cassandra

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 . I found lazyboy and pycassa - maybe there are others too. I've seen many sites recommending lazyboy. IMHO the project seems dead, see https://www.ohloh.net/p/compare?project_0=pycassa&project_1=lazyboy So what's the best option for a new project? Thanks. 回答1: The Cassandra

问题 I have a delicate Spark problem, where i just can't wrap my head around. We have two RDDs ( coming from Cassandra ). RDD1 contains Actions and RDD2 contains Historic data. Both have an id on which they can be matched/joined. But the problem is the two tables have an N:N relation ship. Actions contains multiple rows with the same id and so does Historic . Here are some example date from both tables. Actions time is actually a timestamp id | time | valueX 1 | 12:05 | 500 1 | 12:30 | 500 2 | 12

问题 I am trying to duplicate data in a cassandra nosql database for a school project using datastax ops center. From what I have read, there is three keywords: cluster, node, and datacenter, and from what I have understand, the data in a node can be duplicated in another node, that exists in another cluster. And all the nodes that contains the same (duplicated) data compose a datacenter. Is that right? If it is not, what is the difference? 回答1: The hierarchy of elements in Cassandra is: Cluster

问题 I am using spark-sql 2.4.x version , datastax-spark-cassandra-connector for Cassandra-3.x version. Along with kafka. I have a scenario for some finance data coming from kafka topic, say financeDf I need to remap some of the fields from a metaDataDf = //loaded from cassandra table for look out. But this cassandra table (metaDataDf ) can be updated once in an hour. In spark-sql strucutred streaming application how should I get latest data from cassandra table for every one hour? I dont want to

问题 I have a python script that I want to use to make remote calls on a server, connect to Cassandra CLI, and execute commands to create keyspaces. One of the attempts that I made was something to this effect: connect="cassandra-cli -host localhost -port 1960;" create_keyspace="CREATE KEYSPACE someguy;" exit="exit;" final = Popen("{}; {}; {}".format(connect, create_keyspace, exit), shell=True, stdin=PIPE, stdout=PIPE, stderr=STDOUT, close_fds=True) stdout, nothing = final.communicate() Looking

问题 I am working with an Django application which uses Django 1.8 version . Most of the data we deal with is JSON formatted ones. We are trying to implement any NoSQL database. But I see that MONGODB is not compatible for version 1.8 and over and Is there any NoSQL database that can be efficiently mapped to Django 1.8 or over ?? Thanks in advance. 回答1: NoSQL databases are not officially supported by Django itself. There are, however, a number of side project and forks which allow NoSQL

问题 I want to know if there is any way to perform wildcard searches in cassandra database. e.g. select KEY,username,password from User where username='\*hello*'; Or select KEY,username,password from User where username='%hello%'; something like this. 回答1: There is no native way to perform such queries in Cassandra. Typical options to achieve the same are a) Maintain an index yourself on likely search terms. For example, whenever you are inserting an entry which has hello in the username, insert

问题 I cannot cqlsh to remote host ./cqlsh xx.xx.x.xxx 9042 Connection error: ('Unable to connect to any servers', {'10.101.33.163': ConnectionException(u'Did not get expected SupportedMessage response; instead, got: <ErrorMessage code=0000 [Server error] message="io.netty.handler.codec.DecoderException: org.apache.cassandra.transport.ProtocolException: Invalid or unsupported protocol version: 4">',)}) I am using cqlsh 5.0.1 and python 2.7.10 ./cqlsh --version cqlsh 5.0.1 python -V Python 2.7.10 I

问题 I am running a small Cassandra 2.2.1 test cluster with 3 computers in it. Two of them are i7s and one is a somewhat slower i5, but I didn't bother when first setting things up to give this slower machine a proportionally lower number of vnodes, as I thought things would be IO bound (they all have SSDs and 16GB RAM). They're all on default 256 vnodes. I'm finding Cassandra actually to be quite CPU intensive though and this i5 seems to be holding things up (running 100%x4 on HTOP). Can I reduce

问题 Update 2 There was a bug in Opscenter not matching dsc22 configuration with cassandra community version, this solved one problem. Update After reading the opscenter log again I think there actually something wrong with the 4 authentication fields or some ssh configuration, but I still don't know what exactly should be done, The field says "Local node credentials (sudo) private key (optional) the scenario is as following: I installed 4 nodes with vagrant and ansible where each has dsc22