Class StartBatchTransactionAction (6.89.0)

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Starts a batch read-only transaction in executor. Successful outcomes of this action will contain batch_txn_id--the identificator that can be used to start the same transaction in other Executors to parallelize partition processing.

Example of a batch read flow:

1. Start batch transaction with a timestamp (StartBatchTransactionAction)
2. Generate database partitions for a read or query (GenerateDbPartitionsForReadAction/GenerateDbPartitionsForQueryAction)
3. Call ExecutePartitionAction for some or all partitions, process rows

4. Clean up the transaction (CloseBatchTransactionAction).

   More sophisticated example, with parallel processing:

5. Start batch transaction with a timestamp (StartBatchTransactionAction), note the returned BatchTransactionId
6. Generate database partitions for a read or query (GenerateDbPartitionsForReadAction/GenerateDbPartitionsForQueryAction)

7. Distribute the partitions over a pool of workers, along with the transaction ID.

   In each worker: 4-1. StartBatchTransactionAction with the given transaction ID 4-2. ExecutePartitionAction for each partition it got, process read results 4-3. Close (not cleanup) the transaction (CloseBatchTransactionAction).

   When all workers are done:

8. Cleanup the transaction (CloseBatchTransactionAction). This can be done either by the last worker to finish the job, or by the main Executor that initialized this transaction in the first place. It is also possible to clean it up with a brand new Executor -- just execute StartBatchTransactionAction with the ID, then clean it up right away.

   Cleaning up is optional, but recommended.

Protobuf type google.spanner.executor.v1.StartBatchTransactionAction

The exact timestamp to start the batch transaction.

.google.protobuf.Timestamp batch_txn_time = 1;

The exact timestamp to start the batch transaction.

.google.protobuf.Timestamp batch_txn_time = 1;

Database role to assume while performing this action. Setting the database_role will enforce additional role-based access checks on this action.

string cloud_database_role = 3;

Database role to assume while performing this action. Setting the database_role will enforce additional role-based access checks on this action.

string cloud_database_role = 3;

ID of a batch read-only transaction. It can be used to start the same batch transaction on multiple executors and parallelize partition processing.

bytes tid = 2;

The exact timestamp to start the batch transaction.

.google.protobuf.Timestamp batch_txn_time = 1;

ID of a batch read-only transaction. It can be used to start the same batch transaction on multiple executors and parallelize partition processing.

bytes tid = 2;