Re: 答复: Time serial column family design

Jon, Great article. Thank you. (I have nothing to do with this issue, but I appreciate nuggets of information I glean from the list) Regards, Eric On Tue, Apr 17, 2018 at 10:57 PM Jonathan Haddad wrote: > To add to what Nate suggested, we have an entire blog post on

Re: 答复: Time serial column family design

To add to what Nate suggested, we have an entire blog post on scaling time series data models: http://thelastpickle.com/blog/2017/08/02/time-series-data-modeling-massive-scale.html Jon On Tue, Apr 17, 2018 at 7:39 PM Nate McCall wrote: > I disagree. Create date as a

答复: 答复: Time serial column family design

Hi Javier, VIN is the Vehicle Identity Number, the Vehicle upload the inform from can-bus every 10 second,this table contains about 20 columns,so if we can just VIN as the partition key, every vehicle just has only one partition,the partition will become very large and never stop

Re: 答复: Time serial column family design

I disagree. Create date as a raw integer is an excellent surrogate for controlling time series "buckets" as it gives you complete control over the granularity. You can even have multiple granularities in the same table - remember that partition key "misses" in Cassandra are pretty lightweight as

Is it safe to use paxos protocol in LWT from patent perspective ?

Hi all, I'm wondering if it is safe to use paxos protocol in LWT from patent perspective. I found some paxos-related patents here. Does anyone know about this ? Best regards, Hiroyuki

Re: where does c* store the schema?

Rahul, none of that is true at all. Each node stores schema locally in a non-replicated system table. Schema changes are disseminated directly to live nodes (not the write path), and the schema version is gossiped to other nodes. If a node misses a schema update, it will figure this out

Re: multiple table directories for system_schema keyspace

Happens to any keyspace — not just system — if there are competing processes initializing the system , creating / altering new things without CL=all it may do this. I ran into a scenario where when permissions were flipped to a non Cassandra user, the Cassandra daemon lost access to the data so

Re: Cassandra read process

Did you look at the answer the guy gave? -- Rahul Singh rahul.si...@anant.us Anant Corporation On Apr 17, 2018, 5:12 AM -0500, vishal1.sha...@ril.com, wrote: > Dear Community, > > Can you please help in answering the question below: > >

Re: where does c* store the schema?

It uses a “everywhere” replication strategy and its recommended to do all alter / create / drop statements with consistency level all — meaning it wouldn’t make the change to the schema if the nodes are up. -- Rahul Singh rahul.si...@anant.us Anant Corporation On Apr 17, 2018, 12:31 AM -0500,

Re: copy from one table to another

1. Make a new table with the same schema. For each node 2. Shutdown node 3. Copy data from Source sstable dir to new sstable dir. This will do what you want. -- Rahul Singh rahul.si...@anant.us Anant Corporation On Apr 16, 2018, 4:21 PM -0500, Kyrylo Lebediev ,

Re: 答复: Time serial column family design

Hi David, Could you describe why you chose to include the create date in the partition key? If the vin in enough "partitioning", meaning that the size (number of rows x size of row) of each partition is less than 100MB, then remove the date and just use the create_time, because the date is

Re: 答复: Time serial column family design

Your table design will work fine as you have appropriately bucketed by an integer-based 'create_date' field. Your goal for this refactor should be to remove the "IN" clause from your code. This will move the rollup of multiple partition keys being retrieved into the client instead of relying on

Re: inexistent columns familes

got it thanks! will have to tackle this in another way. Thank you. Regards L. On Tue, Apr 17, 2018 at 1:58 PM, Jeff Jirsa wrote: > I imagine 3.0.16 has THIS bug, but it has far fewer other real bugs. > > > > On Tue, Apr 17, 2018 at 1:56 PM, Luigi Tagliamonte < >

Re: inexistent columns familes

I imagine 3.0.16 has THIS bug, but it has far fewer other real bugs. On Tue, Apr 17, 2018 at 1:56 PM, Luigi Tagliamonte < luigi.tagliamont...@gmail.com> wrote: > Thank you Jeff, > my backup scripts works using the cf folders on disk :) > it parses all the keyspaces and for each performs:

Re: inexistent columns familes

Thank you Jeff, my backup scripts works using the cf folders on disk :) it parses all the keyspaces and for each performs: nodetool flush ${keyspace} ${cf} and then nodetool snapshot ${keyspace} -cf ${cf} Does 3.0.16 not having this "bug"? Regards L. On Tue, Apr 17, 2018 at 1:50 PM, Jeff Jirsa

Re: inexistent columns familes

It's probably not ideal, but also not really a bug. We need to create the table in the schema to see if it exists on disk so we know whether or not to migrate it, and when we learn it's empty, we remove it from the schema but we dont delete the directory. It's not great, but it's not going to

inexistent columns familes

Hello everybody, i'm having a problem with a brand new cassandra:3.0.11 node. The following tables belonging to the system keyspace: - schema_aggregates - schema_columnfamilies - schema_columns - schema_functions - schema_keyspaces - schema_triggers - schema_usertypes get initialised on disk:

multiple table directories for system_schema keyspace

On a couple different occasions I have run into this exception at start up: Exception (org.apache.cassandra.exceptions.InvalidRequestException) encountered during startup: Unknown type org.apache.cassandra.exceptions.InvalidRequestException: Unknown type at

Re: DigestMismatchException after upgrade from c*-2.1.17 to c*-3.0.15

This isn’t really an error and shouldn’t be logged because so few people understand it well enough to find it useful. Some number of digest mismatches are expected if you read as you write. I wouldn’t worry about it unless you’re having a problem. -- Jeff Jirsa > On Apr 17, 2018, at 12:29

Cassandra read process

Dear Community, Can you please help in answering the question below: https://stackoverflow.com/questions/49769643/cassandra-read-process Thanks and regards, Vishal Sharma "Confidentiality Warning: This message and any attachments are intended only for the use of the intended recipient(s). are

SSTable count in Nodetool tablestats(LevelCompactionStrategy)

Dear Community, One of the tables in my keyspace is using LevelCompactionStrategy and when I used the nodetool tablestats keyspace.table_name command, I found some mismatch in the count of SSTables displayed at 2 different places. Please refer the attached image. The command is giving SSTable

Memtable type and size allocation

Dear Community, In Cassandra 3.11.2, there are 3 choices for the type of Memtable allocation and as per my understanding, if I want to keep Memtables on JVM heap I can use heap_buffers and if I want to store Memtables outside of JVM heap then I've got 2 options offheap_buffers and

答复: Time serial column family design

Hi Nate, Thanks for your reply! Is there other way to design this table to meet this requirement? Best Regards, 倪项菲/ David Ni 中移德电网络科技有限公司 Virtue Intelligent Network Ltd, co. Add: 2003,20F No.35 Luojia creative city,Luoyu Road,Wuhan,HuBei Mob: +86 13797007811|Tel: + 86 27 5024 2516 发件人:

A Cassandra Storage Estimation Mechanism

I was going to estimate Hardware requirements for a project which mainly uses Apache Cassandra. Because of rule "Cassandra nodes size better be 2 TB", the total disk usage determines number of nodes, and in most cases the result of this calculation would be so OK for satisfying the required

DigestMismatchException after upgrade from c*-2.1.17 to c*-3.0.15

Hi, We have recently upgraded our cassandra production cluster(2 datacenters , each with 6 nodes, 3 groups) from c*-2.1.17 to c*-3.0.15. After which we are getting too many exceptions as below. org.apache.cassandra.service.DigestMismatchException: Mismatch for key >