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Reference

Glossary

Access token

See Token.

Activity Monitor

A process that monitors a Neon Compute for activity. During periods of inactivity, the Activity Monitor gracefully places the Compute into an idle state to save energy and resources. The Activity Monitor closes idle connections after 5 minutes of complete inactivity. When a connection is made to an idle Compute, the Activity Monitor reactivates the Compute.

API

See Neon API.

API Key

A unique identifier used to authenticate a user or a calling program to an API. An API key is required to authenticate to the Neon API. For more information, see Using API keys.

Backpressure

A mechanism that manages the lag between the Pageserver and compute node or the Pageserver and Write-Ahead Log (WAL) service. If the WAL service runs ahead of the Pageserver, the time to serve page requests increases, which could result in increased query times or timeout errors. The backpressure mechanism manages lag using a stop-and-wait backend throttling strategy.

Availability checker

A periodic load generated by the Control Plane to determine if a compute can start and read and write data. The availability checker queries a system database without accessing user data.

Branch

A copy-on-write clone of a Neon project root branch or previously created child branch. A branch can be created from the current or past state of the parent branch. A branch created from the current state of the parent branch includes the databases and users that existed in the parent branch at the time of branch creation. A branch created from a past state of the parent branch includes the databases and users that existed in the past state. The data in a branch can be modified independently from its originating data. See Branching. Each branch has a dedicated endpoint, which is the compute instance associated with the branch. Connecting to a branch requires connecting to the branch endpoint. For more information, see Connecting to a branch.

CI/CD

Continuous integration and continuous delivery or continuous deployment.

Compute

A service that provides virtualized computing resources (CPU, memory, and storage) for running applications. A Neon Compute runs PostgreSQL. Each Neon project contains a Compute. The amount of Compute resources available to a Neon project is currently subject to the limits defined by the Technical Preview Free Tier. A Neon Compute is stateless and is automatically activated or suspended based on user activity.

Connection pooling

A method of creating a pool of connections and caching those connections for reuse. Neon uses pgbouncer in transaction mode for connection pooling. Neon’s connection pooling feature can be enabled or disabled for a project on the Settings page, under General Settings.

Connection string

A string containing details for connecting to a Neon project branch. The details include a user name, endpoint host address, and database name; for example:

postgres://daniel@ep-polished-water-579720.us-east-2.aws.neon.tech/main

The connection string for a Neon is provided on the Dashboard in the Neon Console, under Connection Details. The connection string that is displayed immediately after creating a project also includes the user’s password, temporarily. For security reasons, the password is removed from the connection string after navigating away from the Neon Console or refreshing the browser. If you misplace your password, your only option is to reset it.

Console

See Neon Console.

Control Plane

A part of the Neon architecture that manages cloud storage and compute resources.

Copy-on-write

A technique used to efficiently copy data. Neon uses the copy-on-write technique to efficiently copy data when creating a branch.

Database

A named collection of database objects. A Neon project has a default database named main which resides in the default public schema. A Neon project can contain multiple databases. Users cannot manipulate system databases, such as postgres, template0, or template1.

Endpoint

The compute instance associated with a branch. A single read-write endpoint is created for each branch, including the project's root branch (main). The endpoint hostname is required to connect to a branch from a client or application. An endpoint hostname can be found in the Connection Details widget on the Neon Dashboard or by selecting the branch on the Branches page in the Neon Console. An endpoint hostname starts with an ep- prefix, as in this example: ep-polished-water-579720.us-east-2.aws.neon.tech. For more information, see Connecting to a branch.

Free Tier

A Neon service tier for which there are no usage charges. For information about Neon’s Free Tier and associated limits, see Technical Preview Free Tier.

LSN

Log Sequence Number. A byte offset to a location in the WAL stream.

Neon

A fully managed serverless PostgreSQL. Neon separates storage and compute and offers modern developer features such as branching and bottomless storage. For more information, see What is Neon?.

Neon API

The Neon RESTful Application Programming Interface. Any operation performed in the Neon Console can also be performed using the Neon API.

Neon Console

A browser-based graphical interface for managing Neon projects and resources.

