Is there a way to check the selected keyspace in Cassandra while using it through Java?
Context:
A subsystem uses authentication credentials to select a keyspace. I'm working on a DTO that executes commands. I have a hunch that i'm operating in the wrong keyspace (commands execute successfully in DevCenter but not within the Java code).
I'm new to Cassandra and this Java application so I apologize if this is a silly question.
Related
I've got an existing Cassandra application I want to try in Datastax Astra. I've created my Astra database and am able to connect to it from NodeJS successfully. The next task I have is to apply my existing schema.cql to the keyspace.
It should be easy enough right? But never-the-less I can't see any obvious way to do this. Can someone walk me through it please. I can then I think use the dsbulk tool to upload a dataset.
Thanks in advance Astra experts.
Rod
The easiest way to do it is to cut-and-paste the CQL statements one-by-one into the CQL console and run them one at a time. This is what I would recommend since you have guarantees that each DDL statement has completed successfully before you can execute the next one.
Alternatively, you can download the Standalone CQL Shell to your laptop/desktop and run the cqlsh commands from there. You will need to configure it with your app token + secure connect bundle to be able to connect to your database.
For more info, see the instructions for Installing standalone cqlsh. Cheers!
Converting comment to answer:
Unauthorized('Error from server: code=2100 [Unauthorized]
message="No SELECT permission on <table system_virtual_schema.keyspaces>
What is the role you have created your token for in Astra DB? Otherwise, create a new one as "Database Administrator" and that should be able to SELECT FROM system_virtual_schema.keyspaces.
While creating use-specific roles is a good idea, only privileged roles can run data definition language (DDL) commands.
I use the community edition of Cassandra (not DSE). Earlier I used to use a tool called descanter. when I click "clone" in descanter on an existing table. it used to give me the CQL necessary to re-create the existing table.
Now on my new MacOS (High Sierra) the devcenter tool is broken. I searched on the forums and found that DataStax has no intention of maintaining the tool.
So I am now using the command line CQLSH. Now in CQLSH if I have an existing table. How to generate the query to clone an existing table?
I only need the table structure. I don't need any data.
I cannot physically login to the Cassandra server. So everything needs to be done by connecting to Cassandra remotely using CQLSH.
DESCRIBE command should help you
I have installed Cassandra CQL Client on window 10.but i want to take cassandra node's backup file from CDATA ADO.NET code, which will be stored on specific directory.
I Need help with code.
There is no way to take node's backup from Cassandra ADO.net drivers. We can achieve this scenario by Cassandra Snapshots for nodes backup.
onfluence.atlassian.com/bitbucketserver/basic-git-commands-776639767.html
I have a large, but simple Cassandra database on a Datastax 4.6 cluster. The license renewal is prohibitive for this very simple use case and I am trying to migrate to either a straight Apache or Datastax Comunity version. First is it possible to do an inline update?
I have altered all the keyspaces to remove the "EverywhereStrategy" replication strategy but I still get an error that the DSC version of cassandra I'm trying to get to join the cluster doesn't support it. I'm using Like Cassandra versions (2.0.16) and most other things seem to be close.
java.lang.RuntimeException: org.apache.cassandra.exceptions.ConfigurationException: Unable to find replication strategy class 'org.apache.cassandra.locator.EverywhereStrategy'
If it's not possible to do an inline upgrade what would be the best strategy to migrate a decent size (30 node, 150Tb) cluster?
So to make this work you have to extract any of the DSE features that you may have on any of your tables.
This meant I had to change the replication strategy on the dse_system table from EverywhereStrategy to SimpleStrategy with RF=3 (or almost anything after conversion you can drop this keyspace) The error message was:
java.lang.RuntimeException: org.apache.cassandra.exceptions.ConfigurationException: Unable to find replication strategy class 'org.apache.cassandra.locator.EverywhereStrategy'
I Also had to drop the unused CFS keyspaces. We never used the hadoop/CFS integration so we had nothing in these keyspaces anyway. I didn't capture the error for this.
We did have a solr index on a table we were testing on this cluster about a year ago so I had to drop this columnfamily. The error message was:
java.lang.RuntimeException: java.lang.ClassNotFoundException: com.datastax.bdp.search.solr.Cql3SolrSecondaryIndex
There may be other incompatibilities if you use other features of Datastax Enterprise that you would have to remove, but this was enough for me to get the migration working.
dse-core.jar contains the EverywhereStrategy class.
We solved this problem by doing the following:
Replace everything except the above JAR so nodes can come up fine. Once all nodes are migrated to OSS, drop the dse_system keyspace (that uses this replication), delete the JAR and restart the nodes one by one.
I am new to cassandra,
I have more than 10 years experience of working with mysql and sql server and it makes my job harder to transfer to nosql databases.
As you know sql databases provide very user friendly workbrench for working with them.
But the only thing that I found for cassandra was datastax and I am not even sure if I can even create nodes and colloections in a visualize way and not by command line. Is it possible to do such a thing in cassandra ?
You can use OpsCenter and DevCenter, both from DataStax. OpsCenter lets you do operations-centric tasks, while DevCenter lets you perform developer-centric tasks.