system_schema.tables id and table uuid on disk mismatch

Hi all, we have detected that table-uuid in linux file directory is different from system_schema.tables id. I have executed nodetool describe cluster and see only one schema version in the cluster. How we can fix this issue do anyone has any idea? Restarting the nodes only create a new empty

Re: Call for Presentations closing TOMORROW: Community over Code EU 2024

The CFP for the Cassandra track at the Community Over Code EU conference, June in Bratislava, closes tomorrow (Friday) !! We'd love to hear your Cassandra experience, operating or coding. Submit before it's too late 拾 see you there, Mick On Mon, 8 Jan 2024 at 20:24, Paulo Motta wrote: > I

Re: Query on version 4.1.3

We are a about to do the same upgrade, although aiming v4.1.2 Highly interested in this topic as well. Luciano Greiner On Thu, Jan 11, 2024 at 4:13 AM ranju goel wrote: > > Hi Everyone, > > We are planning to upgrade from 4.0.11 to 4.1.3, the main motive of upgrading > is 4.0.11 going EOS in

Query on version 4.1.3

Hi Everyone, We are planning to upgrade from 4.0.11 to 4.1.3, the main motive of upgrading is 4.0.11 going EOS in July 2024. On analyzing JIRAs, found an Open ticket, CASSANDRA-18766 (*high speculative retries on v4.1.3*) which talks about Performance Degradation and no activity seen since

Re: unsubscribe

Sorry to see you go. If you'd like to unsubscribe from the user ML, please email user-unsubscr...@cassandra.apache.org. Cheers! >

unsubscribe

-- Best regards, Xiaolong Jiang Senior Software Engineer at Netflix Columbia University

Re: Call for Presentations closing soon: Community over Code EU 2024

Additionally, if you have a talk about some underlying technology that could be applicable across multiple projects submit it or a poster based on it. We are looking for good cross-project presentations. Claude Chair, Community over Code, EU 2024. On Mon, Jan 8, 2024 at 8:24 PM Paulo Motta

Call for Presentations closing soon: Community over Code EU 2024

I wanted to remind that the call for speakers for Community Over Code EU 2024 (formerly Apachecon EU) will be closing this Friday 2024/01/12 23:59:59 GMT. If you reside in Europe/EMEA and have an interesting talk proposal about using, deploying or modifying Apache Cassandra please see details

Re: Upgrade from 3.11.x to 4.1.3

Thanks Scott for the reply. Regards Manish On Sun, Jan 7, 2024 at 12:02 PM C. Scott Andreas wrote: > Upgrading from 3.11.x to 4.1.x is supported, yes. As the documentation > you reference mentions, it is not possible to downgrade from 4.x to 3.x. > > Note that running repair during upgrades

Re: Upgrade from 3.11.x to 4.1.3

Upgrading from 3.11.x to 4.1.x is supported, yes. As the documentation you reference mentions, it is not possible to downgrade from 4.x to 3.x. Note that running repair during upgrades is not supported; please ensure it is disabled before beginning the upgrade and re-enable after. – Scott >

Upgrade from 3.11.x to 4.1.3

Hi Is Cassandra upgrade from Cassandra 3.11.x to Cassandra 4.1.3 is supported. NEWS.txt has a general guideline that Snapshotting is fast (especially if you have JNA installed) and takes effectively zero disk space until you start compacting the live data files again. Thus, best practice is to

Re: Cassandra Summit. What a week!

Back again with an update for everyone asking for the talk recordings. The Linux Foundation has broken up each talk into individual videos and made a playlist. You can find it here: https://www.youtube.com/playlist?list=PLbzoR-pLrL6rgDn-2Yo-d5liFEnuCCi85 Patrick On Mon, Dec 18, 2023 at 11:41 AM

Re: About Map column

Hello Bowen, Arvydas, Thanks for your answers. May I clarify things about compaction. If I have a table with LCS with 160MB of sstable size target, if a partition has many rows so that the total size of the partition is greater than 160MB, then there will eventually be an sstable greater than

Re: About Map column

Sebastien, Another thing to keep in mind when writing/updating a map column is that it is internally (in the memtable) backed by a synchronized data structure - if the rate of writes/updates is sufficiently high, the resulting CPU load will cripple the nodes (see CASSANDRA-15464

Cassandra Summit. What a week!

