Questions tagged [cassandra]

Apache Cassandra is an open source distributed database management system. It is designed to handle very large amounts of data spread out across many commodity servers while providing a highly available service with no single point of failure. It is a NoSQL solution.

Filter by
Sorted by
Tagged with
1
vote
0answers
125 views

Is my schema for a Discussion forum using Cassandra optimum or has a scope for improvement?

I am designing a Discussion Forum for my app which has following primary objects: Image Video Text Audio The owner can start a discussion in context of any of the above object. Based on user ...
1
vote
0answers
56 views

Is it possible to have a partition to distribute transaction load horizontally in SQL Server 2016?

In Cassandra, you can have a partition key to align partitions to particular server nodes. My understanding is that you can distribute transactional responsibility horizontally in SQL Server 2016 (...
7
votes
2answers
30k views

Cassandra - Query a column with collection type

I am pretty new to cassandra, so pardon me if this turns out to be a silly question. I have a table structure as below CREATE TABLE data_points ( id text PRIMARY KEY, created_at timestamp, ...
4
votes
1answer
1k views

Cassandra - Why does Read/Write Latency fluctuate?

Question Why does write (read as well) latency fluctuate in Cassandra? Background Running Cassandra Stress Tool on a node (s01) against another node (m01). Run several times but always saw the ...
3
votes
0answers
152 views

Securing a Cassandra Cluster

We've managed to set up a Cassandra 2.2.6 cluster of two physical nodes (nodetool sees both of them, so I'm quite certain the cluster is indeed active). My steps to create the cluster were (this ...
5
votes
1answer
7k views

Querying from system.schema_keyspaces generates code=2200 [Invalid query]

I'm following Cassandra docs to learn CQL but when I type the query SELECT * from system.schema_keyspaces; the system generates InvalidRequest: code=2200 [Invalid query] message= unconfigured table ...
2
votes
1answer
39 views

Is there a configuration option that lets me limit the percent of a hard drive that Cassandra uses?

I'm doing some testing with a small hard disk and I'd like to basically stop Cassandra in its tracks if a write or compaction or any other service brings that usage of the disk above a certain ...
1
vote
0answers
44 views

What type of primary key we need to use for specific length of bits in Cassandra?

I want to know in which situations which type of primary key I need to use. Situations: 1. If I need 64 bit key than is bigint is the best for it? If I will chose text type will performance will be ...
3
votes
0answers
263 views

Is it good practice to have multiple keyspaces in Cassandra?

I've Cassandra configured on Amazon EC2 having 3 nodes(instances) in single cluster. Now what I want to do is give some space on Cassandra to my clients by creating separate keyspace for each in a ...
5
votes
1answer
4k views

Cassandra “Operation timed out - received only 0 responses.” during write

I'm using Datastax PHP Cassandra Driver and Cassandra 2.2.5 on Windows 10. This is a single-node cluster, and the keyspace replication of { 'class': 'SimpleStrategy', 'replication_factor': 1 }...
2
votes
1answer
2k views

Cassandra nodetool repair scheduling and gc_grace_period

I am trying to devise a scheme with minimal repair frequency to not overload the system, and have a problem to understand how can I ensure that the data is not getting resurrected. I have a cassandra ...
1
vote
1answer
257 views

What's the advantage of the inet datatype in Cassandra vs a plain text string?

What is the inet datatype really for? The documentation refers to its usage having something to do with Python but I'm not much of a Python guy so that aspect is beyond me. Is there any advantage to ...
1
vote
0answers
297 views

Why restore a single node of a cluster?

We were reviewing the restore documentation for Cassandra here, and noted it made the following distinction between restoring a single node or an entire cluster: If restoring a single node, you ...
2
votes
0answers
272 views

What are the implications of using quite large partitions (rows) in Cassandra?

