Re: How can I scale my read rate?

On 24/03/2017 01:00, Eric Stevens wrote: Assuming an even distribution of data in your cluster, and an even distribution across those keys by your readers, you would not need to increase RF with cluster size to increase read performance. If you have 3 nodes with RF=3, and do 3 million reads,

RE: [Cassandra 3.0.9] Cannot allocate memory

Thanks Jayesh, I found the fix for the same. I make below changes : In /etc/sysctl.conf I make below change: vm.max_map_count = 1048575 in the /etc/security/limits.d file: root - memlock unlimited root - nofile 10 root - nproc 32768 root - as unlimited Thanks & Regards, Abhishek Kumar

Re: How can I scale my read rate?

Assuming an even distribution of data in your cluster, and an even distribution across those keys by your readers, you would not need to increase RF with cluster size to increase read performance. If you have 3 nodes with RF=3, and do 3 million reads, with good distribution, each node has served

Re: SSTable Ancestors information in Cassandra 3.0.x

The ancestors were used primarily to clean up leftovers in the case that cassandra was killed right as compaction finished, where the source/origin/ancestors were still on the disk at the same time as the compaction result. It's not timestamp based, though - that compaction process has moved to

Re: SSTable Ancestors information in Cassandra 3.0.x

Thanks, Jeff. Did all the internal tasks and the compaction tasks move to a timestamp-based approach? Regards, Rajath Rajath Subramanyam On Thu, Mar 23, 2017 at 2:12 PM, Jeff Jirsa wrote: > That information was removed, because it was really meant

Re: SSTable Ancestors information in Cassandra 3.0.x

That information was removed, because it was really meant to be used for a handful of internal tasks, most of which were no longer used. The remaining use was cleaning up compaction leftovers, and the compaction leftover code was rewritten in 3.0 / CASSANDRA-7066 (note, though, that it's somewhat

SSTable Ancestors information in Cassandra 3.0.x

Hello Cassandra-Users and Cassandra-dev, One of the handy features in sstablemetadata that was part of Cassandra 2.1.15 was that it displayed Ancestor information of an SSTable. Here is a sample output of the sstablemetadata tool with the ancestors information in C* 2.1.15: [centos@chen-datos

[ANNOUNCE] Apache Gora 0.7 Release

Hi Folks, The Apache Gora team are pleased to announce the immediate availability of Apache Gora 0.7. The Apache Gora open source framework provides an in-memory data model and persistence for big data. Gora supports persisting to column stores, key value stores, document stores and RDBMSs, and

Using datastax driver, how can I read a non-primitive column as a JSON string?

Hi, I have several non-primitive columns in my cassandra tables. Some of them are user-defined-types UDTs. While querying them through datastax driver, I want to convert such UDTs into JSON values. More specifically, I want to get JSON string for the value object below: Row row =

Re: [Cassandra 3.0.9] Cannot allocate memory

Dmesg will often print a message saying that it had to kill a process if the server was short of memory, so you will have to dump the output to a file and check. If a process is killed to reclaim memory for the system, then it will dump a list of all processes and the actual process that was

Re: ONE has much higher latency than LOCAL_ONE

Thanks for the link, I hadn't seen that before. It's unfortunate that they don't explain what they mean by "closest replica". The nodes in the remote DC should not be regarded as "closest". Also, it's not clear what the black arrows mean… the coordinator sends the read to all three replicas,