MySQL利用profile分析慢sql详解（group left join效率高于子查询）

使用profile来分析慢sql

mysql/' target='_blank'>mysql 的 sql 性能分析器主要用途是显示 sql 执行的整个过程中各项资源的使用情况。分析器可以更好的展示出不良 SQL 的性能问题所在。 最近遇到一个查询比较慢的sql语句，用了子查询，大概需要0.8秒左右，这个消耗时间比较长，严重影响了性能，所以需要进行优化。单独查询单表或者子查询记录都很快，下面来看看详细的介绍。

开启profile

MySQL> show profiles; -- 查看是否开启Empty set, 1 warning (0.00 sec)mysql> set profiling=1; -- 开启profileQuery OK, 0 rows affected, 1 warning (0.00 sec)mysql> show profiles;Empty set, 1 warning (0.00 sec)mysql> 

执行查询，方便profile跟踪记录

mysql> SELECT SQL_NO_CACHE ->     t1.amount, ->     t1.count, ->     t1.date , ->     (SELECT (CONCAT(t2.APPROVE_ID,'|' ,t2.PATH)) AS RECEIPT FROM TB_BIS_MERCHANT_SETTLEMENT t2 WHERE t2.`MERCHANT_ID` = t1.`MERCHANT_ID` AND t2.`DATE`=t1.DATE AND t2.APPROVE_STATUS=5) AS receipts ->    FROM ->     TB_BIS_MERCHANT_TURNOVER t1 ->    WHERE t1.MERCHANT_ID='64884DE062BC11E682B00017FA000202' ->         ORDER BY t1.date DESC ->  -> LIMIT 0,100;+-----------+-------+----------+------------------------------------------------------------------------------------------------------------+| amount | count | date  | receipts                         |+-----------+-------+----------+------------------------------------------------------------------------------------------------------------+| 15800.00 |  1 | 20170105 | 0DDFD555F93B45BEB0905B1E6DE89D29|http://testxxx.cn/group1/M00/00/49/CvkBIlhu-yqABqmAABYR7dHOmno819.jpg || 1245.00 |  1 | 20170104 | 0DDFD555F93B45BEB0905B1E6DE89D29|http://testxxx.cn/group1/M00/00/4F/CvkBIVhtpSeAI_YHAADNjq7TPq8244.jpg || 14766.00 |  4 | 20170103 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/45/CvkBIlhrrf6AQ5uIAAEobJv68FU398.jpg || 32449.00 |  2 | 20170102 | 0DDFD555F93B45BEB0905B1E6DE89D29|http://testxxx.cn/group1/M00/00/4C/CvkBIVhrDguAfaMIABjKB9uvu04477.jpg || 37246.00 |  5 | 20170101 | 0DDFD555F93B45BEB0905B1E6DE89D29|http://testxxx.cn/group1/M00/00/4A/CvkBIVhpCnGASEyLAAEu6l9SI0o812.jpg || 105094.00 |  2 | 20161231 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/49/CvkBIVhnwp-ALIvWAAEAaGPayjg732.jpg || 88032.00 |  3 | 20161230 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/47/CvkBIVhmaqSAHcEZAAFAyS8Zx8Q067.jpg || 3845.00 |  1 | 20161229 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/3F/CvkBIlhl206AaS-FAAFMhvX8PYY578.jpg || 2118.00 |  4 | 20161228 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/3D/CvkBIlhjxhyAMOfhAAD8wUzTUUY855.jpg || 2980.00 |  1 | 20161227 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/3B/CvkBIlhicfCAFmwgAAE9ULPqEJ4030.jpg || 1080.00 |  1 | 20161226 | 667E240C44B4469892C261CE9243A8C3|http://testxxx.cn/group1/M00/00/42/CvkBIVhhy6iAMm8tAAFHOT5zBiM875.jpg || 2980.00 |  1 | 20161225 | 0DDFD555F93B45BEB0905B1E6DE89D29|http://testxxx.cn/group1/M00/00/40/CvkBIVhfzCWAdw2LAAFpDXmwio4327.jpg || 10201.00 |  1 | 20161224 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/38/CvkBIlhfJfKAIoBiAADqgbF1pBo054.jpg || 3003.00 |  4 | 20161223 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/3D/CvkBIVhdMHeAQi8cAAGAOQTgxLo422.jpg || 2698.00 |  1 | 20161222 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/3C/CvkBIVhb2U2AXWRuAAEc4LIr2nc172.jpg || 990.00 |  1 | 20161221 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/3B/CvkBIVhbM6aAGMQAAAEQ9ptn0FU333.jpg || 1427.00 |  1 | 20161220 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/31/CvkBIlhZNJqAAsvWAAGuJ6g1pyU541.jpg || 2465.00 |  1 | 20161219 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/30/CvkBIlhX4_mAfn-SAAEptH1Fyp8152.jpg || 2360.00 |  1 | 20161218 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/2F/CvkBIlhWl_-AclhbAAGLv79hoh8428.jpg || 3998.00 |  