spanner-jdbc: Step 21 - ReadWriteTransaction #5898
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| @Override | ||
| void checkValidTransaction() { | ||
| ConnectionPreconditions.checkState( | ||
| state == UnitOfWorkState.STARTED, "This transaction has status " + state.name()); |
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Would slightly change the precondition message to add acceptable status
...gle-cloud-spanner-jdbc/src/main/java/com/google/cloud/spanner/jdbc/ReadWriteTransaction.java
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| } | ||
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| /** Create a pseudo COMMIT statement to allow it to be cancelled or time out. */ | ||
| private final ParsedStatement commitStatement = |
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sorry, could you explain what this does?
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I've added the following javadoc to the field:
/**
* Create a COMMIT statement to use with the {@link #commit()} method to allow it to be
* cancelled, time out or retried.
*
* {@link ReadWriteTransaction} uses the generic methods
* {@link #executeAsync(ParsedStatement, Callable)} and {@link #runWithRetry(Callable)} to
* allow statements to be cancelled, to timeout and to be retried. These methods require a
* {@link ParsedStatement} as input. When the {@link #commit()} method is called directly, we do
* not have a {@link ParsedStatement}, and the method uses this statement instead in order to use
* the same logic as the other statements.
*/| // In case the transaction manager didn't pick up the abort correctly, we'll rollback | ||
| // manually and do another try. This seems to be the case if the transaction was | ||
| // aborted and txContext.executeUpdate(Statement) is called. | ||
| // TODO: Check whether TransactionContextImpl.executeUpdate(Statement) handles |
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do we still need this TODO?
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No, this related to a bug that was in the Spanner client library when the initial copy to the private repo was made. It has long been fixed (and if not, it will be picked up by a test case, as that was how it was found in the first place).
It's removed.
| for (RetriableStatement statement : statements) { | ||
| statement.retry(aborted); | ||
| } | ||
| successfulRetries++; |
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should this be in the loop, or is it per batch of statements?
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It is per successful retry of an entire transaction, i.e. per batch of statements, so it should be outside of the loop.
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| if (retryAbortsInternally) { | ||
| return asyncExecuteStatement( | ||
| statement, | ||
| new Callable<ResultSet>() { |
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minor - can address in a future PR: let's extract out the Callable into a descriptive variable
* add ReadWriteTransaction * refactor inner classes to separate files * included allowed state to error msg * added javadoc to the COMMIT and RUN BATCH statements * removed todo no longer needed in public repo
Adds ReadWriteTransaction including internal retries if the transaction is aborted. All statements that are executed on a ReadWriteTransaction are recorded internally in the transaction, and a running SHA-256 checksum is kept based on all the query results that are returned to the user. If the transaction is aborted by Cloud Spanner, a retry is automatically started and deemed successful if: