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Re: [External]Re: I/O threads busy error


Hi Vishal,
This might be an indication that you are sending several requests in
parallel without waiting for a response and you need to introduce
throttling in your application, as Dinesh mentioned.

This issue is related to the usage of the DataStax C++ driver, you should
consider starting a new mail thread on the driver mailing list:
https://groups.google.com/a/lists.datastax.com/forum/#!forum/cpp-driver-user

Regards,
Jorge

El mar., 20 nov. 2018 a las 13:42, <Vishal1.Sharma@xxxxxxx> escribió:

> This issue is mainly being observed when the table whose data is being
> fetched contains a column which stores a very large text(12.5 KB). Could
> this be a possible reason? How can I solve the issue? Which settings do I
> have to change?
>
> -----Original Message-----
> From: dinesh.joshi@xxxxxxxxx.INVALID [mailto:
> dinesh.joshi@xxxxxxxxx.INVALID]
> Sent: Tuesday, November 20, 2018 3:15 PM
> To: dev@xxxxxxxxxxxxxxxxxxxx
> Subject: [External]Re: I/O threads busy error
>
> You're probably hitting this -
> https://github.com/datastax/cpp-driver/blob/2.0/src/session.cpp#L740
> From my reading it feels you may want to throttle your queries or play
> around with the driver settings. Essentially it seems the number of queries
> you're issuing is greater than what the cluster can handle and therefore
> they're queuing up in the driver.
> Dinesh
>
>     On Monday, November 19, 2018, 10:24:10 PM PST, Vishal1.Sharma@xxxxxxx
> <Vishal1.Sharma@xxxxxxx> wrote:
>
>  Dear all,
> I've got a 2 node Cassandra cluster(3.11.2). I'm using Datastax's c++
> driver(ver 2.7) in my application to fetch/add data from the cluster(RHEL
> 6.9). Sometimes I'm getting the error "All connections on all I/O threads
> are busy" in my application.  I'm unable to figure out why I am getting
> this error infrequently and not everytime.
>
> Has anyone faced such errors before? Please let me know any possible
> reasons behind the issue.
>
> Thanks and regards,
> Vishal Sharma
>
> P.S. I don't really know whether this is a Datastax driver's issue or
> Cassandra's issue that's why I'm posting this query here.
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