SQL Reference

SYSSTAT.FUNCTIONS

Contains a row for each user-defined function (scalar or aggregate). Does not include built-in functions. Statistics are not recorded for inherited columns of typed tables.

Table 105. SYSSTAT.FUNCTIONS Catalog View

Column Name	Data Type	Nullable	Description	Updatable
FUNCSCHEMA	VARCHAR(128)		Qualified function name.
FUNCNAME	VARCHAR(18)
SPECIFICNAME	VARCHAR(18)		Function specific (instance) name.
IOS_PER_INVOC	DOUBLE		Estimated number of I/Os per invocation; -1 if not known (0 default). This column can only be updated with the following values: -1 or >= 0 (zero)	Yes
INSTS_PER_INVOC	DOUBLE		Estimated number of instructions per invocation; -1 if not known (450 default). This column can only be updated with the following values: -1 or >= 0 (zero)	Yes
IOS_PER_ARGBYTE	DOUBLE		Estimated number of I/O's per input argument byte; -1 if not known (0 default). This column can only be updated with the following values: -1 or >= 0 (zero)	Yes
INSTS_PER_ARGBYTE	DOUBLE		Estimated number of instructions per input argument byte; -1 if not known (0 default). This column can only be updated with the following values: -1 or >= 0 (zero)	Yes
PERCENT_ARGBYTES	SMALLINT		Estimated average percent of input argument bytes that the function will actually read; -1 if not known (100 default). This column can only be updated with the following values: -1 or between 100 and 0 (zero)	Yes
INITIAL_IOS	DOUBLE		Estimated number of I/O's performed the first/last time the function is invoked; -1 if not known (0 default). This column can only be updated with the following values: -1 or >= 0 (zero)	Yes
INITIAL_INSTS	DOUBLE		Estimated number of instructions executed the first/last time the function is invoked; -1 if not known (0 default). This column can only be updated with the following values: -1 or >= 0 (zero)	Yes
CARDINALITY	BIGINT		The predicted cardinality of a table function. -1 if not known, or if function is not a table function.	Yes
SELECTIVITY	DOUBLE		Used for user defined predicates. Default = -1 if there are no user defined predicates. See Note 1.
Note: This column will be set to -1 during migration from DB2 Version 5.2 to 6.1 in the system catalogs for all user defined functions. For a user defined predicate, the selectivity in the system catalog will be -1. In this case, the selectivity value used by the optimizer is 0.01.