In my previous blog we discussed about the different format of SQL Server execution plan. Now in upcoming blogs we will discussed about the most commonly seen operators we see when execution plan generates. In this post I will start the easy one that is Table Scan operator.
As with the name of operator Table Scan it indicates that it returns the rows after scanning every row of a table.
When this operator appears in execution plan?
When there is no index present on the table then query optimizer has to scan every row of table to return the result set.
In the returned result set data is retrieved after traversing data row by row.
When a table is having fewer rows and returning maximum rows then it’s faster for query optimizer to scan all rows rather than checking indexes.
That’s all for the day !!!