Problem: Stored procedure that is run hundreds of times per hour is taking a long time.
Change: Multiple changes were made to code inside the procedure
You can see the TOTAL improvement below
Most SQL Servers bottleneck is on Disk access (or disk “reads”).
It’s not CPU or RAM – which most customers often suspect first.
And that makes a lot of sense. Here is why.
Inefficient queries scan (or read) a lot of data. Data read in is stored in RAM. As more data is read in, “older” data is pushed out from RAM. If there isn’t enough RAM to keep ALL data in memory (which is often not possible), SQL Server has to read from disk – and that is the slowest operation SQL Server can do.
When the query can be tuned to read 10 rows vs 10M – less CPU and RAM automatically are necessary. Therefore, tuning for less disk “reads” is often the primary goal.
To the end-user, nothing is more important than Speed (or Duration of the query), though.
Tuning to reduce CPU/RAM resources is helpful too.
When queries are tuned to need less CPU & RAM, it means that the same server now has more capacity. That’s means that the same server can process double or triple the load. Which means it extends the lifespan of the same server. Which means hardware upgrades can be pushed out further into the future.