Create a Full Text Search index with SQLAlchemy on PostgreSQL

You could create index using Index in __table_args__. Also I use a function to create ts_vector to make it more tidy and reusable if more than one field is required. Something like below:

from sqlalchemy.dialects import postgresqldef create_tsvector(*args):    exp = args[0]    for e in args[1:]:        exp += ' ' + e    return func.to_tsvector('english', exp)class Person(db.Model):    id = db.Column(db.Integer, primary_key=True)    name = db.Column(db.String)    __ts_vector__ = create_tsvector(        cast(func.coalesce(name, ''), postgresql.TEXT)    )    __table_args__ = (        Index(            'idx_person_fts',            __ts_vector__,            postgresql_using='gin'        )    )

Update:A sample query using index (corrected based on comments):

people = Person.query.filter(Person.__ts_vector__.match(expressions, postgresql_regconfig='english')).all()

The answer from @sharez is really useful (especially if you need to concatenate columns in your index). For anyone looking to create a tsvector GIN index on a single column, you can simplify the original answer approach with something like:

from sqlalchemy import Column, Index, Integer, Stringfrom sqlalchemy.ext.declarative import declarative_basefrom sqlalchemy.sql import funcBase = declarative_base()class Example(Base):    __tablename__ = 'examples'    id = Column(Integer, primary_key=True)    textsearch = Column(String)    __table_args__ = (        Index(            'ix_examples_tsv',            func.to_tsvector('english', textsearch),            postgresql_using='gin'            ),        )

Note that the comma following Index(...) in __table_args__ is not a style choice, the value of __table_args__ must be a tuple, dictionary, or None.

If you do need to create a tsvector GIN index on multiple columns, here is another way to get there using text().

from sqlalchemy import Column, Index, Integer, String, textfrom sqlalchemy.ext.declarative import declarative_basefrom sqlalchemy.sql import funcBase = declarative_base()def to_tsvector_ix(*columns):    s = " || ' ' || ".join(columns)    return func.to_tsvector('english', text(s))class Example(Base):    __tablename__ = 'examples'    id = Column(Integer, primary_key=True)    atext = Column(String)    btext = Column(String)    __table_args__ = (        Index(            'ix_examples_tsv',            to_tsvector_ix('atext', 'btext'),            postgresql_using='gin'            ),        )

It has been answered already by @sharez and @benvc. I needed to make it work with weights though. This is how I did it based on their answers :

from sqlalchemy import Column, func, Index, Stringfrom sqlalchemy.ext.declarative import declarative_basefrom sqlalchemy.sql.operators import opCONFIG = 'english'Base = declarative_base()def create_tsvector(*args):    field, weight = args[0]    exp = func.setweight(func.to_tsvector(CONFIG, field), weight)    for field, weight in args[1:]:        exp = op(exp, '||', func.setweight(func.to_tsvector(CONFIG, field), weight))    return expclass Example(Base):    __tablename__ = 'example'    foo = Column(String)    bar = Column(String)    __ts_vector__ = create_tsvector(        (foo, 'A'),        (bar, 'B')    )    __table_args__ = (        Index('my_index', __ts_vector__, postgresql_using='gin'),    )