Reduce overhead in blob cache service get #96399
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Avoid the use of KeyedLock, which has a high overhead for uncontended locks. Reduce granularity of lock during #get to the actual region. Relates elastic#96372
henningandersen added >enhancement :Distributed Coordination/Snapshot/Restore 
| Hi @henningandersen, I've created a changelog YAML for you. |
henningandersen commented May 28, 2023
| if (entry.chunk.sharedBytesPos == -1) { | ||
| synchronized (entry.chunk) { | ||
| if (entry.chunk.sharedBytesPos == -1) { | ||
| if (keyMapping.get(regionKey) != entry) { |
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We can also assign -2 to sharedBytesPos in this case instead. I think it does not really matter, we expect near no contention here.
original-brownbear approved these changes May 28, 2023
elasticsearchmachine added the Team:Distributed (Obsolete) | Pinging @elastic/es-distributed (Team:Distributed) |
volodk85 reviewed May 29, 2023
...ugin/blob-cache/src/main/java/org/elasticsearch/blobcache/shared/SharedBlobCacheService.java Show resolved Hide resolved
original-brownbear approved these changes May 30, 2023
| } | ||
| return entry.chunk; | ||
| } | ||
| if (Assertions.ENABLED) { |
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NIT: maybe move this kind of assertion to a separate method (that can just include the next assertion below) to save a little on method size here? (probably not too relevant but also makes the method easier to read IMO)
| Thanks Armin! |
henningandersen added a commit to henningandersen/elasticsearch that referenced this pull request May 31, 2023
In racy evict cases, assertions in blob cache did not hold, adapted test and added fixes. Relates elastic#96399
henningandersen added a commit that referenced this pull request Jun 1, 2023
In racy evict cases, assertions in blob cache did not hold, adapted test and added fixes. Relates #96399
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Avoid the use of KeyedLock, which has a high overhead for uncontended locks. Reduce granularity of lock during #get to the actual region.
Relates #96372