days, I’ll post a series of little entries highlighting a specific point in relation to the use of system statistics and the CPU cost model. In my previous post, we looked at how the cost...
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The CPU Costing Model – A Few Thoughts Part II
As previously discussed, the formula used by the CBO using the CPU costing model is basically: (sum of all the single block I/Os x average wait time for a single block I/O + sum of all the multiblock...
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The CPU Costing Model: A Few Thoughts Part IV (Map of the Problematique)
It’s called the CPU Costing model because among other things, it includes the time associated with performing CPU operations. The CPU Costing model formula once again: (sum of all the single block...
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The CPU Costing Model: A Few Thoughts Part V (Reality)
There’s plenty more I could talk about regarding the CBO CPU costing model and system statistics but I’ll make this my final little comment on this subject for now. As previously discussed, the CPU...
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How Does An Execution Plan Suddenly Change When The Statistics (And...
I’ve slipped this post in as there have been a number of discussions recently on how execution plans have changed while nothing else appears to have changed in the database. How can an execution plan...
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Concatenated Bitmap Indexes Part II (Everybody’s Got To Learn Sometime)
A basic little post to conclude this discussion. The issues regarding whether to go for single column indexes vs. concatenated indexes are similar for Bitmap indexes as they are for B-Tree indexes....
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Important !! Clustering Factor Calculation Improvement (Fix You)
Believe me, this article is worth reading I’m currently not allowed to discuss Oracle 12c Database goodies but I am allowed to discuss things perhaps initially intended for 12c that are currently...
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Clustering Factor Calculation Improvement Part II (Blocks On Blocks)
My previous post on the new TABLE_CACHED_BLOCKS statistics gathering preference certainly generated some interest My blog hits for the week have gone off the charts !! One of the concerns raised by...
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