I have a query that is using a group by and an order by, but it's very slow! I need some help to get the index correct. This is the query I'm running:
select *
from puresen_mv_shop.cache_deals
where feature_ids REGEXP 'i,t,d'
and phone_cost > 100.00
group by handset_numeric_id
order by popularity
LIMIT 0,10;
explain:
1 SIMPLE cache_deals index popularity 5 10 6635320.00 Using where; Using temporary
This runs in about 3 seconds, but I need it under a second. There are over 600k rows in the table. Here is the table structure:
mysql> describe cache_deals
-> ;
+-------------------------+---------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------------------------+---------------+------+-----+---------+-------+
| deal_id | varchar(100) | NO | | NULL | |
| deal_id_replication | varchar(150) | NO | PRI | | |
| handset_numeric_id | int(10) | YES | MUL | NULL | |
| handset_url | varchar(100) | YES | | NULL | |
| image_url | varchar(50) | YES | MUL | NULL | |
| handset_id | varchar(50) | YES | | NULL | |
| phone_cost | decimal(10,2) | YES | | NULL | |
| tariff_numeric_id | int(10) | YES | MUL | NULL | |
| tariff_id | varchar(100) | YES | MUL | NULL | |
| tariff_name | varchar(100) | YES | | NULL | |
| network_name | varchar(20) | YES | | NULL | |
| network_numeric_id | int(5) | YES | MUL | NULL | |
| term | int(5) | YES | MUL | NULL | |
| minutes | int(5) | YES | MUL | NULL | |
| texts | int(5) | YES | MUL | NULL | |
| data | int(5) | YES | MUL | NULL | |
| org_line_rental | decimal(10,2) | YES | MUL | NULL | |
| effective_monthly_cost | decimal(10,2) | YES | MUL | NULL | |
| free_gift_id | int(10) | YES | MUL | NULL | |
| free_gift_name | varchar(50) | YES | | NULL | |
| cashback | int(5) | YES | MUL | NULL | |
| free_lr | int(5) | YES | MUL | NULL | |
| half_lr | int(5) | YES | MUL | NULL | |
| clearance_flag | int(5) | YES | MUL | NULL | |
| manufacturer_numeric_id | int(5) | YES | MUL | NULL | |
| manufacturer_name | varchar(50) | YES | | NULL | |
| full_handset_name | varchar(100) | YES | | NULL | |
| popularity | int(20) | YES | MUL | NULL | |
| handset_colour | varchar(50) | YES | MUL | NULL | |
| feature_ids | varchar(100) | YES | | NULL | |
| operating_system | varchar(30) | YES | MUL | NULL | |
+-------------------------+---------------+------+-----+---------+-------+
Here are the indexes I've currently got on this table:
mysql> show index from cache_deals;
+-------------+------------+-------------------------+--------------+-------------------------+-----------+-------------+----------+--------+------+------------
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type
+-------------+------------+-------------------------+--------------+-------------------------+-----------+-------------+----------+--------+------+------------
| cache_deals | 0 | PRIMARY | 1 | deal_id_replication | A | 663532 | NULL | NULL | | BTREE
| | |
| cache_deals | 1 | handset_numeric_id | 1 | handset_numeric_id | A | 759 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | network_numeric_id | 1 | network_numeric_id | A | 8 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | tariff_numeric_id | 1 | tariff_numeric_id | A | 1091 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | manufacturer_numeric_id | 1 | manufacturer_numeric_id | A | 23 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | operating_system | 1 | operating_system | A | 42 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | image_url | 1 | image_url | A | 755 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | tariff_id | 1 | tariff_id | A | 1091 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | term | 1 | term | A | 7 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | minutes | 1 | minutes | A | 26 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | texts | 1 | texts | A | 14 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | data | 1 | data | A | 14 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | org_line_rental | 1 | org_line_rental | A | 128 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | effective_monthly_cost | 1 | effective_monthly_cost | A | 2147 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | free_gift_id | 1 | free_gift_id | A | 105 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | cashback | 1 | cashback | A | 2 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | free_lr | 1 | free_lr | A | 2 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | half_lr | 1 | half_lr | A | 2 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | clearance_flag | 1 | clearance_flag | A | 2 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | handset_colour | 1 | handset_colour | A | 17 | NULL | NULL | YES | BTREE
| | |
| cache_deals | 1 | popularity | 1 | popularity | A | 718 | NULL | NULL | YES | BTREE
| | |
+-------------+------------+-------------------------+--------------+-------------------------+-----------+-------------+----------+--------+------+------------
Am I indexing this table correctly?
Thanks for you help.
That REGEXP is killing the potential performance since it can't use an index. Can that part of the query be written some other way or possibly normalized to another table? If you can, that will probably help. Other than that, a composite index on phone_cost and handset_numeric_id should help. Also adding popularity to that index might help, but MySQL is already unhappy with the query since you're not really supposed to be able to work with columns that aren't in the GROUP BY clause.
As a side note, the data types of the columns could be more efficient. int(5) works the same as MEDIUMINT due to the limit on the INT except that MEDIUMINT is one byte smaller. Also, int(20) doesn't make sense since the INT type can't be that large.
select [name the columns you actually want returned]
from puresen_mv_shop.cache_deals
where feature_ids = 'i,t,d'
and phone_cost > 100.00
order
by popularity
LIMIT 0,10;
Index features_id or (features_id,phone_cost)
Related
Parent Table,
mysql> desc sattool_testing;
+------------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------------+--------------+------+-----+---------+----------------+
| id | bigint(20) | NO | PRI | NULL | auto_increment |
| circuit_id | varchar(30) | NO | | NULL | |
| coff_id | varchar(100) | NO | | NULL | |
| result | int(11) | YES | | NULL | |
| result_details | text | NO | | NULL | |
| details | longtext | NO | | NULL | |
| reverse_response | varchar(100) | NO | | NULL | |
| start_date | datetime | NO | | NULL | |
| end_date | datetime | YES | | NULL | |
| Modules | varchar(100) | YES | | NULL | |
| rehit | datetime | YES | | NULL | |
| isAuto | tinyint(1) | NO | | 0 | |
+------------------+--------------+------+-----+---------+----------------+
12 rows in set (0.00 sec)
1st Child Table,
mysql> desc sattool_desc;
+--------------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------------------+--------------+------+-----+---------+----------------+
| sattool_desc_id | bigint(20) | NO | PRI | NULL | auto_increment |
| ceinterface | varchar(50) | YES | | NULL | |
| cehostname | varchar(50) | YES | | NULL | |
| vprnno | varchar(50) | YES | | NULL | |
| policyname | varchar(50) | YES | | NULL | |
| cosno | varchar(10) | YES | | NULL | |
| peipaddress | varchar(17) | YES | | NULL | |
| router_type | varchar(5) | YES | | NULL | |
| sattool_testing_id | bigint(20) | YES | | NULL | |
| epipeid | varchar(20) | YES | | NULL | |
| cerouter | varchar(10) | YES | | NULL | |
| service_type | varchar(10) | YES | | NULL | |
| scope_of_manage | varchar(50) | YES | | NULL | |
| service_name | varchar(10) | YES | | NULL | |
| ce_vrf_name | varchar(150) | YES | | NULL | |
+--------------------+--------------+------+-----+---------+----------------+
15 rows in set (0.01 sec)
2nd Child Table (Contain multiple records against one parent table record),
mysql> desc sattool_error_log;
+----------------+--------------+------+-----+-------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+----------------+--------------+------+-----+-------------------+-----------------------------+
| id | bigint(20) | NO | PRI | NULL | auto_increment |
| service_id | varchar(30) | NO | | NULL | |
| coff_id | varchar(50) | NO | | NULL | |
| error_name | varchar(100) | NO | | NULL | |
| error_desc | text | NO | | NULL | |
| error_occurred | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| error_type | int(11) | YES | | NULL | |
| error_code | varchar(10) | YES | | NULL | |
| sattool_id | bigint(20) | YES | | 0 | |
| module_no | int(11) | YES | | 0 | |
+----------------+--------------+------+-----+-------------------+-----------------------------+
