blob_tracking and blob_orphans are temporary tables which contain metadata relating to a single run of trackBlobs/recompressTracked. They need to be truncated each time the scripts are run. Currently they hold data related to a 2011 snapshot of the text table. Unfortunately we forgot to drop them after the last run of recompressTracked.php in 2011. They can be dropped now.
This does not mean that code related to these tables should be deleted. When we are ready to run the code again, we'll recreate the tables.
Original task description:
blob_tracking indexes apparently unused
On enwiki:
+---------------+------------+-----------+ | table_name | index_name | rows_read | +---------------+------------+-----------+ | blob_tracking | bt_moved | NULL | | blob_tracking | bt_cluster | NULL | +---------------+------------+-----------+
NULL rows_read indicates the indexes havn't been used for reading or writing. Stats collection has been running here for over a week. Same results on S1 master and several slaves, and various other wikis.
Data / index disk usage for blob_tracking is roughly 50/50 split. Dropping unused indexes would be good to reduce write load and save disk space.
But are these indexes really likely to be simply unused? Is there any infrequent maintenance or reporting job that requires them?
Version: 1.21.x
Severity: minor
Dropping progress
- s1
- s2
- s3
- s4
- s5
- s6
- s7
- s8 (tables not present)