Jaguar and Cassandra

This blog compares Jaguar and Cassandra (NoSQL distributed database).

1.  Install and setup Cassandra on multiple nodes

Install the package on each host in your Cassandra cluster:

a) Visit  http://cassandra.apache.org/download/  and download  apache-cassandra-3.0.0-bin.tar.gz

b) tar zxf  apache-cassandra-3.0.0-bin.tar.gz

c) cd  apache-cassandra-3.0.0/conf

d) vi   cassandra.yaml

listen_address: 192.168.1.108

(This is the IP address of the host you are on).

seed_provider:

– seeds: “192.168.1.109”

(seeds are the host IP addresses of seed hosts)

You can specify one seed host or multiple seed hosts. If you want to use multiple seed hosts, then specify them as:

– seeds: “192.168.1.109,192.168.1.110”

e) vi cassandra-env.sh

LOCAL_JMX=no
if [ “x$LOCAL_JMX” = “x” ]; then
LOCAL_JMX=yes
fi

……jmxremote.authenticate=false

After the configuration has been completed on all hosts in the cluster, you can login to the seed host(s), and start the cassandra server:

./bin/cassandra

Then start the cassandra server on all non-seed hosts with the same command.

2.  Execute Cassandra commands

From any host in the Cassandra cluster, run this command:

$ bin/cqlsh
cqlsqh> CREATE KEYSPACE mykeyspace WITH REPLICATION = { 'class': 'SimpleStrategy', 'replication_factor' : 1 };
cqlsh> use mykeyspace;
cqlsh:mykeyspace> CREATE TABLE users ( user_id int PRIMARY KEY, fname text,lname text );
cqlsh:mykeyspace> INSERT INTO users (user_id,  fname, lname) VALUES (1745, 'john', 'smith');
cqlsh:mykeyspace> INSERT INTO users (user_id, fname, lname)  VALUES (1744, 'john', 'doe'); 
cqlsh:mykeyspace> INSERT INTO users (user_id, fname, lname)  VALUES (1746, 'john', 'smith');
cqlsh:mykeyspace> select * from users where user_id > 100 and user_id < 200;
InvalidRequest: code=2200 [Invalid query] message="Only EQ and IN relation are supported on the partition key (unless you use the token() function)"
cqlsh:mykeyspace> help select

 SELECT <selectExpr>
 FROM [<keyspace>.]<table>
 [WHERE <clause>]
 [ORDER BY <colname> [DESC]]
 [LIMIT m];

 SELECT is used to read one or more records from a CQL table. 

So Cassandra does not support range query and multi-table join.

   3. Jaguar Supports Range Query and Table Joins

jaguar> select * from users where user_id > 10000; 
jaguar> select * join ( TABLE, TABLE1, TABLE2, ...) [WHERE];
jaguar> select * starjoin (tab1, tab2, tab3 ) [WHERE];
jaguar> select * indexjoin ( index(idex), tab1, tab2 ) [WHERE];