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From Andrew <>
Subject Re: too many open files
Date Sun, 10 Aug 2014 01:50:18 GMT
Yes, that was the problem—I actually knew better, but had briefly overlooked this that when
I was doing some refactoring.  I am not the OP (although he himself realized his mistake).

if you follow the thread, I was explaining that the Datastax Java driver allowed me to basically
open a significantly large number of connections until the Cassandra server ran out of connections.
 Tyler was asking for a repro case and requesting that I file a possible bug, if this was
something that SHOULD have been caught on the client side (via the max connections client


On August 9, 2014 at 2:17:57 PM, Jonathan Haddad ( wrote:

It really doesn't need to be this complicated. You only need 1  
session per application. It's thread safe and manages the connection  
pool for you.  

On Sat, Aug 9, 2014 at 1:29 PM, Kevin Burton <> wrote:  
> Another idea to detect this is when the number of open sessions exceeds the  
> number of threads.  
> On Aug 9, 2014 10:59 AM, "Andrew" <> wrote:  
>> I just had a generator that (in the incorrect way) had a cluster as a  
>> member variable, and would call .connect() repeatedly. I _thought_,  
>> incorrectly, that the Session was thread unsafe, and so I should request a  
>> separate Session each time—obviously wrong in hind sight.  
>> There was no special logic; I had a restriction of about 128 connections  
>> per host, but the connections were in the 100s of thousands, like the OP  
>> mentioned. Again, I’ll see about reproducing it on Monday, but just wanted  
>> the repro steps (overall) to live somewhere in case I can’t. :)  
>> Andrew  
>> On August 8, 2014 at 4:08:50 PM, Tyler Hobbs ( wrote:  
>> On Fri, Aug 8, 2014 at 5:52 PM, Redmumba <> wrote:  
>>> Just to chime in, I also ran into this issue when I was migrating to the  
>>> Datastax client. Instead of reusing the session, I was opening a new session
>>> each time. For some reason, even though I was still closing the session on  
>>> the client side, I was getting the same error.  
>> Which driver? If you can still reproduce this, would you mind opening a  
>> ticket? (  
>> --  
>> Tyler Hobbs  
>> DataStax  

Jon Haddad  
skype: rustyrazorblade  

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