PostgreSQL Database RDMS

PostreSQL Relational Database Management System

Database systems form critical parts of the foundation of any software application, allowing for structured storage and retrieval of data. They come in different types, each tailored for specific needs. On one side, we have Relational Database Management Systems (RDBMS) like PostgreSQL, which represent data in tables and follow a schema. On the other side, we have NoSQL databases like MongoDB, offering flexible, scalable solutions for diverse data.

Among these, PostgreSQL stands out as a versatile, feature-rich RDBMS. It is well-regarded for its robustness, strict standards compliance, and flexibility, serving as the backbone for numerous applications. In the following sections, we will explore PostgreSQL in detail, shedding light on its architecture, features, use cases, and more.

Introducing PostgreSQL

PostgreSQL, commonly referred to as Postgres, is an open-source object-relational database management system (ORDBMS) renowned for its robustness, extensibility, and strict standards compliance. It provides a comprehensive set of features such as Multi-Version Concurrency Control (MVCC), support for a broad range of data types including JSON and arrays, and full ACID compliance, making it a dependable choice for reliable transactions. Its high performance and flexibility allow it to effectively handle diverse workloads, from small single-machine applications to vast data warehousing with many concurrent users. With its wide-ranging capabilities and adaptability, PostgreSQL is trusted by businesses, government agencies, and academic institutions globally for various applications.

Quick Facts About PostgreSQL

  1. Multi-Version Concurrency Control (MVCC): PostgreSQL implements MVCC to enhance concurrent user access. It means multiple transactions can interact with the same data without conflict, providing high performance even during heavy load times.
  2. Object-Relational Database System: PostgreSQL is not just a relational database but an object-relational database, enabling it to support complex structures and a broader set of data types like arrays and JSON.
  3. Extensibility: PostgreSQL is designed to be extensible, allowing users to define their data types, operators, and more. This extensibility also allows for the creation of custom functions and the ability to write code in different programming languages without the need for recompilation.
  4. ACID Compliance: PostgreSQL is fully ACID-compliant (Atomicity, Consistency, Isolation, Durability), ensuring that all transactions are processed reliably in the event of system failure or crashes.
  5. Wide Adoption: PostgreSQL’s versatility has led to its adoption by numerous tech giants and organizations. For instance, companies like Apple, Cisco, Fujitsu, and the U.S. Federal Aviation Administration use PostgreSQL for various applications. It’s also popular among many web-based applications and services.

PostgreSQL’s Role as an RDBMS

Databases play a crucial role for software applications. A database is an organized collection of data stored and accessed electronically. Databases are integral to applications as diverse as websites, mobile apps, games, and data analytics platforms. They serve as the backbone that stores and manages the vast amount of information that these applications generate and use.

There are various types of database systems, each with their unique strengths and use cases. They can be broadly classified into two categories: Relational Database Management Systems (RDBMS) and NoSQL (non-relational) database systems.

Relational databases, like PostgreSQL, MySQL, and SQLite, use a structure that allows us to identify and access data in relation to another piece of data in the database. They are based on the relational model, an intuitive, straightforward way of representing data in tables. In a relational database, each row in the table is a record with a unique ID called the primary key.

On the other hand, NoSQL databases, such as MongoDB, Redis, and Cassandra, are non-tabular and store data differently than relational tables. They were designed for large-scale data storage and for handling data types that relational databases aren’t equipped to handle. NoSQL databases can be document-based, key-value pairs, wide-column stores, or graph databases.

Both relational and NoSQL databases have their place in application development. The choice between these types of databases depends heavily on the specifics of the application being developed, including the scale of data to be handled, the flexibility of the data structures, and the types of queries that will be performed.

In the next sections, we will dive into one of the most popular and powerful relational database management systems – PostgreSQL. It has made a name for itself with its robustness, functionality, and adherence to standards, making it a go-to choice for many organizations around the world. Let’s take a closer look.

Understanding PostgreSQL

As an object-relational database, PostgreSQL offers a fusion of the robustness of relational databases with the versatility and flexibility of object databases. This potent mix allows it to manage structured and semi-structured data with ease, catering to a diverse range of use cases.

