Index Maintenance and Performance (Dear SQL DBA Episode 38)
Category:
query-performance
They made their index maintenance job smarter, and their queries got slower in production afterward. Could the index maintenance have harmed performance?
Category: query-performance
Columnstore Index Returns Zero Rows... Which is One Row
Category:
query-performance
, sql-server
I’ve never claimed to be great at math, but until recently I thought I knew how to count to one. Zero… one. That’s what we learned in kindergarten.
Apparently SQL Server didn’t go to kindergarten.
Data Type Mismatches Do Not Always Cause a Bad Implicit Conversion and Index Scan
Category:
query-performance
Here’s a great recent question that I got about query tuning and index use:
Assuming that the documented levels of data type precedence in SQL Server are true as of SQL 2016, why does a bigint value not force an index scan when compared against an int column?
New online course: Troubleshooting Blocking & Deadlocks for Beginners (Free!)
Category:
query-performance
I made y’all a SQL Server style Valentine’s day present: a new FREE online training course.
Should I Learn Fulltext Indexing? (Dear SQL DBA Episode 29)
Category:
query-performance
This week’s question is about a longstanding feature in SQL Server that sounds really cool: full-text search. If you’re learning performance tuning, how much time should you invest in researching and learning about full-text indexes?
What is that Garbage in my Execution Plan? (Dear SQL DBA Episode 27)
Category:
query-performance
Today I was working on some code samples for a user question, and I hit a weird roadblock.
There was a bunch of garbage in my execution plan that I couldn’t explain. And by ‘garbage’, I mean a nested loop to a whole branch of code that I hadn’t asked SQL Server to run – and a warning about an implicit conversion possibly causing problems with the quality of my execution plan.
How to Find Queries Using an Index (and Queries Using Index Hints)
Category:
query-performance
Sometimes you know a query is out there, but it’s hard to find the exact query.
SQL Server stores query execution plans in cache, but it can be difficult to query the XML it stores. And there’s always a chance that the query plan won’t be there, due to memory pressure, recompile hints, or the plan cache being cleared by setting changes or other administrative actions.