perf: inline BeginTransaction with first statement #466
+300
−75
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Inline the BeginTransaction option with the first statement in the transaction, instead of executing a separate BeginTransaction RPC. This reduces the number of round-trips to Spanner by one for all transactions that have at least one SQL statement. Using line-begin improves performance for most transaction shapes, as it requires one less round-trip to Spanner. Some transaction shapes do not benefit from this. These are: 1. Transactions that only write mutations still need an explicit BeginTransaction RPC to be executed, as mutations are included in the Commit RPC. The Commit RPC can also start a transaction, but such transactions are not guaranteed to be applied only once to Spanner. 2. Transactions that execute multiple parallel queries at the start of the transaction can see higher end-to-end execution times, as only one query can include the BeginTransaction option. All other queries must wait for the first query to return at least one result, which also includes the transaction identifier, before they can proceed. The default for the database/sql driver is to use inline-begin. A follow-up pull request will add an option to the driver to set a different default for a connection.
rahul2393
previously approved these changes
Jul 1, 2025
Adds a BeginTransactionOption configuration field that can be used to determine how the database/sql driver should begin transactions. The default is to inline the BeginTransaction option with the first SQL statement of the transaction. This reduces the number of round-trips needed per transaction by one for most transaction shapes.
rahul2393
approved these changes
Jul 2, 2025
rahul2393
approved these changes
Jul 2, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Inline the BeginTransaction option with the first statement in the transaction, instead of executing a separate BeginTransaction RPC. This reduces the number of round-trips to Spanner by one for all transactions that have at least one SQL statement.
Using line-begin improves performance for most transaction shapes, as it requires one less round-trip to Spanner. Some transaction shapes do not benefit from this. These are:
The default for the database/sql driver is to use inline-begin. A follow-up pull request will add an option to the driver to set a different default for a connection.
BEGIN_COMMIT_OVERRIDE
perf: inline BeginTransaction with first statement
feat: add BeginTransactionOption to configure how to begin a transaction
END_COMMIT_OVERRIDE