Re: Committing `CASSANDRA-13701 Lower default num_tokens` and the dtest slowdown…

> > Now that we have CASSANDRA-16079 created and work is proceeding, can we > please commit CASSANDRA-13701? > Closing the loop on this. CASSANDRA-16079 is ready to be committed. It involves a patch to ccm and to cassandra-dtest, and takes advantage of CASSANDRA-16205. DTest run times are on par

Re: [DISCUSS] Bringing protocol v5 out of beta and dropping support from 3.11.x

> What's the verdict now for CASSANDRA-14973 ? My aim is to have a C* patch and PRs for the python and java drivers this week, but really there's nothing to block cutting a new C* beta now (or whenever we're ready). > On 15 Dec 2020, at 15:39, Mick Semb Wever wrote: > >> >> To use a beta fla

Re: [DISCUSS] Bringing protocol v5 out of beta and dropping support from 3.11.x

> > To use a beta flag, one absolutely has to have matching server > and client versions, since otherwise things can break in unexpected ways. > In fact, this specific issue makes it easy since you'd see that something > has changed immediately. > That could certainly deserve better documentation

Re: [EXTERNAL] Re: Triggers

I checked and cassandra channel was created by zznate at apache.org - To unsubscribe, e-mail: dev-unsubscr...@cassandra.apache.org For additional commands, e-mail: dev-h...@cassandra.apache.org

RE: [EXTERNAL] Re: Triggers

Great idea. Tried that. Don’t have an @apache.org email address? Contact the workspace administrator at ASF for an invitation. But there's no link to contact said admin. -Original Message- From: Stefan Miklosovic Sent: Tuesday, December 15, 2020 1:58 PM To: dev@cassandra.apache.org Su

Re: Triggers

This can be accomplished with batches (logged or unlogged), but that means that all apps need to be updated to dual-write. With a Trigger and admin can tee the data without having to change a line of app code. >Brian > On Dec 15, 2020, at 7:59 AM, Stefan Miklosovic > wrote: > > Hi, >

Re: [EXTERNAL] Re: Triggers

Fair enough, do not hesitate to join us on Slack if you have questions, I bet there are a lot of people willing to gladly answer your questions and concerns about Cassandra and how it differs from your relational world. Nothing bad about a mailing list as such if you prefer it that way, I am just p

RE: [EXTERNAL] Re: Triggers

@Stefan - I'm just exposing my lack of experience with Cassandra and how one goes about improving perf. In my world (relational), perf can be improved by spreading queries out to different databases. I saw a presentation where a Cassandra keyspace was said to be roughly equivalent to a relationa

Re: [EXTERNAL] Re: Triggers

On Tue, 15 Dec 2020 at 14:24, Greg Oliver wrote: > > Why not batches: I thought that it might be best that read and write models > are in different keyspace for perf reasons? As I understand, a batch cannot > span keyspaces. What performance reasons? Do you mean that you want to write into one

RE: [EXTERNAL] Re: Triggers

Why not batches: I thought that it might be best that read and write models are in different keyspace for perf reasons? As I understand, a batch cannot span keyspaces. I've been querying around to see if I can find a "reference implementation" of cqrs using Cassandra to see how people recommend

Re: Triggers

Hi, why can't this be achieved by batches? Do I miss something fundamental here? Batches may write to different tables right ... I am just missing the point of using triggers for this. I add specifics to Brian's first paragraph, this is covered by CASSANDRA-13985 - https://github.com/apache/cassa

Re: Triggers

One challenge to be aware of is that when you use multiple data centers, the users can make changes in either data center and those changes will propagate to the other data center. That is, there is no concept of a “read-only data center” in Cassandra. That may be fine, but some organizations wa

Re: Triggers

To extend Paul's point, datacenters in cassandra are logical concepts which may be useful for your use case and do not necessarily need to be represented by physical data centers. The presentation mentioned by Andrew, while helpful, covers some concepts which are specific to Hadoop and may be outd

RE: Triggers

Can't see it in the email. What's the slide #? From: Andrew Cobley (Staff) Sent: Tuesday, December 15, 2020 12:26 PM To: dev@cassandra.apache.org Subject: [EXTERNAL] Re: Triggers Yes that's right. I remember this illustration: [Diagram Description automatically generated] >From this present

Re: Triggers

Yes that’s right. I remember this illustration: [Diagram Description automatically generated] >From this presentation: https://www.slideshare.net/rastrick/presentation-12982302 Might help. Andy [University of Dundee shield logo] Andy Cobley Senior Lecturer, Pro

Re: Triggers

Hi Greg, Andy is talking about Cassandra datacenters, which can easily be co located in the same physical datacenter. Paul > On 15 Dec 2020, at 12:10, Greg Oliver wrote: > > That's great in theory, but what if your customer is a national government > (they require their data to remain within

RE: Triggers

That's great in theory, but what if your customer is a national government (they require their data to remain within their borders) and there aren't enough DC's in nation to support multiple DC data distribution? To get the throughput needed (say - if the government announces a new program and

Re: Triggers

I may be wrong, but isn’t the correct pattern for this to use two data centres? You write to one data centre, replicate to the other and read from that one. Or am misunderstanding ? Andy [University of Dundee shield logo] Andy Cobley Senior Lecturer, Program Dire

Re: Triggers

Hi Greg, Things are more tricky in an eventually consistent distributed system than they are in a relational database. Even if the C* triggers were perfect (and they are not) and your write and read tables were exactly the same, there is no guarantee that all the updates created by the trigger fro