Neon user

The user that registers and authenticates with Neon using a GitHub or Google account. Once authenticated, a Neon user can create and manage projects, branches, users, databases, and other project resources.

Page

An 8KB unit of data, which is the smallest unit that PostgreSQL uses for storing relations and indexes on disk. In Neon, a page is also the smallest unit of data that resides on a Pageserver. For information about PostgreSQL page format, see Database Page Layout, in the PostgreSQL Documentation.

Pageserver

A Neon architecture component that reads WAL records from Safekeepers to identify modified pages. The Pageserver accumulates and indexes incoming WAL records in memory and writes them to disk in batches. Each batch is written to an immutable file that is never modified after creation. Using these files, the Pageserver can quickly reconstruct any version of a page dating back to the user-defined retention period.

The Pageserver uploads immutable files to cloud storage, which is the final, highly durable destination for data. Once a file is successfully uploaded to cloud storage, the corresponding WAL records can be removed from the Safekeepers.

Passwordless authentication

The ability to authenticate without providing a password. Neon’s Passwordless auth feature supports passwordless authentication.

PostgreSQL user

Two PostgreSQL database users are created with each Neon project. The first is named for the registered Neon account and can be used to access the Neon project from a client. This user’s credentials can be managed and used for password-based psql authentication. The second user is the web-access system user, which is used by the SQL Editor and Neon’s Passwordless auth feature. The web-access user is system managed. It cannot be modified, removed, or used in other authentication scenarios.

Additional PostgreSQL users can be created in the Neon Console.

In PostgreSQL, a role with the LOGIN attribute is considered the same as a database user. For additional information, refer to Database roles and Role Attributes, in the PostgreSQL documentation.

Project

A collection of branches, databases, users, and other project resources and settings. A project contains a compute with a PostgreSQL server as well as storage for the project data.

Proxy

A Neon component which functions as a multitenant service that accepts and handles connections from clients that use the PostgreSQL protocol.

Passwordless auth

A Neon feature that allows users to connect to a Neon project with a single psql command. See Query with psql.

Region

The geographic location where Neon project resource are located. Neon supports creating projects in several Amazon Web Services (AWS) regions. For information about regions supported by Neon, see Regions.

Root branch

The default branch created with each Neon project. The root branch for a Neon project is called main. You cannot delete a project's root branch. Each branch, including the root branch, has a dedicated endpoint, which is the compute instance associated with the branch. Connecting to a branch requires connecting to the branch endpoint. For more information, see Connecting to a branch.

Safekeeper

A Neon architecture component responsible for the durability of database changes. PostgreSQL streams WAL records to Safekeepers. A quorum algorithm based on Paxos ensures that when a transaction is committed, it is stored on a majority of Safekeepers and can be recovered if a node is lost. Safekeepers are deployed in different availability zones to ensure high availability and durability.

Serverless

A cloud-based development model that enables developing and running applications without having to manage servers.

SNI

Server Name Indication. A TLS protocol extension that allows a client or browser to indicate which hostname it wants to connect to at the beginning of a TLS handshake.

SQL Editor

A feature of the Neon Console that enables running queries on a Neon project database. The SQL Editor also enables saving queries, viewing query history, and analyzing or explaining queries.

Storage

Where data is recorded and stored. Neon storage consists of Pageserver which stores hot data and a cloud object store such as Amazon S3 that stores cold data for cost optimization and durability.

Technical Preview

A preview of Neon during which users are able to try Neon's Free Tier. For more information, see Technical Preview Free Tier.

Token

An encrypted access token that enables users to authenticate with Neon using the Neon API. An access token is generated when creating a Neon API key. For more information, see Using API keys.

PostgreSQL users

PostgreSQL users are created as a part of your Neon project and can be managed via the Neon Console. A system user web-access is used for the SQL Editor in the Neon Console and for passwordless authentication. This user cannot be removed or used for authenticating in other scenarios.

User

See Neon user and PostgreSQL user.

WAL

Write-Ahead Logging (WAL). A standard method for ensuring data integrity. Neon relies on WAL to separate storage and compute.

WAL slice

Write-ahead logs in a specific LSN range.

WAL stream

The stream of data that is written to the Write-Ahead Log (WAL) during transactional processing.

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