Pt-table-checksum causing lag on replica - suggestions

Hello, I’m running pt-table-checksum on a master database and it’s creating too much lag on its replica. Checksum queries are causing the replica to lag further and further behind. Before running pt-table-checksum the replica was able to keep up with its master. What is the best method to keep the replica from falling behind? I see pt-table-checksum has a number of options related to lag such as --check-slave-lag and --max-load. Some of the innodb tables that are being checked are over a million records large.


Hi @Ron,
Yes, certainly take advantage of --check-slave-lag which will pause the checksum process if your replica’s start lagging behind and auto-resumes when they catch up. Also, you might try lowering --chunk-time so that less rows are calculated each chunk, thereby processing faster and causing less lag.

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