datastax

问题 I am trying to return a Vertex (in tinkerpop format) that it was just created with Gremlin: DseCluster dseCluster = DseCluster.builder() .addContactPoint(DbC.dseHost) .build(); DseSession dseSession = dseCluster.connect(); GraphTraversal traversal = graph.addV(VertexLabels.User) .property("username", "testuser") GraphStatement graphStatement = DseGraph.statementFromTraversal( traversal ); GraphResultSet grs = dseSession.executeGraph(graphStatement.setGraphName(DbC.graphName)); Vertex v = grs

问题 Blocking execute fethod from com.datastax.driver.core.Session public ResultSet execute(Statement statement); Comment on this method: This method blocks until at least some result has been received from the database. However, for SELECT queries, it does not guarantee that the result has been received in full. But it does guarantee that some response has been received from the database, and in particular guarantee that if the request is invalid, an exception will be thrown by this method. Non

问题 I am trying to install the datastax php driver for Cassandra and when i run the following command: pecl install ext/package.xml after checking it out of git i get the following message: configure: error: Unable to load libcassandra ERROR: `/tmp/pear/temp/cassandra/configure' failed Can anyone point me in the right direction in order to successfully install this driver please? version of cassandra i am using is 2.1.8 so maybe the driver has not been updated to connect to the latest version of

问题 I want to write Structure Streaming Data into Cassandra using Pyspark API. My data flow is like below: Nifi -> Kafka -> Spark Structure Streaming -> Cassandra I have tried below way: query = df.writeStream\ .format("org.apache.spark.sql.cassandra")\ .option("keyspace", "demo")\ .option("table", "test")\ .start() But getting below error message: "org.apache.spark.sql.cassandra" does not support streaming write. Also another approach I have tried: [ Source - DSE 6.0 Administrator Guide] query =

问题 I am not sure about how to filter(lambda x:len(x[1])>=2) in dataframe. I would like to improve the speed of my spark app. Thanks for your help! This some context from my spark app: article_ids = sqlContext.read.format("org.apache.spark.sql.cassandra").options(table="article_by_created_at", keyspace=source).load().where(range_expr).select('article','created_at').repartition(64*2) axes = sqlContext.read.format("org.apache.spark.sql.cassandra").options(table="axes", keyspace=source).load() speed

问题 my partition keys are id(int) and name(text). Below command works fine until there is no space in name(text). nodetool getendpoints test testtable2 1:aaa; if am using nodetool getendpoints test testtable2 3:aac cc; it throws an error as : nodetool: getendpoints requires keyspace, table and partition key arguments See 'nodetool help' or 'nodetool help '. i got token by executing SELECT id,name, token(id,name) FROM test.testtable2 where name='aac cc'AND id=3; and tried to search nodetool

问题 I am unable to connect to any nodes through opscenter. In opscenter it says that agents need to be connected inorder for opscenter to work. I checked in datastax-agent/agent.log file and found below errors. ERROR [clojure-agent-send-off-pool-0] 2016-01-27 09:30:54,545 Can't connect to Cassandra (All host(s) tried for query failed (tried: /127.0.0.1:9042 (com.datastax.driver.core.TransportException: [/127.0.0.1:9042] Cannot connect))), retrying soon. I checked port 9042 and 7199 both are

问题 I am unable to connect to any nodes through opscenter. In opscenter it says that agents need to be connected inorder for opscenter to work. I checked in datastax-agent/agent.log file and found below errors. ERROR [clojure-agent-send-off-pool-0] 2016-01-27 09:30:54,545 Can't connect to Cassandra (All host(s) tried for query failed (tried: /127.0.0.1:9042 (com.datastax.driver.core.TransportException: [/127.0.0.1:9042] Cannot connect))), retrying soon. I checked port 9042 and 7199 both are

问题 My question is a follow up of this topic : Cassandra load balancing with TokenAwarePolicy and shuffleReplicas I'm encountering some issues regarding the TokenAwarePolicy that I don't understand. Cluster configuration : 3 nodes Replication factor = 3 Load balancing policy : new TokenAwarePolicy(new RoundRobinPolicy(), false) Consitancy level (Reads/Writes) : ONE Shuffling replicas is set to false on purpose. But the thing is that I'm encountering consistency problems when reading datas in my

问题 I have a table Called 'usertab' to store user details such as: userid uuid, firstname text, lastname text email text gender int image text Most of the other tables contains userid as a field for referencing 'usertab', but when I retrieve data from other table, I need to execute another select query to get user details. So if 10,000 or more data retrieved, same number of select query executed for getting user details. This makes our system slow. So we add usertab fields such as firstname