Extensions

DB9 ships all extensions compiled into the server binary. There is no runtime dynamic loading — every extension is available immediately, and CREATE EXTENSION records install metadata per database.

Extensions by Task

Files and Data

Extension	What it does	Docs
fs9	Query, read, and write the database filesystem from SQL	fs9 reference
parquet	Read Parquet files from the filesystem or HTTP URLs into SQL tables	Parquet import

Search

Extension	What it does	Docs
vector	pgvector-compatible similarity search with HNSW indexing	Vector Search
embedding	Server-side text embedding via EMBEDDING() and EMBED_TEXT() — no external API needed	Vector Search
Full-Text Search	PostgreSQL-compatible full-text search with language tokenizers	Full-Text Search
zhparser	Chinese full-text search tokenizer (jieba-rs, always available)	Full-Text Search

Integration and Automation

Extension	What it does	Docs
http	Make HTTP requests from SQL (GET, POST, PUT, DELETE as table functions)	HTTP client
pg_cron	Schedule SQL statements to run on a cron expression	pg_cron

Compatibility

Extension	What it does	Docs
uuid-ossp	UUID generation functions (uuid_generate_v4(), etc.)	uuid-ossp
hstore	PostgreSQL-compatible key-value store type	hstore

Enabling Extensions

Most extensions require CREATE EXTENSION before use. A few are pre-enabled or always available.

Pre-enabled (available on every new database)

These extensions are installed automatically when a database is created:

SQL

-- Already enabled — no CREATE EXTENSION needed
SELECT http_get('https://httpbin.org/get');
SELECT count(*) FROM cron.job;

Note

http_get and the other HTTP functions return JSONB — call them as scalar functions (SELECT http_get(...)), not as table-valued functions. See HTTP client for the full reference.

pg_cron job execution is unavailable in the current release

The cron schema functions are installed and callable immediately, but cron.schedule(...) currently returns an error — job scheduling/execution requires the worker subsystem, which is disabled for this release. See pg_cron for details.

• http — HTTP client functions available immediately
• pg_cron — Extension pre-installed; catalog and management functions (cron.job, cron.unschedule, etc.) are available immediately, but job scheduling/execution is unavailable in the current release

Require CREATE EXTENSION

These extensions must be explicitly enabled before their functions are available:

SQL

CREATE EXTENSION IF NOT EXISTS fs9;
CREATE EXTENSION IF NOT EXISTS embedding;
CREATE EXTENSION IF NOT EXISTS parquet;

▶ Run

Metadata shims (built-in, CREATE EXTENSION optional)

These capabilities work without CREATE EXTENSION, but running it records metadata in pg_extension for ORM and tool compatibility:

Run CREATE EXTENSION for ORM compatibility

Even though vector, uuid-ossp, and hstore work without CREATE EXTENSION, running it registers the extension in pg_extension. ORMs like Prisma and Drizzle check this table to detect capabilities — running CREATE EXTENSION prevents false-negative compatibility errors. The same applies to pgcrypto and plpgsql, which exist only as pg_extension entries.

• vector — The vector type and operators (<->, <#>, <=>) work as built-ins. HNSW indexes can be created and the planner uses them for similarity search when the probe is an inlined literal and the query has a LIMIT and no WHERE clause — see Vector Search. CREATE EXTENSION vector is recommended so ORMs that check pg_extension see it as installed.
• uuid-ossp — UUID functions (uuid_generate_v4(), etc.) are built-in. CREATE EXTENSION "uuid-ossp" records metadata for pg_dump/pg_restore compatibility.
• hstore — Extension metadata is recorded for client compatibility. DB9 does not currently implement full hstore semantics.
• pgcrypto — Metadata only, so Supabase and ORM bootstrap scripts that run CREATE EXTENSION pgcrypto succeed unchanged. It registers no functions of its own: gen_random_uuid() and digest() are DB9 built-ins that work with or without it. The rest of pgcrypto is not implemented — see the caution below.
• plpgsql — PL/pgSQL is compiled in. CREATE EXTENSION plpgsql records metadata so restored dumps (which almost always contain it) do not fail.

CREATE EXTENSION pgcrypto succeeds, but the crypto functions do not exist

Running CREATE EXTENSION pgcrypto returns CREATE EXTENSION and adds a row to pg_extension, so a schema restore will not fail on it. It does not make pgcrypto’s functions available. crypt(), gen_salt(), hmac(), encrypt()/decrypt(), pgp_sym_encrypt() and gen_random_bytes() all raise 42883 function ... does not exist when called.

Only gen_random_uuid() and digest() work, and both are DB9 built-ins available on a database with no extensions installed. Hash a value with digest(data, 'sha256'), sha256() or md5(); move password hashing and symmetric encryption into your application layer.

Always available (no-op)

• zhparser — The Chinese full-text tokenizer is compiled in and always active. CREATE EXTENSION zhparser is accepted but has no effect.

Extension Schemas

Extensions install their functions into specific schemas:

Extension	Default schema	Access pattern
http	extensions	http_get(...) for the scalar JSONB form; SELECT * FROM extensions.http_get(...) for the table form. The qualifier is not interchangeable — see http
fs9	extensions	fs9_read(...) or extensions.fs9_read(...) — both resolve on the default search_path
embedding	extensions	embedding(...) — the bare name; extensions.embedding(...) does not resolve
parquet	extensions	SELECT * FROM extensions.read_parquet(...) — table-valued, FROM position only
pg_cron	cron	cron.schedule(...), cron.unschedule(...)
vector	public	Operators and type available directly
uuid-ossp	public	uuid_generate_v4() available directly
hstore	public	Type available directly
pgcrypto	extensions	Metadata only — registers no functions (gen_random_uuid(), digest() are built-ins)
plpgsql	public	Metadata only — PL/pgSQL is compiled in

Choosing the Right Extension

I want to…	Use
Store and search vector embeddings	vector + embedding
Build a RAG pipeline without external APIs	embedding + fs9
Call an external API from SQL	http
Query files on the database filesystem	fs9
Watch filesystem changes in real time	fs9 events + CLI watch
Import Parquet data	parquet
Schedule a recurring cleanup or report	pg_cron
Search text content	Full-Text Search
Generate UUIDs	uuid-ossp

Next Steps

• Architecture — How extensions fit into the DB9 server
• SQL Reference — SQL engine compatibility and features
• RAG with Built-in Embeddings — End-to-end tutorial using embedding() and vector search
• Analyze Agent Logs with fs9 — Tutorial: write and query agent logs from SQL
• HTTP from SQL — Tutorial: call APIs, webhooks, and enrich data from SQL
• Scheduled Jobs with pg_cron — Tutorial: periodic tasks, monitoring, and job management
• Agent Workflows — Extensions in agent pipelines
• CLI Reference — db9 db sql for running extension commands