在Sybase / SQLServer数据库上拥有过时表统计信息的含义是什么？

For example, for heavily used tables with volumes in the order of 10 million rows that grow by a million rows a month, if the stats are 6-8 months old how detrimental to the performance of the database is this going to be? How often should you be refreshing the stats?For example, for heavily used tables with volum