Keyphrases
- query optimization
- database systems
- query rewriting
- query processing
- cost model
- multidatabase systems
- query execution
- cardinality estimation
- query scheduling
- semantic query optimization
- query optimizer
- xml data
- materialized views
- cost estimation
- efficient execution
- selectivity estimation
- database
- recursive queries
- query optimizers
- approximate query answering
- data placement
- query containment
- relational database systems
- data sources
- databases