Originally published by Tricore: Aug 24, 2017
In Part 1 of this series, we shared some tips for using MongoDB. In Part 2, we cover several more MongoDB topics, including optimization, performance, speed, indexing, schema design, and data safety.
--notablescanoption in development (but not in production)
MongoDB has a
--notablescan option that returns an error when a query
needs to perform a full table scan. This option can be handy in development
environments if you want to make sure that all of your queries are hitting
indexes. However, we don’t recommend using it in a production environment
because it might cause performance issues. The problem is that many simple
administrative tasks require table scans. This option enables you to see a
list of the collections in your database that require a full table scan.
By default, MongoDB connects to
localhost: 27017. You can connect to any
server on startup by running
mongo host: port/database. You can also
connect to multiple servers or databases within the shell.
For example, suppose that we have an application that uses both a dealer’s database and a distributor’s database. With MongoDB, we could switch back and forth between the two databases within the same shell.
To take a backup of a database with journaling enabled, you can either
take a file system snapshot or do a normal
fsync+lock and then a dump.
Note that you can’t just copy all of the files without
locking, because copying is not an instantaneous operation. If the copy of
the journal files and the backups reside on different volumes, then the
backups might become useless at a later point in time.
The term application unit is used for some types of application work. An application unit is essentially a discrete unit of work that your application does that might involve accessing a database. You should design MongoDB schemas to do one query per application unit.
If you have a web or mobile application, you can think of an application unit as a request to the back end.
Here are a some other examples:
For a desktop application, an application unit might refer to a user-client interaction.
For an analytics system, an application unit might refer to a dashboard load.
MongoDB is a fast, robust, and highly scalable database. It works on many platforms and has many language drivers for optimal usage.
MongoDB is becoming more popular every day. Understanding the basics of MongoDB and how to use it well is a great move for any developer.
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