Saturday 2 November 2024

Index Update operator in SQL Server execution plan

The Index Update operator in SQL Server is used in execution plans when performing an UPDATE operation on a table that has indexes. This operator modifies index entries when indexed columns are updated, ensuring that the index remains consistent with the table's current data.

The Index Update operator appears in an execution plan when:

Ø  An UPDATE statement modifies a column that is part of a non-clustered or clustered index.

Ø  SQL Server needs to adjust the index entries to reflect the changes in the indexed column(s).

Icon of index update operator

See the example

For the demo we are creating a table and non-cluster index and inserting some records in this table.

CREATE TABLE Products (

    ProductID INT PRIMARY KEY,

    ProductName VARCHAR(50),

    Price DECIMAL(10, 2)

);

-- Create a non-clustered index on the Price column

CREATE INDEX IX_Products_Price ON Products(Price);

 INSERT INTO Products (ProductID, ProductName, Price)

VALUES (1, 'Laptop', 1200.00),

       (2, 'Smartphone', 700.00),

       (3, 'Tablet', 300.00);

See the records in the table


Now updating the records in this table

UPDATE Products

SET Price = 700.00

WHERE ProductID = 2;

Running this query

See here 2 rows affected. One update in the table and other update on index.

See the execution plan



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