Summary: Neon's Postgres compatibility reference catalogs managed-service deviations from standard Postgres: no superuser access (replaced by neon_superuser), compute-size-dependent defaults for max_connections, shared_buffers, and maintenance_work_mem, plus unsupported features like tablespaces and persistent unlogged tables. Use this page when migrating to Neon to identify which permissions, extensions, collation providers, or session behaviors differ from a self-hosted install. Instance-level parameters are not user-configurable on Neon except on the Scale plan via Neon Support.

Learn about Neon as a managed Postgres service

Neon is Postgres. However, as a managed Postgres service, there are some differences you should be aware of.

Neon supports Postgres 14, 15, 16, 17, and 18. You select the Postgres version you want to use when creating a Neon project. For information about creating a Neon project, see Manage projects. Minor Postgres point releases are rolled out by Neon after extensive validation as part of regular platform maintenance.

For the current latest minor version available on Neon for each major version, and for details on how minor and major version updates work, see the Lakebase Postgres version support policy.

Neon supports numerous Postgres extensions, and we regularly add support for more. For the extensions that Neon supports, see Postgres Extensions. To request support for additional extensions, please reach out to us on our Discord Server. Please keep in mind that privilege requirements, local file system access, and functionality that is incompatible with Neon features such as Autoscaling and Scale to Zero may prevent Neon from being able to offer support for certain extensions.

Neon is a managed Postgres service, so you cannot access the host operating system, and you can't connect using the Postgres superuser account. In place of the Postgres superuser role, Neon provides a neon_superuser role.

Roles created in the Neon Console, CLI, or API, including the default role created with a Neon project, are granted membership in the neon_superuser role. For information about the privileges associated with this role, see The neon_superuser role.

Roles created in Neon with SQL syntax, from a command-line tool like psql or the Neon SQL Editor, have the same privileges as newly created roles in a standalone Postgres installation. These roles are not granted membership in the neon_superuser role. You must grant these roles the privileges you want them to have. For more information, see Manage roles with SQL.

Neon roles cannot install Postgres extensions other than those supported by Neon.

The following table shows parameter settings that are set explicitly for your database. These values may differ from standard Postgres defaults, and a few settings differ based on your Neon compute size.

Note: Because Neon is a managed Postgres service, Postgres parameters are not user-configurable outside of a session, database, or role context.

If you are a Neon Scale plan user and require a different Postgres instance-level setting, you can contact Neon Support to see if the desired setting can be supported. Please keep in mind that it may not be possible to support some parameters due to platform limitations and constraints.

Of the parameter settings listed above, the max_connections, maintenance_work_mem, shared_buffers, max_worker_processes, and effective_cache_size differ by your compute size (defined in Compute Units (CU)) or by your autoscaling configuration, which has a minimum and maximum compute size. To understand how values are set, see the formulas below.

• The formula for max_connections is:

  compute_size = min(max_compute_size, 8 × min_compute_size)
  max_connections = max(100, min(4000, floor(compute_size × 419.66)))

  In simpler terms:

  • Neon first determines the effective compute size by taking the smaller of: your maximum size, or 8 times your minimum size
  • This compute size is then multiplied by approximately 420 connections per CU
  • The result is capped between a minimum of 100 and a maximum of 4,000 connections

  Examples:

  • Fixed compute size of 4 CU:
    • Since your min and max are both 4 CU, the compute size is 4.
    • Max connections = 4 × 419.66 = 1,678 connections
  • Autoscaling from 0.25 to 2 CU:
    • Compute size = min(2, 8 × 0.25) = min(2, 2) = 2
    • Max connections = 2 × 419.66 = 839 connections
  • Autoscaling from 0.25 to 4 CU:
    • Compute size = min(4, 8 × 0.25) = min(4, 2) = 2
    • Max connections = 2 × 419.66 = 839 connections
  • Autoscaling from 2 to 8 CU:
    • Compute size = min(8, 8 × 2) = min(8, 16) = 8
    • Max connections = 8 × 419.66 = 3,357 connections

You can view your max_connections setting in the Neon Console by navigating to Branches, selecting your compute, and clicking Edit on the Compute tab. The value is displayed as direct connections. As you adjust your compute settings, you'll see how changes to your min/max compute size affect the number of direct connections available.

