SQL/MX 2.x Query Guide (G06.24+, H06.03+)

Reviewing Query Execution Plans
HP NonStop SQL/MX Query Guide—523728-003
4-4
Description of the EXPLAIN Function Results
The DETAIL_COST column of the EXPLAIN function results contains these cost
factors:
PLAN_ID LARGEINT Unique system-generated plan ID automatically
assigned by SQL; generated at compile time.
SEQ_NUM INT Sequence number of the current node in the
operator tree; indicates the sequence in which the
operator tree is generated.
OPERATOR CHAR(30) Current node type. For a full list of valid operator
types, see Section 7, Operators and Operator
Groups.
LEFT_CHILD_
SEQ_NUM
INT Sequence number for the first child operator of the
current node (or operator); null if node has no child
operators.
RIGHT_CHILD_
SEQ_NUM
INT Sequence number for the second child operator of
the current node (or operator); null if node does not
have a second child.
TNAME CHAR(60) For operators in scan group, full name of base table,
truncated on the right if too long for column. If
correlation name differs from table name, simple
correlation name first and then table name in
parentheses.
CARDINALITY REAL Estimated number of rows that will be returned by
the current node.
OPERATOR_COST REAL Estimated cost associated with the current node to
execute the operator.
TOTAL_COST REAL Estimated cost associated with the current node to
execute the operator, including the cost of all
subtrees in the operator tree.
DETAIL_COST VARCHAR
(200)
Cost vector of five items, which are described in
detail in the next table.
DESCRIPTION VARCHAR
(3000)
Additional information about the operation in the
form of a stream of token pairs. For a detailed look at
the tokens for all operators, see Section 7, Operators
and Operator Groups.
CPU_TIME An estimate of the number of seconds of processor time it might take
to execute the instructions for this node. A value of 1.0 is 1 second.
IO_TIME An estimate of the number of seconds of I/O time (seeks plus data
transfer) to perform the I/O for this node.
MSG_TIME An estimate of the number of seconds it takes for the messaging for
this node. The estimate includes the time for the number of local and
remote messages and the amount of data sent.
Column Name Data Type Description