Re: Effective partition key for time series data, which allows range queries?

Jim's basic model is similar to how we've solved this exact kind of problem many times. From my own experience, I strongly recommend that you make a `bucket` field in the partition key, and a `time` field in the cluster key. Make both of these of data type `timestamp`. Then use application

Re: Making a Cassandra node cluster unique

Hi, Cluster name should be unique because with misconfiguration you might make the nodes connect to either of the cluster and then you will have nodes is wrong clusters. Theoretically it can work with same names as well but to be on the safe side, make the cluster names unique. Hannu On Wed, 5

Re: Copy from CSV on OS X problem with varint values <= -2^63

It doesn't look like the embedded driver, it should come from a zip file labeled with version *3.7.0.post0-2481531* for cassandra 3.10: *Using CQL driver: * Sorry, I should have posted this example in my previous email, rather than an example based on the non-embedded driver. I don't know who

how to recover a dead node using commit log when memtable is lost

Hi, I read in Cassandra architecture documentation that if a node dies and there is some data in memtable which hasn't been written to the sstable, the commit log replay happens (assuming the commit log had been flushed to disk) when the node restarts and hence the data can be recovered.

antlr-runtime-3.2.jar is turning into 0 bytes and dse is going down

Hi, We have single node instance where we have cassandra , mysql and application running at the same node for developers. We are at dse 4.8.9 and dse is going down after sometime . What we have noticed is that few of the jar at /usr/share/dse/common are turning into 0 bytes. Jars are as follows:

Re: Cassandra and LINUX CPU Context Switches

This would be normal if the switches are user to kernel mode (disk & network IO are kernel mode activities). If your run queue (jobs waiting to run) is much larger than the number of cores (just a swag but less than 2-3*# of cores), you might have other issues. *...* *Daemeon C.M.

Re: how to recover a dead node using commit log when memtable is lost

Flushes have nothing to do with data persistence and node failure. Each write is acknowledged only when data has been written to the commit log AND memtable. That solves the issues of node failures and data consistency. When the node boots back up it replays commit log files and you don't loose

Re: Making a Cassandra node cluster unique

You CAN have two separate clusters with same name and configuration. Separation of the clusters is just a matter of defining seed nodes properly. That being said, it doesn't mean you SHOULD have clusters with same name. We usually run same cluster name when testing on test/stage cluster and

Re: Effective partition key for time series data, which allows range queries?

That's an interesting refinement! I'll keep it in mind the next time this sort of thing comes up. Jim On Wed, Apr 5, 2017 at 9:22 AM, Eric Stevens wrote: > Jim's basic model is similar to how we've solved this exact kind of > problem many times. From my own experience, I

Re: how to recover a dead node using commit log when memtable is lost

Very good explanation. One follow-up question. If CL is set to 1 and RF to 3, then there are chances of the data being lost if the machine crashes before replication happens and the commit log (on the node which processed the data for CF=1) is not synced yet. Right? Thanks, Preetika On Wed, Apr

Re: how to recover a dead node using commit log when memtable is lost

Assuming we are using periodic mode for commit log sync. On Wed, Apr 5, 2017 at 3:29 PM, preetika tyagi wrote: > Very good explanation. > One follow-up question. If CL is set to 1 and RF to 3, then there are > chances of the data being lost if the machine crashes before

Re: Copy from CSV on OS X problem with varint values <= -2^63

Stefania This is the output of my --debug, I never touched CQLSH_NO_BUNDLED and did not know about it. As you can see I have used homebrew to install Cassandra and looks like its the embedded version as it sits under the Cassandra folder ? cqlsh --debug Using CQL driver: Using connect

Re: how to recover a dead node using commit log when memtable is lost

I beg to differ with @Matija here, IMO by default cassandra syncs data into commit log in a periodic fashion with a fsync period of 10 sec (Ref - https://github.com/apache/cassandra/blob/trunk/conf/cassandra.yaml#L361). If a write is not written to disk and RF is 1 else CL is Local One & node goes

Making a Cassandra node cluster unique

Someone on my team asked me a question that I could not find an easy answer and I was hoping someone could answer for me. When we configure Cassandra, we use the Cluster Name, Data Center, and Rack to define the group of Cassandra nodes involved in holding our keyspace records. If a second set

Cassandra and LINUX CPU Context Switches

I've noticed that my apache-cassandra 2.2.6 process is consistently performing CPU Context Switches above 10,000 per second. Is this to be expected or should I be looking into ways to lower the number of context switches done on my Cassandra cluster? Thanks in advance.