相关疑难解决方法(0)

我想了解为什么在 UAT（3 秒内运行）与 PROD（23 秒内运行）上执行相同查询时会有如此巨大的差异。

UAT 和 PROD 都拥有准确的数据和索引。

询问：

set statistics io on;
set statistics time on;

SELECT CONF_NO,
       'DE',
       'Duplicate Email Address ''' + RTRIM(EMAIL_ADDRESS) + ''' in Maintenance',
       CONF_TARGET_NO
FROM   CONF_TARGET ct
WHERE  CONF_NO = 161
       AND LEFT(INTERNET_USER_ID, 6) != 'ICONF-'
       AND ( ( REGISTRATION_TYPE = 'I'
               AND (SELECT COUNT(1)
                    FROM   PORTFOLIO
                    WHERE  EMAIL_ADDRESS = ct.EMAIL_ADDRESS
                           AND DEACTIVATED_YN = 'N') > 1 )
              OR ( REGISTRATION_TYPE = 'K'
                   AND (SELECT COUNT(1)
                        FROM   CAPITAL_MARKET
                        WHERE  EMAIL_ADDRESS = ct.EMAIL_ADDRESS …