Misuse of BATCH statement

Misused BATCH statements can cause many problems. 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 significant 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.

    cql
    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;

    In this example, four partitions are accessed, but consider the effect of including 100 partitions in a batch - the performance would degrade considerably.

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