DBI tab

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Main: Project > Settings > Program Options
Main: CTRL + O

The DBI tab controls how Petra uses the available system memory

DBI DataBase Client Cache Optimization

This option sets the the amount of memory used by the DBI database engine for local (client-side) caching. The default value (minimum setting) is usually sufficient. Be careful not to exceed your systems memory capabilities. Over commitment of memory to the database cache could result in extensive user of the system virtual memory, ie, swap file or create "out-of-memory" errors during data import.

Do Not Cache table Buffers on Client

This option improves performance only on very old hardware.  Any personal computer built after 1990 will run much better without this option checked