1 | 20161217 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/35/CvkBIVhVSLGAFct_AAFQRetyWnc285.jpg ||  0.00 |  0 | 20161216 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/2D/CvkBIlhU8g-AXywcAAGn1gdsQQc959.jpg ||  0.00 |  0 | 20161215 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/2A/CvkBIlhSmryAZXITAG-zN3WQv4c789.jpg || 9900.00 |  1 | 20161214 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/31/CvkBIVhRTrOALwG6AAE_csC3lvk695.jpg || 4320.00 |  1 | 20161213 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/28/CvkBIlhQrzCAfApEAAFKbHqkH3w634.jpg || 8760.00 |  2 | 20161212 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/26/CvkBIlhOqjeAO1BdAAGHdajOU2E697.jpg || 213335.00 |  4 | 20161211 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/2D/CvkBIVhNYQSAfxXgAAHZL9a8Nrs596.jpg || 47104.00 |  5 | 20161210 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/2C/CvkBIVhMsPSAAnrAAAETxX9fCuw946.jpg || 6100.00 |  1 | 20161209 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/23/CvkBIlhLfXOAClJVAAFmuoqBI5o264.jpg || 13515.00 |  2 | 20161208 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/21/CvkBIlhJZ06AbuaNAAGg7Bz3OsA569.jpg || 26769.00 |  4 | 20161207 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/20/CvkBIlhIGgeAdNxuAAETxX9fCuw408.jpg ||  0.00 |  0 | 20161206 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/1E/CvkBIlhGxAuAfQr8AAFatVZ2sFk337.jpg ||  0.00 |  0 | 20161205 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/1D/CvkBIlhGKy-AU9guAAGm4jFhmoU601.jpg || 20000.00 |  3 | 20161204 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/23/CvkBIVhEIDGAMPuIAAH6chL6Wo8684.jpg || 20275.00 |  4 | 20161203 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/21/CvkBIVhCyrSAE-uGAAGf0CWFbZM991.jpg || 3988.00 |  1 | 20161202 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/19/CvkBIlhCI7mAUN_9AAIsSLMhcns351.jpg || 4460.00 |  1 | 20161201 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/17/CvkBIlhAKwmACroNAAGpJUqVqIA247.jpg || 10498.00 |  2 | 20161130 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/16/CvkBIlg-3euAbsd5AAGr-r7GCH0254.jpg || 11080.00 |  2 | 20161129 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/1C/CvkBIVg9i6WAD4Z0AAHLB1yISaQ864.jpg || 6100.00 |  1 | 20161128 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/1B/CvkBIVg8OHGABTZOAAG1ZWoLoXY932.jpg || 5580.00 |  1 | 20161127 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/19/CvkBIVg65aKAcRWWAAFnaqaodKs660.jpg || 32630.00 |  2 | 20161126 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/18/CvkBIVg5kveALns0AAHLB1yISaQ850.jpg || 9800.00 |  1 | 20161125 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/17/CvkBIVg4Qg2AMqoNAAH--He3hsg726.jpg || 32500.00 |  2 | 20161124 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/16/CvkBIVg27_OAAV5OAAE8vRiZWHs684.jpg || 2700.00 |  1 | 20161123 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/0E/CvkBIlg2T4OAL3t5AAFsAWaUI98731.jpg || 4580.00 |  1 | 20161122 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/14/CvkBIVg0-UeAFDr_AAIBY_LNIxs656.jpg || 14120.00 |  1 | 20161121 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/0B/CvkBIlgy_EeAaPdBAAHeyO5nxeo952.jpg || 41510.00 |  2 | 20161120 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/12/CvkBIVgyYRKAZKi3AAGEp_IGjVM389.jpg || 7800.00 |  2 | 20161118 | C91D5E7905BA44C8A14045C9C228157F|http://testxxx.cn/group1/M00/00/09/CvkBIlgw_viAFHiPAAH0MZwoiCE530.jpg |+-----------+-------+----------+------------------------------------------------------------------------------------------------------------+48 rows in set (0.75 sec)mysql> 

