this.cancelButtonClasses = options.cancelClass;

        if (typeof options.maxSpan === 'object')
            this.maxSpan = options.maxSpan;

        if (typeof options.dateLimit === 'object') //backwards compat
            this.maxSpan = options.dateLimit;

        if (typeof options.opens === 'string')
            this.opens = options.opens;

	defer close(cacheStmt.prepared)

	// Reason why cannot lock conn.PrepareContext
	// suppose the maxopen is 1, g1 is creating record and g2 is querying record.
	// 1. g1 begin tx, g1 is requeue because of waiting for the system call, now `db.ConnPool` db.numOpen == 1.
	// 2. g2 select lock `conn.PrepareContext(ctx, query)`, now db.numOpen == db.maxOpen , wait for release.