Invalidating query cache entries table mysql


This feature requires no extra work to use, but it is limited to USE Northwind2; DBCC FREEPROCCACHE; GO SELECT * FROM Orders WHERE Customer ID = 'HANAR'; GO SELECT * FROM Orders WHERE Customer ID = 'CHOPS'; GO SELECT * FROM Orders WHERE Customer ID = 'HANAR'; GO SELECT usecounts, cacheobjtype, objtype, [text] FROM sys.dm_exec_cached_plans P CROSS APPLY sys.dm_exec_sql_text (plan_handle) WHERE cacheobjtype = 'Compiled Plan' AND [text] NOT LIKE '%dm_exec_cached_plans%'; You should get two rows back, because the NOT LIKE condition filters out the row for the usecount query itself.The two rows are shown here and indicate that one plan was used only once, and the other was used twice: The results show that with a change of the actual data value, the same plan cannot be reused.



This ensures that autoparameterization won’t degrade a query’s performance.The move to this model provides for more frequent milestone releases, with each milestone proceeding through a small number of releases having a focus on a specific subset of thoroughly tested features.Following the releases for one milestone, development proceeds with the next milestone; that is, another small number of releases that focuses on the next small set of features, also thoroughly tested.Previously, My SQL development proceeded by including a large set of features and moving them over many versions within a release series through several stages of maturity (Alpha, Beta, and so forth).

This development model had a disadvantage in that problems with only part of the code could hinder timely release of the whole.

The is guaranteed to never find more than one row, so a plan using a seek on that unique index can be useful no matter what actual value is used.