It's not a CPU issue. Some queries can prevent replag
I understand, some queries could in theory prevent replag, but how queries users run on tables in their user databases could prevent replag if they cannot cause any locks on tables being replicated?
The only way is through intensive CPU or HDD or mem usage. Note that such queries are being killed for now.
My view is that query killer algorithms are to be revised. Replag is caused not necesserily by long running queries but by some special types of queries, which can work not that long.
mashiah