sql: cache role existence checks to fix perf regression #111934
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
|
This change is |
rafiss
changed the title
In 12ec26f, we started to check for the existence of a role whenever a privilege for the public role was checked. This can hapen multiple times during some pg_catalog queries, so it introduced a performance regression. Now, the role existence is cached so we avoid the penalty. The existence of a role is cached for the duration of the entire transaction, and also gets inherited by any internal executor used to implement a command run by the user's transaction. No release note since this is new in 23.2. Release note: None
rafiss
force-pushed
the
cache-role-exists
branch
from
7178d4b to
cf61b37
Compare
ecwall
reviewed
Oct 9, 2023
| func (p *planner) RoleExists(ctx context.Context, role username.SQLUsername) (bool, error) { | ||
| return RoleExists(ctx, p.InternalSQLTxn(), role) | ||
| cache := p.EvalContext().RoleExistsCache | ||
| if cache != nil { |
There was a problem hiding this comment.
What causes the cache to be nil here?
There was a problem hiding this comment.
it shouldn't be nil, it was just a defensive check
There was a problem hiding this comment.
IMO defensive checks like this make the code harder to maintain because it is hard to tell the difference between something that is expected to be nil and a bug, but I'll leave it up to you if you want to keep it.
ecwall
approved these changes
Oct 10, 2023
|
tftr bors r+ |
|
Build succeeded: |
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Outdated suggestions cannot be applied.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.
In 12ec26f, we started to check for the existence of a role whenever a privilege for the public role was checked. This can hapen multiple times during some pg_catalog queries, so it introduced a performance regression.
Now, the role existence is cached so we avoid the penalty. The existence of a role is cached for the duration of the entire transaction, and also gets inherited by any internal executor used to implement a command run by the user's transaction.
No release note since this is new in 23.2.
informs #20718
fixes #112102
Release note: None