For most applications, we recommend using connection pooling, which supports up to 10,000 concurrent connections regardless of compute size. Direct connections are best for specific use cases like running pg_dump, session-dependent features, or schema migrations. For more information, see Connection pooling.

• The maintenance_work_mem value is set according to your minimum compute size RAM. The formula is:

  maintenance_work_mem = max(min_compute_size RAM in bytes * 1024/63,963,136, 65,536)

  However, you can increase the setting for the current session; for example:

  SET maintenance_work_mem='10 GB';

  If you do increase maintenance_work_mem, your setting should not exceed 60 percent of your compute's available RAM.

  Compute Units (CU) .	RAM .	maintenance_work_mem .
  0.25 .	1 GB .	64 MB .
  0.50 .	2 GB .	64 MB .
  1 .	4 GB .	67 MB .
  2 .	8 GB .	134 MB .
  3 .	12 GB .	201 MB .
  4 .	16 GB .	268 MB .
  5 .	20 GB .	335 MB .
  6 .	24 GB .	402 MB .
  7 .	28 GB .	470 MB .
  8 .	32 GB .	537 MB .
  9 .	36 GB .	604 MB .
  10 .	40 GB .	671 MB .
  11 .	44 GB .	738 MB .
  12 .	48 GB .	805 MB .
  13 .	52 GB .	872 MB .
  14 .	56 GB .	939 MB .
  15 .	60 GB .	1007 MB .
  16 .	64 GB .	1074 MB .
  18 .	72 GB .	1208 MB .
  20 .	80 GB .	1342 MB .
  22 .	88 GB .	1476 MB .
  24 .	96 GB .	1610 MB .
  26 .	104 GB .	1744 MB .
  28 .	112 GB .	1878 MB .
  30 .	120 GB .	2012 MB .
  32 .	128 GB .	2146 MB .
  34 .	136 GB .	2280 MB .
  36 .	144 GB .	2414 MB .
  38 .	152 GB .	2548 MB .
  40 .	160 GB .	2682 MB .
  42 .	168 GB .	2816 MB .
  44 .	176 GB .	2950 MB .
  46 .	184 GB .	3084 MB .
  48 .	192 GB .	3218 MB .
  50 .	200 GB .	3352 MB .
  52 .	208 GB .	3486 MB .
  54 .	216 GB .	3620 MB .
  56 .	224 GB .	3754 MB .

• The formula for max_worker_processes is:

  max_worker_processes := 13 + floor(2 * max_compute_size)

  For example, if your max_compute_size is 4 CU, your max_worker_processes setting would be 21.

• The formula for shared_buffers is:

  backends = 1 + max_connections + max_worker_processes
  shared_buffers_mb = max(128, (1023 + backends * 256) / 1024)

  On large fixed-size computes (18 CU and above), shared_buffers is instead set to 75% of your compute's RAM (backed by huge pages) and the secondary file cache is disabled, so this formula does not apply. See What is the compute cache?.

• The effective_cache_size parameter is set based on the compute cache size of your maximum Neon compute size. This helps the Postgres query planner make smarter decisions, which can improve query performance. For details on compute cache size by compute size, see the table in How to size your compute.

Neon permits configuring parameters that have a user context, meaning that these parameters can be set for a session, database, or role. You can identify Postgres parameters with a user context by running the following query:

SELECT name
FROM pg_settings
WHERE context = 'user';

To set a parameter for a specific session, use a SET command.

For example, the maintenance_work_mem parameter supports a user context, which lets you set it for the current session with a SET command:

SET maintenance_work_mem='1 GB';

To set parameters for a database or role:

ALTER DATABASE neondb SET maintenance_work_mem='1 GB';

ALTER USER neondb_owner SET maintenance_work_mem='1 GB';

Neon does not support PostgreSQL tablespaces. Attempting to create a tablespace with the CREATE TABLESPACE command will result in an error. This is due to Neon's managed cloud architecture, which does not permit direct file system access for custom storage locations.

If you have existing applications or scripts that use tablespaces for organizing database objects across different storage devices, you'll need to remove or modify these references when migrating to Neon.

