cassandra-2.0

问题 I have tried RCassandra and RJDBC but unfortunately it seems that these bindings work only with the old Cassandra 1.x. Is there any binding for Cassandra 2.x in R language? 回答1: This is not true, the current version of RJDBC works with Cassandra 2.X. Download latest release, with C* 2.x compatibility : cassandra-jdbc-2.1.1.jar However there's one caveat that you have to also download the java dependencies and put them into your JAVA ClassPath (MacOS: /Library/Java/Extensions), otherwise you

问题 How to read the cassandra nodetool histograms percentile and other coulmns? Percentile SSTables Write Latency Read Latency Partition Size Cell Count (micros) (micros) (bytes) 50% 1.00 14.24 4055.27 149 2 75% 35.00 17.08 17436.92 149 2 95% 35.00 24.60 74975.55 642 2 98% 86.00 35.43 129557.75 770 2 99% 103.00 51.01 186563.16 770 2 Min 0.00 2.76 51.01 104 2 Max 124.00 36904729.27 12359319.16 924 2 回答1: They show the distribution of the metrics. For example, in your data the write latency for 95%

问题 I have the following 'Tasks' table in Cassandra. Task_ID UUID - Partition Key Starts_On TIMESTAMP - Clustering Column Ends_On TIMESTAMP - Clustering Column I want to run a CQL query to get the overlapping tasks for a given date range. For example, if I pass in two timestamps (T1 and T2) as parameters to the query, I want to get the all tasks that are applicable with in that range (that is, overlapping records). What is the best way to do this in Cassandra? I cannot just use two ranges on

问题 We are building a Cassandra (2.1.5) cluster for storing large amount of timeseries data, and we are planning to utilize existing hardware, problem is the hardware available is really different. 2 machines with: 4 core, 8 GB, SSD 2 machines with: 8 core, 16 GB, SSD 2 machines with: 32 core, 64 GB, HDD Obviously, the 32 core machine can handle much larger load than the 4 core machines, how should we configure Cassandra to handle this. We are using RF 3 and the latest datastax java driver. Any

问题 Being newbie on apache spark, facing some issue on fetching Cassandra data on Spark. List<String> dates = Arrays.asList("2015-01-21","2015-01-22"); CassandraJavaRDD<A> aRDD = CassandraJavaUtil.javaFunctions(sc). cassandraTable("testing", "cf_text",CassandraJavaUtil.mapRowTo(A.class, colMap)). where("Id=? and date IN ?","Open",dates); This query is not filtering data on the cassandra server. While this java statement is executing its shooting up the memory and finally throwing spark java.lang

问题 This is a super basic question but it's actually been bugging me for days. Is there a good way to obtain the equivalent of a COUNT(*) of a given table in Cassandra? I will be moving several hundreds of millions of rows into C* for some load testing and I'd like to at least get a row count on some sample ETL jobs before I move massive amounts of data over the network. The best idea I have is to basically loop over each row with Python and auto increment a counter. Is there a better way to

问题 How to get Last 6 Month data comparing with timestamp column using cassandra query? I need to get all account statement which belongs to last 3/6 months comparing with updatedTime(TimeStamp column) and CurrentTime . For example in SQL we are using DateAdd() function tor this to get. i dont know how to proceed this in cassandra. If anyone know,reply.Thanks in Advance. 回答1: Cassandra 2.2 and later allows users to define functions (UDT) that can be applied to data stored in a table as part of a

问题 How can atomic batches guarantee that either all statements in a single batch will be executed or none? 回答1: In order to understand how batches work under the hood, its helpful to look at the individual stages of the batch execution. The client Batches are supported using CQL3 or modern Cassandra client APIs. In each case you'll be able to specify a list of statements you want to execute as part of the batch, a consistency level to be used for all statements and an optional timestamp. You'll

问题 I am reading this post on read operations and consistency level in Cassandra. According to this post: For example, in a cluster with a replication factor of 3, and a read consistency level of QUORUM, 2 of the 3 replicas for the given row are contacted to fulfill the read request. Supposing the contacted replicas had different versions of the row, the replica with the most recent version would return the requested data. In the background, the third replica is checked for consistency with the

问题 I have built Cassandra server 2.0.3, then run it. It is starting and then stopped with messages: X:\MyProjects\cassandra\apache-cassandra-2.0.3-src\bin>cassandra.bat >log.txt java.lang.RuntimeException: Unable to gossip with any seeds at org.apache.cassandra.gms.Gossiper.doShadowRound(Gossiper.java:1160) at org.apache.cassandra.service.StorageService.checkForEndpointCollision (StorageService.java:416) at org.apache.cassandra.service.StorageService.joinTokenRing(StorageServ ice.java:608) at