add embedding cache and clean embedding cache job (#3087)

Co-authored-by: jyong <jyong@dify.ai>

api/migrations/versions/a8d7385a7b66_add_embeddings_provider_name.py

@@ -0,0 +1,34 @@
+"""add-embeddings-provider-name
+
+Revision ID: a8d7385a7b66
+Revises: 17b5ab037c40
+Create Date: 2024-04-02 12:17:22.641525
+
+"""
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = 'a8d7385a7b66'
+down_revision = '17b5ab037c40'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table('embeddings', schema=None) as batch_op:
+        batch_op.add_column(sa.Column('provider_name', sa.String(length=40), server_default=sa.text("''::character varying"), nullable=False))
+        batch_op.drop_constraint('embedding_hash_idx', type_='unique')
+        batch_op.create_unique_constraint('embedding_hash_idx', ['model_name', 'hash', 'provider_name'])
+
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table('embeddings', schema=None) as batch_op:
+        batch_op.drop_constraint('embedding_hash_idx', type_='unique')
+        batch_op.create_unique_constraint('embedding_hash_idx', ['model_name', 'hash'])
+        batch_op.drop_column('provider_name')
+    # ### end Alembic commands ###