查看当前的profile记录，主要获得Query_ID值

mysql> show profiles;+----------+------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+| Query_ID | Duration | Query                                                                          |+----------+------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+|  1 | 0.00009250 | show warning                                                                         ||  2 | 0.00013125 | show warnings                                                                        ||  3 | 0.00014375 | set profiling=1                                                                        ||  4 | 0.75458525 | SELECT SQL_NO_CACHE    t1.amount,    t1.count,    t1.date ,     (SELECT (CONCAT(t2.APPROVE_ID,'|' ,t2.PATH)) AS RECEIPT FROM TB_BIS_MERCHANT_SETTLEMENT t2 WHERE t2.`MERCHANT_ID` = t1.`MERCHANT_ID` AND t2.`DATE`=t1.DATE AND t2.APPROVE_STATUS=5) AS r |+----------+------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+4 rows in set, 1 warning (0.00 sec)mysql>

查看刚才执行的Query_ID为4的跟踪记录

mysql> show profile for query 4;+--------------------+----------+| Status    | Duration |+--------------------+----------+| executing   | 0.000017 || Sending data  | 0.018048 || executing   | 0.000028 || Sending data  | 0.018125 || executing   | 0.000022 || Sending data  | 0.015749 || executing   | 0.000017 || Sending data  | 0.015633 || executing   | 0.000017 || Sending data  | 0.015382 || executing   | 0.000015 || Sending data  | 0.015707 || executing   | 0.000023 || Sending data  | 0.015890 || executing   | 0.000022 || Sending data  | 0.015908 || executing   | 0.000017 || Sending data  | 0.015761 || executing   | 0.000022 || Sending data  | 0.015542 || executing   | 0.000014 || Sending data  | 0.015561 || executing   | 0.000016 || Sending data  | 0.015546 || executing   | 0.000037 || Sending data  | 0.015555 || executing   | 0.000015 || Sending data  | 0.015779 || executing   | 0.000026 || Sending data  | 0.015815 || executing   | 0.000015 || Sending data  | 0.015468 || executing   | 0.000015 || Sending data  | 0.015457 || executing   | 0.000015 || Sending data  | 0.015457 || executing   | 0.000014 || Sending data  | 0.015500 || executing   | 0.000014 || Sending data  | 0.015557 || executing   | 0.000015 || Sending data  | 0.015537 || executing   | 0.000014 || Sending data  | 0.015395 || executing   | 0.000021 || Sending data  | 0.015416 || executing   | 0.000014 || Sending data  | 0.015416 || executing   | 0.000014 || Sending data  | 0.015399 || executing   | 0.000023 || Sending data  | 0.015407 || executing   | 0.000014 || Sending data  | 0.015585 || executing   | 0.000014 || Sending data  | 0.015385 || executing   | 0.000014 || Sending data  | 0.015412 || executing   | 0.000014 || Sending data  | 0.015408 || executing   | 0.000014 || Sending data  | 0.015753 || executing   | 0.000014 || Sending data  | 0.015376 || executing   | 0.000014 || Sending data  | 0.015416 || executing   | 0.000019 || Sending data  | 0.015368 || executing   | 0.000014 || Sending data  | 0.015481 || executing   | 0.000015 || Sending data  | 0.015619 || executing   | 0.000015 || Sending data  | 0.015662 || executing   | 0.000016 || Sending data  | 0.015574 || executing   | 0.000015 || Sending data  | 0.015566 || executing   | 0.000015 || Sending data  | 0.015488 || executing   | 0.000013 || Sending data  | 0.015493 || executing   | 0.000015 || Sending data  | 0.015386 || executing   | 0.000015 || Sending data  | 0.015485 || executing   | 0.000018 || Sending data  | 0.015760 || executing   | 0.000014 || Sending data  | 0.015386 || executing   | 0.000015 || Sending data  | 0.015418 || executing   | 0.000014 || Sending data  | 0.015458 || end    | 0.000016 || query end   | 0.000019 || closing tables  | 0.000018 || freeing items  | 0.000825 || logging slow query | 0.000067 || cleaning up  | 0.000025 |+--------------------+----------+100 rows in set, 1 warning (0.00 sec)mysql> 

