Most performance problems can be resolved by tuning operating
system resources.
Slow indexing
Indexing can be slow for a variety of reasons. Slow indexing
can cause a backlog of index requests in the index request queue.
Slow queries
Slow queries are usually the result of the following items
that are not tuned: query SQL, database indexes, or operating system
resources. The performance problems that have distinct symptoms are
usually related to operating system resources.
System resource misutilization
Independently of any perceived performances problems with
indexing or queries, you might notice that system resources are not
being used in an optimal way.
Index request queue
The index requests queue consists of those index requests
that are waiting to be processed. Monitor the size of the queue to
determine whether your indexing rate equals the document ingestion
rate. If the ingestion rate is greater than the index rate, how quickly
a document gets indexed can vary considerably.