cassandra

问题 I am new to CQL and trying to add pagination support for my tables defined in cassandra as shown below - cqlsh:dev> create table emp4 (empid uuid , year varchar , month varchar , day varchar, primary key((year, month, day), empid)); cqlsh:dev> insert into emp4 (empid, year, month, day) values (08f823ac-4dd2-11e5-8ad6-0c4de9ac7563,'2014','03','19'); cqlsh:dev> insert into emp4 (empid, year, month, day) values (08f823ac-4dd2-11e5-8ad6-0c4de9ac7562,'2016','03','19'); cqlsh:dev> select * from

问题 I am new to CQL and trying to add pagination support for my tables defined in cassandra as shown below - cqlsh:dev> create table emp4 (empid uuid , year varchar , month varchar , day varchar, primary key((year, month, day), empid)); cqlsh:dev> insert into emp4 (empid, year, month, day) values (08f823ac-4dd2-11e5-8ad6-0c4de9ac7563,'2014','03','19'); cqlsh:dev> insert into emp4 (empid, year, month, day) values (08f823ac-4dd2-11e5-8ad6-0c4de9ac7562,'2016','03','19'); cqlsh:dev> select * from

问题 We have Cassandra cluster with single token per node, total 22 nodes, average load per node is 500Gb. It has SimpleStrategy for the main keyspace and SimpleSnitch. We need to migrate all data to the new datacenter and shutdown the old one without a downtime. New cluster has 28 nodes. I want to have vnodes on it. I'm thinking of the following process: Migrate the old cluster to vnodes Setup the new cluster with vnodes Add nodes from the new cluster to the old one and wait until it balances

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 6 years ago . What are the strengths and weaknesses of the various NoSQL databases available? In particular, it seems like Redis is weak when it comes to distributing write load over multiple servers. Is that the case? Is it a big problem? How big does a service have to grow before that

问题 Using Node.js I need to load three files dynamically with a require() function by fetching the file path from Cassandra. From each file I need to fetch data that is in Redis and do some validation before loading another file from Cassandra. The issue here is: before the validation logic executes and provides results the next file's start to get loaded in parallel. The validation result comes after the loading of the second file, which shouldn't happen. The second file loading should wait for

问题 Using Node.js I need to load three files dynamically with a require() function by fetching the file path from Cassandra. From each file I need to fetch data that is in Redis and do some validation before loading another file from Cassandra. The issue here is: before the validation logic executes and provides results the next file's start to get loaded in parallel. The validation result comes after the loading of the second file, which shouldn't happen. The second file loading should wait for

问题 I've spent the last week trying to figure out how to use sparlyr to get spark to connect to cassandra on our local cluster, and I've hit a wall - any help would be greatly appreciated. I'm the only one trying to use R/Rstudio to make this connection (everyone else uses Java on NetBeans and Maven), and am not sure what I need to do to make this work. The stack I'm using is: Ubuntu 16.04 (in a VM) sparklyr: 0.5.3 Spark: 2.0.0 Scala: 2.11 Cassandra: 3.7 relevant config.yml file settings: #

问题 I'm using virtual box to act as Linux guest to Cassandra DB, and I'm trying to access it through my windows host, however, i don't know what are the right configurations to do that. on virtual box I'm using "host only networking" to communicate from windows. Anyone knows how to do these configurations? 回答1: Maybe, it's the network configuration of the guest. In VirtualBox environment, if you want communicate to the guest from the host, the network type of the VM must be "bridged networking"

问题 I created an Apache Cassandra 2.1.2 cluster of 50 nodes. I named the cluster as "Test Cluster", the default. Then for some testing, I separated one node out of the 50 node cluster. I shut down Cassandra, deleted data dirs, flushed nodetool. Then I edited the single node cluster and called it as "Single Node Test Cluster" I edited seeds, cluster_name and listen_address fields appropriately. I also setup JMX correctly. Now here is what happens. 1. When I run nodetool status on the single node,

问题 i want to include properties file explicitly and include it in spark code , instead of hardcoding directly in spark code with all credentials. i am trying following approach but not able to do, AppContext is not able to be resolved. please guide me how to achieve this. Spark_env.properties (under src/main/resourcses in maven project for spark with scala) CASSANDRA_HOST1=127.0.0.133 CASSANDRA_PORT1=9042 CASSANDRA_USER1=usr1 CASSANDRA_PASS1=pas2 DataMigration.cassandra.keyspace1=demo2