Make sure lookup vindexes are queryable inside transaction #6499
Conversation
This file contains 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
Signed-off-by: Andres Taylor <andres@planetscale.com>
Signed-off-by: Andres Taylor <andres@planetscale.com>
sougou
approved these changes
Aug 2, 2020
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Outdated suggestions cannot be applied.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.
When adding data to tables that have consistent lookup vindexes defined on them, Vitess uses different connections to be able to commit data in discrete chunks - we
INSERTnew data to indexes before we add data to the base table. If something goes wrong along the way, it's acceptable to have data exist in the vindex that is not present in the base table - this will lead to unnecessary queries, but not inconsistent results.The issue this PR is solving is that we were not querying the lookup vindex on the correct connection while still inside the transaction, which leads to no data being found.
Note: for
DELETEd rows, we will query the vindex on the wrong connection, which will lead to unnecessary queries, butno wrong results, since the data has been deleted from the base table.