text: -- +migrate Up
  
  ALTER TABLE history_transactions
      ALTER COLUMN fee_charged TYPE bigint,
      ALTER COLUMN max_fee TYPE bigint,
      ADD inner_transaction_hash character varying(64),
      ADD fee_account character varying(64),
      ADD inner_signatures character varying(96)[],
      ADD new_max_fee bigint;
  
  CREATE INDEX by_inner_hash ON history_transactions USING btree (inner_transaction_hash) WHERE inner_transaction_hash IS NOT NULL;
  CREATE INDEX by_fee_account ON history_transactions USING btree (fee_account) WHERE fee_account IS NOT NULL;
  
  -- +migrate Down
  
  DROP INDEX by_inner_hash;
  DROP INDEX by_fee_account;
  
  ALTER TABLE history_transactions
      ALTER COLUMN fee_charged TYPE integer,
      ALTER COLUMN max_fee TYPE integer,
      DROP COLUMN inner_transaction_hash,
      DROP COLUMN fee_account,
      DROP COLUMN inner_signatures,
      DROP COLUMN new_max_fee;