accumulo-notifications mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Josh Elser (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (ACCUMULO-3508) Zoocache utilizes course grained locking causing unnecessary synchronization in many tserver ops
Date Thu, 22 Jan 2015 18:06:35 GMT

    [ https://issues.apache.org/jira/browse/ACCUMULO-3508?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14287874#comment-14287874
] 

Josh Elser commented on ACCUMULO-3508:
--------------------------------------

[~phrocker], I've added you as a contributor. Look forward to a patch -- thanks!

> Zoocache utilizes course grained locking causing unnecessary synchronization in many
tserver ops
> ------------------------------------------------------------------------------------------------
>
>                 Key: ACCUMULO-3508
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-3508
>             Project: Accumulo
>          Issue Type: Sub-task
>          Components: fate
>    Affects Versions: 1.6.0
>            Reporter: marco polo
>            Priority: Minor
>             Fix For: 1.6.3
>
>
> Through jstacking I have observed busy tablet server threads waiting for the Zoocache
to be updated or even read. Profiling via yourkit indicates potential deadlocks when threads
wait for a long period of time ( in my case my waits were 10+s ) when many scans were running
against my instance.
> My patch, which is forthcoming, removes synchronization and utilizes a reentrant read/write
lock (RERWL) to synchronize the maps. My initial design utilized concurrent hash maps, but
the design of existence becomes simpler and changes fewer by using the RERWL. 



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

Mime
View raw message