Does Postgres cache query plan?
PostgreSQL does not have a shared query plan cache, but it has an optional query plan cache for prepared statements. That means that the developer has the choice to use a prepared statement with or without cached query plan. But note that the cache is dropped when the prepared statement is closed.
Does SQL cache query results?
SQL Server does NOT cache results from a query. This is the important distinction. When you use application cache, you store your result-sets in Memcached RAM. Then reuse them over and over again without connecting to the database server, thus offloading workloads from your database server.
Is the query plan cache available in SQL Server?
The query plan cache is not exposed to us easily in SQL Server, but the many views available to us allow quite a bit of in-depth research into the queries that have run recently and how they have performed. This data can provide valuable insight into more metrics than I could ever list in this article.
How does the plan cache change over time?
The data in the plan cache is not static, and will change over time. Execution plans, along with their associated query and resource metrics will remain in memory for as long as they are deemed relevant.
What happens when I clear out my cache?
When you clear out your query plan cache, or mark a stored procedure for recompile the optimizer has to re-create the plan for that piece of code. This of course takes time. And if you have an active system completely clearing out your cache will slow your whole system down for a period of time while everything is re-created.
Is there a way to flush the database plan cache?
Flush the database plan cache for database MyDB. Releases all unused cache entries from all caches. You can use this command to manually remove unused entries from all caches or from a specific Resource Governor pool.