This page allows you to optimize/repair/remove a collection for general use. When a collection is done indexing or a collection is constantly changed by deleting, adding and updating documents, you may want to perform optimizations to improve search performance for general use. Here you can select an existing collection and optimize it. When a collection is corrupted due to machine failures such as disk crash, the search engine will mark it as "DOWN" and the collection will not be available for retrieval until it is fixed. You can start repair service to bring the damaged collection back up. You must be careful when you delete a collection. If a collection is deleted, the collection directory will be removed and you will not be able to search the collection any more. But all those original documents indexed in the collection are still there.