I am looking to store data in Cassandra, due to the fact that I have many writes that need to perform well, and all my reads can be done based on primary key. While doing the data modeling, however, I ...
1
vote
1answer
183 views

sstableloader returns `java.lang.NumberFormatException: For input string: “Filter.db”`

I've been using the Java API to create an SSTable by following the instructions on this site. The program compiles and works fine; no errors. However when I try to load the table using the following ...
1
vote
1answer
66 views

Error after upgrading datastax to version 5

After upgrading to DataStax Enterprise version 5, the node does not come up, and I get this error in the log: Insufficient permissions on directory /hints Where is this directory located?
0
votes
1answer
64 views

Setup Cassandra Database

I have a very simple cassandra database with just one table containing the following records: device ID - long integer representing the device the 'value' came from - primary key tag ID ...
0
votes
1answer
58 views

customize permission in Cassandra

i want to grant user update permission in Table and deny delete permission for this user. Is there any way to accomplish this?
2
votes
1answer
145 views

DSE Cassandra decimal type

I generated solrschema with dsetool on a table name seriesdata (its key is composed by seriesmetadata_id, initialtime; two decimal field). These fields are defined as DecimalStrField but they are ...
0
votes
2answers
1k views

Cassandra - save file

I'm new with Cassandra, and even more - I never have such task for habitual RDMS systems, like MariaDB or Oracle. So, how can I store file in to Cassandra's table? Preferably using Python-driver, but ...
1
vote
1answer
112 views

Cassandra change replication factor hive datastore

I am trying to change replication factor of HiveMetaStore but I receive this message: cassandra@cqlsh:system> alter KEYSPACE HiveMetaStore with replication = {'class': '...
6
votes
1answer
5k views

Cassandra one-to-many table design

I am new to Cassandra from 20 years of RDBMS, and over the last few days have been reading and watching everything I can get my hands on that applies to my situation. I'm sure this is a basic ...
1
vote
1answer
153 views

How to predict new node allocation in a Cassandra cluster?

I have a 5-node Cassandra cluster. Each node has disk space of 5TB. The real usage for each node is around 2.5TB depending on allocations and compactions (some are around 2TB some around 2.8). I ...
-1
votes
1answer
506 views

Slow select from one billion rows GreenPlum DB

I've created the following table on GreenPlum: CREATE TABLE data."CDR" ( mcc text, mnc text, lac text, cell text, from_number text, to_number text, cdr_time timestamp ...
9
votes
2answers
6k views

Cassandra: maintenance

I am inexperienced with Cassandra, but I have some experience with SQL-based relational databases. I have been unable to find best practices information about how to maintain Cassandra once deployed. ...
5
votes
2answers
881 views

Cassandra cluster monitoring

We using Nagios for our servers monitoring. Each web-environment have 1 cluster as backend - Cassanra 2.0. Each cluster have 3-5 nodes. Question is: I want write a plugin for Nagios, for Cassandra's ...
3
votes
1answer
2k views

How does the Cassandra distribute data?

I cannot find a detailed document on this anywhere, however, that being said, if anyone has an answer to my question, I would be extremely grateful. In regards to Cassandra's standard node ...
3
votes
1answer
822 views

Keeping rows ordered by counter value

I'm storing linked words in a Cassandra v2 cluster and I'm having a hard time doing efficient reads. I'm trying to fetch the top X rows with the highest counter value. Cassandra doesn't store the ...
1
vote
1answer
915 views

Cassandra: memtable_offheap_space_in_mb and memtable_cleanup_threshold

I use C* v2.1.2 do write only workload (into one column family) and experiment with offheap-objects memtable space. I set parameters to: memtable_offheap_space_in_mb = 51200 # 50Gb ...
11
votes
2answers
25k views

What is a good way to copy data from one Cassandra ColumnFamily to another on the same Keyspace (like SQL's INSERT INTO)?

Trying to find a way to easily transfer all the rows from a Cassandra ColumnFamily/Table to another. The COPY command, as I understand, is a good option. However, as it dumps all the data to .csv on ...
9
votes
2answers
2k views

NoSQL : What is unstructured data?

we are currently running at the edge of resources with our mssql server based solution. We have now many traditional options regarding the next move to tackle the load: buy faster CPUs and IO split ...
7
votes
1answer
6k views

Modeling Graph Data in Cassandra DB

I want to use Apache Cassandra to store a large amount of graph data according to a property graph model. The model contains the following entities: Vertices: Contains a map of key/value pairs (...
0
votes
1answer
2k views

A good dataset to experiment NoSQL databases [closed]

