Re: Practical use of counters in the industry

On Thu, Dec 18, 2014 at 7:19 PM, Rajath Subramanyam wrote: > > Thanks Ken. Any other use cases where counters are used apart from > Rainbird ? > Disqus use(d? s?) them behind an in-memory accumulator which batches and periodically flushes. This is the best way to use "old counters." "New counters

Re: In place vnode conversion possible?

On Fri, Dec 19, 2014 at 12:25 AM, Jonas Borgström wrote: > > Why would any streaming take place? > > Simply changing the tokens and restarting a node does not seem to > trigger any streaming. Oh, sorry for not reading the whole mail, I figured you were going to do something less low level hacky.

Re: High Bloom Filter FP Ratio

Hi Tyler, I tried what you said and false positives look much more reasonable there. Thanks for looking into this. -Chris - Original Message - From: "Tyler Hobbs" To: user@cassandra.apache.org Sent: Friday, December 19, 2014 1:25:29 PM Subject: Re: High Bloom Filter FP Ratio I took a

Re: High Bloom Filter FP Ratio

I took a look at the code where the bloom filter true/false positive counters are updated and notice that the true-positive count isn't being updated on key cache hits: https://issues.apache.org/jira/browse/CASSANDRA-8525. That may explain your ratios. Can you try querying for a few non-existent

Re: Multi DC informations (sync)

Your gc grace should be longer than your repair schedule. You're likely going to have deleted data resurface. On Fri Dec 19 2014 at 8:31:13 AM Alain RODRIGUEZ wrote: > All that you said match the idea I had of how it works except this part: > > "The request blocks however until all CL is satis

Re: Key Cache Questions

if you have JNA installed it's stored off-heap in ram, without JNA it's stored on heap in ram. The following should help explain in more depth http://www.datastax.com/dev/blog/maximizing-cache-benefit-with-cassandra On Fri, Dec 19, 2014 at 8:35 AM, Batranut Bogdan wrote: > > Hello all, > I just

Re: Multi DC informations (sync)

replies inline On Fri, Dec 19, 2014 at 10:30 AM, Alain RODRIGUEZ wrote: > > All that you said match the idea I had of how it works except this part: > > "The request blocks however until all CL is satisfied" --> Does this mean > that the client will see an error if the local DC write the data cor

Node down during move

Hi list, we added a new node to existing 8-nodes cluster with C* 1.2.9 without vnodes and because we are almost totally out of space, we are shuffling the token fone node after another (not in parallel). During one of this move operations, the receiving node died and thus the streaming failed: W

Re: simple data movement ?

It may be more valuable to set up your test cluster as the same version, and make sure your tokens are the same. then copy over your sstables. you'll have an exact replica of prod & you can test your upgrade process. On Fri Dec 19 2014 at 11:04:58 AM Ryan Svihla wrote: > In theory, you could a

Re: simple data movement ?

In theory, you could always do a data dump ..sstable to json and back for example, but you'd have to have your schema setup ,and I've not actually done this myself so YMMV. I've helped a bunch of folks with that upgrade path and while it's time consuming it does work. On Fri, Dec 19, 2014 at 8:49

Re: Multi DC informations (sync)

All that you said match the idea I had of how it works except this part: "The request blocks however until all CL is satisfied" --> Does this mean that the client will see an error if the local DC write the data correctly (i.e. CL reached) but the remote DC fails ? This is not the idea I had of so

Re: High Bloom Filter FP Ratio

We're seeing similar behavior except our FP ratio is closer to 1.0 (100%). We're using Cassandra 2.1.2. Schema --- CREATE TABLE contacts.contact ( id bigint, property_id int, created_at bigint, updated_at bigint,

Re: simple data movement ?

