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 indexes	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 * FROM http_get('https://httpbin.org/get');
SELECT cron.schedule('nightly', '0 3 * * *', 'VACUUM');

• http — HTTP client functions available immediately
• pg_cron — Cron scheduling available immediately (functions in the cron schema)

Require CREATE EXTENSION

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

SQL

CREATE EXTENSION fs9;
CREATE EXTENSION embedding;
CREATE EXTENSION parquet;

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:

• vector — The vector type, operators (<->, <#>, <=>), and HNSW indexes work as built-ins. 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.

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	extensions.http_get(...) or http_get(...) if extensions is on search_path
fs9	extensions	extensions.fs9_read(...) or set search_path
embedding	extensions	extensions.embedding(...)
parquet	extensions	extensions.read_parquet(...)
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

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
Import Parquet data	parquet
Schedule a recurring cleanup or report	pg_cron
Search text content	Full-Text Search
Generate UUIDs	uuid-ossp

Related Docs

• 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