*Hi everyone,It was great seeing everyone who could attend the Cassandra Summit last week. Thanks to everyone that helped make it successful. Speakers. Attendees. Sponsors. You all had your role at bringing this back. For those who couldn’t attend, every talk was recorded and is now up on the LF

Re: About Map column

Hi Sebastien, It's a bit more complicated than that. To begin with, the first-class citizen in Cassandra is partition, not row. All map fields in the same row are in the same partition, and all rows with the same partition key but different clustering keys are also in the same partition.

About Map column

Hello If i have a colum of type Map, then with many insertions, the map grows, but after compation, as the full map is 1 column of a table, will it be contained fully in 1 SSTable? I guess yes cause the map is contained in a single row. Am I right? Versus if we use a clustering key + a standard

Re: Design Query Optimization for Cassandra Table with Date-based Filtering

Hi Arjun, this is strange. You should be able to use a range query on a column that is part of the clustering key, as long as all columns in the clustering key left to this column are set to fixed values. So, given the table definition that you specified, your query should work (I just

Design Query Optimization for Cassandra Table with Date-based Filtering

Hello team, I'm new to Cassandra and I've created a table using the following command: CREATE TABLE instant_cdr ( rowid int, msisdn varchar, id bigint, date_id int, channel varchar, usage_type varchar, ac_type varchar, voice_amt int, sms_amt int, data_amt int, field1

Re: Schema inconsistency in mixed-version cluster

A static collection is probably atypical, and again, would encourage you to open a JIRA. This seems like a case we should be able to find in a simulator. On Tue, Dec 12, 2023 at 2:05 PM Sebastian Marsching wrote: > I assume these are column names of a non-system table. > > This is correct. It

Re: Schema inconsistency in mixed-version cluster

> I assume these are column names of a non-system table. > This is correct. It is one of our application tables. The table has the following schema: CREATE TABLE pv_archive.channels ( channel_name text, decimation_level int, bucket_start_time bigint, channel_data_id uuid static,

Re: Schema inconsistency in mixed-version cluster

I don't recognise those names: * channel_data_id * control_system_type * server_id * decimation_levels I assume these are column names of a non-system table. From the stack trace, this looks like an error from a node which was running 4.1.3, and this node was not the coordinator for this

Re: Schema inconsistency in mixed-version cluster

> If an upgrade involves changing the schema, I think backwards compatibility > would be out of the question? That’s a good point. I just noticed that during the upgrade, the output of “nodetool describecluster” showed a schema version disagreement, where the nodes running 3.11.14 were on

Re: Schema inconsistency in mixed-version cluster

If an upgrade involves changing the schema, I think backwards compatibility would be out of the question? On Tue, Dec 12, 2023 at 10:36 AM Jeff Jirsa wrote: > This deserves a JIRA > > > > On Tue, Dec 12, 2023 at 8:30 AM Sebastian Marsching < > sebast...@marsching.com> wrote: > >> Hi, >> >>

[RELEASE] Apache Cassandra Java Driver 4.18.0 released

The Cassandra team is pleased to announce the release of Cassandra Java Driver version 4.18.0 The Source release and Binary convenience artifacts are available here: https://dist.apache.org/repos/dist/release/cassandra/cassandra-java-driver/4.18.0/ The Maven artifacts can be found at:

Re: Schema inconsistency in mixed-version cluster

This deserves a JIRA On Tue, Dec 12, 2023 at 8:30 AM Sebastian Marsching wrote: > Hi, > > while upgrading our production cluster from C* 3.11.14 to 4.1.3, we > experienced the issue that some SELECT queries failed due to supposedly no > replica being available. The system logs on the C* nodes

Schema inconsistency in mixed-version cluster

Hi, while upgrading our production cluster from C* 3.11.14 to 4.1.3, we experienced the issue that some SELECT queries failed due to supposedly no replica being available. The system logs on the C* nodes where full of messages like the following one: ERROR [ReadStage-1] 2023-12-11

Can't make it to Cassandra Summit but want to see the talks?

