tools/mariadb_query_io.py: new tool #5108
Open
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Outdated suggestions cannot be applied.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.
I developed this script while analyzing a scalability problem in MariaDB. It turned about that MariaDB had a lot of contention on the global "dict_sys.latch" lock which caused all queries to become extremely slow.
This tool does not depend on userspace tracepoints, and can therefore be used on MariaDB without recompiling. I tested it on MariaDB 10.11.6 (Debian Bookworm).