There is a subtle difference. Inserted records via INSERT remain if you set all non-key fields to null. Records inserted via UPDATE go away if you set all non-key fields to null. Try this: CREATE TABLE T ( pk int, f1 int, PRIMARY KEY (pk) ); INSERT INTO T (pk, f1) VALUES (1, 1); UPDATE … Read more
You shouldn’t put the quotes around the UUID to stop it being interpreted as a string i.e. insert into devices (device_id, geohash,name, external_identifier, measures, tags) values (c37d661d-7e61-49ea-96a5-68c34e83db3a,’9q9p3yyrn1′, ‘Acme1’, ‘936’, {‘aparPower’,’actPower’,’actEnergy’},{‘make’:’Acme’});
As of Cassandra 2.0.7 you can just use uuid(), which generates a random type 4 UUID: INSERT INTO users(uid, name) VALUES(uuid(), ‘my name’);
select * from update_audit where scopeid=35 and formid=78005 and record_link_id=9897; How the above query will work internally in cassandra? Essentially, all data for partition scopeid=35 and formid=78005 will be returned, and then filtered by the record_link_id index. It will look for the record_link_id entry for 9897, and attempt to match-up entries that match the rows … Read more
You can use the truncate thrift call, or the TRUNCATE <table> command in CQL. http://www.datastax.com/docs/1.0/references/cql/TRUNCATE
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