Hi everyone, The Linux Foundation will be streaming all of the talks from the Cassandra Summit. Finding the streams is very easy. Go to the conference schedule: https://events.linuxfoundation.org/cassandra-summit/program/schedule/ Each talk has a YouTube link associated with it. The Keynotes

Re: Remove folders of deleted tables

There's no requirement for the partition key to contain the date/time for a TWCS table. The important thing is data need to be written to the table in chronological order (i.e. do not use the "USING TIMESTAMP" in the CQL queries) and the same TTL is used for all partitions. TWCS was introduced

Re: Remove folders of deleted tables

Thanks Bowen, I also thought about using TTL and TWCS, but in my past experience with Cassandra I have had a lot of issues with data models using TTL and creating many tombstones. I was probably not using the right compaction at that time, but this experiences has a great impact on me and I would

Re: Remove folders of deleted tables

There are many different ways to avoid or minimise the chance of schema disagreements, the easiest way is to always send DDL queries to the same node in the cluster. This is very easy to implement and avoids schema disagreements at the cost of creating a single point of failure for DDL

Re: Remove folders of deleted tables

Hello Jeff, Bowen Thanks for your answer. Now I understand that there is a bug in Cassandra that can not handle concurrent schema modifications, I was not aware of that severity, I thought that temporary schema mismatches were eventually resolved smartly, by a kind of "merge" mechanism. For my

Re: Remove folders of deleted tables

The same table name with two different CF IDs is not just "temporary schema disagreements", it's much worse than that. This breaks the eventual consistency guarantee, and leads to silent data corruption. It's silently happening in the background, and you don't realise it until you suddenly do,

Re: Remove folders of deleted tables

The last time you mentioned this: On Tue, Dec 5, 2023 at 11:57 AM Sébastien Rebecchi wrote: > Hi Bowen, > > Thanks for your answer. > > I was thinking of extreme use cases, but as far as I am concerned I can > deal with creation and deletion of 2 tables every 6 hours for a keyspace. > So it

Re: Remove folders of deleted tables

Hi Bowen, Thanks for your answer. I was thinking of extreme use cases, but as far as I am concerned I can deal with creation and deletion of 2 tables every 6 hours for a keyspace. So it lets around 8 folders of deleted tables per day - sometimes more cause I can see sometimes 2 folders created

Re: Remove folders of deleted tables

I can't think of a reason to keep empty directories around, seems like a reasonable change, but I don't think you're butting up against a thing that most people would run into, as snapshots are enabled by default (auto_snapshot: true) and almost nobody changes it. The use case you described

[RELEASE] Apache Cassandra 5.0-beta1 released

The Cassandra team is pleased to announce the release of Apache Cassandra version 5.0-beta1. Apache Cassandra is a fully distributed database. It is the right choice when you need scalability and high availability without compromising performance. Downloads of source and binary distributions are

Re: Remove folders of deleted tables

Please rethink your use case. Create and delete tables concurrently often lead to schema disagreement. Even doing so on a single node sequentially will lead to a large number of tombstones in the system tables. On 04/12/2023 19:55, Sébastien Rebecchi wrote: Thank you Dipan. Do you know if

Re: Remove folders of deleted tables

Thank you Dipan. Do you know if there is a good reason for Cassandra to let tables folder even when there is no snapshot? I'm thinking of use cases where there is the need to create and delete small tables at a high rate. You could quickly end with more than 65K (limit of ext4) subdirectories in

