Reference managed MultiReader #14486
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Going by #13976 and this dated stack overflow thread, it seems like there is desire for a reference managed MultiReader.
The implementation should provide a way to safely share a multi-reader across multiple threads, refresh underlying sub-readers periodically to pick new changes, and ensure that sub-readers are not closed until all threads have finished using them. I hacked together a quick prototype based on my understanding of the requirements. If this seems useful, I can add some tests and refine it. Or, @Shibi-bala, since you wrote the initial PR, feel free to take this further if you like.
Following discussions from the PR, this manager exposes a Multi-Reader and expects users to create their own IndexSearcher on top of it. The managed multi-reader uses
DirectoryReader.openIfChangedto refresh its sub-readers, and as such, requires its sub-readers to beDirectoryReaderinstances. I'm not sure if there are non DirectoryReader implementations that we want to handle via this manager.This manager will increase / decrease refCount for each subReader on acquire and release.
acquirewill fail if refCount cannot be incremented for any of the subReaders, i.e. if any of the sub-readers have closed.