Postgresql updating millions of rows aramex tracking updating shipment status
As years went by, he started working more on writing queries in SQL Server.He now has good level of knowledge in SQLServer, Oracle, My SQL and Postgre SQL as well.Many a times, you come across a requirement to update a large table in SQL Server that has millions of rows (say more than 5 millions) in it.In this article I will demonstrate a fast way to update rows in a large table Consider a table called which has more than 5 millions rows.The usual way to write the update method is as shown below: The issue with this query is that it will take a lot of time as it affects 2 million rows and also locks the table during the update.You can improve the performance of an update operation by updating the table in smaller groups.If the table has too many indices, it is better to disable them during update and enable it again after update3.Instead of updating the table in single shot, break it into groups as shown in the above example.
Always use a WHERE clause to limit the data that is to be updated2.He is also one of the leading posters at a moderator at Suppose you want to update a column with the value 0, if it that column contains negative value.Let us also assume that there are over 2 million row in that column that has a negative value.
You may also want to read my article Find the Most Time Consuming Code in your SQL Server Database Madhivanan,an MSc computer Science graduate from Chennai-India, works as a works as a Lead Subject Matter Expert at a company that simplifies BIG data.
He started his career as a developer working with Visual Basic 6.0, SQL Server 2000 and Crystal Report 8.