Re: Remove folders of deleted tables

Hello Sebastien, There are no inbuilt tools that will automatically remove folders of deleted tables. Thanks, Dipan Shah From: Sébastien Rebecchi Sent: 04 December 2023 13:54 To: user@cassandra.apache.org Subject: Remove folders of deleted tables Hello,

Remove folders of deleted tables

Hello, When we delete a table with Cassandra, it lets the folder of that table on file system, even if there is no snapshot (auto snapshots disabled). So we end with the empty folder {data folder}/{keyspace name}/{table name-table id} containing only 1 subfolder, backups, which is itself empty.

Re: Introducing the Cassandra Catalyst program!

So excited for this program! It's been a long time coming but wow, what a great way to recognize individuals advocating for Cassandra in their own communities. Let's get out there and start nominating! Patrick On Fri, Dec 1, 2023 at 9:51 AM Melissa Logan wrote: > The Cassandra community is

Introducing the Cassandra Catalyst program!

The Cassandra community is excited to introduce the Cassandra Catalyst program, a new initiative that aims to recognize individuals who invest in the growth of the community by enthusiastically sharing their expertise, encouraging participation, and creating a welcoming environment. This is the

Re: Cassandra Summit: Engage those networks!

+1 we will be two people from the Microsoft Cassandra team this time around  From: Paulo Motta Sent: Wednesday, November 29, 2023 7:11 PM To: user@cassandra.apache.org Subject: [EXTERNAL] Re: Cassandra Summit: Engage those networks! This Cassandra Summit is

Re: Cassandra Summit: Engage those networks!

Looking forward to seeing you all! Cassandra 5* has so many game changing features in it, I'm super excited. On Thu, 30 Nov 2023 at 07:55, Bhagdev, Meet wrote: > I’m going and hope to see you there  > > > > Cheers, > > Meet > > *From: *Paulo Motta > *Reply-To: *"user@cassandra.apache.org"

Re: Cassandra Summit: Engage those networks!

I’m going and hope to see you there  Cheers, Meet From: Paulo Motta Reply-To: "user@cassandra.apache.org" Date: Wednesday, November 29, 2023 at 7:12 PM To: "user@cassandra.apache.org" Subject: RE: [EXTERNAL] Cassandra Summit: Engage those networks! CAUTION: This email originated from

Fwd: Reminder: CFP for Community Over Code Europe is now open

There will be a Cassandra track at Community Over Code Europe 2024 (formerly known as Apachecon EU) that will happen on Bratislava, Slovakia on 3 Jun 2024. If you have any talks proposals about using, deploying or modifying Apache Cassandra please make a submission before 12 Jan 2024 to speak at

Re: Cassandra Summit: Engage those networks!

This Cassandra Summit is going to be epic! Looking forward to meet the Cassandra community in two weeks! 落 On Wed, 29 Nov 2023 at 18:26 Patrick McFadin wrote: > Hi everyone, > > We are a couple of weeks away from Cassandra Summit. People get busy and > forget to register or miss that there is

Cassandra Summit: Engage those networks!

Hi everyone, We are a couple of weeks away from Cassandra Summit. People get busy and forget to register or miss that there is even a summit happening. Let's make sure everyone who wants to go gets a chance! - If you are going, get on the social media of your choice and let everyone know you'll

Nov. 30 Cassandra virtual meetup with MondayDB and PMC Chair

Tomorrow (Thursday, Nov. 30) please join the Cassandra community for talks from: - mondayDB - Crafting a Database from Scratch with Liran Brimer - The State of the Cassandra Development Community with Josh McKenzie, Cassandra PMC Chair How to join:

Re: Memory and caches

Hello Bowen, Jon, Thank you for your answers. I will continue investigating following your advice, currently there is no performance issue, and we have good HW etc, so probably no need to optimize caches. Have a good day, Sébastien. Le lun. 27 nov. 2023 à 20:00, Jon Haddad a écrit : > I

