Remove

Uninstall PostgreSQL extensions

Removing extensions involves two levels: dropping extension objects (database level) and uninstalling packages (operating system level).

Drop Extension Objects

Use DROP EXTENSION to remove extensions from the database:

-- Drop extension
DROP EXTENSION pgvector;

-- If there are dependent objects, cascade delete is required
DROP EXTENSION pgvector CASCADE;

Warning: CASCADE will drop all objects that depend on this extension (tables, functions, views, etc.). Use with caution.

Check Extension Dependencies

It’s recommended to check dependencies before dropping:

-- View objects that depend on an extension
SELECT
    classid::regclass,
    objid,
    deptype
FROM pg_depend
WHERE refobjid = (SELECT oid FROM pg_extension WHERE extname = 'pgvector');

-- View tables using extension types
SELECT
    c.relname AS table_name,
    a.attname AS column_name,
    t.typname AS type_name
FROM pg_attribute a
JOIN pg_class c ON a.attrelid = c.oid
JOIN pg_type t ON a.atttypid = t.oid
WHERE t.typname = 'vector';

Remove Preload

If the extension is in shared_preload_libraries, it must be removed from the preload list after dropping:

# Modify shared_preload_libraries, remove extension
pg edit-config pg-meta --force -p shared_preload_libraries='pg_stat_statements, auto_explain'

# Restart to apply configuration
pg restart pg-meta

Uninstall Packages

After dropping the extension from the database, you can optionally uninstall the package:

# EL systems
sudo yum remove pgvector_18*

# Debian/Ubuntu systems
sudo apt remove postgresql-18-pgvector

# Using pig package manager
pig remove pgvector

Typically keeping the package doesn’t cause issues. Only uninstall when you need to free disk space or resolve conflicts.

Important Notes

Data loss risk: Using CASCADE will drop dependent objects, potentially causing data loss.
Application compatibility: Ensure applications no longer use the extension’s functionality before dropping.
Preload order: If dropping a preloaded extension, be sure to also remove it from shared_preload_libraries, otherwise the database may fail to start.
Master-slave environments: In replication environments, DROP EXTENSION automatically replicates to slaves.

Operation Sequence

Complete extension removal workflow:

# 1. Check dependencies
psql -d mydb -c "SELECT * FROM pg_depend WHERE refobjid = (SELECT oid FROM pg_extension WHERE extname = 'pgvector');"

# 2. Drop extension from database
psql -d mydb -c "DROP EXTENSION pgvector;"

# 3. If it's a preloaded extension, remove from shared_preload_libraries
pg edit-config pg-meta --force -p shared_preload_libraries='pg_stat_statements, auto_explain'

# 4. Restart database (if preload configuration was modified)
pg restart pg-meta

# 5. Optional: Uninstall package
sudo yum remove pgvector_18*