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Administration Guide


The EXPLAIN_PREDICATE table identifies which predicates are applied by a specific operator.

Column Name Data Type Nullable? Key? Description
EXPLAIN_REQUESTER CHAR(8) No FK Authorization ID of initiator of this Explain request.
EXPLAIN_TIME TIMESTAMP No FK Time of initiation for Explain request.
SOURCE_NAME CHAR(8) No FK Name of the package running when the dynamic statement was explained or name of the source file when the static SQL was explained.
SOURCE_SCHEMA CHAR(8) No FK Schema, or qualifier, of source of Explain request.
EXPLAIN_LEVEL CHAR(1) No FK Level of Explain information for which this row is relevant.
STMTNO SMALLINT No FK Statement number within package to which this explain information is related.
SECTNO SMALLINT No FK Section number within package to which this explain information is related.
OPERATOR_ID SMALLINT No No Unique ID for this operator within this query.
PREDICATE_ID SMALLINT No No Unique ID for this predicate for the specified operator.
HOW_APPLIED CHAR(5) No No How predicate is being used by the specified operator.
WHEN_EVALUATED CHAR(3) No No Indicates when the subquery used in this predicate is evaluated.

Possible values are:

This predicate does not contain a subquery.

The subquery used in this predicate is evaluated at application (EAA). That is, it is re-evaluated for every row processed by the specified operator, as the predicate is being applied.

The subquery used in this predicate is evaluated at open (EAO). That is, it is re-evaluated only once for the specified operator, and its results are re-used in the application of the predicate for each row.

There is more than one type of subquery in this predicate.
RELOP_TYPE CHAR(2) No No The type of relational operator used in this predicate.
SUBQUERY CHAR(1) No No Whether or not a data stream from a subquery is required for this predicate. There may be multiple subquery streams required.

Possible values are:

No subquery stream is required

One or more subquery streams is required
FILTER_FACTOR DOUBLE No No The estimated fraction of rows that will be qualified by this predicate.
PREDICATE_TEXT CLOB(64K) Yes No The text of the predicate as recreated from the internal representation of the SQL statement.

Null if not available.

Table 129. Possible HOW_APPLIED Values
Value Description
JOIN Used to join tables
RESID Evaluated as a residual predicate
SARG Evaluated as a sargable predicate for index or data page
START Used as a start condition
STOP Used as a stop condition

Table 130. Possible RELOP_TYPE Values
Value Description
blanks Not Applicable
EQ Equals
GE Greater Than or Equal
GT Greater Than
IN In list
LE Less Than or Equal
LK Like
LT Less Than
NE Not Equal
NL Is Null
NN Is Not Null

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