diff --git a/app/models.py b/app/models.py
index 1f600c5a..ae274b6d 100644
--- a/app/models.py
+++ b/app/models.py
@@ -711,7 +711,7 @@ class PostReply(db.Model):
     community_id = db.Column(db.Integer, db.ForeignKey('community.id'), index=True)
     domain_id = db.Column(db.Integer, db.ForeignKey('domain.id'), index=True)
     image_id = db.Column(db.Integer, db.ForeignKey('file.id'), index=True)
-    parent_id = db.Column(db.Integer)
+    parent_id = db.Column(db.Integer, index=True)
     root_id = db.Column(db.Integer)
     depth = db.Column(db.Integer, default=0)
     instance_id = db.Column(db.Integer, db.ForeignKey('instance.id'), index=True)
diff --git a/migrations/versions/d37fe77e043c_index_parent_id.py b/migrations/versions/d37fe77e043c_index_parent_id.py
new file mode 100644
index 00000000..8f0cf62b
--- /dev/null
+++ b/migrations/versions/d37fe77e043c_index_parent_id.py
@@ -0,0 +1,32 @@
+"""index parent_id
+
+Revision ID: d37fe77e043c
+Revises: f19d761c216d
+Create Date: 2024-02-09 15:14:13.274755
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'd37fe77e043c'
+down_revision = 'f19d761c216d'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table('post_reply', schema=None) as batch_op:
+        batch_op.create_index(batch_op.f('ix_post_reply_parent_id'), ['parent_id'], unique=False)
+
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table('post_reply', schema=None) as batch_op:
+        batch_op.drop_index(batch_op.f('ix_post_reply_parent_id'))
+
+    # ### end Alembic commands ###