Key Features

  1. Object-Relational Database: PostgreSQL goes beyond the typical relational database, offering a blend of features that treat data as objects. This enables it to support complex structures and a broader set of data types like arrays and JSON, fostering rich application development.
  2. ACID Compliance: PostgreSQL is fully ACID-compliant, which stands for Atomicity, Consistency, Isolation, and Durability. These are the key properties that ensure reliable processing of database transactions, offering a strong guarantee of data integrity, even in the event of a system failure.
  3. Extensible and Secure: PostgreSQL is designed to be extensible, which means users can define their own data types, operators, and more. This adaptability extends to its security measures, which include robust access controls, views, and granular permissions to help protect data.
  4. Rich set of Data Types: In addition to standard numeric, string, and date/time data types, PostgreSQL supports geometric shapes, network addresses, text searches, JSON entries, and more, offering tremendous flexibility in storing and manipulating data.
  5. Procedural Languages: PostgreSQL supports a variety of procedural languages, such as PL/pgSQL (similar to Oracle’s PL/SQL), JavaScript, Python, and more. This means users can write stored procedures in a language they are comfortable with.
  6. MVCC Support: PostgreSQL implements Multi-Version Concurrency Control, which allows multiple transactions to interact with the same data simultaneously without conflicts. This leads to high performance and good utilization of system resources, even in high-load scenarios.

In the following sections, we’ll look at the architecture that supports these features and see how to work with PostgreSQL, helping us understand why it’s a top pick for developers and organizations worldwide.

Architecture of PostgreSQL

Understanding the architecture of PostgreSQL is key to comprehending its strength, efficiency, and capabilities. Let’s dive into a high-level overview of its structure.

PostgreSQL System Architecture

PostgreSQL follows a process-based architecture instead of a threaded one, meaning it creates child processes, not threads. Each connection to the database is represented by a separate backend process in the operating system. This model has a notable benefit: it isolates server sessions from one another, preventing a crash in one session from affecting others.

  1. Backend Processes: These are processes that deal with client connections, parse queries, manage transactions, and return results to the clients.
  2. Shared Buffers: This is a cache of disk pages maintained in the server’s memory to speed up database operations by minimizing disk I/O.
  3. Write-Ahead Log (WAL): PostgreSQL uses WAL to achieve durability. When a transaction is committed, its effects are not immediately flushed to the disk; instead, they are recorded in the WAL, which gets flushed regularly. In the event of a crash, the WAL can be replayed to recover lost transactions.
  4. Background Writer: This process is responsible for writing dirty pages (modified pages) from shared buffers back to disk, helping to minimize the amount of work the system must do during checkpoints.
  5. Vacuum Processes: PostgreSQL uses multi-version concurrency control (MVCC), resulting in multiple versions of a row in a table. The Vacuum process is used to clean up these outdated row versions.

Understanding the Flow of a Query

When a client sends a query, the backend process receives it and checks the shared buffer. If the data needed for the query is not present in the buffer, it reads the data from the disk. The query executor comes into play after the parser and the rewriter have processed the query. Once the execution is complete, the result is sent back to the client.

PostgreSQL’s architecture contributes to its robust performance, high reliability, and extensive scalability, making it a popular choice for businesses of all sizes. In the next section, we’ll explore how to work with PostgreSQL and the variety of applications and tech stacks it supports.

Working With PostgreSQL

To fully understand the power and versatility of PostgreSQL, we’ll explore how to get started with it and some basic operations you can perform.

  1. Installation: PostgreSQL can be installed on various operating systems, such as Windows, MacOS, Linux, and more. Installation methods can include direct download from the PostgreSQL official website, using package management tools like apt for Debian-based systems or yum for Red Hat-based systems, or through a version management tool like or pgAdmin.
  2. Basic Commands: Once you have PostgreSQL installed, you can interact with it through the psql command-line interface or use a graphical interface like pgAdmin. Standard SQL commands, such as CREATE, SELECT, UPDATE, DELETE, etc., are employed to manage and manipulate your data.
  3. Connection: PostgreSQL uses TCP/IP or Unix domain sockets for communication between its client and server. Connection parameters like the username, password, and port number are required for establishing a connection.

In the next section, we’ll dive deeper into the use of PostgreSQL in various tech stacks and see why it’s a preferred choice in many of them.

