Space set aside on disk when a hashed table is created. The size of this space is equal to the modulo of the table multiplied by the frame size.
The Primary Table Space of a hashed table is a binary host table, created when the D3 table is created, internally divided in a number of equal size frames of a size chosen at creation time from 1 KB to 4 MB (4 KB by default). Records are written into the primary space using a hash coding technique. When records do not fit in the frame they hash into, the data is stored in an overflow table, which is created only when the primary space overflows for the first time. An overflow table is an optional table used to extend a hashed table. The overflow table is created only if the primary space of the hashed table becomes full. The overflow table is itself extended on demand, as required. If the overflow table becomes large, it is an indication that the hashed table is not properly sized and should be resized.
The overflow table is an extensible binary host table, divided in frames of a size equal to the table it is complementing, and managed with a bit map to determine what is used.
See Also