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 <mac.mik...@googlemail.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 <mac.mik...@googlemail.com> > wrote: >> >> I've just found, that JNA will be not used from 1.1 release - >> https://issues.apache.org/jira/browse/CASSANDRA-3271 >> I would be also nice to know what was the reason for this decision. >> >> Regards, >> Maciej >> >> On Wed, Nov 2, 2011 at 1:34 PM, Viktor Jevdokimov >> <viktor.jevdoki...@adform.com> wrote: >>> >>> Up, also interested in answers to questions below. >>> >>> >>> Best regards/ Pagarbiai >>> >>> Viktor Jevdokimov >>> Senior Developer >>> >>> Email: viktor.jevdoki...@adform.com >>> Phone: +370 5 212 3063 >>> Fax: +370 5 261 0453 >>> >>> J. Jasinskio 16C, >>> LT-01112 Vilnius, >>> Lithuania >>> >>> >>> >>> Disclaimer: The information contained in this message and attachments is >>> intended solely for the attention and use of the named addressee and may be >>> confidential. If you are not the intended recipient, you are reminded that >>> the information remains the property of the sender. You must not use, >>> disclose, distribute, copy, print or rely on this e-mail. If you have >>> received this message in error, please contact the sender immediately and >>> irrevocably delete this message and any copies.-----Original Message----- >>> From: Maciej Miklas [mailto:mac.mik...@googlemail.com] >>> Sent: Tuesday, November 01, 2011 11:15 >>> To: user@cassandra.apache.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? >>> >>> Thanks, >>> Maciej >>> >> > > -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
