Re: Cassandra source code explained

2013-01-23 Thread Radek Gruchalski
Thanks everyone, This is very helpful. Kind regards,
 Radek Gruchalski radek.gruchal...@technicolor.com (mailto:radek.gruchal...@technicolor.com) | radek.gruchal...@portico.io (mailto:radek.gruchal...@portico.io) | 
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Unavaible Exception with Chunked Object Store

2013-01-23 Thread Sávio Teles
We are using ChunkedStorage described in https://github.com/Netflix/astyanax/wiki/Chunked-Object-Store to store large objects (about 40 MB). We have defined the chunk size to 1 MB. But, when this code is called, the exception UnavaibleException is thrown. Does anyone has any idea? Thanks in

Large commit log reasons

2013-01-23 Thread Víctor Hugo Oliveira Molinar
Hi fellows. I current have 3 nodes cluster running with a replication factor of 1. It's a pretty simple deployment and all my enforcements are focused in writes rather than reads. Actually I'm noticing that my commit log size is always very big if compared to the ammout of data being

Large commit log reasons

2013-01-23 Thread vhmolinar
Hi fellows. I current have 3 nodes cluster running with a replication factor of 1. It's a pretty simple deployment and all my enforcements are focused in writes rather than reads. Actually I'm noticing that my commit log size is always very big if compared to the ammout of data being

Re: Large commit log reasons

2013-01-23 Thread Edward Capriolo
By default Cassandra uses 1/3rd heap size for memtable storage. If you make sure memtables smaller they should flush faster and you commit logs should not grow large. Large commit logs are not a problem, some use cases that write to some Column Families more then other can make the commit log

Re: Is this how to read the output of nodetool cfhistograms?

2013-01-23 Thread Brian Tarbox
Wei, Thank you for the explanation (Offset is always the x-axis, the other columns represent the y-axis (taken 5 independent times)). Part of this still doesn't make sense. If I look at just read latencies for example...am I to believe that 1916 times I had a latency of exactly 3229500 usecs?

Re: Large commit log reasons

2013-01-23 Thread Edward Capriolo
1. The commit log is only read on startup. W: If writes are unflushed then the commit logs need to be replayed 2: shrink the memtable settings. but you dont want to do this. 3. Commit log size is not directly related to sstable size. E.g. if you write the same row a billion times the commit log

Re: Is this how to read the output of nodetool cfhistograms?

2013-01-23 Thread Derek Williams
The histogram uses buckets, so it isn't exact (which would be much more expensive to record). And you are reading it the wrong way, you have 3M reads taking ~1.9ms (just like you don't have 1 read using 16k sstables. which would be a bit extreme). On Wed, Jan 23, 2013 at 9:02 AM, Brian Tarbox

Re: Cassandra timeout whereas it is not much busy

2013-01-23 Thread Nicolas Lalevée
Le 22 janv. 2013 à 21:50, Rob Coli rc...@palominodb.com a écrit : On Wed, Jan 16, 2013 at 1:30 PM, Nicolas Lalevée nicolas.lale...@hibnet.org wrote: Here is the long story. After some long useless staring at the monitoring graphs, I gave a try to using the openjdk 6b24 rather than openjdk

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2013-01-23 Thread Samuel Lugassy
Cordialement, Samuel Lugassy Customer Solution Architect Mob: +33 6 30 01 24 68 samuel.luga...@scality.com

Perfroming simple CQL Query using pyhton db-api 2.0 fails

2013-01-23 Thread Paul van Hoven
I try to access my local cassandra database via python. Therefore I installed db-api 2.0 and thrift for accessing the database. Opening and closing a connection works fine. But a simply query is not working: The script looks like this: c = conn.cursor() c.execute(select * from users;)

Re: Cassandra pending compaction tasks keeps increasing

2013-01-23 Thread aaron morton
The histogram does not look right to me, too many SSTables for an LCS CF. It's a symptom no a cause. If LCS is catching up though it should be more like the distribution in the linked article. Cheers - Aaron Morton Freelance Cassandra Developer New Zealand @aaronmorton

Re: node down = log explosion?

2013-01-23 Thread aaron morton
and would it really hurt anything to add something like can't handle load to the exception message? Feel free to add a ticket with your experience. The event you triggered is a safety valve to stop the server failing. - My total replication factor is 4 over two DCs -- I suppose you mean 3

Re: Unavaible Exception with Chunked Object Store

2013-01-23 Thread aaron morton
UnavaibleException is thrown. Does anyone has any idea? Do you have the stack trace ? UnavailableException is thrown when there are less than Consistent Level number of replicas available, from the point of view of the coordinator you are talking to. So if you have 3 nodes and RF 3, using

Re: Large commit log reasons

2013-01-23 Thread aaron morton
I current have 3 nodes cluster running with a replication factor of 1. That is a very strange setup. Actually I'm noticing that my commit log size is always very big How big? The commitlog_total_space_in_mb setting in the yaml file controls the maximum size. note that these files are