The
AMS RECORDSIZE parameter requires the average and maximum record size,
in bytes, of the alternate index record. When you calculate the maximum
record size, if the alternate index record spans control intervals,
the RECORDSIZE parameter can be larger than the CONTROLINTERVALSIZE.
Use the following formula to calculate the maximum record size of
spanned records:
-
MAXLRECL=CI/CA x (CISZ - 10)
MAXLRECL is the maximum
spanned record size. CI/CA represents the number of control intervals
per control area. CA is the number of control areas. CISZ is the quantity
control interval size.
Use the following formulas
to determine the average size of the alternate index record when the
alternate index supports ESDS or KSDS.
-
-
RECSZ= 5 + AIXKL + (
n x 4)
-
-
RECSZ= 5 + AIXKL + (
n x BCKL)
-
AIXKL is the alternate-key length.
(See the KEYS parameter.)
-
BCKL is the base cluster's prime-key
length. (You can issue the AMS LISTCAT command to determine the base
cluster's prime-key length.)
-
n=1 when the UNIQUEKEY parameter is specified. (In this case, RECSZ
is also the maximum record size.)
-
n is equal to the number of base cluster records that have the same
alternate index key when NONUNIQUEKEY is specified.
In the preceding examples,
the average record size for alternate key STATE was calculated as
follows:
-
5 + 2 + (3 x 4)= 19 for the ESDS
-
5 + 2 + (3 x 9)= 34 for the KSDS
Specifying the same
value for average and maximum identifies the records as fixed length.
See IBM Documentation for more information
about calculating record size.