Re: Memory and caches

I haven't found chunk cache to be particularly useful. It's a fairly small cache that could only help when you're dealing with a small hot dataset. I wouldn't bother increasing memory for it. Key cache can be helpful, but it depends on the workload. I generally recommend optimizing for your

Re: Migrating to incremental repair in C* 4.x

Hi Jeff, Does subrange repair mark the SSTable as repaired? From my memory, it doesn't. Regards, Bowen On 27/11/2023 16:47, Jeff Jirsa wrote: I don’t work for datastax, thats not my blog, and I’m on a phone and potentially missing nuance, but I’d never try to convert a cluster to IR by

Re: Memory and caches

Hi Sebastien, What's your goal? Improving cache hit rate purely for the sake of having a higher hit rate is rarely a good goal, because higher cache hit rate doesn't always mean faster operations. Do you have specific issues with performance? If so, can you please tell us more about it?

Re: Migrating to incremental repair in C* 4.x

I don’t work for datastax, thats not my blog, and I’m on a phone and potentially missing nuance, but I’d never try to convert a cluster to IR by disabling auto compaction . It sounds very much out of date or its optimized for fixing one node in a cluster somehow. It didn’t make sense in the 4.0

Memory and caches

Hello When I use nodetool info, it prints that relevant information Heap Memory (MB) : 14229.31 / 32688.00 Off Heap Memory (MB) : 5390.57 Key Cache : entries 670423, size 100 MiB, capacity 100 MiB, 13152259 hits, 47205855 requests, 0.279 recent hit rate, 14400 save period in

Re: Migrating to incremental repair in C* 4.x

Hi Sebastian, It's better to walk down the path on which others have walked before you and had great success, than a path that nobody has ever walked. For the former, you know it's relatively safe and it works. The same can hardly be said for the later. You said it takes a week to run the

Migrating to incremental repair in C* 4.x

Hi, we are currently in the process of migrating from C* 3.11 to C* 4.1 and we want to start using incremental repairs after the upgrade has been completed. It seems like all the really bad bugs that made using incremental repairs dangerous in C* 3.x have been fixed in 4.x, and for our

Cassandra Summit: Early registration discount ends tomorrow

Hi everyone, If you've registered for Cassandra Summit, then ignore this email. If not! Time to get moving. The deadline ends tomorrow. Link to register: https://events.linuxfoundation.org/cassandra-summit/register/ Discount code: 23CS20 (Yes you can use it with the early registration price)

Re: Cassandra 4 production settings

Thank you for the answer Scott! Le lun. 20 nov. 2023 à 16:57, a écrit : > Hi Sébastien, > > Thanks for reaching out. > > This documentation is from the DataStax website rather than the Apache > Cassandra project. However, no major changes suggested between 3.x vs. 4.x > regarding what’s

Re: Cassandra 4 production settings

Hi Sébastien, Thanks for reaching out. This documentation is from the DataStax website rather than the Apache Cassandra project. However, no major changes suggested between 3.x vs. 4.x regarding what’s published here, aside from JDK version. Cassandra 4.0 supports JDK11 and adopting it is

Cassandra 4.0.10 snapshot failure during sequential repair

Hi all, we experience the following issue when executing full sequential repairs in Cassandra 4.0.10. ERROR [RepairSnapshotExecutor:1] 2023-11-07 13:22:50,267 CassandraDaemon.java:581 - Exception in thread Thread[RepairSnapshotExecutor:1,5,main] java.lang.RuntimeException: Tried to create

Cassandra 4 production settings

Hello There is no such page for Cassandra 4: https://docs.datastax.com/en/cassandra-oss/3.0/cassandra/install/installRecommendSettings.html Do the recommended settings for Cassandra 3 still apply as such to Cassandra 4. Thank you in advance. Sébastien.

