Few days back I needed to write a small utility program in C# to update few million (91 to be exact) records in a table.
I thought it is fairly straight forward, single user, single connection application scenario hence I used WPF and Linq to do the job.
First run and updated record number started to fly like Jet. In a minute or two it processed entire table (yes! With 91 Million records). I was surprised to see that kind of performance.
Then I want to check database to check updated records, there were none
I was scratching my head for a while and it occurred to me that there may be some problem in table structure; hence I checked table structure, to my surprise there was no primary key defined (no wonder it got processed so fast !!!).
I requested that change to our DBA, and updated code accordingly, and I started the program again
Now I started to get more believable numbers (like 200 - 500 records / second)