Super - thank you for help :)
Relying on that was always a terrible idea because you could easily
OOM before it could help. There's no substitute for "don't make the
caches too large" in the first place.
We're working on https://issues.apache.org/jira/browse/CASSANDRA-3143
to make cache sizing easier.
On Thu, Nov 3, 2011 at 3:16 AM, Maciej Miklas <email@example.com> wrote:
> According to source code, JNA is being used to call malloc and free. In this
> case each cached row will be serialized into RAM.
> We must be really careful when defining cache size - to large size would
> cause out of memory. Previous Cassandra releases has logic that would
> decrease cache size if heap is low.
> Currently each row will be serialized without any memory limit checks -
> assuming that I understood it right.
> Those properties:
> reduce_cache_sizes_at: 0.85
> reduce_cache_capacity_to: 0.6
> are not used anymore - at least not when JNA is enabled, witch is default
> from Cassandra 1.0
> On Wed, Nov 2, 2011 at 1:53 PM, Maciej Miklas <firstname.lastname@example.org>
>> I've just found, that JNA will be not used from 1.1 release -
>> I would be also nice to know what was the reason for this decision.
>> On Wed, Nov 2, 2011 at 1:34 PM, Viktor Jevdokimov
>> <Viktor.Jevdokimov@adform.com> wrote:
>>> Up, also interested in answers to questions below.
>>> Best regards/ Pagarbiai
>>> Viktor Jevdokimov
>>> Senior Developer
>>> Email: Viktor.Jevdokimov@adform.com
>>> Phone: +370 5 212 3063
>>> Fax: +370 5 261 0453
>>> J. Jasinskio 16C,
>>> LT-01112 Vilnius,
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>>> irrevocably delete this message and any copies.-----Original Message-----
>>> From: Maciej Miklas [mailto:email@example.com]
>>> Sent: Tuesday, November 01, 2011 11:15
>>> To: firstname.lastname@example.org
>>> Subject: Cassandra 1.x and proper JNA setup
>>> Hi all,
>>> is there any documentation about proper JNA configuration?
>>> I do not understand few things:
>>> 1) Does JNA use JVM heap settings?
>>> 2) Do I need to decrease max heap size while using JNA?
>>> 3) How do I limit RAM allocated by JNA?
>>> 4) Where can I see / monitor row cache size?
>>> 5) I've configured JNA just for test on my dev computer and so far I've
>>> noticed serious performance issues (high cpu usage on heavy write load), so
>>> I must be doing something wrong.... I've just copied JNA jars into
>>> Cassandra/lib, without installing any native libs. This should not work at
>>> all, right?
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support