Re: Cassandra 5 - Driver 3.11 support plans

I must be using an old driver version, I can see its there https://github.com/apache/cassandra-java-driver/blob/0e4f40121d65d600b123cea4bfe365dbc09bfbad/core/src/main/java/com/datastax/oss/driver/internal/core/metadata/schema/parsing/DataTypeCqlNameParser.java#L143 Sorry! Jackson From:

Re: Cassandra 5 - Driver 3.11 support plans

Apologies for the double up email but here’s the stack trace I get from using the 3.11 driver on a Cassandra 5 cluster using the vector type (I forgot to include it in my previous email) [cluster19-worker-1] ERROR c.datastax.driver.core.SchemaParser - Error parsing schema for table

Cassandra 5 - Driver 3.11 support plans

Hi All, Asking a bit of a silly question on this list I expect I already know the answer to, but are there any plans to support the new vector datatype in the 3.11 version of the java driver (https://github.com/apache/cassandra-java-driver)? I assume the answer will be no, but it might be a

Re: Time to register for the Cassandra Summit 2023!

One other important point. In talking to our friends at the Linux Foundation, they reminded me about scholarships for attending Cassandra Summit. If you would like to apply for travel or ticket assistance, follow this link and apply:

Time to register for the Cassandra Summit 2023!

Hi everyone! I'm going to keep this short, but it's time to gather the Cassandra community. December 12-13 in San Jose. Earlybird registration pricing ends November 21 so don't delay. Registration page: https://events.linuxfoundation.org/cassandra-summit/register/ Use my discount code for 20%

[RELEASE] Apache Cassandra 5.0-alpha2 released

The Cassandra team is pleased to announce the release of Apache Cassandra version 5.0-alpha2. This release contains Vector Similarity Search (CEP-30). http://cassandra.apache.org/ Downloads of source and binary distributions are listed in our download section:

Questions regarding Cassandra 4 and Cassandra 4.1

Hi all, Earlier this year, we upgraded our fleet from C* 3.0 to C* 4.0. Given the exciting new features in C* 4.1, we are contemplating an upgrade from C* 4.0 to C* 4.1. Can anyone share their experience regarding the stability of C* 4.1? Are any of you running C* 4.1 at scale? Additionally, I

November community meetings with mondayDB, PMC chair, and 5.0

Join us for our virtual community meetings in November including: - Tuesday, Nov. 28: 5.0 Release Preview - Thursday, Nov. 30: mondayDB - Crafting a Database from Scratch with Liran Brimer + The State of the Cassandra Development Community with Josh McKenzie Register:

Re: Cassandra stopped responding but still alive

What do you mean by saying "Cassandra stopped responding ... to nodetool requests"? Is it a specific nodetool command (e.g. "nodetool status") or all nodetool commands? What's the issue? Was it an error message, such as connection refused? Or freezes/unresponsive? It's common to see Cassandra

Re: Cassandra stopped responding but still alive

Can you describe the type of environment you are running in? This sure sounds like odd firewall behavior I’ve seen in the past. > On Oct 31, 2023, at 4:56 PM, Ben Klein wrote: > > On October 30, 2023, at approximately 15:38 UTC, Cassandra stopped responding > to TCP pings on port 9042 and to

Fwd: Upcoming Community Meetings

Today is the monthly Cassandra contributor meeting at 10:00 PT / 13:00 ET / 17:00 UTC / 22:30 IST. Piotr Kołaczkowski will share details about CEP-29: CQL Not operator and how to use and contribute. How to join:

RE: Upgrade from C* 3 to C* 4 per datacenter

Hello everyone, @Sebastian thanks a lot for the indication about cloning the cluster to do the tests. It is really good information. @Aaron thanks a lot for the heads up. Thanks a lot for the valuable contribution of the community in this case!!! BR MK From: Aaron Ploetz Sent: October 26, 2023

