Explaining RBAR

Kenneth Fisher explains RBAR with the help of an animated GIF:

So 23 milliseconds for the batch version and 850 milliseconds for RBAR. What a difference.

Now in this case the code for the RBAR is also a lot more complicated. But that isn’t always the case. It also isn’t always the case that RBAR is slower. But it’s almost always a lot slower than batch.

So, while the code for RBAR is often easier to write, even though it might be physically longer, it’s probably going to be slower too.

Well-written, set-based solutions aren’t always guaranteed to be faster, but that’s one of the safest bets to make with T-SQL.

Related Posts

Storing Constants For MDX Calculated Measures

Chris Webb walks us through an interesting performance problem when using Analysis Services multidimensional: All it does is take the value of the Sales Amount measure at the lowest granularities of the Customer, Date and Product dimensions, multiply it by 0.08 to find a tax value, and because [Tax Amount] is a real, non-calculated measure, […]

Read More

What sys.dm_exec_query_stats Can Miss

Matthew McGiffen takes us through a scenario where sys.dm_exec_query_stats did not give a complete view of what was running on SQL Server: I got less than 50 rows back so figured I had everything covered, but the total elapsed time across all the queries was less than ten minutes, I knew the server hadn’t been […]

Read More

Categories

August 2016
MTWTFSS
« Jul Sep »
1234567
891011121314
15161718192021
22232425262728
293031