根据分析结果可以看到，有大量的Sending data消耗，而且是持续不断的，这样的可以判断为子查询导致的，所以在这个case里面，子查询不适合用，效率太低。 那该用什么来避免呢？

用group by + left join 改写

mysql> SELECT SQL_NO_CACHE DISTINCT ->     t1.amount, ->     t1.count, ->     t1.date, GROUP_CONCAT(CONCAT(t2.APPROVE_ID,'|' ,t2.PATH)) AS RECEIPT  ->    FROM ->     TB_BIS_MERCHANT_TURNOVER t1 LEFT JOIN TB_BIS_MERCHANT_SETTLEMENT t2 ON t2.`MERCHANT_ID` = t1.`MERCHANT_ID` AND t2.`DATE`=t1.DATE AND t2.APPROVE_STATUS=5 ->    WHERE t1.MERCHANT_ID='64884DE062BC11E682B00017FA000202' ->    GROUP BY t1.amount, ->     t1.count, ->     t1.date ->         ORDER BY t1.date DESC ->  -> LIMIT 0,100;+-----------+-------+----------+------------------------------------------------------------------------------------------------------------+| amount | count | date  | RECEIPT                         |+-----------+-------+----------+------------------------------------------------------------------------------------------------------------+| 15800.00 |  1 | 20170105 | 0DDFD555F93B45BEB0905B1E6DE89D29|http://testxxx.cn/group1/M00/00/49/CvkBIlhu-yqABqmAABYR7dHOmno819.jpg || 1245.00 |  1 | 20170104 | 0DDFD555F93B45BEB0905B1E6DE89D29|http://testxxx.cn/group1/M00/00/4F/CvkBIVhtpSeAI_YHAADNjq7TPq8244.jpg || 14766.00 |  4 | 20170103 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/45/CvkBIlhrrf6AQ5uIAAEobJv68FU398.jpg || 32449.00 |  2 | 20170102 | 0DDFD555F93B45BEB0905B1E6DE89D29|http://testxxx.cn/group1/M00/00/4C/CvkBIVhrDguAfaMIABjKB9uvu04477.jpg || 37246.00 |  5 | 20170101 | 0DDFD555F93B45BEB0905B1E6DE89D29|http://testxxx.cn/group1/M00/00/4A/CvkBIVhpCnGASEyLAAEu6l9SI0o812.jpg || 105094.00 |  2 | 20161231 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/49/CvkBIVhnwp-ALIvWAAEAaGPayjg732.jpg || 88032.00 |  3 | 20161230 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/47/CvkBIVhmaqSAHcEZAAFAyS8Zx8Q067.jpg || 3845.00 |  1 | 20161229 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/3F/CvkBIlhl206AaS-FAAFMhvX8PYY578.jpg || 2118.00 |  4 | 20161228 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/3D/CvkBIlhjxhyAMOfhAAD8wUzTUUY855.jpg || 2980.00 |  1 | 20161227 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/3B/CvkBIlhicfCAFmwgAAE9ULPqEJ4030.jpg || 1080.00 |  1 | 20161226 | 667E240C44B4469892C261CE9243A8C3|http://testxxx.cn/group1/M00/00/42/CvkBIVhhy6iAMm8tAAFHOT5zBiM875.jpg || 2980.00 |  1 | 20161225 | 0DDFD555F93B45BEB0905B1E6DE89D29|http://testxxx.cn/group1/M00/00/40/CvkBIVhfzCWAdw2LAAFpDXmwio4327.jpg || 10201.00 |  1 | 20161224 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/38/CvkBIlhfJfKAIoBiAADqgbF1pBo054.jpg || 3003.00 |  4 | 20161223 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/3D/CvkBIVhdMHeAQi8cAAGAOQTgxLo422.jpg || 2698.00 |  1 | 20161222 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/3C/CvkBIVhb2U2AXWRuAAEc4LIr2nc172.jpg || 990.00 |  1 | 20161221 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/3B/CvkBIVhbM6aAGMQAAAEQ9ptn0FU333.jpg || 1427.00 |  1 | 20161220 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/31/CvkBIlhZNJqAAsvWAAGuJ6g1pyU541.jpg || 2465.00 |  1 | 20161219 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/30/CvkBIlhX4_mAfn-SAAEptH1Fyp8152.jpg || 2360.00 |  1 | 20161218 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/2F/CvkBIlhWl_-AclhbAAGLv79hoh8428.jpg || 3998.00 |  1 | 20161217 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/35/CvkBIVhVSLGAFct_AAFQRetyWnc285.jpg ||  0.00 |  0 | 20161216 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/2D/CvkBIlhU8g-AXywcAAGn1gdsQQc959.jpg ||  0.00 |  0 | 20161215 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/2A/CvkBIlhSmryAZXITAG-zN3WQv4c789.jpg || 9900.00 |  1 | 20161214 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/31/CvkBIVhRTrOALwG6AAE_csC3lvk695.jpg || 4320.00 |  1 | 20161213 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/28/CvkBIlhQrzCAfApEAAFKbHqkH3w634.jpg || 8760.00 |  2 | 20161212 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/26/CvkBIlhOqjeAO1BdAAGHdajOU2E697.jpg || 213335.00 |  4 | 20161211 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/2D/CvkBIVhNYQSAfxXgAAHZL9a8Nrs596.jpg || 47104.00 |  5 | 20161210 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/2C/CvkBIVhMsPSAAnrAAAETxX9fCuw946.jpg || 6100.00 |  1 | 20161209 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/23/CvkBIlhLfXOAClJVAAFmuoqBI5o264.jpg || 13515.00 |  2 | 20161208 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/21/CvkBIlhJZ06AbuaNAAGg7Bz3OsA569.jpg || 26769.00 |  4 | 20161207 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/20/CvkBIlhIGgeAdNxuAAETxX9fCuw408.jpg ||  0.00 |  0 | 20161206 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/1E/CvkBIlhGxAuAfQr8AAFatVZ2sFk337.jpg ||  0.00 |  0 | 20161205 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/1D/CvkBIlhGKy-AU9guAAGm4jFhmoU601.jpg || 20000.00 |  3 | 20161204 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/23/CvkBIVhEIDGAMPuIAAH6chL6Wo8684.jpg || 20275.00 |  4 | 20161203 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/21/CvkBIVhCyrSAE-uGAAGf0CWFbZM991.jpg || 3988.00 |  1 | 20161202 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/19/CvkBIlhCI7mAUN_9AAIsSLMhcns351.jpg || 4460.00 |  1 | 20161201 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/17/CvkBIlhAKwmACroNAAGpJUqVqIA247.jpg || 10498.00 |  2 | 20161130 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/16/CvkBIlg-3euAbsd5AAGr-r7GCH0254.jpg || 11080.00 |  2 | 20161129 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/1C/CvkBIVg9i6WAD4Z0AAHLB1yISaQ864.jpg || 6100.00 |  1 | 20161128 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/1B/CvkBIVg8OHGABTZOAAG1ZWoLoXY932.jpg || 5580.00 |  1 | 20161127 | 98FDB31FE4B04C21BC7EBE8A22981DA0|http://testxxx.cn/group1/M00/00/19/CvkBIVg65aKAcRWWAAFnaqaodKs660.jpg || 32630.00 |  2 | 20161126 | 2154FDCDA51A4257811F1EA886AACD14|http://testxxx.cn/group1/M00/00/18/CvkBIVg5kveALns0AAHLB1yISaQ850.jpg || 9800.00 |  1 | 20161125 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/17/CvkBIVg4Qg2AMqoNAAH--He3hsg726.jpg || 32500.00 |  2 | 20161124 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/16/CvkBIVg27_OAAV5OAAE8vRiZWHs684.jpg || 2700.00 |  1 | 20161123 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/0E/CvkBIlg2T4OAL3t5AAFsAWaUI98731.jpg || 4580.00 |  1 | 20161122 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/14/CvkBIVg0-UeAFDr_AAIBY_LNIxs656.jpg || 14120.00 |  1 | 20161121 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/0B/CvkBIlgy_EeAaPdBAAHeyO5nxeo952.jpg || 41510.00 |  2 | 20161120 | EC481757CFDB445092D16D6B616350C8|http://testxxx.cn/group1/M00/00/12/CvkBIVgyYRKAZKi3AAGEp_IGjVM389.jpg || 7800.00 |  2 | 20161118 | C91D5E7905BA44C8A14045C9C228157F|http://testxxx.cn/group1/M00/00/09/CvkBIlgw_viAFHiPAAH0MZwoiCE530.jpg |+-----------+-------+----------+------------------------------------------------------------------------------------------------------------+48 rows in set (0.15 sec)mysql> 

