[IMPALA-9197] Hash table lookup should be read-only

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: Impala 3.4.0
• Component/s: Backend
• Labels: multithreading
• Epic Link: Impala Multi-threaded query execution
• Epic Color: ghx-label-12
• Assignee: Tim Armstrong
• Reporter: Tim Armstrong
• Created: 25/Nov/19 17:57
• Updated: 17/Jan/20 22:19
• Resolved: 17/Jan/20 22:19

Description

For IMPALA-9156, we need concurrent lookups to the hash table to be thread safe. We are pretty close to that, except a few stats are maintained in HashTable and would be modified concurrently from multiple threads.

We should modify those places to update the stats in HashTableCtx instead.

Issue Links

• is depended upon by: IMPALA-9156 Share broadcast join builds between fragments