[HBASE-27796] Improve MemcachedBlockCache

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.5.4
• Fix Version/s: 2.6.0, 3.0.0-alpha-4, 2.5.5
• Hadoop Flags: Reviewed
• Assignee: Andrew Kyle Purtell
• Reporter: Andrew Kyle Purtell
• Created: 14/Apr/23 17:57
• Updated: 19/Apr/23 05:37
• Resolved: 17/Apr/23 21:19

Description

MemcachedBlockCache is apparently not used, given the bugs I have found, but provides some useful functionality that we are investigating at $dayjob. Fix it.

• Track and log better stats

• Fix use of memcached API such that we are not accidentally immediately expiring keys.

• Use a default retention period of 30 days, the max per memcached spec

• Use set instead of add to store keys

• Gracefully handle failures to cache and read timeouts

• Add unit tests using jmemcached as a test dependency

Issue Links

• links to: GitHub Pull Request #5181