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Table 9-7 Columns of table
Column Description
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| Column | Description |
|---|---|
| Indicates whether the column is part of the selected index and whether it is sorted in ascending or descending order. |
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| Column | Displays the column name. |
| Key |
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| Number | Displays the key number of the column in the index. |
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| Type | Displays the physical storage type of the column. |
Displaying statistical information on operators in the execution plan tree
The Statistics tab displays statistical information of all operators in the Execution Plan tree. When you sort a table, you can locate operators by their estimated cost or by any other column in the table.
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Table 9-8 About viewing statistics on Operator ID and Type
Column Description
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| Column | Description |
|---|---|
 | Click to locate and highlight the operator in the Execution Plan tree that matches the selected operator in the grid. |
| Operator ID and |
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| Type | Displays the operator ID and type. |
| Logical |
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| Reads | Number of logical reads performed on the specified table. The number of logical reads estimated by the optimizer is based on the access method and the size of cache. In this case, the optimizer is estimating how many pages are likely to be in cache. |
| Physical Reads | Physical |
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| reads are estimated based on the number of logical reads and the cache size. The optimizer is estimating how many pages will not be available in cache and will need to be read from disk. |
| Subtree |
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| Cost | Displays the total estimated cost of all the current operation's sons. |
| Estimated |
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| Cost | Displays the estimated cost of the current operation. A high cost value may indicate a problem in the current implementation of the operation. Estimated cost is calculated as followed: Logical Reads * 2 milliseconds (which is the assumption of how long a logical read takes) + Physical Reads * 18 milliseconds (which is the assumption of how long a physical read takes). |
| Estimated Cost (%) |
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| Displays the estimated cost (in percentage) of the current operator. | |
| Estimated |
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| Rows | Number of rows from the current table that is estimated to satisfy the join. |
| Scan |
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| Count | A "scan" can represent any of these access methods:
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| More |
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| Displays additional information according to the specified operation. For example, in a table scan operation, the scan type (forward/backward), I/O size and buffer replacement strategy will be displayed. |
| Parallel |
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| Indicates whether the operator is running in parallel. |
About viewing statistical information on operation types
The Operations item under the Menu tab displays two tables that show statistical information broken down into operation types of all operators in the Execution Plan tree.
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Table 9-9 Major operations
Column Description
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| Column | Description |
|---|---|
| Click to locate and highlight the operators in the Execution Plan tree that match the selected major operation type. |
| Major Operation |
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| Type | Displays the major types of the operators.
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| Estimated |
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| Cost | Displays the total estimated cost breakdown according to major operation types. |
| Operations |
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| Indicates the number of operators of a specific major operation type. |
| Objects |
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| Indicates the number of referenced tables/indexes of the specified operation type. This column is only relevant for table and index operation types. |
The table below describes the information displayed for regular operation types.
Table 9-10 Operations
Column Description
Click to locate and highlight the operators in the Execution Plan tree that match the selected operation type.
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