Config Preference

If the server can read none critical settings from two places in addition to the jde_settings table in the database something has to win. The config_preference setting controls that.

Config Preference States

tables (default)

Database always wins. If a value exists in jde_settings it overrides whatever the config files say (unless its a criticial setting)

This is the default because you usually want admins to be able to change stuff at runtime via the database without having to edit files and restart.

local

Config file wins for keys that were explicitly written in the config file. If you actually typed session_timeout_minutes = 120 in your security config then that value sticks regardless of whats in the database.

But for settings you didnt write in the file (or ones that got set as default because empty) the database can still override them.

This is useful when you want your local file to be the source of truth but still allow the database to fill in settings you havent configured locally.

Notes

the database is always read regardless of this setting. config_preference only controls who wins when they are fighting and having a hissifit as to who wins.
this applies to security settings, permission definitions, group configs etc
changing this setting itself requires editing the config file (its not a DB overridable setting, that would be idiotic)
after changing settings in the database call some servers might choose not to implement live hot reloading for all settings, use POST /reload to apply them