Request new system variable: binlog_keep_max

I have binary logs that are inconsistent in rate. That is, some days I write a tremendous amount to the log, and some days comparatively very little.

I have a partition dedicated to binary logs, and I always want to keep a minimum of 3 days' worth of logs. That part is easily achievable by setting binlog_expire_logs_seconds (or its alias, expire_logs_days).

But most of the time, I have plenty of disk space on that partition and would like to store far more than 3 days' worth of logs. Most of the time, setting it to 7 days works, but then every once in a while I run out of space.

What I would like to do is set binlog_expire_logs_seconds to 3 days, and then have a new "binlog_keep_max" Boolean variable. Setting that to true would always allow the binary logs to fill up the partition, only deleting logs when the partition is full (but of course refusing to delete logs if they're newer than binlog_expire_logs_seconds). There's no reason NOT to have that partition be full of binary logs.