Optimizing single-table queries
Consider all possible plans
Combine index scans
Bitmap Index Scan
- During the index scan, populate a bitmap identifying pages. I.e.
bitmap[i] is 0 if page i of the heap is not needed, 1 if
it is needed.
- After the index scan, the heap pages can be read.
- Consolidates references to pages.
- Also orders them, which may trade random accesses for sequential accesses.
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