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From Mark Jones <MJo...@imagehawk.com>
Subject RE: Trove maps
Date Fri, 23 Apr 2010 20:59:18 GMT
Eliminating GC hell would probably do a lot to help Cassandra maintain speed vs periods of
superfast/superslow performance.  I look forward to hearing how this experiment goes.

From: Eric Hauser [mailto:ewhauser@gmail.com]
Sent: Friday, April 23, 2010 3:37 PM
To: user@cassandra.apache.org
Subject: Re: Trove maps

According to their license page, it is LGPL.

On Fri, Apr 23, 2010 at 4:25 PM, Avinash Lakshman <avinash.lakshman@gmail.com<mailto:avinash.lakshman@gmail.com>>
wrote:
I think the GPL license of Trove prevents us from using it in Cassadra. But yes for all its
maps it uses Open Addressing which is much more memory efficient than linear chaining that
is employed in the JDK.

Avinash
On Fri, Apr 23, 2010 at 1:22 PM, Carlos Sanchez <carlos.sanchez@riskmetrics.com<mailto:carlos.sanchez@riskmetrics.com>>
wrote:
I will try to modify the code... what I like about Trove is that even for regular maps (non
primitive) there are no Entry objects created so there are much less references to be gced

On Apr 23, 2010, at 2:55 PM, Jonathan Ellis wrote:

> From what I have seen Trove is only a win when you are doing Maps of
> primitives, which is mostly not what we use in Cassandra.  (The one
> exception I can think of is a map of int -> columnfamilies in
> CommitLogHeader.  You're welcome to experiment and see if using Trove
> there or elsewhere makes a measurable difference with stress.py.)
>
> -Jonathan
>
> On Fri, Apr 23, 2010 at 2:50 PM, Carlos Sanchez
> <carlos.sanchez@riskmetrics.com<mailto:carlos.sanchez@riskmetrics.com>> wrote:
>> Jonathan,
>>
>> Have you thought of using Trove collections instead of regular java collections (HashMap
/ HashSet) in Cassandra? Trove maps are faster and require less memory
>>
>> Carlos
>>
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