Increasing Cache Size
When InterBase reads a page from the database onto disk, it stores that page in its cache, which is a set of buffers that are reserved for holding database pages. Ordinarily, the default cache size of 2,048 buffers is adequate. If your application includes joins of five or more tables, InterBase automatically increases the size of the cache. If your application is well localized, that is, it uses the same small part of the database repeatedly, you might want to consider increasing the cache size so that you never have to release one page from cache to make room for another.
You can use the gfix utility to increase the default number of buffers for a specific database using the following command:
gfix -buffers n database_name
You can also change the default cache size for an entire server either by setting the value of
DATABASE_CACHE_PAGES in the configuration file or by changing is on the IB Settings page of the InterBase Server Properties dialog on Windows platforms. This setting is not recommended because it affects all databases on the server and can easily result in overuse of memory or in small caches, that are un-usable. It is is better to tune your cache on a per-database basis using