The Plan tab displays a GUI representation of an execution engine’s plan for the
currently running SQL text, and helps you understand the performance and statistic
characteristics of the currently running query.
Note:
The Plan tab only appears if you connect to Adaptive Server version 15.0 and later.
The top half of the Plan tab shows the logical flow of the operators used in the plan in
a tree-based, hierarchal structure, with each operator a separate node of the tree. The
cost of each operator is based on the cost model used by the query processor. Each
operator node in the tree is costed relative to other nodes, which makes it easier to
identify operators based on their costs.
Each node includes tooltip text (text that appears when you move your mouse over the
node) that provides details about each operator, so you do not have to select the nodes to
compare details between operators.
| Plan Tab Information | Description |
|---|
Details |
Shows the details of the operator statistics as: - Node Statistics table – shown for all the operators, and includes statistics
like row count, logical I/O, and physical I/O.
- Subtree Statistics table – the aggregate sum of all the operators below, and
are shown for the non-leaf operators, and include statistics on row count,
logical I/O, and physical I/O.
|
XML | Shows the result set as XML output. |
Text | Shows the text version of the query plan (the same as the output of
showplan). |
Advanced |
Includes: - Abstract query plan – shows the abstract query plan used by the query.
- Resource utilization – describes the resources used by the plan, including
number of threads and the auxiliary session descriptors (SDESs; every table scan
requires one session descriptor to track the scan).
- Cost – lists costs associated with the plan, including logical I/O, Physical
I/O, and CPU usage.
- Optimizer Metrics – lists the query-plan statistics, including query run time,
run time for the first plan, number of plans evaluated, number of plans that
were valid, and amount of procedure cache used.
- Optimizer Statistics – lists the last time you ran update
statistics on the table, any missing histogram steps, and the
density of the steps.
|