How to obtain number of tables in a keyspace in Cassandra?

Question

For example, we can use

select count(*) from student_database;

to calculate the number of rows in a table. But how do we calculate the number of tables in a keyspace?

DESCRIBE TABLES;

gives you the list of all tables in that keyspace.

score 3 · Answer 1 · answered Feb 22 '17 at 13:36

3

And for a Cassandra 2.x (and lower) answer:

SELECT COUNT(*) FROM system.schema_columnfamilies 
    WHERE keyspace_name='your keyspace';

answered Feb 22 '17 at 13:36

Aaron

score 2 · Answer 2 · answered Feb 22 '17 at 11:51

2

SELECT count(*) FROM system_schema.tables WHERE keyspace_name='your keyspace'

The above query will work in cassandra 3.0 and above

answered Feb 22 '17 at 11:51

Can you please help me in this answer for cassandra 3.0 and above... http://stackoverflow.com/questions/42469341/how-do-i-retrieve-table-names-in-cassandra-using-java – Kangkan Lahkar Feb 26 '17 at 18:06

score 0 · Answer 3 · edited Nov 25 '20 at 21:42

0

rows = session.execute("SELECT count(*) FROM system_schema.tables WHERE keyspace_name = 'your_keyspace_name'")

print(list(rows))

Result:

[Row(count=2)]

edited Nov 25 '20 at 21:42

Jeremy Caney

answered Nov 25 '20 at 21:09

ruyaenes

Answers should mention how the code works not just provide the solution in code. – Shawn Nov 26 '20 at 00:52
This query works only for specific versions of the Cassandra. If you're using Python, then you need to use functionality of the driver that works with different Cassandra versions – Alex Ott Nov 26 '20 at 09:18

3 Answers3