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Dokuschablonen 19x24 Version 7.3us für FrameMaker V7.x vom 14.02.2007 © cognitas GmbH 2001-2007
24. Oktober 2007 Stand 08:58.55 Pfad: G:\vogt\fsc\uds\Manuale\en\udsent_e\udsent.k05
Size of the hash area for a secondary key
DATABASE-KEY-TRANSLATION-TABLE IS integer
integer specifies the number of records of a record type.
– If the database has a page length of 2048 bytes, you may specify a maximum value of
2
24
-1 for integer. If the record type in question is the owner in a set, the maximum
possible value for integer is 16 711 679.
– If the database has a page length of 4000 or 8096 bytes, the maximum value that can
be specified for integer is 2
31
-1.
Using this number, UDS/SQL not only calculates the size of the DBTT, but also the minimum
number of pages required for the distributed storage of the record addresses (see the
section “Indirect CALC page” on page 213).
UDS/SQL then reserves a number of pages corresponding to the next higher prime number.
A hash area is extended by means of overflow pages if the data assigned to a page by a
hash routine exceeds the maximum capacity of the page. The overflowing page is linked to
the overflow page by means of act-keys.
A hash area can be extended at a later time by means of the BREORG utility routine (see
the "Recovery, Information and Reorganization" manual, BREORG).
By default, UDS/SQL sets up a hash area of one page for each secondary key.