facebook/presto — pull request #1987 by martint (2014-11-18 21:11:17+00:00)
Title: Optimize partition pruning for Hive client

- replace usage of Warehouse.makeSpecFromName with a more efficient implementation
- build filters based on all partition keys, even if they are missing and call
getPartitionNamesByParts. Use empty string as placeholder for missing filters
- short-circuit parsing partition key values and creating partition objects if
we can determine the partition doesn't match the predicate

This results in a speedup in planning time for a table with 500k partitions from 19s to 150ms.