cassandra 2.0 catch 101 – part4

It has been a while since I last post, mainly was due to the abundane works. :-(  In this article, I'm gonna share with the lesson learned on cassandra 2.0.2 learned using cqlsh 4.1.0.

Last we had to remove all the files in /var/lib/cassandra/ simply because somewhere it break when we upgraded from cassandra 2.0.0 to 2.0.2 and everybody in the teams just do not have the time to goes into details. So since this is just4fun cluster, we agreed to removed the dir /var/lib/cassandra/ and start the cluster using cassandra 2.0.2.

In order to better understand cassandra, we take a detail look at alter table. But before that, let's create a new keyspace and table.

cqlsh> CREATE KEYSPACE jw_schema1 WITH replication = {'class':'SimpleStrategy', 'replication_factor':3};
cqlsh>

and the correspondance cassandra system.log

INFO [Thrift:7] 2013-12-06 16:17:21,902 MigrationManager.java (line 217) Create new Keyspace: jw_schema1, rep strategy:SimpleStrategy{}, strategy_options: {replication_factor=3}, durable_writes: true

cassandra 2.0 catch 101 – part3

So many of us are from mysql / postgres background and we quickly interface to the database using the command line. In order to comment in cassandra cql, it is different than in sql. Read the example below

cqlsh:jw_schema1> #select * from users;
Invalid syntax at line 1, char 1
#select * from users;
^
cqlsh:jw_schema1> --select * from users;
cqlsh:jw_schema1> -select * from users;
Bad Request: line 1:0 no viable alternative at input '-'
cqlsh:jw_schema1> -- select * from users;
cqlsh:jw_schema1>

So as you can see, the hash glyph do not work in cqlsh, you need to use double dashes in front of the comment you want to made.

Voila! =)