Returned object not currently part of this pool

Question background

Use the org.apache.commons.pool2 dependency to do some pooling operations, pool some clients that have been instantiated successfully into the object pool, and speed up the query efficiency of the interface through pooling.

Problem Analysis

The above exception is translated as [The returned object does not currently belong to this pool]. Why does this happen? Because the interface that causes this error report allows to receive multiple parameters, and then return the results together. In order to improve the query efficiency, soIntroduced multi-threaded query, and then each thread runs and executes the underlying logic method, there is a core logic that will go to the object pool to get the client object, if it can't get it, it will create the object pool and generate the client object and put it into the objectin the pool.Under normal circumstances, there is no such exception. The problem is that in the case of multi-threaded concurrency, if the bottom layer does not lock or something to ensure synchronization, then multiple object pools are likely to be created, but there is actually a reference relationship.It is the last generated object pool, so when some objects created earlier are returned to the pool, they will find that the object does not belong to the last referenced object pool, and will report [Returned object not currently part]of this pool] error.

Solution

1. If there is no idea of ​​lazy loading, it is recommended to initialize the object pool when the project starts.
2. If you are afraid that some objects will not be used at all and will be initialized at the beginning, which will lead to waste of resources, it is recommended to try locking, but this will affect the overall query efficiency.