/* Acquire an exclusive lock on BuildSteps to ensure that we don't
       race with other threads creating a step of the same build. */
    txn.exec("lock table BuildSteps in exclusive mode");

 restart:

    txn.parameterized
        ("insert into BuildSteps (build, stepnr, type, drvPath, busy, startTime, system, status, propagatedFrom, errorMsg, stopTime, machine) values ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12)")

    auto r = txn.parameterized
        ("insert into BuildSteps (build, stepnr, type, drvPath, busy, startTime, system, status, propagatedFrom, errorMsg, stopTime, machine) values ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12) on conflict do nothing")

    if (r.affected_rows() == 0) goto restart;

 restart:

    txn.parameterized
        ("insert into BuildSteps (build, stepnr, type, drvPath, busy, status, startTime, stopTime) values ($1, $2, $3, $4, $5, $6, $7, $8)")

    auto r = txn.parameterized
        ("insert into BuildSteps (build, stepnr, type, drvPath, busy, status, startTime, stopTime) values ($1, $2, $3, $4, $5, $6, $7, $8) on conflict do nothing")

    if (r.affected_rows() == 0) goto restart;