Mon, Oct 25, 1999
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- Overview of Database Tuning

- Two Considerations (OLTP/OLAP)

- Options:
	- Tune Schema
		- Multiple Choices of Normalized Schema
		- BCNF vs 3NF
		- Horizontal Partitioning
			- e.g. students with gpa <= 2.5 and > 2.5
			- Use a VIEW to combine partitions
		- Vertical Partitioning
		- Store Aggregate Values
			- Differences among various aggregates
                          for "maintainability"
			- SUM (easiest)
			- AVG (need O(1) storage)
			- MAX (extremely difficult)

	- Index Options
		- Primary vs. Secondary
		- Dense vs. Sparse
		- B-Trees vs. Hash-tables etc.
		- Attribute to place index on
		- when to use a secondary index?

	- Query Optimization, by Hand
		- Controlling the use of indices
			- rewrite a=6 as a+0=6
			- rewrite a=b*2 as a/2 = b
			- table scans for small tables etc.
		- Try to replace subqueries by joins
			- not always possible
				- particularly when we have a DISTINCT
				  in the sub-block without a DISTINCT
				  at top
		- Try to replace multiple query "blocks" by one

- Examples of Tuning Tools
	- AutoAdmin for Microsoft SQL Server
	- RDB Expert for ORACLE