Postgres logs can be accessed through the Datadog or OpenTelemetry integration on the Scale plan. The integration forwards logs including error messages, database connection events, system notifications, and general PostgreSQL logs. For other plans or if you need specific log information for troubleshooting purposes, please contact Neon Support.

Unlogged tables are tables that do not write to the Postgres write-ahead log (WAL). In Neon, these tables are stored on compute local storage and are not persisted across compute restarts or when a compute scales to zero. This is unlike standard Postgres, where unlogged tables are only truncated in the event of abnormal process termination. Additionally, unlogged tables are limited by compute local disk space. Computes allocate 20 GiB of local disk space or 15 GiB x the maximum compute size (whichever is highest) for temporary files used by Postgres.

Temporary tables are tied to a session (or optionally a transaction). They exist only for the lifetime of the session or transaction and are automatically dropped when it ends. Like unlogged tables, they are stored on compute local storage and limited by compute local disk space.

SQL queries and index builds can generate large volumes of data that may not fit in memory. In Neon, the size of your compute determines the amount of memory that is available. For information about compute size and available memory, see How to size your compute.

The Neon cloud service automatically closes idle connections after a period of inactivity, as described in Compute lifecycle. When connections are closed, anything that exists within a session context is forgotten and must be recreated before being used again. For example, parameters set for a specific session, in-memory statistics, temporary tables, prepared statements, advisory locks, and notifications and listeners defined using NOTIFY/LISTEN commands only exist for the duration of the current session and are lost when the session ends. To avoid losing session-level contexts in Neon, you can disable Neon's Scale to Zero feature, which is possible on any of Neon's paid plans. However, disabling scale to zero also means that your compute will run 24/7. You can't disable scale to zero on Neon's Free plan, where your compute always suspends after 5 minutes of inactivity.

Statistics collected by the Postgres cumulative statistics system are not saved when a Neon compute (where Postgres runs) is suspended due to inactivity or restarted. For information about the lifecycle of a Neon compute, see Compute lifecycle. For information about configuring Neon's scale to zero behavior, see Scale to Zero.

Neon supports UTF8 encoding (Unicode, 8-bit variable-width encoding). This is the most widely used and recommended encoding for Postgres.

To view the encoding and collation for your database, you can run the following query:

SELECT
    pg_database.datname AS database_name,
    pg_encoding_to_char(pg_database.encoding) AS encoding,
    pg_database.datcollate AS collation,
    pg_database.datctype AS ctype
FROM
    pg_database
WHERE
    pg_database.datname = 'your_database_name';

You can also issue this command from psql or the Neon SQL Editor:

\l

Note: In Postgres, you cannot change a database's encoding or collation after it has been created.

A collation is an SQL schema object that maps an SQL name to locales provided by libraries installed in the operating system. A collation has a provider that specifies which library supplies the locale data. For example, a common standard provider, libc, uses locales provided by the operating system C library.

By default, Neon uses the C.UTF-8 collation. C.UTF-8 supports the full range of UTF-8 encoded characters.

Another provider supported by Neon is icu, which uses the external ICU library. In Neon, support for standard libc locales is limited compared to what you might find in a locally installed Postgres instance where there's typically a wider range of locales provided by libraries installed on your operating system. For this reason, Neon provides a full series of predefined icu locales in case you require locale-specific sorting or case conversions.

To view all of the predefined locales available to you, use the query SELECT * FROM pg_collation, or the command \dOS+ from the Neon SQL Editor or an SQL client like psql.

To create a database with a predefined icu locale, you can issue a query similar to this one with your preferred locale:

CREATE DATABASE my_arabic_db
LOCALE_PROVIDER icu
icu_locale 'ar-x-icu'
template template0;

To specify the locale for individual columns, you can use this syntax:

CREATE TABLE my_ru_table (
    id serial PRIMARY KEY,
    russian_text_column text COLLATE "ru-x-icu",
    description text
);

ICU also supports creating custom collations. For more information, see ICU Custom Collations.

For more about collations in Postgres, see Collation Support.

The track_commit_timestamp Postgres parameter is currently not supported in Neon due to platform constraints.

• Data types
• Functions
• Indexes
• Optimize queries
• Query reference
• Postgres RLS
• Version support
• Upgrade

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