Postgres extensions

Postgres extensions add data types, functions, operators, background workers, and other capabilities to Postgres. Extensions that do not require a profile-level toggle install in a logical database with CREATE EXTENSION.

Extension availability

Extensions marked Always enabled are part of Neki’s managed configuration and cannot be toggled. Other extensions can use either of these workflows:

A checkbox enables server configuration that the extension needs, such as a preload setting. Changing it creates a configuration-profile change.
An extension without a checkbox does not require a profile-level toggle. You install it in a logical database with CREATE EXTENSION when it is available.

Enabling an extension for a configuration profile and installing its database objects are separate operations. A profile-level change applies to the Postgres instances in shards assigned to that profile. CREATE EXTENSION installs objects in the logical database to which you are connected.

Enable an extension for a profile

You must have permission to update the database, and the branch must be ready.

From the PlanetScale dashboard, select your Neki database and branch.

Open Clusters and select the configuration profile used by the target shards.

Select the Extensions tab.

Enable the extension. If the extension exposes parameters, review and update them.

Select Apply now for any parameter changes.

Open Changes and wait for the configuration change to finish before using the extension.

A configuration-profile change affects every shard assigned to that profile. Confirm the assigned shards before changing an extension or its parameters.

Some profile changes can restart Postgres processes or roll through the instances in the profile. Use the change status to follow the rollout and avoid making dependent application changes before it completes. The available extension list for a profile is also available from pscale branch config-profile extensions. Enable or disable a catalog extension that the profile marks as enablable with pscale branch config-profile extensions enable or pscale branch config-profile extensions disable.

Install an extension in a logical database

After any required profile change has completed, connect to the target logical database with its default role. When the extension’s instructions require database installation, run:

CREATE EXTENSION IF NOT EXISTS extension_name;

Replace extension_name with the extension you want to install. Repeat the command for each logical database that needs the extension. To see extensions that are installed in the current logical database:

SELECT name, default_version, installed_version, comment
FROM pg_available_extensions
WHERE installed_version IS NOT NULL
ORDER BY name;

To see every extension that Postgres reports as available to the current logical database:

SELECT name, default_version, installed_version, comment
FROM pg_available_extensions
ORDER BY name;

During Platform Preview, do not use ALTER EXTENSION ... ADD to attach a user-created table, type, function, sequence, view, or other object to an extension. A shard created or rebuilt later may not recreate that object. Contact PlanetScale Support before using extension-membership DDL.

Supported extensions

Always enabled

These extensions are part of Neki’s managed configuration and cannot be disabled.

Extension	Version	Purpose
`neki_xxhash`	0.4	Hash functions used by Neki distribution
`pg_pscale_utils`	—	Handles privileged actions without granting superuser access
`pgextwlist`	—	Controls which extensions can be installed
`pginsights`	—	Collects per-query execution statistics for Query Insights
`plpgsql`	1.0	Built-in PL/pgSQL procedural language

Customer-configurable

Extension	Version	Profile toggle	Database install	Notes
`citext`	1.8	—	`CREATE EXTENSION citext`
`cube`	1.5	—	`CREATE EXTENSION cube`
`fuzzystrmatch`	1.2	—	`CREATE EXTENSION fuzzystrmatch`
`hstore`	1.8	—	`CREATE EXTENSION hstore`
`intarray`	1.5	—	`CREATE EXTENSION intarray`
`ltree`	1.3	—	`CREATE EXTENSION ltree`
`pg_trgm`	1.6	—	`CREATE EXTENSION pg_trgm`
`pgcrypto`	1.4	—	`CREATE EXTENSION pgcrypto`
`unaccent`	1.1	—	`CREATE EXTENSION unaccent`
`uuid-ossp`	1.1	—	`CREATE EXTENSION "uuid-ossp"`
`vector` (pgvector)	0.8.6	Enable	`CREATE EXTENSION vector`	Usable on unsharded and sharded Neki with query-shape limits
`vectorscale`	0.9.0	Enable	`CREATE EXTENSION vectorscale`	Requires `vector`. Exposes DiskANN query parameters. Inherits the pgvector query-shape limits

