Server ceilings ​

Server resource settings constrain saved database resource settings. For time, memory, result rows and response bytes, a request uses the stricter nonzero limit.

Zero means no added ceiling at that scope; it does not disable a nonzero ceiling from the other scope.

Example ​

With XML max_result_rows set to 1000:

Saved database value	Effective maximum
0	1000 rows.
5000	1000 rows.
100	100 rows.

system.settings and SHOW SETTINGS expose the effective value. The saved value remains available in main.settings.

Changing a ceiling ​

XML changes require a restart and do not rewrite stored database values. Lowering the server ceiling can therefore change the effective setting while leaving its saved value unchanged.

This mechanism is distinct from per-user profiles or permissions, which are not implemented. See request limits and the settings reference.