PAGEIOLATCH is one of the most commonly seen wait types and basically represents the time that SQL Server had to wait while pages were being read from disk into memory. When the data pages that SQL Server needs to traverse… Read More ›
#sqlserverperformance
Masking Poor Data Type Choices with Compression
In this post we’re going to evaluate the possibility of concealing poor data type choices with compression. Why are we doing this? If you don’t know yet, life is made of bad ideas. If you know, you know, you know?… Read More ›
Performance Woes & Wows #6: I Pity The Spool
Actually, I pity the SQL Server that has to create Spools in order to handle nasty queries. But that is too long for a title. The title is a lie. With that being said, spools may appear in specific situations,… Read More ›
Performance Woes & Wows #5: IN vs UNION
Querying the Same Thing. Faster. In a previous post, we’ve seen that equivalent queries can produce distinct execution plans – Yes, how nice and intuitive of you SQL Server. But this happens for a logical reason: The Query Optimizer hates… Read More ›
Not All Seeks Are Created Equal #2
As we saw in the previous post, Index Seek operations can look for single rows (Singleton Seek) or specific subsets of rows (Range Seek). Singleton Seek A Singleton Seek occurs when just one single row, at most, will satisfy the… Read More ›
Not All Seeks Are Created Equal #1
Seeks seeks seeks… The number of the beast. Seeks are cool though. I like seeks. Sometimes, at least. Perhaps some seeks are cooler than others. I just said seeks six times, now we’re ready to go. Let’s begin by creating… Read More ›
Performance Woes & Wows #2: LIKE ‘%Make This Query Go Slower Please%’
Sargability is a funny word that’s used to characterize the ability of the engine to take advantage of and index, in order to speed up the execution of a query. The legend says that it is derived from a contraction… Read More ›
