Hello everyone, 

why this line is inside the loop?

https://github.com/odoo/odoo/blob/132c7e75e57321c77aac9250a2587c74c5da7857/addons/account/models/account_move.py#L1364

We were removing 100k~ account.move.line records for testing purposes. It took ages. So we do some little investigation and saw this, we took out from the loop the process duration became minutes from hours.

Regards from Projet
""" change index on partner_id to a multi-column index on (partner_id, ref), the new index will behave in the
            same way when we search on partner_id, with the addition of being optimal when having a query that will
            search on partner_id and ref at the same time (which is the case when we open the bank reconciliation widget)
        """
        cr.execute('DROP INDEX IF EXISTS account_move_line_partner_id_index')
        cr.execute('SELECT indexname FROM pg_indexes WHERE indexname = %s', ('account_move_line_partner_id_ref_idx',))
        if not cr.fetchone():
            cr.execute('CREATE INDEX account_move_line_partner_id_ref_idx ON account_move_line (partner_id, ref)')
    @api.depends('debit', 'credit', 'amount_currency', 'currency_id', 'matched_debit_ids', 'matched_credit_ids', 'matched_debit_ids.amount', 'matched_credit_ids.amount', 'move_id.state')
    def _amount_residual(self):
        """ Computes the residual amount of a move line from a reconciliable account in the company currency and the line's currency.
            This amount will be 0 for fully reconciled lines or lines from a non-reconciliable account, the original line amount
            for unreconciled lines, and something in-between for partially reconciled lines.
        """
        for line in self:
            if not line.account_id.reconcile:
                line.reconciled = False
                line.amount_residual = 0
                line.amount_residual_currency = 0
                continue
            
            amount = abs(line.debit - line.credit)
            amount_residual_currency = abs(line.amount_currency) or 0.0
            sign = 1 if (line.debit - line.credit) > 0 else -1
            if not line.debit and not line.credit and line.amount_currency and line.currency_id:
                
                sign = 1 if float_compare(line.amount_currency, 0, precision_rounding=line.currency_id.rounding) == 1 else -1
            for partial_line in (line.matched_debit_ids + line.matched_credit_ids):