Advanced PostgreSQL Features

PostgreSQL stands out for its advanced features that go beyond traditional relational databases. It’s often described as an object-relational database management system, emphasizing its capability to handle complex data structures and provide extensibility. Let’s delve into some of these remarkable features:

  1. Extensibility: PostgreSQL is highly extensible. It allows for custom functions to be written in different programming languages such as C, Python, Java, Perl, Ruby, and more. It also supports adding new data types, operators, and index types.
  2. Data Types: Alongside common data types like numeric, string, and date/time, PostgreSQL also supports advanced types such as arrays, hstore for key-value storage, JSON/JSONB for storing JSON documents, and range types.
  3. Indexes: PostgreSQL offers several indexing techniques, including B-tree, Hash, GiST, SP-GiST, GIN, and BRIN. These offer excellent query performance for different use cases. It also supports partial indexes and expression indexes.
  4. Concurrent Transactions: With its Multi-Version Concurrency Control (MVCC) model, PostgreSQL allows for high concurrency and performance. This means multiple transactions can occur simultaneously without locking resources, increasing the throughput of the system.
  5. Replication and Partitioning: PostgreSQL offers built-in replication and partitioning. Replication can be asynchronous or synchronous, and it provides options for read scalability and high availability. Table partitioning can be performed based on range, list, or hash, aiding in query performance and management of large tables.
  6. Full Text Search: PostgreSQL provides powerful text search capabilities, which is a strong alternative to search-specific software. It supports vector space model, ranking, stemming, and more.
  7. Security: PostgreSQL has robust security features. It includes a system for managing access permissions and roles, and supports native SSL for encrypting client/server communications. It also offers Row Level Security (RLS) that enables fine-grained access control over rows in a table.
  8. Stored Procedures and Triggers: PostgreSQL supports stored procedures in multiple languages, which can be compiled and stored on the server. It also supports triggers, allowing for automated actions when certain operations, such as insert, update, or delete, occur.

These advanced features make PostgreSQL a powerful, robust, and flexible database system capable of handling a variety of tasks in complex environments, making it the preferred choice for many developers and businesses.

PostgreSQL in Popular Tech Stacks

PostgreSQL’s robust feature set, open-source nature, and ability to handle a high volume of transactions make it a go-to database for a variety of tech stacks across the industry. Here’s a look at how PostgreSQL fits into some of the most popular tech stacks:

  1. LAPP Stack (Linux, Apache, PostgreSQL, PHP): This is an open-source web development platform that uses Linux as the operating system, Apache as the web server, PostgreSQL as the relational database management system, and PHP as the object-oriented scripting language. It is a variant of the popular LAMP stack where PostgreSQL is used instead of MySQL.
  2. Django and Python: PostgreSQL is often the database of choice for Python applications using the Django framework. Django’s ORM works very well with PostgreSQL, taking full advantage of its advanced features like hstore, array, and JSON fields.
  3. Ruby on Rails: Rails has built-in support for PostgreSQL. It allows developers to harness some of the advanced features of PostgreSQL such as hstore for storing schema-less data, array data type, and JSON data type.
  4. MEAN/MERN Stack: While MongoDB is traditionally a part of the MEAN (MongoDB, Express.js, Angular, Node.js) or MERN (MongoDB, Express.js, React, Node.js) stacks, PostgreSQL can be used as an alternative especially when the application requires ACID transactions or complex joins.
  5. Java Spring Boot: In Java ecosystems, PostgreSQL is a popular choice due to its strong performance, full ACID compliance, and strong JDBC driver support.

Popular Apps that Use Postgres

The Postgres RDBMS is used by many highly recognizable apps. Here is a small sample of how Postgres is used by popular apps.

  1. Instagram: One of the largest photo-sharing social networks uses PostgreSQL due to its ability to manage large volumes of data and perform complex queries.
  2. Apple: Various Apple services such as iCloud leverage PostgreSQL.
  3. Spotify: The music streaming giant uses PostgreSQL to handle a large amount of metadata for its music catalog.
  4. Uber: While Uber initially used Postgres for its scalability, they eventually moved some services to MySQL due to specific use-cases. However, PostgreSQL is still in use for certain applications within Uber.
  5. TripAdvisor: The world’s largest travel platform uses PostgreSQL as one of their database systems.
  6. Fujitsu: The IT services company uses PostgreSQL for many of their applications, favoring its robustness and advanced features.
  7. The U.S. Federal Aviation Administration (FAA): The FAA uses PostgreSQL for some of its databases related to air traffic management.
  8. Slack: The popular communication platform uses PostgreSQL to handle its active workload and large data requirements.
  9. Robinhood: The commission-free investing platform uses PostgreSQL for its backend database requirements.
  10. Sony: Sony uses PostgreSQL in its PlayStation Network, due to its ability to scale and handle high loads.

