When does performance degradation of a database occur?
Performance degradation of the database over time happens when your database was performing optimally in the past, such as 6 months ago, but has gradually degraded to a point where it becomes noticeable to the users.
What are the different types of query performance issues?
Beyond the database compatibility level, a disabled or enabled trace flag 4199 or a changed state of the database-scoped configuration QUERY_OPTIMIZER_HOTFIXES can also influence query execution plan choices at compile time. Trace flags 9481 (force legacy CE) and 2312 (force default CE) also affect the plan.
What causes slow query performance in Azure SQL?
Waiting-related problems: Waiting-related problems are generally related to: A suboptimal plan generated by the SQL Query Optimizer may be the cause of slow query performance.
Can a query optimizer generate a different query plan?
The SQL Query Optimizer may generate a different query plan depending upon the compatibility level for your database. Higher compatibility levels provide more intelligent query processing capabilities. For more information on query processing, see Query Processing Architecture Guide.
When to update statistics after a maintenance procedure?
After Maintenance Operations Consider updating statistics after performing maintenance procedures that change the distribution of data, such as truncating a table or performing a bulk insert of a large percentage of the rows. This can avoid future delays in query processing while queries wait for automatic statistics updates.”
When to use exec SP _ updatestats on your system?
You might use “EXEC sp_updatestats” from time to time on your system (scheduled some time) or use the function STATS_DATE on all the objects and see when their statistics were actually updated last time and if there was too much time since then, use UPDATE STATISTICS for that particular object.