These index design rules came from a client’s list of ten index don’ts, and readers argued with several of them. This post turns the checkable rules into read-only queries on a demo database, and it measures what each rule really costs. The rest are warnings, not laws, and the post says which is which.
DISABLE_PARAMETER_SNIFFING Hint: Turn Off Sniffing for One Query
The DISABLE_PARAMETER_SNIFFING hint makes one query ignore the parameter value it was first compiled for. This post compares it with the default, OPTIMIZE FOR UNKNOWN and RECOMPILE on a table where one customer owns 40 percent of the rows. The reads show which variant fits which workload.
OPTION FAST N: First Rows Sooner, Total Reads Higher
OPTION FAST N tells SQL Server to plan for the first N rows, so the first rows arrive in milliseconds and the whole result costs much more. This post measures both sides on 300,000 rows with logical reads and time to the first row. It also explains why the hint belongs to paging and not to tuning.
What is the Replacement of DBCC DBREINDEX? – Interview Question of the Week #263
Question: What is the Replacement of DBCC DBREINDEX?
Answer: The answer to this question is very simple.
Here is the syntax:
DISABLE_OPTIMIZER_ROWGOAL: How a Row Goal Changes the Plan
DISABLE_OPTIMIZER_ROWGOAL switches off a row goal, the optimizer’s bet that a query needs only a few rows, and TOP, FAST, IN and EXISTS all place that bet. This post reads the estimates behind it, shows how the plan shape changes, and shows when the bet fails. A covering index fixes the failure, and the hint does not.
Dynamics SQL Server Settings: Five Checks for NAV, AX and CRM
Dynamics SQL Server settings decide most of the speed you get from NAV, AX and CRM, because you rarely control the application code. Five read-only checks cover tempdb, autogrowth, MAXDOP, automatic statistics and statistics age. Each one comes with a short query and a clear rule.
DROP STATISTICS Script: Remove Auto-Created Statistics
A DROP STATISTICS script can remove every auto-created statistic in a database, and SQL Server builds the useful ones again on demand. This post previews the statements, runs them behind a switch and shows what happens to the next query. It also says when the cleanup helps.