MongoDB Questions and Answers – Indexing Strategies

This set of MongoDB Multiple Choice Questions & Answers (MCQs) focuses on “Indexing Strategies”.

1. _________ operations that use an index often have better performance than those that do not use an index.
a) Select
b) Update
c) Delete
d) Sort
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2. Point out the wrong statement.
a) The query scans the index and the collection
b) An index supports a query when the index contains all the fields scanned by the query
c) Creating indexes that support queries results in greatly increased query performance
d) None of the mentioned
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3. A prefix of a _______ index is a subset that consists of one or more keys at the start of the index key pattern.
a) unique
b) primary
c) compound
d) none of the mentioned
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4. Sort operations that do not use an index will abort when they use _______ megabytes of memory.
a) 16
b) 32
c) 64
d) All of the mentioned
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5. Point out the correct statement.
a) If you only ever query on a single key in a given collection, then you need to create just multikey index for that collection
b) If you sometimes query on only one key and at other times query on that key combined with a second key, then creating a compound index is more efficient than creating a single-key index
c) The choice between creating compound indexes that support your queries or relying on index intersection is independent of specifics of your system
d) None of the mentioned
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6. An index can support sort operations on a non-prefix subset of the index key pattern using _________ condition.
a) predicate
b) selection
c) equality
d) none of the mentioned
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7. __________ method provides a wrapper around the totalIndexSize output of the collStats (i.e. db.collection.stats()) operation.
a) db.collection.totalallIndexSize()
b) db.collection.totalIndexSizeAll()
c) db.collection.totalIndexSize()
d) all of the mentioned
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8. Indexes do not have to fit entirely into ______ in all cases.
a) ROM
b) RAM
c) Secondary Storage
d) None of the mentioned
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9. ________ is the ability of a query to narrow results using the index.
a) Causality
b) Cardinality
c) Selectivity
d) All of the mentioned
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Sanfoundry Global Education & Learning Series – MongoDB.

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