Updating large tables tyler perry and tyra banks dating
Asked: November 10, 2002 - pm UTC Answered by: Tom Kyte - Last updated: May 10, 2019 - am UTC Category: Developer - Version: 8.1.7 Viewed 100K times! One of our apps updates a table of several hundred million records. For loop approach for the update was calculated to take 53.7 years to complete!We institued the Insert into a dummy table append with nologging, and were able to complete the "update" in under 30 minutes.You’ve still got good options, they’re just a few more steps: My goal is for you to understand your SQL Server’s behavior– and learn how to change it.When I’m not figuring out the solutions to your database problems, you’ll find me at user group meetings in Portland, Oregon. Hi, I am using this sql for updating a large table. The first select will return 'abc' and the second select will return '123'. If the second select returns null then the updated record should be a.p_cd = 'abc'. Thanks, Hevan Hi, I have 3 tables which i have to update tab1 using this update. But i want to use one update query: update tab1 a set a.p_cd = (select b.p_cd from tab2 b where = fetch first row only)
When done, we swap the partition of original data with the 'dummy' table (the one containing new values), rebuild indexes in parallel, and wha-la! i.e, to update field2 in a table:1) First create your dummy hold table: create table xyz_HOLD as select * from xyz where rownum Hi Tom, As u suggested us to create a new table ,then drop the original table and rename the new table to original table instead of updating a table with millions of records.
I start up an Extended Events trace to capture IO from sp_statements completed, then run the command the maintenance plan was going to use to update every statistic on this table with fullscan: Here’s the trace output –click to view it in a larger image: Looking at the Extended Events trace output, I can see the commands that were run as well as their logical reads.
The commands look like this: The “logical_reads” column lets me know that updating four of these statistics had to do four separate scans of my table– and three of them are all on the Title column! Person shows 5,664 logical reads by comparison.) IO was lower for statistics related to nonclustered indexes because those NC indexes have fewer pages than the clustered index.
If you omit the WHERE clause, all records in the table will be updated!
The WHERE clause specifies which record(s) that should be updated.