cassandra-3.0

问题 Cassandra doc mentions that "nodetool snapshot" command takes snapshot of table data. However, I am also able to see schema.cql and manifest.json file in my snapshot directory where all snapshot files are generated. Is this expected behavior? Also can I use this schema.cql file to restore the schema if needed? My cassandra version cqlsh> show version [cqlsh 5.0.1 | Cassandra 3.0.9 | CQL spec 3.4.0 | Native protocol v4] >nodetool version ReleaseVersion: 3.0.9 EDIT: Is it mandatory to use cql

问题 I am not sure about setting the policy 'DowngradingRetryPolicy' in nodejs using Cassandra. policies : { loadBalancing : new cassandra.policies.loadBalancing.RoundRobinPolicy, retry: new cassandra.policies.retry.IdempotenceAwareRetryPolicy(new cassandra.policies.retry.RetryPolicy()) } }); This is how I set the IdempotenceAwareRetryPolicy policy and it is working as expected but How to set the ' DowngradingRetryPolicy ' policy in Cassandra using nodejs For reference adding the ruby

问题 I have an enum field that i want to map to a column in cassandra public enum MyEnum { Aa, Bb, Cc, } and here is how i registered it CodecRegistry myCodecRegistry = new CodecRegistry(); myCodecRegistry.register(new EnumOrdinalCodec<MyEnum>(MyEnum.class)); cluster = Cluster.builder().addContactPoint(cassandraHosts).withPort(cassandraPort).withCodecRegistry(myCodecRegistry).build(); i am able to connect to cassandra just fine. Here is a snippet of the model class public class MyModel {

问题 I have a 4 node setup in Cassandra and decided to go with the following configuration, but ppl are saying this will be same as 3 node setup, So could somebody please give me a light and say why, Nodes = 3, Replication Factor = 2, Write Consistency = 2, Read Consistency = 1 Nodes = 4, Replication Factor = 3, Write Consistency = 3, Read Consistency = 1 As per my understanding, Nodes = 4, provide the two node failure, It is beneficial to have RF as '3' but ppl are saying RF = 2 will be same as

问题 I have created a unit-test which uses embedded-cassandra and executes some scripts. But I am not able to figure out if the scripts ran successfully or not. I see the following two prints (maybe because I have two statements). Is there a way to get the result of the execution and print it on the console. WARN c.d.d.c.Connection - /127.0.0.1:9042 did not send an authentication challenge; This is suspicious because the driver expects authentication (configured auth provider = com.datastax.driver

问题 Our use case with Cassandra is to show top 10 recent visitors of a blogpost. Following is the Cassandra table definition CREATE TABLE blogs_by_visitor ( blogposturl text, visitor text, visited_ts timestamp, PRIMARY KEY (blogposturl, visitor) ); Now in order to show top 10 recent visitors for a given blogpost, there needs to be an explicit "order by" clause on timestamp desc. Since visted_ts isn't part of the clustering column in Cassandra, we aren't able to get this done. The reason for

问题 Our use case with Cassandra is to show top 10 recent visitors of a blogpost. Following is the Cassandra table definition CREATE TABLE blogs_by_visitor ( blogposturl text, visitor text, visited_ts timestamp, PRIMARY KEY (blogposturl, visitor) ); Now in order to show top 10 recent visitors for a given blogpost, there needs to be an explicit "order by" clause on timestamp desc. Since visted_ts isn't part of the clustering column in Cassandra, we aren't able to get this done. The reason for

问题 I have a machine the commit logs keeps increasing upto 7.8 GB and still growing, I checked a property commitlog_total_space_in_mb: 8192 which is commented in cassandra.yaml. I suspect it has to be the default. 1) What is the problem in growing commit log size? 2) Is it says my memtable treshold is not reached? EDITED : memtable_cleanup_threshold = 1/(memtable_flush_writers + 1) * (memtable_offheap_space_in_mb + memtable_heap_space_in_mb) where recommended values are, memtable_flush_writers -

问题 When querying a Cassandra 3.0.0 cluster using Presto 0.131 I get: All host(s) tried for query failed [..snip...] InvalidQueryException: unconfigured table schema_keyspaces I assume this is due to some change in Cassandra's system schemas? If so is there a workaround or should we wait for Presto to support Cassandra 3.0.0? 2016-11-05 Update : Newer versions of PrestoDB work fine with Cassandra 3+. Currently using 0.147 but the latest version is 0.156 and they all work fine with the new

问题 I am trying to insert data with spring-data-cassandra. But I am getting bellow error , when my app is running with SpringBoot(version is 1.5.3) I add a custom CallHistoriyRespority object implemented CrudResposity in spring-data, and use the save method to insert the data object I can't find any reason and the problem confused me Full stack trace : Caused by: com.datastax.driver.core.exceptions.InvalidQueryException: Expected 8 or 0 byte long for date (13) at com.datastax.driver.core