Updating linked database c
Here’s what the statistics look like on the table in Object Explorer. If you want to verify which column is in each auto-created statistic, you can do that with this query: SELECT s.name, s.auto_created, s.user_created, as colname FROM sys.stats AS s JOIN sys.stats_columns as sc on s.stats_id=sc.stats_id and s.object_id=sc.object_id JOIN sys.columns as c on sc.object_id=c.object_id and sc.column_id=c.column_id WHERE s.object_id=OBJECT_ID('agg.
First Name By Year') and s.auto_created = 1 ORDER BY sc.stats_column_id; GO Sure enough, here are our statistics, and they are on Gender and First Name Id.
but keep reading to find out what those are and why it’s rare to require them.
Auto-created statistics are incredibly small, and you only get one per column in a table.
For SQL Server 2005 – SQL Server 2014 (with no trace flags) to make an optimization decision that the update is kicked off. Trace Flag 2371 makes the formula for large tables more dynamic.
(I think we know which team really felt some pain and wanted this trace flag to exist, because the trace flag was announced on their blog! So if you’re using SQL Server 2016, you don’t need to decide.If you’re interested in that, head on over and read the fahhhbulous white paper, Statistics Used by the Query Optimizer in SQL Server 2008. Unfortunately, Aristotle was right when it comes to statistics maintenance in SQL Server. This is because you didn’t do any proactive work at all.Then wait a couple days and chase it with it’s charming cousin, Optimizing Your Query Plans with the SQL Server 2014 Cardinality Estimator. ⇒ If you’re too proactive, you’ll eventually be sorry: If you set up statistics maintenance too aggressively, your maintenance windows can start to run long.With default database settings, the SQL Server optimizer looks at how many changes have occurred for a given column statistic as part of query optimization.
If it looks like a significant amount of rows in the column have changed, SQL Server updates the statistic, then optimizes the query.If you’re managing lots of SQL Server instances and want ultimate customization, there is a free version of Minion Reindex. The answers to both of these questions impact what it does to GROUP those rows and SUM the Name Count column.