IBM Books

Administration Guide


EXPLAIN_OPERATOR Table

The EXPLAIN_OPERATOR table contains all the operators needed to satisfy the SQL statement by the SQL compiler.

Table 126. EXPLAIN_OPERATOR Table
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.
OPERATOR_TYPE CHAR(6) No No Descriptive label for the type of operator.
TOTAL_COST DOUBLE No No Estimated cumulative total cost (in instructions) of executing the chosen access plan up to and including this operator.
IO_COST DOUBLE No No Estimated cumulative I/O cost (in data page I/Os) of executing the chosen access plan up to and including this operator.
CPU_COST DOUBLE No No Estimated cumulative CPU cost (in instructions) of executing the chosen access plan up to and including this operator.
FIRST_ROW_COST DOUBLE No No Estimated cumulative cost (in timerons) of fetching the first row for the access plan up to and including this operator. This value includes any initial overhead required.
RE_TOTAL_COST DOUBLE No No Estimated cumulative cost (in timerons) of fetching the next row for the chosen access plan up to and including this operator.
RE_IO_COST DOUBLE No No Estimated cumulative I/O cost (in data page I/Os) of fetching the next row for the chosen access plan up to and including this operator.
RE_CPU_COST DOUBLE No No Estimated cumulative CPU cost (in timerons) of fetching the next row for the chosen access plan up to and including this operator.
COMM_COST DOUBLE No No Estimated cumulative communication cost (in TCP/IP frames) of executing the chosen access plan up to and including this operator.
FIRST_COMM_COST DOUBLE No No Estimated cumulative communications cost (in TCP/IP frames) of fetching the first row for the chosen access plan up to and including this operator. This value includes any initial overhead required.
NODES_USED CLOB(64K) Yes No Cumulative list of nodes involved in executing the chosen access plan up to and including this operator.

Table 127. OPERATOR_TYPE Values
Value Description
DELETE Delete
FETCH Fetch
FILTER Filter rows
GENROW Generate Row
GRPBY Group By
HSJOIN Hash Join
INSERT Insert
IXAND Dynamic Bitmap Index ANDing
IXSCAN Index Scan
MSJOIN Merge Scan Join
NLJOIN Nested loop Join
RETURN Result
RIDSCN Row Identifier (RID) Scan
SORT Sort
TBSCAN Table Scan
TEMP Temporary Table Construction
TQ Table Queue
UNION Union
UNIQUE Duplicate Elimination
UPDATE Update


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