How do you update a table with a large number of updates?

How do you update a table with a large number of updates?

1 Answer

1. Gather the updates you want to do into a temporary table with a RowID, call it #Updates.
2. Create another temporary table just to hold RowIDs, call it “#Done”
3. Start a loop which runs until there are 0 rows in #Updates which aren’t in #Done.

Why is it a good idea to DELETE an UPDATE query after it runs?

A delete query automatically creates a new table from data that already exists in a database. The delete query saves you the chore of having to locate and delete records manually. You should NOT rerun an action query. An append query is used to update or change data automatically based on criteria that you specify.

How do you update a large table with millions of rows in Oracle?

Efficient way to UPDATE bulk of records in Oracle Database

1. Update each record individually and COMMIT in FOR LOOP.
2. Update each record individually in FOR LOOP but COMMIT after the loop.
3. BULK UPDATE using BULK COLLECT and FOR ALL.
4. DIRECT UPDATE SQL.
5. MERGE STATEMENT.
6. UPDATE using INLINE View Method.

How to speed up the SQL update query?

An update statement is a fully logged operation and thus it will certainly take considerable amount of time if millions of rows are to be updated.The fastest way to speed up the update query is to replace it with a bulk-insert operation. It is a minimally logged operation in simple and Bulk-logged recovery model.

How to improve SQL Server query performance on large tables?

I have a relatively large table (currently 2 million records) and would like to know if it’s possible to improve performance for ad-hoc queries. The word ad-hoc being key here. Adding indexs is not an option (there are already indexs on the columns which are queried most commonly).

How to increase performance of bulk updates in MySQL?

One of the biggest performance boosts was to drop all indexes from all the tables that needed to be updates, except for the primary key indexes (those on the id fields). It is much faster to just drop the indexes and recreate them when you’re done.

What’s the best way to improve MySQL performance?

The key to getting decent performance is too start simple, and slowly expand your script while keeping a close eye on performance. If you see a dip, investigate immediately to mitigate the problem. Useful ways of investigation slow performance is by using tools to unearth evidence of the root of the problem.