Each tech stack benefits from PostgreSQL’s flexibility, reliability, and comprehensive feature set. Regardless of the application requirements, PostgreSQL can integrate seamlessly and provide the necessary database support.

PostgreSQL Use Cases

PostgreSQL’s advanced features, coupled with its performance and extensibility, make it suitable for a broad range of applications and industries. Let’s explore some specific use cases:

  1. Web Applications: Due to its ACID compliance, scalability, and support for complex queries, PostgreSQL is widely used as a backend for web applications. Companies like Instagram and Tripadvisor use PostgreSQL for their web application needs.
  2. Geospatial Databases: PostgreSQL, in combination with the PostGIS extension, is a popular choice for Geospatial databases. It provides advanced geospatial features, making it suitable for applications like location-based services, geographic information systems, and more.
  3. Data Warehousing: PostgreSQL’s support for parallel query processing, partitioning, and its ability to handle large amounts of data make it suitable for data warehousing. It can also integrate with popular data visualization tools, aiding in business intelligence and analytics.
  4. Financial Systems: PostgreSQL’s ACID compliance and strong performance under high transaction loads make it an excellent choice for financial systems, which require high data integrity and reliability.
  5. Scientific Research: PostgreSQL’s support for advanced data types, including arrays and range types, makes it useful for scientific research where complex data structures are common.
  6. Content Management and Delivery: Popular Content Management Systems (CMS) like WordPress and Drupal can use PostgreSQL as their backend database, benefitting from its reliability and extensibility.

These examples illustrate the versatility and power of PostgreSQL in handling different types of data workloads, making it a favorite among many businesses and developers.

PostgreSQL Comparison with Other Database Systems

Comparing PostgreSQL to other database systems helps highlight its strengths and potential considerations based on specific use cases:

  1. PostgreSQL vs. MySQL: Both PostgreSQL and MySQL are popular open-source relational databases, but there are differences. While MySQL is known for its speed and ease of use, PostgreSQL stands out for its advanced features such as support for a variety of data types, extensibility, and conforming more closely to SQL standards. In terms of performance, both can handle high loads, but PostgreSQL’s performance remains more consistent under concurrent operations.
  2. PostgreSQL vs. MongoDB: MongoDB is a NoSQL document store and differs from PostgreSQL in many ways. While MongoDB excels at handling unstructured data, PostgreSQL shines with structured data and complex queries. However, PostgreSQL’s JSONB data type provides similar functionality to MongoDB for handling unstructured JSON data.
  3. PostgreSQL vs. MariaDB: MariaDB, a fork of MySQL, has many similarities to PostgreSQL, but also some differences. MariaDB, like MySQL, is known for its speed and efficiency. However, PostgreSQL provides a broader range of features, such as support for custom data types, languages, and functions.
  4. PostgreSQL vs. SQLite: SQLite is a lightweight, file-based database. It’s an excellent choice for standalone applications, development, and testing due to its simplicity and zero-configuration. On the other hand, PostgreSQL, as a full-featured RDBMS, is more suited for complex applications requiring multi-user access, high performance, and a rich feature set.
  5. PostgreSQL vs. Oracle: Oracle is a commercial database widely used in enterprise settings. It offers robust performance, advanced features, and comprehensive support services. PostgreSQL, while also offering advanced features and robust performance, is open-source and free, making it a popular choice for applications of all sizes.


From a deep dive into the intricacies of PostgreSQL, we find that its robustness, versatility, advanced feature set, and ACID compliance make it a highly reliable choice for applications of all sizes. Whether you’re a small startup developing your first web application, an organization handling massive amounts of data, or a large corporation dealing with a high volume of transactions, PostgreSQL can cater to your needs.

PostgreSQL’s comprehensive community support and regular updates ensure its continuous growth and development, providing solutions to emerging technological demands and trends. From its robust standard SQL support to its unique object-relational features, PostgreSQL offers a multifaceted approach to data management, making it a significant player in the world of database systems.

As we move forward into an era where data-driven decision-making is key, the need for powerful, flexible, and reliable database systems will continue to grow. With its open-source nature and continuously expanding capabilities, PostgreSQL stands as a solid choice for anyone looking to leverage the power of data in their applications. Regardless of your tech stack or specific use case, PostgreSQL brings to the table a host of features and benefits that can help elevate your application to the next level.

In conclusion, while each database system has its unique strengths, PostgreSQL’s advanced features, versatility, robustness, and strong community support make it a worthy contender in various use cases, ranging from small projects to large enterprise applications.

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