Where is slow query in MongoDB?
One can identify slow queries in MongoDB by enabling the profiler and configuring it to its some specifications or executing db. currentOp() on a running mongod instance. By looking at the time parameters on the returned result, we can identify which queries are lagging.
How fast is MongoDB find?
1. Check Your MongoDB Log. By default, MongoDB records all queries which take longer than 100 milliseconds. Its location is defined in your configuration’s systemLog.
Are MongoDB joins slow?
The conclusion is that MongoDB joins are very brittle (when things change, application programs must be extensively recoded), and often MongoDB offers very poor performance, relative to Postgres.
How to find long running queries in MongoDB?
Probably easier for finding your long-running queries and aggregations is: At some point, you’ll discover that it is a great advantage to comment your queries so you can select the one you want by searching for the comment, and you’ll be able to immediately be able to work out what the long-running query is from the comment.
Which is the best profiling level for MongoDB?
You are likely to find, in a system that is under load, that there is much too much ‘noise’: very rapid queries doing minor housekeeping tasks such as logging usage. In this case, it is much better to use profiling level 1, which stores only the slow queries.
What does the explain command do in MongoDB?
MongoDB provides an ‘explain’ facility that gives you a tool for troubleshooting queries, which comes in three flavors: db.collection.explain () method. the cursor.explain () method. the explain command. All three can be used to return information on query plans and the execution statistics of those query plans.
Is there a way to tune the performance of MongoDB?
MongoDB has a very sensible range of information that is available for tuning the performance of queries and aggregations. When tuning queries, it generally pays to pick off the worst-offending ones first and to tackle the most obvious problems first.