Re: Resources to understand rebalancing

Thanks for sharing this clear explanation, Jeff. Cheers! On Wed, Oct 25, 2023 at 5:58 PM Jeff Jirsa wrote: > Data ownership is defined by the token ring concept. > > Hosts in the cluster may have tokens - let's oversimplify to 5 hosts, each > with 1 token A=0, B=1000, C=2000, D=3000, E=4000 > >

Re: Backup and Restore Strategy and Tools

Hi Bhavesh, have you gone through Cassandra tools here (1)? Just search for "backup", there are couple (CLI) solutions out there for your problem. Feel tree to ping me on Cassandra Slack or privately if you want. Cheers https://cassandra.apache.org/_/ecosystem.html

Backup and Restore Strategy and Tools

Hi, I have 48 nodes, single DC, Apache Cassandra cluster running in Prod – version is 4.0.6. Currently, we are using a home-grown backup script based on nodetool snapshot that uploads backup to s3. We are using a home-grown restore script to recover incase of disaster. I am looking for a

Re: Upgrade from C* 3 to C* 4 per datacenter

Just a heads-up, but there have been issues (at least one) reported when upgrading a multi-DC cluster from 3.x to 4.x when the cluster uses node-to-node SSL/TLS encryption. This is largely attributed to the fact that the secure port in 4.x changes to 9142, whereas in 3.x it continues to run on

Re: Upgrade from C* 3 to C* 4 per datacenter

Hi, as we are currently facing the same challenge (upgrading an existing cluster from C* 3 to C* 4), I wanted to share our strategy with you. It largely is what Scott already suggested, but I have some extra details, so I thought it might still be useful. We duplicated our cluster using the

RE: Upgrade from C* 3 to C* 4 per datacenter

Hello Jeff et al, Thanks a lot for your valuable info. Your comment covers all my queries. BR MK From: Jeff Jirsa Sent: October 26, 2023 15:48 To: user@cassandra.apache.org Cc: Michalis Kotsiouros (EXT) Subject: Re: Upgrade from C* 3 to C* 4 per datacenter On Oct 26, 2023, at 12:32 AM,

Re: Upgrade from C* 3 to C* 4 per datacenter

> On Oct 26, 2023, at 12:32 AM, Michalis Kotsiouros (EXT) via user > wrote: > >  > Hello Cassandra community, > We are trying to upgrade our systems from Cassandra 3 to Cassandra 4. We plan > to do this per data center. > During the upgrade, a cluster with mixed SW levels is expected. At

RE: Upgrade from C* 3 to C* 4 per datacenter

Hello Scott, Thanks a lot for the immediate answer. We use a semi automated procedure to do the upgrade of the SW in our systems which is done per datacenter. Our limitation is that if we want to rollback we need to rollback the Cassandra nodes from the whole datacenter. May I return to the

Re: Upgrade from C* 3 to C* 4 per datacenter

The recommended approach to upgrading is to perform a replica-safe rolling restart of instances in each datacenter, one datacenter at a time. > In case of an upgrade failure, would it be possible to remove the data center from the cluster, restore the datacenter to C*3 SW and add it back to

Upgrade from C* 3 to C* 4 per datacenter

Hello Cassandra community, We are trying to upgrade our systems from Cassandra 3 to Cassandra 4. We plan to do this per data center. During the upgrade, a cluster with mixed SW levels is expected. At this point is it possible to perform topology changes? In case of an upgrade failure, would it

Re: Unsubscribe

Hi, you need to unsubscribe as shown here https://cassandra.apache.org/_/community.html#discussions Regards From: Daniel Stibor Sent: Wednesday, October 25, 2023 15:17 To: user@cassandra.apache.org Subject: Unsubscribe You don't often get email from

Unsubscribe

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Re: Resources to understand rebalancing

