Database Reference
In-Depth Information
Table 10-1.
Columns of the Table Containing the Execution Plan
Column
Description
Basics
(Always Available)
Id
The identifier of each operation (line) in the execution plan. If the
number is prefixed by an asterisk, it means that predicate information for
that line is available later.
Operation
The operation to be executed. This is also known as the
row source
operation
.
Name
The object on which the operation is executed.
Query Optimizer Estimations
Rows
and
E-Rows
The estimated number of rows returned by the operation.
Bytes
and
E-Bytes
The estimated amount of data returned by the operation.
TempSpc
and
E-Temp
The estimated amount of temporary space (in bytes) required by the
operation.
Cost (%CPU)
The estimated cost of the operation. The percentage of CPU cost is given
in parentheses. Note that this value is cumulated through the execution
plan. In other words, the cost of parent operations contains the cost of
their child operations.
Time
and
E-Time
The estimated amount of time needed to execute the operation
(HH:MM:SS).
Partitioning
Pstart
The number of the first partition to be accessed. If that number isn't
known at parse time, either
KEY
or
INVALID
.
KEY
is used when the first
partition is determined during the execution phase.
Pstop
The number of the last partition to be accessed. If that number isn't
known at parse time, either
KEY
or
INVALID
.
KEY
is used when the last
partition is determined during the execution phase.
Parallel and Distributed Processing
Inst
For distributed processing, the name of the database link used by the
operation.
TQ
For parallel processing, the table queue used for the communication
between slave processes.
IN-OUT
The relationship between parallel or distributed operations.
PQ Distrib
For parallel processing, the distribution used by producers to send data to
consumers.
(
continued
)
