Contenu connexe
Similaire à Indexing & query optimization (20)
Indexing & query optimization
- 4. Ack! My queries are slow! http://michaelprescott.typepad.com/.a/6a00d83451574c69e20134858a87a2970c-800wi
- 7. Table scans 1 2 3 4 5 6 7 Looked at 7 objects Find where x equals 7
- 8. Tree Lookup 7 6 5 4 3 2 1 Looked at 3 objects Find where x equals 7
- 9. O(n) vs. O(log n) Table scan Index Number of records Number of comparisons