Data ownership is defined by the token ring concept. Hosts in the cluster may have tokens - let's oversimplify to 5 hosts, each with 1 token A=0, B=1000, C=2000, D=3000, E=4000 The partition key is hashed to calculate the token, and the next 3 hosts in the ring are the "owners" of that data - a

Resources to understand rebalancing

Hi folks, I am looking for some resources to understand the internals of rebalancing in Cassandra. Specifically: - How are read and write queries served during data migration? - How is the cutover from the current node to the new node performed? Any help is greatly appreciated. Thanks, Vikas

Re: Cassandra 4.0.6 token mismatch issue in production environment

Sounds good. Thanks a lot for all your help! Jaydeep On Mon, Oct 23, 2023 at 3:30 PM Jeff Jirsa wrote: > Not aware of any that survive node restart, though in the past, there were > races around starting an expansion while one node was partitioned/down (and > missing the initial gossip / UP).

Re: Cassandra 4.0.6 token mismatch issue in production environment

Not aware of any that survive node restart, though in the past, there were races around starting an expansion while one node was partitioned/down (and missing the initial gossip / UP). A heap dump could have told us a bit more conclusively, but it's hard to guess for now. On Mon, Oct 23, 2023

Re: Cassandra 4.0.6 token mismatch issue in production environment

The issue was persisting on a few nodes despite no changes to the topology. Even node restarting did not help. Only after we evacuated those nodes, the issue got resolved. Do you think of a possible situation under which this could happen? Jaydeep On Sat, Oct 21, 2023 at 10:25 AM Jaydeep

Upcoming Community Meetings

Hi all, There are two Apache Cassandra community events coming up this week and next: *October Town Hall * - this month we'll be hearing from Patrick Lee at Walmart about the interesting

Re: Cassandra 4.0.6 token mismatch issue in production environment

Thanks, Jeff! I will keep this thread updated on our findings. Jaydeep On Sat, Oct 21, 2023 at 9:37 AM Jeff Jirsa wrote: > That code path was added to protect against invalid gossip states > > For this logger to be issued, the coordinator receiving the query must > identify a set of replicas

Re: Cassandra 4.0.6 token mismatch issue in production environment

That code path was added to protect against invalid gossip states For this logger to be issued, the coordinator receiving the query must identify a set of replicas holding the data to serve the read, and one of the selected replicas must disagree that it’s a replica based on its view of the

Cassandra 4.0.6 token mismatch issue in production environment

Hi, I am using Cassandra 4.0.6 in production, and receiving the following error. This indicates that Cassandra nodes have mismatch in token-owership. Has anyone seen this issue before? Received a read request from /XX.XX.XXX.XXX:Y for a range that is not owned by the current replica

Cassandra Summit Update!

Hello Cassandra Community, Below you'll find the updated announcement being posted on the Cassandra website. The short version for short attention spans: - Cassandra Summit will be co-located with the AI.Dev conference. One ticket, two conferences. - CFP for an AI track for the Cassandra

Re: java driver with cassandra proxies (option: -Dcassandra.join_ring=false)

Hi Jeff Today, we use proxy nodes with php, and we are migrating from php to java. Our farm of php servers is made of 80 physical servers, all of them having a local proxy node. So our cassandra cluster is made of : - DC1 : 6 data nodes + 40 proxies - DC2 : 6 data nodes + 40 proxies During our

Re: java driver with cassandra proxies (option: -Dcassandra.join_ring=false)

Hi Stefan, Your analysis is exactly what happen ! What I can say is that we are migrating from php to java and the behaviour of the php (or cpp) driver is completely different. * The topology of the cassandra cluster returned by the contact point with the php driver includes data nodes + proxy

Re: java driver with cassandra proxies (option: -Dcassandra.join_ring=false)

It will use the first contact point to connect to the database and once connected, it will read that peers table, which is empty. Contact points are really just that - contact points. I think it does not mean that all of them will be used in some round-robin fashion or what. They are there just

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