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Scan Count    A "scan" can represent any of these access methods:•    A

  • A table scan.

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  • Access using a clustered index. Each time the query starts at the root page of the index and follows pointers to the data pages, it is counted as a scan.

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  • Access using a non-clustered index. Each time the query starts at the root page of the index and follows pointers to the leaf level of the index (for a covered query) or to the data pages, it is counted.

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  • If queries run in parallel, each worker process access to the table is counted as a scan.

More    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.

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The table below describes the information displayed for major operation types .

Table 9-9    Major 9 Major operations

Column    Description

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Major Operation Type    Displays the major types of the operators.•    The

  • The operators in the Execution Plan tree are separated into the following major types:

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  • Table (any Read access to table)

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  • Index (any Read access to index)

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  • Sort (any sort operation)

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  • Join (any join operation)

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  • Spooling

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  • Other (all other operations)

Estimated Cost    Displays the total estimated cost breakdown according to major operation types.

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The table below describes the information displayed for regular operation types.

Table 9-10    Operations10 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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Major Operation Type    Displays the major types of the operators. The operators in the Execution Plan tree are separated into the following major types:•    Table

  • Table (any access to table)

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  • Index (any access to index)

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  • Sort (any sort operation)

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  • Join (any join operation)

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  • Spooling

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  • Other (all other operations)

Estimated Cost    Total estimated cost breakdown according to operation types.

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Objects    Indicates the number of referenced tables/indexes of the specified operation type. 

About viewing general properties of a selected statement

The Properties item under the More tab displays general details of the selected statement. The table below describes the properties displayed for a selected statement.

Table 9-11    Selected 11 Selected statement properties

Column    Description

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The History view is divided into the following areas:•    Main

  • Main area

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  • Change history area

About the Main area

The Main area (upper area) displays Resource Consumption Over Time vs. Cost and Changes Over Time.

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The Change History area (lower area) displays all the Access Plan changes made over a specified time period. 

About viewing Access Plan Changes

The Access Plan Changes view displays a list of all the Access Plans of the statement as detected by the Explain Statement process.

Table 9-12    Access 12 Access Plan Changes table

Column    Description

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The table below describes the information displayed in the Statement's View table.

Table 9-13    Statement13 Statement's View table

Column    Description

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Table Scans    Displays the number of Table Scans performed in the specified statement. 

Table 9-13    Statement13 Statement's View table

Column    Description

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The Actions tab, on the Precise bar, lets you perform additional actions. You can perform the following actions:•    Create

  • Create a new statement

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  • Open an existing statement

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  • Edit an existing statement

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  • Re-Explain an existing statement

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  • Display the Sybase plan using Sybase SQL Advantage and Interactive SQL

Creating a new statement

You can create a new Statement and save it in the PMDB in a logical cabinet and folder hierarchy. You can also rewrite statements and view their Access Plans.

To create a new statement1.    On

  1. On the Precise bar, click Actions>New.

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  1. In the New Statement dialog box, choose the relevant properties for the new statement from the drop-down lists and enter a statement name, as follows:
    • Instance    Indicates the name of the instance that the statement belongs to.
    • Cabinet    Indicates the name of the cabinet that the statement is saved in (creates a cabinet if it does not already exist).
    • Folder    Indicates the name of the folder that the statement is saved in (creates a folder if it does not already exist).
    • Name    Indicates the name of the statement (generated randomly).
    • Database    Indicates the name of the database where the statement is running.
    • User    Indicates the statement's parsing user.

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  1. Enter the SQL text for the statement in the text frame.

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  1. Click OK.

The new statement is saved in the PMDB in a logical cabinet and folder hierarchy. 

Opening an existing statement

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