grahamc/hydra - Change LJILHOJ7QYXNTMKDQS6OU4PVCXPQ27C5KMQWHDBELCYP7FG3ZFYAC

Create BuildSteps race-free

If multiple threads create a step for the same build, they could get the same "max(stepnr)" and allocate conflicting new step numbers. So lock the BuildSteps table while doing this. We could use a different isolation level, but this is easier.

Created by Eelco Dolstra on June 9, 2015

LJILHOJ7QYXNTMKDQS6OU4PVCXPQ27C5KMQWHDBELCYP7FG3ZFYAC

Dependencies

In channels

upstream

main

Change contents

Insertion in src/hydra-queue-runner/hydra-queue-runner.cc at line 361 [3.4840]

[3.8256]

    /* 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");

Deletion in src/hydra-queue-runner/hydra-queue-runner.cc at line 899 [3.4840]
B:BD[3.16702] → [2.1232:1366]
∅:D[2.1366] → [3.16786:16787]
∅:D[4.14169] → [3.16786:16787]
B:BD[3.16786] → [3.16786:16787]
```
            finishBuildStep(txn, result.startTime, result.stopTime, build->id, stepNr, machine->sshName, bssFailed, result.errorMsg);
```

Insertion in src/hydra-queue-runner/hydra-queue-runner.cc at line 903 [3.4840]

[3.16983]


            finishBuildStep(txn, result.startTime, result.stopTime, build->id, stepNr, machine->sshName, bssFailed, result.errorMsg);