cassandra-3.0

问题 I have 20 columns in a table in Cassandra. Will there be a performance impact in performing select * from table where partitionKey = 'test'; I am not able to understand from this link, https://wiki.apache.org/cassandra/CassandraLimitations 1) What will be the consequence of having too many columns (say 20) in the Cassandra tables? 回答1: Unless you have a lot of rows on the partition, I don't see an impact with having 20 columns. As stated in the documentation that you linked: The maximum

问题 I have a case class which represents partition key values. case class UserKeys (bucket:Int, email: String) I create query Clauses as follows: def conditions(id: UserKeys):List[Clauses] = List( QueryBuilder.eq("bucket", id.bucket), //TODOM - pick table description from config/env file. QueryBuilder.eq("email", id.email) ) And use the query as follows val selectStmt = select() .from(tablename) .where(QueryBuilder.eq(partitionKeyColumns(0), whereClauseList(0))).and(QueryBuilder.eq

问题 Cassandra version :- [cqlsh 5.0.1 | Cassandra 3.0.9 | CQL spec 3.4.0 | Native protocol v4] My Table structure CREATE TABLE test ( id1 text, id2 text, id3 text, id4 text, clinet_starttime timestamp, avail_endtime timestamp, starttime timestamp, client_endtime timestamp, code int, status text, total_time double, PRIMARY KEY (id1, id2, id3, id4, client_starttime) ) WITH CLUSTERING ORDER BY (id2 ASC, id3 ASC, id4 ASC, client_starttime ASC) AND bloom_filter_fp_chance = 0.01 AND caching = {'keys':

问题 I might be missing something very basic, or there is something very wrong; I am using Apache Cassandra 3.11.4 . Version details are as follows: Connected to Test Cluster at 127.0.0.1:9042. [cqlsh 5.0.1 | Cassandra 3.7.0 | CQL spec 3.4.2 | Native protocol v4] I have the following table and I want to get the count of individual citizen-ship status. CREATE TABLE population.residents ( residentId bigint, name varchar, office varchar, dob date, citizen text, PRIMARY KEY((residentId), dob) );

问题 File "src/gevent/greenlet.py", line 705, in gevent._greenlet.Greenlet.run File "/home/interview/BEMOSS3.5/volttron/platform/auth.py", line 147, in zap_loop time = gevent.core.time AttributeError: 'module' object has no attribute 'core' 2018-05-16T09:52:00Z <Greenlet "Greenlet-0" at 0x7f37102cd998: <bound method AuthService.zap_loop of <volttron.platform.auth.AuthService object at 0x7f3718630050>>(<volttron.platform.vip.agent.core.Core object at 0)> failed with AttributeError 2018-05-16 15:22

问题 I use the nodejs in three environments and the Cassandra is running in all the three nodes. I totally understand using nodetool status I will be able to get the status of each node. But the problem is If my current node is down then I will not be able to perform nodetool status in the current node, So Is there a way to get the status using nodejs Cassandra driver? Any help is appreciated. EDITED : As per dilsingi's suggestion, I used the client.hosts but the problem is, In the following

问题 I'm getting a connection error "unable to connect to any server" when I run .cqlsh command from the bin directory of my node. I'm using an edited yaml file containing only the following(rest all values present in the default yaml have been omitted) : cluster name, num tokens, partitioner, data file directories, commitlog directory, commitlog sync, commitlog sync period, saved cache directory, seed provider info, listen address and endpoint snitch. Is this error because I've not included some

问题 To understand the ring without vNodes, I tried initial token in Node 1 as 25 and Node 2 as 50 like below, Address Rack Status State Load Owns Token 50 172.30.56.60 rack1 Up Normal 82.08 KiB 100.00% 25 172.30.56.61 rack1 Up Normal 82.09 KiB 100.00% 50 I expect only the partition ranges between 0 to 50 should be added in database, But It is allowing any primary key / partition key value I provide as follows (user_id - primary / partition key). user_id | user_name | user_phone ------------+-----

问题 I am trying to design the application log table in Cassandra, CREATE TABLE log( yyyymmdd varchar, created timeuuid, logMessage text, module text, PRIMARY KEY(yyyymmdd, created) ); Now when I try to perform the following queries it is working as expected, select * from log where yymmdd = '20182302' LIMIT 50; Above query is without grouping, kind of global. Currently I did an secondary index for 'module' so I am able to perform the following, select * from log where yymmdd = '20182302' WHERE

问题 My sample cassandra table looks like id | article_read | last_hours | name ----+----------------------------------- 5 | [4, 5, 6] | 5 | shashank 10 | [12, 88, 32] | 1 | sam 8 | [4, 5, 6] | 8 | aman 7 | [5, 6] | 7 | ashif 6 | [4, 5, 6] | 6 | amit 9 | [4, 5, 6] | 9 | shekhar My java code to read data from Cassandra table using cql queries, Scanner sc = new Scanner(System.in); System.out.println("enter name1 "); String name1 = sc.nextLine(); System.out.println("enter name2"); String name2 = sc