[
https://issues.apache.org/jira/browse/CASSANDRA-9472?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15112647#comment-15112647
]
Jack Krupansky commented on CASSANDRA-9472:
-------------------------------------------
A couple quick questions:
1. Does this Jira move memtables "entirely" offheap, or just "partially"? (Back
in July the discussion was that fully offheap was too large an effort.)
2. Is there still an "arena" allocation onheap?
3. What ballpark fraction of a typical Cassandra heap is consumed by memtables
- 80%, more, less?
4. Does moving memtables offheap get Cassandra to the point where a default JVM
heap allocation is sufficient? If not, please be sure to offer new recommended
best practice guidance as to how to estimate heap requirements when memtables
are offheap.
5. What heuristic rule/threshold is used to determine how much of system memory
can be consumed by offheap memtables? Is that limit user-controllable by a
(documented) configuration setting?
6. Are offheap memtables an optional configuration setting, or hardwired?
7. Is this coming soon, like 3.4, or is it still a ways off?
> Reintroduce off heap memtables
> ------------------------------
>
> Key: CASSANDRA-9472
> URL: https://issues.apache.org/jira/browse/CASSANDRA-9472
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Benedict
> Assignee: Benedict
> Fix For: 3.x
>
>
> CASSANDRA-8099 removes off heap memtables. We should reintroduce them ASAP.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
