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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Timed out reads still in queue
Date Wed, 12 May 2010 14:40:21 GMT
This is a slightly different way of describing
https://issues.apache.org/jira/browse/CASSANDRA-685

On Tue, May 11, 2010 at 9:01 PM, Jeremy Dunck <jdunck@gmail.com> wrote:
> Reddit posted a blog entry about some recent downtime, partially due
> to issues with Cassandra.
> http://blog.reddit.com/2010/05/reddits-may-2010-state-of-servers.html
>
> This part surprised me:
> "
> First, Cassandra has an internal queue of work to do. When it times
> out a client (10s by default), it still leaves the operation in the
> queue of work to complete (even though the person that asked for the
> read is no longer even holding the socket), which given a constant
> stream of requests makes the amount of pending work snowball
> effectively infinitely (specifically, ROW-READ-STAGE's PENDING
> operations grow unbounded).
> "
>
> I've searched Jira for an issue related to this -- it seems like a bug
> to have reads in queue when the result is useless (because the reader
> is gone).  Obviously a 10-second read is not a normal run condition,
> but removing stale reads could remove a cause of cascading failure.
>
> Should I open a ticket, or have I misunderstood something?
>



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com

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