Question

我有一个包含4397898条记录的表TABLE_A

+-------------------+---------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------------------+---------------+------+-----+---------+----------------+ | id | bigint(11) | NO | PRI | NULL | auto_increment | | usrid | int(11) | YES | | NULL | | | grpid | int(11) | YES | | NULL | | | catid | int(11) | YES | MUL | NULL | | | folderid | int(11) | NO | MUL | 5 | | | popid | int(11) | YES | MUL | NULL | | | accid | int(11) | YES | MUL | NULL | | | contentid | bigint(11) | YES | MUL | NULL | | | priority | smallint(6) | YES | | NULL | | | rating | smallint(6) | NO | | 3 | | | fromid | int(11) | YES | | NULL | | | ctxid | varchar(255) | YES | | NULL | | | ctxmsgid | varchar(255) | YES | | NULL | | | starred | enum('Y','N') | YES | | N | | | links | enum('y','n') | YES | | n | | +-------------------+---------------+------+-----+---------+----------------+

并将其编入索引

+---------+----+--------------+-----+-------------+-----+-------------+----------+--------+------+------------+ | Table | Nu | Key_name | Seq | Column_name | Col | Cardinality | Sub_part | Packed | Null | Index_type | +---------+----+--------------+-----+-------------+-----+-------------+----------+--------+------+------------+ | TABLE_A | 0 | PRIMARY | 1 | id | A | 4617132 | NULL | NULL | | BTREE | | TABLE_A | 1 | catIndx | 1 | catid | A | 256507 | NULL | NULL | YES | BTREE | | TABLE_A | 1 | contentIndx | 1 | contentid | A | 4617132 | NULL | NULL | YES | BTREE | | TABLE_A | 1 | catIndx_2 | 1 | catid | A | 18 | NULL | NULL | YES | BTREE | | TABLE_A | 1 | catIndx_2 | 2 | popid | A | 2013 | NULL | NULL | YES | BTREE | | TABLE_A | 1 | folderidIndx | 1 | folderid | A | 13619 | NULL | NULL | | BTREE | | TABLE_A | 1 | accIndex | 1 | accid | A | 1532 | NULL | NULL | YES | BTREE | | TABLE_A | 1 | popindx | 1 | popid | A | 1532 | NULL | NULL | YES | BTREE | +---------+----+--------------+-----+-------------+-----+-------------+----------+--------+------+------------+

以下查询

explain SELECT intCommIndx FROM TABLE_A WHERE ( (popid IN('-1',2407 ,22 ,1203 ,1342 ,1207 ,3 ,1254 ,2663 ,1250 ,3461 ,1251 ,14 ,1174 ,120 ,2406 ,2402 ,325 ,925 ,1210 ,2280 ,1 ,1202 ,1560 ,775 ,776 ,789 ,777 ,778 ,12 ,779 ,780 ,781 ,782 ,783 ,784 ,785 ,786 ,787 ,788 ,1209 ,19 ,26 ,9 ,24 ,4 ,25 ,21 ,18 ,1309 ,967 ,1212 ,6 ,9633 ,5 ,2671 ,17 ,13 ,1211 ,749 ,752 ,747 ,750 ,748 ,9302 ,1470 ,190 ,188 ,9711 ,9710 ,9512 ,11512 ,9514 ,9515 ,9516 ,11511 ,9513 ,9316 ,9453 ,1641 ,4986 ,1639 ,1640 ,7814 ,10042 ,9452 ,11236 ,11241 ,11238 ,11239 ,11237 ,11242 ,11240 ,1711 ) OR intpop3indx = -1) AND catid = 5 )

explain SELECT id FROM TABLE_A WHERE ( (popid IN('-1',2407 ,22 ,1203 ,1342 ,1207 ,3 ,1254 ,2663 ,1250 ,3461 ,1251 ,14 ,1174 ,120 ,2406 ,2402 ,325 ,925 ,1210 ,2280 ,1 ,1202 ,1560 ,775 ,776 ,789 ,777 ,778 ,12 ,779 ,780 ,781 ,782 ,783 ,784 ,785 ,786 ,787 ,788 ,1209 ,19 ,26 ,9 ,24 ,4 ,25 ,21 ,18 ,1309 ,967 ,1212 ,6 ,9633 ,5 ,2671 ,17 ,13 ,1211 ,749 ,752 ,747 ,750 ,748 ,9302 ,1470 ,190 ,188 ,9711 ,9710 ,9512 ,11512 ,9514 ,9515 ,9516 ,11511 ,9513 ,9316 ,9453 ,1641 ,4986 ,1639 ,1640 ,7814 ,10042 ,9452 ,11236 ,11241 ,11238 ,11239 ,11237 ,11242 ,11240 ,1711 ) OR popid = -1) AND catid = 5 ) 给出