I need to do some experiments in HBase and Cassandra and to do that I need an adequate dataset. The dataset I'm looking for has to be large enough (i.e. more than 2GB) and the data in it has to be ...
1
vote
1answer
772 views

cassandra in memory tables

I am planning to use Cassandra in memory tables for my particular work load. THe problem is I am worried if the node fails then what will happen to the data in memory that was not flushed to disk ? ...
1
vote
1answer
3k views

Cassandra: Request did not complete within rpc_timeout

i was working with Cassandra 1.2.4 probably, after restoring some key-space when i tried to query in a key-space it gave me Request did not complete within rpc_timeout so i checked system.log & ...
1
vote
1answer
205 views

How to Query Properties of an Entity in Apache Cassandra

I am new to Apache Cassandra, and I would like to know how to create a table in which I can filter rows by non-key columns. In relational databases, I would simply create a table with an ID as a ...
0
votes
0answers
1k views

What kind of database is Cassandra DB?

I was taking some courses to understand better the way Cassandra works (at academy.datastax.com) and by what I gathered it came to me that it is a Key Value Database because of the way it stores data ...
0
votes
1answer
153 views

How Wide-columns databases achieve dynamic columns on the storage layout? [closed]

As known, in relational databases, when adding a new column, data must be reallocated (https://stackoverflow.com/questions/463677/alter-table-without-locking-the-table) to maintain a single row ...
2
votes
0answers
130 views

Update a Record in Cassandra

I'm having the following query while updating a particular record. I've a user Column Family CF as follow:- class User(Model): user_id = UUID(default=uuid.uuid4,primary_key= True) date = ...
0
votes
1answer
2k views

What is the Cassandra setting for coordinator timeouts for schema change queries?

In my testing, I've found that the write_request_timeout_in_ms setting does not have any bearing on the timeouts for CREATE TABLE or ALTER TABLE statements in CQL. For instance, I have it set to ...
-1
votes
1answer
566 views

Database migration for Large Data Set from MySQL to NoSQL

I have an existing APP that has N types of products that is normalized with MySQL. Each types of products have over 500K skus, and one of them are in the in 2M currently. We are currently tracking on ...
3
votes
1answer
16k views

Cassandra row ordering best practice

I have a column family that store articles. I'll need to get those articles from the most recent to the oldest, getting them from Country, and of course the ability to limit the number of fetched ...
3
votes
1answer
2k views

Upgrading Cassandra from 1.1.0 to latest

I have a single node cassandra database running since 2 years now... never had any issues with it, but I would like to upgrade it to the latest cassandra (2.1.2 at the time I write those lines), of ...
2
votes
0answers
85 views

Cassandra Deployement Architecture

I'm new to Cassandra. I have the responsibility to design a basic deployment architecture for a use case. I'd like to know if my solution is correct, and get advice and recommendations from you. Here ...
1
vote
1answer
560 views

Date model for commenting system stored in a key-value NoSQL DB?

I'm trying to leverage Cassandra's strong support for time series data to build a commenting system. So far I'm thinking that each row would be a particular topic, and each comment would be a new ...
2
votes
1answer
4k views

Small startup: Cassandra + Hadoop or ElasticSearch

To give some context, I am from a small start up (4 team members) and we work in the education space. We've developed an e-learning platform that several schools are already using. We currently have ...
1
vote
1answer
4k views

Allow filtering not working as expected

I'm having issues with getting ALLOW FILTERING to work. In our Cassandra 1.2 database, we have a table like this: CREATE TABLE some_table partition_key text, other_key text, non_key ...
4
votes
1answer
6k views

How can I get nodetool without Cassandra

I have Cassandra pool across machines in LAN. I need nodetool on machine without Cassandra installed. How can I get it? Is the installing Cassandra and disabling db service is the best way?
2
votes
1answer
2k views

Cassendra schema design suggestion for chat archive

I have gone though this article and here is the schema I have got from it. This is helpful for my application for maintaining statuses of a user, but how can extend this to maintain one to one chat ...
0
votes
1answer
247 views

Cassandra with Hadoop

Cassandra uses Cassandra File System (CFS) and Hadoop uses Hadoop Distributed File System (HDFS) I'm already using Pig over HDFS and i would like to install Cassandra. Having additional servers for ...