可以看到，执行时间变成了0.15秒，提升了5倍的效率。再看profile的跟踪分析。

mysql> show profile for query 8;+-------------------------------+----------+| Status      | Duration |+-------------------------------+----------+| starting      | 0.000125 || checking permissions   | 0.000015 || checking permissions   | 0.000014 || Opening tables    | 0.000029 || init       | 0.000055 || System lock     | 0.000020 || Waiting for query cache lock | 0.000013 || System lock     | 0.000050 || optimizing     | 0.000023 || statistics     | 0.000087 || preparing      | 0.000066 || Creating tmp table   | 0.000062 || Creating tmp table   | 0.000028 || Sorting result    | 0.000016 || executing      | 0.000012 || Sending data     | 0.148283 || Creating sort index   | 0.000342 || Creating sort index   | 0.000223 || end       | 0.000015 || query end      | 0.000046 || removing tmp table   | 0.000017 || query end      | 0.000012 || removing tmp table   | 0.000062 || query end      | 0.000015 || closing tables    | 0.000017 || freeing items     | 0.000019 || removing tmp table   | 0.000025 || freeing items     | 0.000016 || Waiting for query cache lock | 0.000012 || freeing items     | 0.000915 || Waiting for query cache lock | 0.000015 || freeing items     | 0.000011 || storing result in query cache | 0.000013 || cleaning up     | 0.000024 |+-------------------------------+----------+34 rows in set, 1 warning (0.00 sec)mysql> 

可以看到，只有一次| Sending data | 0.148283 |的消耗，所以效率提升很快。

扩展部分

SELECT  NAME, VALUE FROM v $ parameter WHERE NAME IN ( 'pga_aggregate_target', 'sga_target' ) UNIONSELECT  'maximum PGA allocated' AS NAME, TO_CHAR (VALUE) AS VALUE FROM v $ pgastat WHERE NAME = 'maximum PGA allocated' ;

-- insert datainsert into t1 select 1,'a' from db1.t2;call db1.proc_get_fints

总结

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