+----+-------------+---------+------+---------------------------+---------+---------+-------+--------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+---------+------+---------------------------+---------+---------+-------+--------+-------------+ | 1 | SIMPLE | TABLE_A | ref | catIndx,catIndx_2,popindx | catIndx | 5 | const | 649800 | Using where | +----+-------------+---------+------+---------------------------+---------+---------+-------+--------+-------------+

如何提高查询速度？

结果中只有850行。 mysql> SELECT -> count(id) -> FROM TABLE_A -> WHERE ( -> (popid IN('-1',2407,22,1203,1342,1207,3,1254,2663,1250,3461,1251,14,1174,120,2406,2402,325,925,1210,2280,1,1202,1560,775,776,789,777,778,12,779,780,781,782,783,784,785,786,787,788,1209,19,26,9,24,4,25,21,18,1309,967,1212,6,9633,5,2671,17,13,1211,749,752,747,750,748,9302,1470,190,188,9711,9710,9512,11512,9514,9515,9516,11511,9513,9316,9453,1641,4986,1639,1640,7814,10042,9452,11236,11241,11238,11239,11237,11242,11240,1711) OR intpop3indx = -1) -> AND catid = 5 ); +--------------------+ | count(id) | +--------------------+ | 850 | +--------------------+ 1 row in set (11.22 sec)

我可以在几毫秒内完成850条记录的哪些更改？

Answer 1

这是查询：

SELECT intCommIndx 
FROM TABLE_A
WHERE ( (popid IN('-1',2407 ,22 ,1203   ,1342   ,1207   ,3  ,1254   ,2663   ,1250   ,3461   ,1251   ,14 ,1174   ,120    ,2406   ,2402   ,325    ,925    ,1210   ,2280   ,1  ,1202   ,1560   ,775    ,776    ,789    ,777    ,778    ,12 ,779    ,780    ,781    ,782    ,783    ,784    ,785    ,786    ,787    ,788    ,1209   ,19 ,26 ,9  ,24 ,4  ,25 ,21 ,18 ,1309   ,967    ,1212   ,6  ,9633   ,5  ,2671   ,17 ,13 ,1211   ,749    ,752    ,747    ,750    ,748    ,9302   ,1470   ,190    ,188    ,9711   ,9710   ,9512   ,11512  ,9514   ,9515   ,9516   ,11511  ,9513   ,9316   ,9453   ,1641   ,4986   ,1639   ,1640   ,7814   ,10042  ,9452   ,11236  ,11241  ,11238  ,11239  ,11237  ,11242  ,11240  ,1711   ) OR intpop3indx = -1
        ) AND
        catid = 5
       )

or的查询可能很难优化。我建议在表上创建两个索引，然后重写查询。这两个索引是intCommIndx(catid, popid, intCommIndx)和intCommIndx(catid, intpop3indx, intCommIndx)。然后新查询是：

SELECT intCommIndx 
FROM TABLE_A
WHERE catid = 5 and
      popid IN ('-1',2407 ,22 ,1203   ,1342   ,1207   ,3  ,1254   ,2663   ,1250   ,3461   ,1251   ,14 ,1174   ,120    ,2406   ,2402   ,325    ,925    ,1210   ,2280   ,1  ,1202   ,1560   ,775    ,776    ,789    ,777    ,778    ,12 ,779    ,780    ,781    ,782    ,783    ,784    ,785    ,786    ,787    ,788    ,1209   ,19 ,26 ,9  ,24 ,4  ,25 ,21 ,18 ,1309   ,967    ,1212   ,6  ,9633   ,5  ,2671   ,17 ,13 ,1211   ,749    ,752    ,747    ,750    ,748    ,9302   ,1470   ,190    ,188    ,9711   ,9710   ,9512   ,11512  ,9514   ,9515   ,9516   ,11511  ,9513   ,9316   ,9453   ,1641   ,4986   ,1639   ,1640   ,7814   ,10042  ,9452   ,11236  ,11241  ,11238  ,11239  ,11237  ,11242  ,11240  ,1711   )
UNION
SELECT intCommIndx 
FROM TABLE_A
WHERE catid = 5 and intpop3indx = -1;

这将允许仅使用索引来满足每个子查询。

Answer 2

我会尝试将最后的条件放在第一位。因此，当其中一个未经验证时，我们会直接转到另一行：

catid = 5 AND (intpop3indx = -1 OR popid IN (...))

因此，当catid != 5时，查询会直接传递给另一行。（即使catid = 5 AND intpop3indx = -1）

Answer 3

您的查询是从表格中选择列intCommIndx，但该列未显示为表格列之一。

快速回答是创建一个＆＃34;覆盖索引＆＃34;例如

... ON TABLE_A (catid, intpop3indx, popid, intCommIndx)

EXPLAIN输出应显示＆＃34;使用索引＆＃34;在Extra列中，这意味着查询完全从索引中得到满足，而无需从表中查找页面。

需要Mysql优化帮助

3 个答案: