Misuse of BATCH statement
How to misuse a BATCH statement.
Misused, BATCH statements can cause many problems in a distributed
database like Cassandra. Batch operations that involve multiple nodes are a definite
anti-pattern. Keep in mind which partitions data will be written to when grouping
INSERT and UPDATE statements in a
BATCH statement. Writing to several partitions might require
interaction with several nodes in the cluster, causing a great deal of latency for
the write operation.
Procedure
This example shows an anti-pattern since the
BATCH statement
will write to several different partitions, given the partition key
id.
cqlsh> BEGIN BATCH
INSERT INTO cycling.cyclist_name (id, lastname, firstname) VALUES (6d5f1663-89c0-45fc-8cfd-60a373b01622,'HOSKINS', 'Melissa');
INSERT INTO cycling.cyclist_name (id, lastname, firstname) VALUES (38ab64b6-26cc-4de9-ab28-c257cf011659,'FERNANDES', 'Marcia');
INSERT INTO cycling.cyclist_name (id, lastname, firstname) VALUES (9011d3be-d35c-4a8d-83f7-a3c543789ee7,'NIEWIADOMA', 'Katarzyna');
INSERT INTO cycling.cyclist_name (id, lastname, firstname) VALUES (95addc4c-459e-4ed7-b4b5-472f19a67995,'ADRIAN', 'Vera');
APPLY BATCH;