Changing the compression level of query plans

摘要

In an embodiment, a query plan is compressed to data in a cache at a high compression level if a runtime of a query that the query plan implements is greater than a high time threshold. The query plan is compressed to the data in the cache at a medium compression level if the runtime of the query that the query plan implements is less than the high time threshold and greater than a low time threshold. The query plan is stored to the data in the cache at an uncompressed level if the runtime of the query that the query plan implements is less than the low time threshold.

主权项

1. A computer-implemented method, comprising:
generating a plurality of query plans, each plan for executing a respective query against data in a database; with respect to each query plan of said plurality of query plans, selectively determining whether the respective query plan should be stored to data in a cache in a compressed form; with respect to each query plan of said plurality of query plans for which it is selectively determined that the respective query plan should be stored to data in a cache in a compressed form, storing the query plan to data in the cache in a compressed form; and with respect to each query plan of said plurality of query plans for which it is selectively determined that the respective query plan should not be stored to data in a cache in a compressed form, storing the query plan to data in the cache in an uncompressed form; wherein said selectively determining whether the respective query plan should be stored to data in a cache in a compressed form comprises determining whether at least one parameter of characterization data exceeds at least one threshold.