Why is OUTER JOIN not allowed in indexed views? A reader was confused by the white paper answer, so I explain it with an example and ask for yours.
SQL SERVER – Disabled Index and Update Statistics
A reader asked how disabled indexes affect statistics. With the clustered index disabled, Update Statistics throws an error; see what happens once you enable it.
Estimated and Actual Execution Plans
Estimated and actual execution plans answer different questions; compare compiled choices with runtime rows, warnings, and resource use.
SQL SERVER – Update Statistics are Sampled By Default
A reader asked if statistics are sampled by default. They are, and a one million row test table proves it. You can set the rate up to 100%.
When Are Statistics Updated? What Triggers an Automatic Update
Statistics updated automatically need two things: enough changed rows, and a query that uses the statistic. This post explains the old 500 plus 20 percent rule and the newer square root threshold, then shows a million-row demo where last_updated changes only after a query compiles. It also covers FULLSCAN, asynchronous updates and when to update by hand.
Correlated Columns and Multi-Column Statistics in SQL Server
Investigate multi-column statistics with correlated city and state values, density vectors, and plans before expecting better estimates.
SQL SERVER – Find Statistics Update Date – Update Statistics
Stale statistics can hurt a query plan. Use STATS_DATE to find the statistics update date for each index, then update them if they look outdated.