cats: add missing database locks #1787
Open
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 function is not safe to use if you dont actually own the lock, but misuse should hopefully lead to a crash anyways.
sebsura
force-pushed
the
dev/ssura/master/fix-database-locking
branch
from
aabaf91
to
c83d9a4
Compare
This is not checked in case of private connections since they are not shared automatically. It probably makes sense to also check them since they might get shared by accident (e.g. setting a pointer in jcr and then another thread accessing that jcr).
sebsura
force-pushed
the
dev/ssura/master/fix-database-locking
branch
from
c83d9a4
to
f438920
Compare
arogge
requested changes
Jun 7, 2024
| @@ -828,6 +844,7 @@ void BareosDbPostgresql::SqlUpdateField(int i) | |||
|
|
|||
| SQL_FIELD* BareosDbPostgresql::SqlFetchField(void) | |||
| { | |||
| AssertOwnership(); | |||
There was a problem hiding this comment.
do we have any idea how this will influence runtime?
SqlFetchField() is called a lot in pretty tight loops.
Its happy-path boils down to:
- integer comparison
- nullptr check
- boolean check
- add two pointers (for array access)
- integer increment
Calling AssertOwnership() while assuming we're on Linux, it is completly inlined, on the happy path, and having is_private_ == false:
- boolean check
- pointer dereference
- integer equality comparison
- integer comparison
- library call to
pthread_self()(cannot be inlined) - long integer equality comparison (always inlined from
pthread_equal())
I don't say this will be a performance issue. But it definitely looks like could be. Especially with the redundant check in SqlUpdateField() above we would call AssertOwnership() twice for each field.
| @@ -800,6 +815,7 @@ uint64_t BareosDbPostgresql::SqlInsertAutokeyRecord(const char* query, | |||
|
|
|||
| void BareosDbPostgresql::SqlUpdateField(int i) | |||
| { | |||
| AssertOwnership(); | |||
There was a problem hiding this comment.
SqlUpdateField() is only called by SqlFetchField(), so this check is redundant.
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.
Thank you for contributing to the Bareos Project!
By default, bareos db connections get shared by multiple jobs/threads. It is of utmost importance to ensure that those shared connections only get written to/read from if the calling thread has acquired the lock.
This PR by no means ensures that this is done correctly everywhere, but the start of an ongoing process to weed out every race condition in the database code.
This PR adds some missing locks as well as assertions that locks were taken correctly at the relevant places.
Additionally it renames
bac_cursor_tobar_cursor_.Please check
If you have any questions or problems, please give a comment in the PR.
Helpful documentation and best practices
Checklist for the reviewer of the PR (will be processed by the Bareos team)
Make sure you check/merge the PR using
devtools/pr-toolto have some simple automated checks run and a proper changelog record added.General
Source code quality
Tests