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- Evaluate Performance of Current Operations
Evaluate Performance of Current Operations¶
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The following sections describe techniques for evaluating operational performance.
Use the Database Profiler to Evaluate Operations Against the Database¶
MongoDB provides a database profiler that shows performance characteristics of each operation against the database. Use the profiler to locate any queries or write operations that are running slow. You can use this information, for example, to determine what indexes to create.
For more information, see Database Profiling.
Use db.currentOp() to Evaluate mongod Operations¶
The db.currentOp() method reports on current operations
running on a mongod instance.
Use explain to Evaluate Query Performance¶
The cursor.explain() and db.collection.explain()
methods return information on a query execution, such as the index
MongoDB selected to fulfill the query and execution statistics. You can
run the methods in queryPlanner
mode, executionStats mode, or
allPlansExecution mode to
control the amount of information returned.
Example
To use cursor.explain() on a query
for documents matching the expression { a: 1 }, in the
collection named records, use an operation that resembles the
following in the mongo shell:
db.records.find( { a: 1 } ).explain("executionStats")
For more information, see Explain Results,
cursor.explain(), db.collection.explain(), and
Analyze Query Performance.