[jira] [Updated] (CASSANDRA-4865) Off-heap bloom filters

["Vijay (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CASSANDRA-4865?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Vijay updated CASSANDRA-4865:
-----------------------------

    Attachment: 0001-CASSANDRA-4865.patch

Good news, The new implementation uses byte's instead of longs which gives us approximately 20% better performance. In Practice it should save some GC time too.

Time taken for approx 200 Million iterations each.

|Open BS set's|Open BS get's|Offheap BS set's|Offheap BS get's|
|502||371||311||64|
|507||444||257||366|
|496||478||310||367|
|504||473||306||369|
|490||481||305||367|
|502||472||314||363|
|489||476||305||367|
|486||474||303||364|
|489||474||307||365|
|492||477||305||365|
|490||475||307||367|

Attached patch enables offheap BS only for SSTable BF's and leaves the Promoted indexes alone.
Attached patch will break the existing 1.2-beta users, New BF serialization is changed. (is that expected or ok to do?)

Pending/ TODO's: 
1) have to figure out why Scrub test trys to free memory twice.
2) Have to regenerate Corrupted SST's (unit test failure).

                
> Off-heap bloom filters
> ----------------------
>
>                 Key: CASSANDRA-4865
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-4865
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Jonathan Ellis
>            Assignee: Vijay
>             Fix For: 1.2.1
>
>         Attachments: 0001-CASSANDRA-4865.patch
>
>
> Bloom filters are the major user of heap as dataset grows.  It's probably worth it to move these off heap.  No extra refcounting needs to be done since we already refcount SSTableReader.

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