RE: supercolumns with TTL columns not being compacted correctly

Hi, This means I got a serious flaw in my column family design. At this moment I am storing sensor data into the database, rowkey is the sensor ID, supercolumn is the timestamp, and the different columns in the supercolumn are sensor readings. This means with my current design it is almost impo

Re: Exception when truncate

It's look s very strange but yes. Now i can't reproduce this 2012/5/22 aaron morton : > The first part of the name is the current system time in milliseconds. > > If you run it twice do you get log messages about failing to create the same > directory twice ? > > Cheers > > - > Aar

Re: Cassandra 0.8.5: Column name mystery in create column family command

When you say > comparator=BytesType You are telling cassandra that the column names in the CF's are just bytes. But when you create the column meta data you are specifying the column names as strings. use UTF8Type as the comparator. Cheers - Aaron Morton Freelance Develope

Re: RE Ordering counters in Cassandra

> Just out of curiosity, is there any underlying architectural reason why it's > not possible to order a row based on its counters values? or is it something > that might be in the roadmap in the future? it wouldn't work well with the consistency level. Also, sorting a list of values at the same

Re: Cassandra 0.8.5: Column name mystery in create column family command

On Wed, May 23, 2012 at 3:07 PM, aaron morton wrote: > When you say > > comparator=BytesType > > > You are telling cassandra that the column names in the CF's are just > bytes. But when you create the column meta data you are specifying the > column names as strings. > > use UTF8Type as the compa

Re: Tuning cassandra (compactions overall)

I've not heard of anything like that in the recent versions. There were some issues in the early 0.8 https://github.com/apache/cassandra/blob/trunk/NEWS.txt#L383 If you are on a recent version can you please create a jira ticket https://issues.apache.org/jira/browse/CASSANDRA describing what yo

Re: unknown exception with hector

No sure but >at > org.apache.thrift.transport.TIOStreamTransport.read(TIOStreamTransport.java:132) Looks like the client is not using framed transport. The server defaults to framed. Cheers - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com

Re: Replication factor

RF is normally adjusted to modify availability (see http://thelastpickle.com/2011/06/13/Down-For-Me/) > for example, if I have 4 nodes cluster in one data center, how can RF=2 vs > RF=4 affect read performance? If consistency level is ONE, looks reading does > not need to go to another hop to g

Re: Number of keyspaces

> We were thinking of doing a major compaction after each year is 'closed off'. Not a terrible idea. Years tend to happen annually, so their growth pattern is well understood. > This would mean that compactions for the current year were dealing with a > smaller amount of data and hence be fast

Re: Confusion regarding the terms "replica" and "replication factor"

> Now if a row key hash is mapped to a range owned by a node in DC3, > will the Node in DC3 still store the key as determined by the > partitioner and then walk the ring and store 2 replicas each in DC1 > and DC2 ? No, only nodes in the DC's specified in the NTS configuration will be replicas. >

Re: how to get list of snapshots

> 1) is there any good guide for scheduling backups ? this http://www.datastax.com/docs/1.0/operations/backup_restore ? > 2) is there way to get list of snapshots ? (without "ls" in directory) No. Cheers - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.c

Re: how to get list of snapshots

I seen that guide. It's missing several important things 1) ok, I can schedule snapshots using cron (snapshot's name will be ganarated from current date) how can I remove snapshots older than a week ? 2) ok, I can enable increment backups. How can I remove incremental SSTables older than 1 week

RE: Replication factor

> When RF == number of nodes, and you read at CL ONE you will always be reading > locally. "always be reading locally" - only if Dynamic Snitch is "off". With dynamic snitch "on" request may be redirected to other node, which may introduce latency spikes. Best regards / Pagarbiai Viktor Jevd

Re: Confusion regarding the terms "replica" and "replication factor"

Thanks Aaron. That makes things clear. So I guess the 0 - 2^127 range for tokens corresponds to a cluster -level top-level ring. and then you add some logic on top of that with NTS to logically segment that range into sub-rings as per the notion of data clusters defined in NTS. Whats the advantage

Re: Number of keyspaces

On Wed, May 23, 2012 at 8:09 PM, aaron morton wrote: > We were thinking of doing a major compaction after each year is 'closed > off'. > > Not a terrible idea. Years tend to happen annually, so their growth > pattern is well understood. > > This would mean that compactions for the current year wer

Re: Correct way to set strategy options in cqlsh?

Since this is the EC2MultiRegionSnitch, how do you suggest I change name? It needs to match the datacenter name that is bound to aws region names, so it seems like this is a bug to me.. On 5/23/12 2:33 AM, "Romain HARDOUIN" wrote: You *must* remove the hyphen. According to the csql 2.0 do

Re: Replication factor

Thanks guys. Aaron, I am confused about this. from wiki http://wiki.apache.org/cassandra/ReadRepair, looks for any consistency level. Read Repair will be done either before or after responding data. >Read Repair does not run at CL ONE Daning On Wed, May 23, 2012 at 3:51 AM, Viktor Jevdokimov

Re: Number of keyspaces

On Tue, May 22, 2012 at 4:56 AM, samal wrote: > Not ideally, now cass has global memtable tuning. Each cf correspond to > memory  in ram. Year wise cf means it will be in read only state for next > year, memtable  will still consume ram. An empty memtable seems unlikely to consume a meaningful am

Re: Correct way to set strategy options in cqlsh?

I agree, this is a bug. I opened https://issues.apache.org/jira/browse/CASSANDRA-4278 to track it. The workaround for now is to use the CLI or the thrift interface to create your keyspace. p On Wed, May 23, 2012 at 8:29 AM, Damick, Jeffrey wrote: > Since this is the EC2MultiRegionSnitch, how

Re: Replication factor

On Wed, May 23, 2012 at 5:51 AM, Viktor Jevdokimov < viktor.jevdoki...@adform.com> wrote: > > When RF == number of nodes, and you read at CL ONE you will always be > reading locally. > > “always be reading locally” – only if Dynamic Snitch is “off”. With > dynamic snitch “on” request may be r

Error loading data: Internal error processing get_range_slices / Unavailable Exception

Hi All, i am facing problem while setting up my database. The error under mentioned is reflected every time i try to setup the DB. Unable to understand why these are occurring? though previously it was working fine, i guess it is some connection related issues. UnknownException: [host=192.168.2.1

RE: Replication factor

Depends on use case. For ours we have another experience and statistics, when turning dynamic snitch off makes overall latency and spikes much, much lower. Best regards / Pagarbiai Viktor Jevdokimov Senior Developer Email: viktor.jevdoki...@adform.com Phon

Re: unknown exception with hector

i've notice the my nodes seem to have a large (?, not really sure what acceptable numbers are) read dropped count from tpstats. could they be related? On 5/23/2012 2:55 AM, aaron morton wrote: No sure but at org.apache.thrift.transport.TIOStreamTransport.read(TIOStreamTransport.java:

Query on how to count the total number of rowkeys and columns in them

Hi I am trying to learn Cassandra and I have one doubt. I am using the Thrift API, to count the number of row keys I am using KeyRange to specify the row keys. To count all of them, I specify the start and end as "new byte[0]". But the count is set to 100 by default. How do I use this method to

Re: Query on how to count the total number of rowkeys and columns in them

default count is 100, set this to some max value, but this won't guarantee actual count. Something like paging can help in counting. Get the last key as start in second query, end as null, count as some value. But this will port data to client where as we only need count. Other solution may be (i