COBOL to BigQuery

Why BigQuery

Serverless analytics without mainframe infrastructure

No servers to size or patch

Mainframe batch jobs require MIPS capacity planning and z/OS maintenance. BigQuery runs SQL at warehouse scale with zero infrastructure. Pay per query, not per MIPS.

BigQuery SQL for most logic, Dataproc for the rest

COBOL business rules with IF/ELSE, COMPUTE, and EVALUATE map cleanly to BigQuery SQL. Complex programs with nested PERFORM loops and table handling become PySpark on Dataproc, writing results back to BigQuery tables.

Cloud Composer replaces JCL scheduling

JCL defines job steps, dataset allocation, and execution order. Cloud Composer (managed Airflow) handles the same DAG orchestration with retry, alerting, and cross-service integration across GCP.

Parser output

Copybook + COBOL logic to BigQuery SQL

A COBOL copybook and batch program converted to BigQuery DDL and SQL. When logic requires Python, MigryX outputs PySpark on Dataproc instead.

COBOL Copybook + Program

       COPY TXN-REC.
       05 TXN-ID        PIC X(12).
       05 TXN-AMT       PIC S9(7)V99 COMP-3.
       05 TXN-TYPE      PIC X(1).
          88 CREDIT      VALUE 'C'.
          88 DEBIT       VALUE 'D'.
       05 ACCT-NO        PIC X(10).

       PROCEDURE DIVISION.
           PERFORM UNTIL END-OF-FILE
               READ TXN-FILE INTO TXN-REC
               IF CREDIT
                   ADD TXN-AMT TO WS-TOTAL-CR
               ELSE
                   ADD TXN-AMT TO WS-TOTAL-DB
               END-IF
               WRITE SUMMARY-REC
           END-PERFORM.

→

MigryX
converts

BigQuery SQL

-- Copybook → DDL
CREATE TABLE IF NOT EXISTS
  `project.dataset.txn_summary` (
    txn_id    STRING,
    txn_amt   NUMERIC,
    txn_type  STRING,
    acct_no   STRING
);

-- Program → BigQuery SQL
SELECT
    acct_no,
    SUM(CASE WHEN txn_type = 'C'
             THEN txn_amt ELSE 0 END)
        AS total_credit,
    SUM(CASE WHEN txn_type = 'D'
             THEN txn_amt ELSE 0 END)
        AS total_debit
FROM `project.dataset.txn_raw`
GROUP BY acct_no;

PIC clauses become BigQuery types. 88-level conditions become CASE WHEN. COMP-3 becomes NUMERIC with preserved precision.

Coverage