| 摘要 |
The subject technology provides querying structured and unstructured data across disparate incompatible systems with a single language and connection point. Cost based optimizations are provided for executing the query. In some configurations, logical plans for executing a query are generated. For each of the logical plans, the subject technology generates a set of physical plans for executing the query on data systems, determines an execution cost for each physical plan from the physical plans, and selects a respective physical plan with a lowest determined execution cost among the determined execution cost for each physical plan. A physical plan is then selected for execution with a lowest execution cost among the selected respective physical plans of each of the logical plans. Data from an operation from the query may then be persisted and then used for generating a new set of logical and physical plans for executing a remaining set of operations from the query.
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