MongoDB

MongoDB

Analyze Query Performance has 10 Questions

A query _______ consists of a combination of query, sort, and projection specifications.

plan
shape
stats
All of the mentioned
An ________ query plan has returned a threshold number of matching results

execution
unordered
ordered
None of the mentioned
_________ is used to view statistics about the query plan for a given query.

db.explain()
cursor.explain()
cursor.explainstats()
All of the mentioned
The update() method uses the _______ command, which uses the default write concern.

find
read
update
modify
_____ can modify specific fields of an existing document or documents or replace an existing document entirely, depending on the update parameter.

modify()
update()
find()
None of the mentioned
Point out the correct statement :

An equality match on the unique _id field is less selective as it can match at most one document
The selectivity of regular expressions depends on the expressions themselves
Less selective queries can use indexes effectively or even at all
All of the mentioned
The ________ message is used to update a document in a collection.

UPDATE
OP_UPDATE
OP_UPDATES
All of the mentioned
___________ is used to determine whether a query is a covered query .

explainstats()
explain()
explainall()
All of the mentioned
Point out the wrong statement :

Query selectivity refers to how well the query predicate excludes or filters out documents in a collection
Query selectivity can determine whether or not queries can use indexes effectively or even use indexes at all
More selective queries match a larger percentage of documents
All of the mentioned
Indexes are typically available in ______ or located sequentially on disk.

RAM
ROM
CMOS
None of the mentioned