Re: Netflix Billing Migration to AWS

[daemeon reiydelle]

Thanks, interesting.


*...*



*Daemeon C.M. ReiydelleUSA (+1) 415.501.0198London (+44) (0) 20 8144 9872*

On Tue, Jun 21, 2016 at 9:24 PM, Mahdi Mohammadi  wrote:

> Worth reading. It has references to Cassandra and how/where they use it.
>
> http://techblog.netflix.com/2016/06/netflix-billing-migration-to-aws.html
>
>
> Best Regards
>

Netflix Billing Migration to AWS

[Mahdi Mohammadi]

Worth reading. It has references to Cassandra and how/where they use it.

http://techblog.netflix.com/2016/06/netflix-billing-migration-to-aws.html


Best Regards

BufferPool always allocates on heap?

[Nimi Wariboko Jr]

Hi,

I'm trying to debug an issue I'm having with Cassandra 3.6+ and Snappy
compressed tables - CASSANDRA-11993 (that may be related to CASSANDRA-5863).

I'm probably 3% familiar with Cassandra internals, so apologies if I'm
wrong here - I was looking at a change in CASSANDRA-5863 where a cache was
added to the SSTableIterator code path, which may have
included org.apache.cassandra.utils.memory.BufferPool into the read path.

My confusion comes from here - AFAICT, when the BufferPool needs to
allocate more memory, it calls allocate(int size, boolean onHeap) (
https://github.com/apache/cassandra/blob/30bb255ec9fb36ace2aab51474bd3bfb9bbd3bed/src/java/org/apache/cassandra/utils/memory/BufferPool.java#L82).
The value for whether onHeap is true is
constant ALLOCATE_ON_HEAP_WHEN_EXAHUSTED.

ALLOCATE_ON_HEAP_WHEN_EXAHUSTED is defined by the yaml
setting buffer_pool_use_heap_if_exhausted which is true by default (and was
so in my install).

Further still (
https://github.com/apache/cassandra/blob/30bb255ec9fb36ace2aab51474bd3bfb9bbd3bed/src/java/org/apache/cassandra/utils/memory/BufferPool.java),
I can't see any logic where BufferPool will actually allocate off heap
memory - it seems, due to the buffer_pool_use_heap_if_exhausted setting,
always allocate memory on heap. It never checks if the off heap memory is
exhausted (AFAICT from these 3 files).

Sure enough, if I set buffer_pool_use_heap_if_exhausted, my issue at
CASSANDRA-11993 goes away (I think? I'm having a number of issues lately
and I may have traded one exception for another).

Is this the correct behavior of buffer_pool_use_heap_if_exhausted?

Nimi

Easy path to the latest Cassandra in Ubuntu

[Evan Dandrea]

Hi,

Ubuntu 16.04 comes with a new way to deliver applications (
http://snapcraft.io), and I thought it would be a great way to simplify
getting set up with Cassandra.

So now, if you run the following on any Ubuntu 16.04 system

snap install cassandra && snap connect cassandra:mount-observe
ubuntu-core:mount-observe

Cassandra 3.7 will be installed with Java and the rest of the dependencies
bundled in. You can even install the tip of master (built about once a day):

snap install --channel=edge cassandra && snap connect
cassandra:mount-observe ubuntu-core:mount-observe

Or if you already installed 3.7:

snap refresh --channel=edge cassandra

None of this requires complex packaging or approval from the distribution
powers that be. If we move the snapcraft.yaml file [1] to a tree owned by
the dev community you can completely control upload and publishing.

This isn't limited to Ubuntu, either. If you install snapd this will work
on Arch, Debian, Fedora, and Gentoo too.

What do you think? I'd be happy to walk anyone through the details or put
together a pull request.

1: https://github.com/evandandrea/cassandra-snap/blob/master/snapcraft.yaml