FPA page Structure of pages
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7.3 FPA page FPA pages constitute one level of the three-level UDS/SQL Free Place Administration and
are used to administer free place on the realm level. There is also a free pla ce adminis-
tration facility on the page and table levels.
Note that if a database page contains tables, the value specified in the FPA page does not
always indicate storage space actually occupied.
Every FPA page contains a separate act-key, which specifies the address of the page. The
pair associated with a given act-key (i.e. the FPA page and entry within the page) can be
specifically defined with the help of the information ab out the FPA base and the FPA extent
table in the act-key-0 page.
Depending on which page length was defined for the database, the length of an FPA page
may be 2048 bytes, 4000 bytes or 8096 bytes.
Additional free place administration tables (FPA extents) may be present in a realm in
addition to the base free place administration table (FPA base).
The FPA base consists of the FPA pages created when the realm is created or when the
realm is converted by BPGSIZE. FPA extents may be created when the realm is extended.
It does not matter in this case if the realm is extended online or offl ine mode using the
BREORG utility routine.
Every FPA extent is 128 KB in size. In 2 KB databases it consists of 64 pages, in 4 KB
databases of 32 pages and in 8 KB databases of 16 pages. FPA extents are managed
through the act-key-0 page. The BPRECORD utility routine can be used to output infor-
mation on the FPA base and the FPA extents (see the “Recovery, I nformation and Reorga-
nization“ manual).