Statistics in Catalogs
- Number of Tuples
- Number of Pages
- Number of Distinct Key Values
- Low/High Key Values
- Index Tree Height
- Number of Index Pages
- 1 / Number of Distinct Key Values
- 1 / Max (Number of Distinct Key Values in A, Number of Distinct Key Values in B)
- Size of Selected Range in A / Total Range in A
- Input Size * All Reduction Factors = Output Size
- Join Output Size: Number of Tuples in A * Number of Tuples in B / Number of Distinct Key Values for Join Attributes
- Only consider left-deep plans which can be fully pipelined.
- Pass 1: Find best 1-relation plans for each relations. Enumerating all access methods, selectivities, etc.
- Pass 2: Find best join of each 1-relation plan as outer to another relation, considering all join methods.
- Pass 3: Find best join for remaining relations
Transactions, Concurrency and Recovery
Another good slides: