I am running the command pt-online-schema-change --bin-log --host=127.0.0.1 --user=xxx --password=xxx D=xxx,t=xxx,P=8306 --alter "CONVERT TO CHARACTER SET utf8mb4" --execute, however it outputs: "Unknown option: bin-log". There is a --bin-log option clearly mentioned in their docs, so what's going on? I have pt-online-schema-change 3.1.0.
Despite the documentation page, pt-online-schema-change does not have a --bin-log option. You can verify this by running:
pt-online-schema-change --help
I searched their bug database, and found that there is some discussion that it's important for pt-online-schema-change to write the binlog. It does this by default, and this matches my experience with it.
You don't need this option. I don't know why it appears in the documentation.