PostgreSQL Glossary

PostgreSQL is an open source, object-relational database built for extensibility, data integrity, and speed. Its concurrency support makes it fully ACID-compliant, and it supports dynamic loading and catalog-driven operations to let users customize its data types, functions, and more.

This glossary defines the core concepts behind PostgreSQL to help build your mental model of how PostgreSQL work and understand what the documentation is referring to when it uses certain terminology.

ACID compliance is a set of database characteristics consisting of Atomicity, Consistency, Isolation, and Durability that ensure that database transactions are completed efficiently.
An access control list, or ACL, is a list of user permissions that controls access to a system resource.
Cache hit ratio is a metric that measures the efficiency of key retrieval in a database.
Connection pooling is a cache of database connections used for future requests to the database as required.
A connection string is a string of characters that provides necessary information and parameters to establish a connection between a software application and the database. Connection strings are considered sensitive information and we recommend handling them securely, such as by avoiding hardcoding the string into the application’s code or configuration files.
A central processing unit, also called a processor or CPU, is an essential piece of computer hardware that executes the instructions from a computer program.
Database as a Service, Managed Database Service, or DBaaS for short, is a cloud service that allows users to access a cloud database system without having a personal cloud data system on a subscription basis.
A deadlock is a situation when two or more programs, processes, or other components are mutually waiting for the other in order to access a resource, which prevents all of them from proceeding.
The deadlocks plot shows the rate of deadlock creation in the database.
Failover is a high availability (HA) mechanism that monitors servers for failures and reroutes traffic or operations to a redundant server when the primary server fails.
High Availability (HA) is an approach to infrastructure design focusing on reducing downtime and eliminating single points of failure.
Hot standby is the act of listening for when a primary node fails in order for the standby node to take its place.
The Internet Protocol (IP) is a communications protocol used to connect computers across a network, specifically the Internet. IP consists of rules and regulations for transmission of packets across a network including routing and addressing. IP ensures that the packets of data that travel across a network arrives at the correct location.
Linux Unified Key Setup (LUKS) is an open source disk encryption specification for block storage devices.
Machine type is the set of virtualized hardware resources used for a virtual machine (VM) instance.
Node plan, database or cluster configuration is the hardware plan for node specifications.
Operations throughput metric is a measurement of throughput of fetch, insert, update, and delete operations across all databases on the server.
PgBouncer is an open-source, single-binary Postgres Pro connection pooler for PostgreSQL.
Point-in-time recovery, or PITR for short, ensures that automatic backups are made in order to restore or recover data made in a previous state of the server.
A port is a communication endpoint of a network connection. A port is identified using a port number for each transport protocol.
Random-Access Memory, or RAM, is a memory storage made to store and access memory on a short-term basis.
A read-only node is a replica of the cluster’s primary node.
Relational database is a type of database that organizes data in tables with predefined relationships. These tables consist of rows (records) and columns (attributes).
Scaling is the process of adding more capacity to a resource in your app.
SSL certificate is a digital document outlining the identity of the website.
A standby node is a node that is set aside idling on hot standby.
Tags are keywords associated with resources which help with managing resource ownership and organize lookups and actions on resources.
The Transmission Control Protocol (TCP) is a communication standard for programs and computing devices to exchange messages over a network.