OPTION (RECOMPILE): Faster Queries or Persistent Performance Problem?

Option (Recompile) Enhancement: Faster Execution or Persistent Conundrum?

When executing a query, the database engine creates an execution plan to optimize the process. However, in certain situations, using the OPTION (RECOMPILE) may present a perplexing scenario where it significantly enhances query performance. This article delves into the reasons why OPTION (RECOMPILE) can improve execution speed and addresses the doubts surrounding its application.

One reason for OPTION (RECOMPILE)'s improved performance lies in dynamic SQL. When dynamic SQL is used, the query being executed changes dynamically, making it difficult for the database engine to determine the optimal execution plan. By specifying OPTION (RECOMPILE), the engine is forced to create a new plan each time the query is executed, ensuring optimal performance regardless of the data changes.

Another factor to consider is database statistics. Outdated or incorrect statistics can lead to suboptimal execution plans, resulting in slower query execution. By using OPTION (RECOMPILE), the database engine is forced to rebuild the execution plan, taking into account any updates to the database statistics, which can significantly improve performance.

However, it's important to note that OPTION (RECOMPILE) is not a universal solution. It can be a potential performance hazard when executed repeatedly, as the constant recompilation of execution plans can consume valuable server resources. Therefore, it is crucial to analyze the impact of OPTION (RECOMPILE) on your particular database environment and determine whether it is the best option for achieving optimal performance.

In the example provided, rebuilding statistics and recreating the execution plan are suggested as initial steps to resolve the performance issue without using OPTION (RECOMPILE). If these measures do not yield the desired results, posting both execution plans (with and without OPTION (RECOMPILE)) for analysis can help identify the root cause of the performance degradation.

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