sql - How to efficiently delete rows while NOT using Truncate Table in a 500,000+ rows table

Question

Let's say we have table Sales with 30 columns and 500,000 rows. I would like to delete 400,000 in the table (those where "toDelete='1'").

But I have a few constraints :

• the table is read / written "often" and I would not like a long "delete" to take a long time and lock the table for too long
• I need to skip the transaction log (like with a TRUNCATE) but while doing a "DELETE ... WHERE..." (I need to put a condition), but haven't found any way to do this...

Any advice would be welcome to transform a

DELETE FROM Sales WHERE toDelete='1'

to something more partitioned & possibly transaction log free.

Answer 1

Calling DELETE FROM TableName will do the entire delete in one large transaction. This is expensive.

Here is another option which will delete rows in batches :

deleteMore:
DELETE TOP(10000) Sales WHERE toDelete='1'
IF @@ROWCOUNT != 0
    goto deleteMore