Extension-specific caveats

Neki can use an extension without implementing every function, cast, or cross-shard query shape that Postgres accepts on a single node. Prefer the working forms below. A rejected shape often returns NK013 for an unimplemented input, receive, or user-defined function.

pgvector

Install pgvector after you enable it on the configuration profile:

CREATE EXTENSION IF NOT EXISTS vector;

Nearest-neighbor search works for vector, halfvec, sparsevec, and binary vectors, including HNSW and IVFFlat indexes. Tenant-scoped and shard-targeted searches work. Cross-shard search works when the distance expression is projected once and the global sort references that projected value:

SELECT tenant_id, item_id, embedding <-> '[1,0,0]'::vector AS distance
FROM public.vector_items
ORDER BY distance
LIMIT 20;

The same alias-based shape works for cosine (<=>), inner product (<#>), L1, halfvec, sparsevec, Hamming, and Jaccard distance. Repeating the distance expression in ORDER BY fails on sharded Neki:

-- Rejected: NK013 receive function vector_recv is not implemented
SELECT tenant_id, item_id, embedding <-> '[1,0,0]'::vector AS distance
FROM public.vector_items
ORDER BY embedding <-> '[1,0,0]'::vector
LIMIT 20;

Other current limits:

A prepared parameter declared as vector fails with NK013 because vector_in is not implemented. Declare the parameter as text and cast $1::vector inside the query.
ARRAY[...]::vector and ARRAY[...]::vector(8) are rejected. Use a vector literal such as '[1,0,0]'::vector.
l2_norm(embedding) is rejected as ambiguous even when the column type is vector.
Global avg(vector) and sum(vector) fail on sharded tables with vector_recv. Tenant-scoped and direct-shard aggregates work.
Routed INSERT ... SELECT of vector values can hit the same vector_recv limit. Insert vector literals, or load rows with a query that stays on one shard.
IVFFlat recall is poor at the default ivfflat.probes=1. Raise probes when you need higher recall. HNSW recall depends on hnsw.ef_search.

vectorscale

vectorscale adds StreamingDiskANN indexes on top of pgvector. Install vector first, then:

CREATE EXTENSION IF NOT EXISTS vectorscale;

Tenant-routed and scatter searches that use a StreamingDiskANN index work when they follow the pgvector ORDER BY distance shape. The pgvector parameter-binding, literal-cast, and vector_recv limits also apply, including routed INSERT ... SELECT of vector values. After vectorscale is enabled, the Extensions tab exposes these DiskANN query parameters:

Parameter	Dashboard default	Description
`diskann.query_search_list_size`	`100`	The size of the search list used in queries.
`diskann.query_rescore`	`50`	The number of elements rescored (`0` disables rescoring).

Change extension parameters

Parameters associated with an extension appear beneath it after the extension is enabled. Their valid values, defaults, and restart requirements are shown in the dashboard. Updating them creates the same kind of configuration-profile change as other configuration parameters.

Disable or remove an extension

Disabling a profile-level extension setting does not run DROP EXTENSION and does not remove database objects from logical databases. Before disabling it, remove or migrate any database objects and application features that depend on it according to that extension’s instructions. DROP EXTENSION is a separate Postgres operation and can remove dependent objects. Review the objects that depend on an extension before running it.

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Architecture

Pricing

Platform

Guides

Extension availability

Enable an extension for a profile

Install an extension in a logical database

Supported extensions

Always enabled

Customer-configurable

Extension-specific caveats

pgvector

vectorscale

Change extension parameters

Disable or remove an extension

Need help?

​Extension availability

​Enable an extension for a profile

​Install an extension in a logical database

​Supported extensions

​Always enabled

​Customer-configurable

​Extension-specific caveats

​pgvector

​vectorscale

​Change extension parameters

​Disable or remove an extension

​Need help?

Extension availability

Enable an extension for a profile

Install an extension in a logical database

Supported extensions

Always enabled

Customer-configurable

Extension-specific caveats

pgvector

vectorscale

Change extension parameters

Disable or remove an extension

Need help?