PG-1056 xmin and xmax correctness #292
Merged
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
|
Performance test results: |
artemgavrilov
changed the title
|
@dutow see my commit's message.
Am I missing something?
|
If `get_heap_tuple` is NULL, the core uses `copy_heap_tuple` instead. The former returns a pointer to a tuple in the slot and the latter makes a copy of such a tuple. For UPDATE SET, the core uses the slot for INSERT and later for RETURNING processing. If we copy the tuple the next happens: 1. The core creates a slot with the generic tuple. 2. It passed to `pg_tdeam_tuple_update()` and it gets a copy of the tuple here [https://github.com/Percona-Lab/pg_tde/blob/6d4f7e5b7bd2507ce65deb315ea8d5647f474cf9/src17/access/pg_tdeam_handler.c#L336]. 3. This generic tuple is filled with the proper data and used for the update here [https://github.com/Percona-Lab/pg_tde/blob/6d4f7e5b7bd2507ce65deb315ea8d5647f474cf9/src17/access/pg_tdeam_handler.c#L343]. 4. Later on, RETURNING processing uses the slot's tuple but is still a generic unmodified one because of the copy. 5. That results in wrong RETURNING data. To avoid this, we should return a pointer to the slot's tuple instead of copying it. Fixes PG-1056
dAdAbird
force-pushed
the
PG-1056-xmin-xmax
branch
from
39ccd65
to
b451158
Compare
|
@dAdAbird my concern was that if we only get the tuple and do not copy it, we might find issues because we reuse the same memory again for the next tuple. If I understand the API correctly, this shouldn't happen, but it seemed safer to disable get, and force copy. Looks like I was wrong about that. |
|
Before merge I think we should remove test it this PR because it's isolated case from PG regression suite. Not sure that we need it in tde repo. What do you think? |
dutow
approved these changes
Oct 1, 2024
codeforall
approved these changes
Oct 8, 2024
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.
https://perconadev.atlassian.net/browse/PG-1056