cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "graham sanderson (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (CASSANDRA-7546) AtomicSortedColumns.addAllWithSizeDelta has a spin loop that allocates memory
Date Fri, 10 Oct 2014 22:02:34 GMT

     [ https://issues.apache.org/jira/browse/CASSANDRA-7546?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

graham sanderson updated CASSANDRA-7546:
----------------------------------------
    Attachment: graph4_7546.png

See previous comment for discussion (note I also realized I didn't change the labels correctly
on graph3, but that was of heap_buffers and hinting)

!graph4_7546.png!

> AtomicSortedColumns.addAllWithSizeDelta has a spin loop that allocates memory
> -----------------------------------------------------------------------------
>
>                 Key: CASSANDRA-7546
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7546
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>            Reporter: graham sanderson
>            Assignee: graham sanderson
>             Fix For: 2.1.1
>
>         Attachments: 7546.20.txt, 7546.20_2.txt, 7546.20_3.txt, 7546.20_4.txt, 7546.20_5.txt,
7546.20_6.txt, 7546.20_7.txt, 7546.20_7b.txt, 7546.20_alt.txt, 7546.20_async.txt, 7546.21_v1.txt,
cassandra-2.1-7546-v2.txt, cassandra-2.1-7546.txt, graph2_7546.png, graph3_7546.png, graph4_7546.png,
graphs1.png, hint_spikes.png, suggestion1.txt, suggestion1_21.txt, young_gen_gc.png
>
>
> In order to preserve atomicity, this code attempts to read, clone/update, then CAS the
state of the partition.
> Under heavy contention for updating a single partition this can cause some fairly staggering
memory growth (the more cores on your machine the worst it gets).
> Whilst many usage patterns don't do highly concurrent updates to the same partition,
hinting today, does, and in this case wild (order(s) of magnitude more than expected) memory
allocation rates can be seen (especially when the updates being hinted are small updates to
different partitions which can happen very fast on their own) - see CASSANDRA-7545
> It would be best to eliminate/reduce/limit the spinning memory allocation whilst not
slowing down the very common un-contended case.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message