Comment 2 for bug 1115556

No, it is ignoring --max-lag unless set explicitly in version 2.1.8.

I tested with several backup servers (no load other than replication) and in each case it delayed replication significantly using 2.1.8. In checking the binary logs, the only thing occurring during these intervals were the checksums, and very few small write queries.

While I do see that set to 1 if I do the --help | grep max-lag I unfortunately see significant delay in replication specifically caused by pt-table-checksum.

The specific arguments we're using in our call to pt-table-checksum are:

--quiet
--ignore-databases=mysql,percona,information_schema,performance_schema
--user (removed) --password (removed)
--lock-wait-time=50
--chunk-size-limit=0
--no-check-plan
--replicate percona.checksums
(and more recently the addition of --no-check-binlog-format (because we use all MIXED mode servers)

If you'd like, I can also see about grabbing base64 decoded binary logs for that interim, but it is indeed only the checksum queries causing the replication delay.