add pg_trgm index on Alias.note to speed up LIKE search

app/models.py

@@ -1136,6 +1136,10 @@ class Alias(db.Model, ModelMixin):
 
     __table_args__ = (
         Index("ix_video___ts_vector__", ts_vector, postgresql_using="gin"),
+        # index on note column using pg_trgm
+        Index('note_pg_trgm_index', "note",
+              postgresql_ops={"note": "gin_trgm_ops"},
+              postgresql_using='gin'),
     )
 
     user = db.relationship(User, foreign_keys=[user_id])

migrations/versions/2021_082012_424808e1fe49_.py

@@ -0,0 +1,31 @@
+"""empty message
+
+Revision ID: 424808e1fe49
+Revises: d4392342465f
+Create Date: 2021-08-20 12:11:57.901994
+
+"""
+import sqlalchemy_utils
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '424808e1fe49'
+down_revision = 'd4392342465f'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.execute('CREATE EXTENSION pg_trgm')
+    op.create_index('note_pg_trgm_index', 'alias', ['note'], unique=False, postgresql_ops={'note': 'gin_trgm_ops'}, postgresql_using='gin')
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index('note_pg_trgm_index', table_name='alias')
+    op.execute('DROP EXTENSION pg_trgm')
+    # ### end Alembic commands ###