Yes, for Cassandra UPDATE is synonymous with INSERT, as explained in the CQL documentation where it says the following about UPDATE: Note that unlike in SQL, UPDATE does not check the prior existence of the row: the row is created if none existed before, and updated otherwise. Furthermore, there is no mean to know which … Read more
How about the following, using Cassandra’s Lightweight transactions 1 – Create IDs table: CREATE TABLE ids ( id_name varchar, next_id int, PRIMARY KEY (id_name) ) 2 – Insert every id you’d like to use a global sequence with For example: INSERT INTO ids (id_name, next_id) VALUES (‘person_id’, 1) 3 – Then, when inserting to a … Read more
You can rename the cluster without deleting data by updating it’s name in the system.local table (but you have to do this for each node…) cqlsh> UPDATE system.local SET cluster_name=”test” where key=’local’; # flush the sstables to persist the update. bash $ ./nodetool flush Finally you need to rename the cluster to the new name … Read more
This is either https://issues.apache.org/jira/browse/CASSANDRA-4687 or https://issues.apache.org/jira/browse/CASSANDRA-5202 You can run the command “nodetool invalidatekeycache” on all of the server showing the error. If it keeps coming back you may want to disable key cache. If it is 5202 it should only happen after dropping and recreating a column family using the same name.
If you don’t mind your data using a pipe (‘|’) as a delimiter, you can try using the -e flag on cqlsh. The -e flag allows you to send a query to Cassandra from the command prompt, where you could redirect or even perform a grep/awk/whatever on your output. $ bin/cqlsh -e’SELECT video_id,title FROM stackoverflow.videos’ … Read more
UUID and TIMEUUID are stored the same way in Cassandra, and they only really represent two different sorting implementations. TIMEUUID columns are sorted by their time components first, and then by their raw bytes, whereas UUID columns are sorted by their version first, then if both are version 1 by their time component, and finally … Read more
Yes, you can use COUNT(*). Here’s the documentation. A SELECT expression using COUNT(*) returns the number of rows that matched the query. Alternatively, you can use COUNT(1) to get the same result. Count the number of rows in the users table: SELECT COUNT(*) FROM users;
Use the SOURCE http://www.datastax.com/documentation/cql/3.1/cql/cql_reference/source_r.html You can use -f option as well to execute commands from file http://www.datastax.com/documentation/cql/3.1/cql/cql_reference/cqlsh.html
You need to edit cassandra.yaml on the node you are trying to connect to and set the node ip address for rpc_address and listen_address and restart Cassandra. rpc_address is the address on which Cassandra listens to the client calls. listen_address is the address on which Cassandra listens to the other Cassandra nodes.
You can use the timeuuid functions now() and dateof() (or in later versions of Cassandra, toTimestamp()), e.g., INSERT INTO TEST (ID, NAME, VALUE, LAST_MODIFIED_DATE) VALUES (‘2’, ‘elephant’, ‘SOME_VALUE’, dateof(now())); The now function takes no arguments and generates a new unique timeuuid (at the time where the statement using it is executed). The dateOf function takes … Read more