Re: *URGENT* Migration across different Cassandra cluster few having same keyspace/table names
Hi, Did you consider adding Cassandra nodes from cluster B, into cluster A as a different data center ? Your keyspace would than be on Network topology data strategy. In this case, all data can be synced between both data centers by Cassandra using rebalancing. At client/application level you will have to ensure local quorum/ local consistency so that there is no impact on latencies. Once you have moved data applications to new cluster , you can then remove the old data center (cluster A), and cluster B would have fresh data. On Fri, Jan 17, 2020, 6:59 PM Ankit Gadhiya wrote: > Thanks but there’s no DSE License. > Wondering how sstableloader will help as some oh the Keyspace and tables > names are same. Also how do i sync few system keyspaces. > > > Thanks & Regards, > Ankit > > On Fri, Jan 17, 2020 at 1:11 AM Vova Shelgunov wrote: > >> Loader* >> >> https://www.datastax.com/blog/2018/05/introducing-datastax-bulk-loader >> >> On Fri, Jan 17, 2020, 09:09 Vova Shelgunov wrote: >> >>> DataStax bulk loaded can be an option if data is large. >>> >>> On Fri, Jan 17, 2020, 07:33 Nitan Kainth wrote: >>> If the keyspace already exist, use copy command or sstableloader to merge data. If data volume it too big, consider spark or a custom java program Regards, Nitan Cell: 510 449 9629 On Jan 16, 2020, at 10:26 PM, Ankit Gadhiya wrote: Any leads on this ? — Ankit On Thu, Jan 16, 2020 at 8:51 PM Ankit Gadhiya wrote: > Hi Arvinder, > > Thanks for your response. > > Yes - Cluster B already has some data. Tables/KS names are identical ; > for data - I still haven't got the clarity if it has identical data or no > - > I am assuming no since it's for different customers but need the > confirmation. > > *Thanks & Regards,* > *Ankit Gadhiya* > > > > On Thu, Jan 16, 2020 at 8:49 PM Arvinder Dhillon < > dhillona...@gmail.com> wrote: > >> So as I understand, Cluster B already has some data and not an empty >> cluster. >> >> When you say, clusters share same keyspace and table names, do you >> mean both clusters have identical data on those ks/tables? >> >> >> -Arvi >> >> On Thu, Jan 16, 2020, 5:27 PM Ankit Gadhiya >> wrote: >> >>> Hello Group, >>> >>> I have a requirement in one of the production systems where I need >>> to be able to migrate entire dataset from Cluster A (Azure Region A) to >>> Cluster B (Azure Region B). >>> >>> Each cluster have 3 Cassandra nodes (RF=3) running used by different >>> applications. Few of the applications are common is Cluster A and >>> Cluster B >>> thereby sharing same keyspace/table names. >>> Need suggestion for the best possible migration strategy here >>> considering - 1. No Application code changes possible - Minor >>> config/infra >>> changes can be considered. 2. Zero data loss. 3. No/Minimal downtime. >>> >>> It'd be great to hear ideas from all of you based on your >>> experiences. >>> >>> Cassandra Version - Cassandra 3.0.13 on both sides. >>> Total Data size - Cluster A: 70 GB, Cluster B: 15 GB >>> >>> *Thanks & Regards,* >>> *Ankit Gadhiya* >>> >>> -- *Thanks & Regards,* *Ankit Gadhiya* -- > *Thanks & Regards,* > *Ankit Gadhiya* > >
Re: Cassandra LWT Writes inconsistent
Thanks Hiro & Jeff Jeff, My LWT(Insert if not exists) query is executed in parallel by 6 threads, with a possibility of collision. So, all threads may request to write same data on Cassandra tables. What would you suggest here ? Hiro, i am using Datastax Mapper & Accessor for this. Something similar to this : https://docs.datastax.com/en/developer/java-driver/3.6/manual/object_mapper/creating/ Do you have a suggestion , how can i verify that my code is actually setting query consistency? Thank you for your response. On Tue, Jul 9, 2019 at 5:30 PM Hiroyuki Yamada wrote: > Do you also set SERIAL CONSISTENCY properly ? > > https://docs.datastax.com/en/archived/cql/3.3/cql/cql_reference/cqlshSerialConsistency.html > > Hiro > > On Tue, Jul 9, 2019 at 2:25 PM Jeff Jirsa wrote: > > > > If applied is false it’s not the first write, the value already exists. > You’ve likely got a concurrency issue app side or you don’t understand the > concurrent queries you’re issuing to the db > > > > On Jul 8, 2019, at 10:08 PM, raman gugnani > wrote: > > > > Hi Team, > > > > Can anyone help on the same. > > > > Cassnadra driver says write is not done but eventually write has been > done. > > > > On Mon, 8 Jul 2019 at 12:31, Upasana Sharma <028upasana...@gmail.com> > wrote: > >> > >> > >> Hi, > >> > >> I am using an LWT Insert transaction similar to: > >> > >> INSERT INTO table1 (code, id, subpart) VALUES (:code, :id, :subpart) IF > NOT EXISTS > >> > >> With > >> readConsistency="LOCAL_SERIAL" > >> writeConsistency="LOCAL_QUORUM" > >> > >> Cassandra Driver: 3.6.0 > >> Cassandra Version: Cassandra 3.11.2 > >> > >> > >> The problem is that I am getting [applied] false on the first write to > cassandra. > >> > >> I have set retry policy as writeTimes = 0, so no retries are attempted. > >> > >> My application logs for reference: > >> > >> c-7967981443032352 - [INFO ] 2019-06-18T19:46:16.276Z > [pool-15-thread-5] CreateService - SubPartition 104 > >> c-7967981443032352 - [INFO ] 2019-06-18T19:46:16.805Z > [pool-15-thread-5] Repository - Row[false, A, 1, 104] > >> c-7967981443032352 - [INFO ] 2019-06-18T19:46:16.805Z > [pool-15-thread-5] CreateService - SubPartition 104 CodeNumber 75191 > DuplicateCodeGenerated A > >> > >> This is causing my count of writes to tables to differ from required > 10, to 11, writing extra codes. > >> > >> Please guide here. > >> > >> -- > >> Regards, > >> Upasana Sharma > > > > > > > > -- > > Raman Gugnani > > > > 8588892293 > > Principal Engineer > > ixigo.com > > - > To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org > For additional commands, e-mail: user-h...@cassandra.apache.org > > -- Regards, Upasana Sharma
Cassandra LWT Writes inconsistent
Hi, I am using an LWT Insert transaction similar to: INSERT INTO table1 (code, id, subpart) VALUES (:code, :id, :subpart) IF NOT EXISTS With readConsistency="LOCAL_SERIAL" writeConsistency="LOCAL_QUORUM" Cassandra Driver: 3.6.0 Cassandra Version: Cassandra 3.11.2 The problem is that I am getting* [applied] false* on the *first write* to cassandra. I have set retry policy as writeTimes = 0, so no retries are attempted. My application logs for reference: c-7967981443032352 - [INFO ] 2019-06-18T19:46:16.276Z [pool-15-thread-5] CreateService - SubPartition 104 c-7967981443032352 - [INFO ] 2019-06-18T19:46:16.805Z [pool-15-thread-5] *Repository - Row[false, A, 1, 104]* c-7967981443032352 - [INFO ] 2019-06-18T19:46:16.805Z [pool-15-thread-5] CreateService - SubPartition 104 CodeNumber 75191 *DuplicateCodeGenerated A* This is causing my count of writes to tables to differ from required 10, to 11, writing extra codes. Please guide here. -- Regards, Upasana Sharma