Thanks, this looks uglier , I double checked my production cluster ( I have a staging and development cluster as well ) and production is on 1.2.8. A copy of the data resulted in a mssage : Exception encountered during startup: Incompatible SSTable found. Current version ka is unable to read fil

Re: Multi DC informations (sync)

More accurately,the write path of Cassandra in a multi dc sense is kinda like the following 1. write goes to a node which acts as coordinator 2. writes go out to all replicas in that DC, and then one write per remote DC goes out to another node which takes responsibility for writing to all replica

Key Cache Questions

Hello all,I just read that the default size of the Key cache is 100 MB. Is it stored in memory or disk? 

Re: 答复: Cassandra 2.1.0 Crashes the JVM with OOM with heaps of memory free

It does appear to be a ulimit issue to some degree as some settings are lower than recommended by a few factors (namely nproc). http://www.datastax.com/documentation/cassandra/2.0/cassandra/install/installRecommendSettings.html * - memlock unlimited * - nofile 10 * - nproc 32768 * - as unlimi

Re: Drivers performance

Better question for the java driver mailing list, but I see a number of problems in your Datastax java driver code, and without knowing the way Astyanax handles caching of prepared statements I can tell you 1. You're re repreparing a statement on _every_ iteration, and these are not cached b

Re: Multi DC informations (sync)

Hi Jens, thanks for your insight. Replication lag in Cassandra terms is probably “Hinted handoff” --> Well I think hinted handoff are only used when a node is down, and are not even mandatory enabled. I guess that cross DC async replication is something else, taht has nothing to see with hinted ha

Drivers performance

https://github.com/michalsvec/astyanax-datastax-benchmark It was tested against Cassandra 1.2 and 2.1. Testing conditions were naive (localhost, single node, ...) but still the difference is huge. 10 000 iterations: * Astyanax:2734 ms * Astyanax prepared:1997 ms * Data

Re: Understanding tombstone WARN log output

Hi again, A follow-up question (to my yet unanswered question): How come the first localDeletion is Integer.MAX_VALUE above? Should it be? Cheers, Jens ——— Jens Rantil Backend engineer Tink AB Email: jens.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook Linkedin 

Re: Multi DC informations (sync)

Alain, AFAIK, the DC replication is not linearizable. That is, writes are are not replicated according to a binlog or similar like MySQL. They are replicated concurrently. To answer you questions: 1 - Replication lag in Cassandra terms is probably “Hinted handoff”. You’d want to check t

Re: 2014 nosql benchmark

Today I've also seen this benchmark in Chinese websites. "SequoiaDB" seems come from a Chinese startup company, and in db-engines ranking it's score is 0.00. So IMO I have to say I think this benchmark is a "soft sell". They compare three databases, two written by

Multi DC informations (sync)

Hi guys, We expanded our cluster to a multiple DC configuration. Now I am wondering if there is any way to know: 1 - The replication lag between these 2 DC (Opscenter, nodetool, other ?) 2 - Make sure that sync is ok at any time I guess big companies running Cassandra are interested in these ki

Reset cfhistograms

Hi, I am using cassandra 2.1.2 with 5 node cluster single DC. I've read that histograms are reset after node restart or rerun of command. But in my case it's not resetting by running every time. Could someone point what could be the issue or how could I reset it without restarting node. Thanks! in

Re: In place vnode conversion possible?

On 18/12/14 21:45, Robert Coli wrote: > On Tue, Dec 16, 2014 at 12:38 AM, Jonas Borgström > wrote: > > That said, I've done some testing and it appears to be possible to > perform an in place conversion as long as all nodes contain all data (3 > nodes and re

答复: Cassandra 2.1.0 Crashes the JVM with OOM with heaps of memory free

​What's your vm.max_map_count​ setting? Best Regards, Liang 发件人: Leon Oosterwijk 发送时间: 2014年12月19日 11:55 收件人: user@cassandra.apache.org 主题: Cassandra 2.1.0 Crashes the JVM with OOM with heaps of memory free All, We have a Cassandra cluster which seems to be s