flink-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-9070) Improve performance of RocksDBMapState.clear()
Date Wed, 16 May 2018 18:28:01 GMT

    [ https://issues.apache.org/jira/browse/FLINK-9070?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16477867#comment-16477867
] 

ASF GitHub Bot commented on FLINK-9070:
---------------------------------------

Github user StephanEwen commented on the issue:

    https://github.com/apache/flink/pull/5979
  
    Could you share some micro-benchmark numbers?
    When we change something that we know works well to something new, would be good to understand
what benefits we are talking about.


> Improve performance of RocksDBMapState.clear()
> ----------------------------------------------
>
>                 Key: FLINK-9070
>                 URL: https://issues.apache.org/jira/browse/FLINK-9070
>             Project: Flink
>          Issue Type: Improvement
>          Components: State Backends, Checkpointing
>    Affects Versions: 1.6.0
>            Reporter: Truong Duc Kien
>            Assignee: Sihua Zhou
>            Priority: Major
>             Fix For: 1.6.0
>
>
> Currently, RocksDBMapState.clear() is implemented by iterating over all the keys and
drop them one by one. This iteration can be quite slow with: 
>  * Large maps
>  * High-churn maps with a lot of tombstones
> There are a few methods to speed-up deletion for a range of keys, each with their own
caveats:
>  * DeleteRange: still experimental, likely buggy
>  * DeleteFilesInRange + CompactRange: only good for large ranges
>  
> Flink can also keep a list of inserted keys in-memory, then directly delete them without
having to iterate over the Rocksdb database again. 
>  
> Reference:
>  * [RocksDB article about range deletion|https://github.com/facebook/rocksdb/wiki/Delete-A-Range-Of-Keys]
>  * [Bug in DeleteRange|https://pingcap.com/blog/2017-09-08-rocksdbbug]
>  



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

Mime
View raw message