![]() ![]() So that, optimizer estimates how much memory and other resources are required for a query When we create an index this data distribution information is also stored for the NULL valued columns. “How does the SQL Server query optimizer know how many NULL rows are stored for a column in a table?”īasically, the statistics store the data distribution about the tables, and the query optimizer makes use of this information during the creation of a query plan. Most likely, the following question will pop up in your mind. This situation shows that the query optimizer finds accurate information about how many NULL rows are stored in the The index seek operator details show us there is not any difference between the Actual Number of Rows and the Estimated Number of Rows. Without a doubt, the created index is used by the database engine and it boosts the performance of the query because the logical reads number is lower than the previous one.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |