MySQL’s SHOW STATUS and SHOW VARIABLES commands (or queries against the corresponding INFORMATION_SCHEMA tables) don’t always show what they say. In particular, SHOW STATUS contains several rows that aren’t status-related, but are really configuration variables in my opinion (and it is an opinion — sometimes the difference isn’t black and white).
Here’s a short list of some status counters that I think are really better off as configuration variables:
- Innodb_page_size
- Slave_heartbeat_period
- Ssl_cipher
- Ssl_cipher_list
- Ssl_ctx_verify_depth
- Ssl_ctx_verify_mode
- Ssl_default_timeout
- Ssl_session_cache_mode
- Ssl_verify_depth
- Ssl_verify_mode
- Ssl_version
Most of those are legacy, but Slave_heartbeat_period is a recent addition.
Can you think of others? What are your favorite oddities of SHOW STATUS and SHOW VARIABLES?
Further Reading:
- How to monitor MySQL status and variables with innotop
- Breaking news: SHOW INNODB STATUS ported to XML
- Formatting mysqladmin extended-status nicely
- Collaborate versus the MySQL UC
- Status update on High Performance MySQL
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