Q:

Magento 2 - Catalog rules cronjob stuck at working with increased number of backlogs

Catalog Rule Product, it always shows as working and and 735 in backlog

Tried these but didn't work for me:

Reindexing
Changed state to "Update on Save" then revert back to scheduled
Wait for a day to reindex using magento cron

A:

You need to do the following stuff:
First You need to change the mode of indexing to Update on Save by using this command
php bin/magento indexer:set-mode realtime

After that you need to reset the indexing
php bin/magento indexer:reset

After that truncate _cl tables related to your issue occuring indexing
After that reindex the indexing
php bin/magento indexer:reindex 

Finally you need to change the mode of indexing to Update by Schedule
php bin/magento indexer:set-mode schedule

I hope it may help you in empty the backlog of indexing

