[ACCUMULO-4641] Modify BlockCache interface to avoid race conditions

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.0.0
• Labels: pull-request-available
• Assignee: Keith Turner
• Reporter: Keith Turner
• Created: 19/May/17 17:03
• Updated: 06/Feb/23 13:44
• Resolved: 15/Feb/18 17:09

Description

Currently the BlockCache interface has functions to get and put. Accumulo will try to get a block, if it does not exist load it, and then put it in the cache. This can lead to race conditions where multiple threads unnecessarily load the same block.

I think it would be better to modify the block cache interface to only have a function like the following.

  CacheEntry get(String blockName, BlockLoader loader)

BlockLoader represents a function that the cache can call if a block is not present. The cache implementation can attempt to handle load race conditions however it likes..

Issue Links

• duplicates: ACCUMULO-4462 Refactor cache code to avoid dog piliing
• links to: GitHub Pull Request #321