[HIVE-16520] Cache hive metadata in metastore

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0
• Component/s: Metastore
• Target Version/s: 3.0.0
• Hadoop Flags: Reviewed
• Release Note: To use CachedStore, please set hive.metastore.rawstore.impl to "org.apache.hadoop.hive.metastore.cache.CachedStore" in hive-site.xml.
• Assignee: Daniel Dai
• Reporter: Daniel Dai
• Created: 24/Apr/17 18:04
• Updated: 01/Nov/18 19:33
• Resolved: 01/May/17 20:55

Description

During Hive 2 benchmark, we find Hive metastore operation take a lot of time and thus slow down Hive compilation. In some extreme case, it takes much longer than the actual query run time. Especially, we find the latency of cloud db is very high and 90% of total query runtime is waiting for metastore SQL database operations. Based on this observation, the metastore operation performance will be greatly enhanced if we have a memory structure which cache the database query result.

Issue Links

• is related to: HIVE-18039 Use ConcurrentHashMap for CachedStore
• links to: GitHub Pull Request #173
• links to: Proposal

Sub-Tasks

• CachedStore: make prewarm and background cache update multithreaded: Open
• Fix remaining unit test failures when CachedStore is enabled: Open
• CachedStore: Investigate TestCachedStore#testTableColStatsOps: Open
• CachedStore: Fix UT when CachedStore is enabled: Patch Available
• CachedStore: Run a select q file tests with CachedStore enabled: Open