I don't think key_buffer_size
is deprecated, mysql use key_buffer_size
in the documentation on their website from the earliest available right up to the latest version. There is also a bug report that requests deprecated variables emit warnings at startup which suggests that it's key_buffer
that is deprecated.
I personally would go with the documentation as it should be authoritative and whilst the internet is full of useful information it's also full of misinformation.
Having said that it seems like mysql goes out of it's way to match variable names you provide to it's variables and will do so as long as the name you provide is unique
With key_buffer_size = 16m
mysql> show variables like '%key_buffer%';
+-----------------+----------+
| Variable_name | Value |
+-----------------+----------+
| key_buffer_size | 16777216 |
+-----------------+----------+
1 row in set (0.00 sec)
Change to key_buffer = 6m
mysql> show variables like '%key_buffer%';
+-----------------+---------+
| Variable_name | Value |
+-----------------+---------+
| key_buffer_size | 6291456 |
+-----------------+---------+
1 row in set (0.00 sec)
Change to key_b =16m
mysql> show variables like '%key_buffer%';
+-----------------+----------+
| Variable_name | Value |
+-----------------+----------+
| key_buffer_size | 16777216 |
+-----------------+----------+
1 row in set (0.00 sec)
Change to key_ = 16m and mysql fails to start as key_ isn't unique.