Question 6

Which of following statements is/are true?

Answer:
  • An index doesn't become multikey until a document is inserted that has an array value - True
  • Running performance tests from the mongo shell is an acceptable way to benchmark your database - False. Performance tests should be as close to production environment as possible. The mongo shell is designed for administrative tasks and ah-hoc queries, not performance benchmarks. You'd also be running in a single thread, which is unlikely how you'd be operating in production.
  • You can use the --wiredTigerDirectoryForIndexes option to place your indexes on a different disk than your data - True
  • Indexes can only be traversed forward - False - Indexes can traverse both forward as well as backward.
  • The ideal ratio between nReturned and totalKeysExamined is 1 - True.


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