When comparing MariaDB vs PostgreSQL, the Slant community recommends PostgreSQL for most people. In the question“What are the best databases for a small .NET application?” PostgreSQL is ranked 2nd while MariaDB is ranked 8th. The most important reason people chose PostgreSQL is:
PostgreSQL is known to have a very holistic approach to robustness and data integrity which is reflected by it being fully [ACID](https://en.wikipedia.org/wiki/ACID) compliant. PostgreSQL has always been strict about making sure data is valid before allowing it into the database, and there is no way for a client to bypass those checks. Depending on your requirements, ACID compliance might be important.
Ranked in these QuestionsQuestion Ranking
Pro Truly open development community
All development decisions for MariaDB can be reviewed and debated on a public mailing list or in the public bug tracker. Contributing to MariaDB is easy and the patch flow is fully transparent and public. But it's not all about the code contribution either - MariaDB also has very active documentation efforts and other related things that help developers in their day-to-day database administration.
Pro More cutting edge features
e.g. GIS since 5.3
Pro Dynamic column support
MariaDB has dynamic column support which allows for some NoSQL type functionality. So one database interface can provide both SQL and NoSQL for different software development needs.
Pro Fully ACID compliant
PostgreSQL is known to have a very holistic approach to robustness and data integrity which is reflected by it being fully ACID compliant.
PostgreSQL has always been strict about making sure data is valid before allowing it into the database, and there is no way for a client to bypass those checks.
Depending on your requirements, ACID compliance might be important.
Pro High performance
PostgreSQL performance increases with each release, this is also proven by many benchmark tests.
Notable performance features include:
As PostgreSQL only supports one storage engine, it has been able to integrate and optimise it and with the rest of the database. This has resulted in multiple benefits such as the ability to allow different transaction types to co-exist efficiently without the need to select storage engine types once for each table ahead of time.
On the fly data compression resulting in less IO required for reading.
Asynchronous + synchronous Replication.
PostgreSQL supports a asynchronous API for use by client applications. It is reported to increase performance by up to 40% and is not supported by MySQL.
Designed to scale very well with large numbers of cores at high concurrency levels.
Pro Strong community
PostgreSQL has a strong community backing it, with guides, tutorials and support for any kind of problem a developer may have.
Pro Support for JSON data type
JSON data can be stored as a column with optional indexes. In 9.4 (upcoming at the time of this writing), JSONB will be a binary version of JSON that will save space. It's like the best of the NO-SQL world without having to give up ACID and Relationships. This means that cascading deletes can be done in a single Transaction across multiple JSON documents.
Pro Actively developed
Regular fixes and features are released
Pro Support for geographic objects
PostgreSQL can be extended to have geographic object support through PostGIS and allows for location queries to be run through SQL.
Pro Multiple node packages available
There are many packages (like Sequelize) that integrate deeply with the features Postgres offers.
Pro Support Perl and Python for coding stored procedures
Postgres supports popular languages for coding stored procedures, such as Perl and Python. So, you can fairly easy transform just DB-server to reliable Service with complex business logic.
Pro Open Source, powerful and on par with other paid RDBMS'
It is a powerful, open source product that has all the bells and whistles when compared with its costly, proprietary counterparts.
Con Not suited for small apps
Because of it's complexity and power, it may be an overkill to use PostgreSQL in small applications that will not make use of it's full power.