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https://issues.apache.org/jira/browse/CASSANDRA-8897?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14481220#comment-14481220
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Benedict commented on CASSANDRA-8897:
-------------------------------------
bq. Does the buffer pool need to support metrics just like the FileCacheService
did?
Perhaps. At most, though, we need to indicate how often we fail a cache lookup,
since it shouldn't really ever happen in the new scheme on a healthy system.
bq. What about the maximum memory size beyond which it cannot grow?
The file cache size in Config.java specifies how big we should keep any cached
portion to, but we will have to still produce a buffer if this cache is
exhausted.
bq. Should we create an initial number of buffers or should we just grow the
pool dynamically?
I don't think it matters terribly. I would personally opt for a small core pool
of a few megabytes allocated upfront, with the remainder grown dynamically.
bq. Should the pool be only a replacement of FileCacheService, therefore used
only by PoolingSegmentedFile and derived classes when calling
createPooledReader(), or should the scope be extended to all RARs created by
SegmentedFile instances?
I think PoolingSegmentedFile and PoolingBufferedFile can simply be removed
entirely, and these pooled buffers can be shared between all SegmentedFile
instances
> Remove FileCacheService, instead pooling the buffers
> ----------------------------------------------------
>
> Key: CASSANDRA-8897
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8897
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Benedict
> Assignee: Stefania
> Fix For: 3.0
>
>
> After CASSANDRA-8893, a RAR will be a very lightweight object and will not
> need caching, so we can eliminate this cache entirely. Instead we should have
> a pool of buffers that are page-aligned.
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