10 rows in set (0.00 sec)
SQL Query :-
SELECT GROUP_CONCAT(sattool_error_log.error_desc) AS err_desc, GROUP_CONCAT(sattool_error_log.error_type) AS err_type, sattool_testing.*, sattool_desc.service_type, sattool_desc.service_name, sattool_desc.scope_of_manage
FROM sattool_testing
LEFT JOIN sattool_desc ON sattool_testing.id = sattool_desc.sattool_testing_id
LEFT JOIN sattool_error_log ON sattool_testing.id = sattool_error_log.sattool_id
WHERE sattool_testing.isAuto = 1 GROUP BY sattool_testing.id ORDER BY sattool_testing.id DESC limit 100
Current Execution Time is (22.76 sec)
Explain Query :-
+----+-------------+-------------------+------+---------------+------+---------+------+------+----------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------------------+------+---------------+------+---------+------+------+----------------------------------------------+
| 1 | SIMPLE | sattool_testing | ALL | NULL | NULL | NULL | NULL | 3578 | Using where; Using temporary; Using filesort |
| 1 | SIMPLE | sattool_desc | ALL | NULL | NULL | NULL | NULL | 4009 | |
| 1 | SIMPLE | sattool_error_log | ALL | NULL | NULL | NULL | NULL | 8904 | |
+----+-------------+-------------------+------+---------------+------+---------+------+------+----------------------------------------------+
3 rows in set (0.00 sec)
I want to increase speed to above query execution.
Please give me suggestion on that.
Thanks!!!
I have added index to the columns used in the join/where clauses.
Like :-
ALTER TABLE sattool_desc ADD INDEX sattool_testing_id (sattool_testing_id);
ALTER TABLE sattool_error_log ADD INDEX sattool_id (sattool_id);
ALTER TABLE sattool_testing ADD INDEX isAuto (isAuto);
Now the execution time is 100 rows in set (0.00 sec).
Thanks again.
im stuck with a query which take more than 13 secs to return output
i did create the indexes but the execution plan doesnt seem to use them. Below are some information regarding
Query
SELECT userinfo.username,userinfo.firstname,userinfo.lastname,userinfo.email,
radcheck.attribute,radcheck.value,radusergroup.groupname, userinfo.id,
userinfo.workphone,userinfo.homephone,
userinfo.mobilephone,userinfo.address, userinfo.zone,
userinfo.account_state,userinfo.device_owner,userinfo.link_type,userinfo.account_type
FROM userinfo
INNER JOIN radcheck ON userinfo.username = radcheck.username
INNER JOIN radusergroup ON userinfo.username = radusergroup.username
WHERE radcheck.attribute='Expiration' and
STR_TO_DATE(radcheck.value, '%d %M %Y') < CURDATE()
and radusergroup.groupname='Customer30M';
Explain output
+----+-------------+--------------+------+--------------------+-----------+---------+--------------------------------+------+-----------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+--------------+------+--------------------+-----------+---------+--------------------------------+------+-----------------------------------+
| 1 | SIMPLE | radusergroup | ref | username,groupname | groupname | 66 | const | 5 | Using where with pushed condition |
| 1 | SIMPLE | radcheck | ref | username,attribute | attribute | 34 | const | 9 | Using where |
| 1 | SIMPLE | userinfo | ref | username | username | 131 | ctradius.radusergroup.username | 10 | Using where |
+----+-------------+--------------+------+--------------------+-----------+---------+--------------------------------+------+-----------------------------------+
3 rows in set (0.00 sec)
Table Info
Table: radusergroup
+-----------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+-------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| username | varchar(64) | NO | MUL | | |
| groupname | varchar(64) | NO | MUL | | |
| priority | int(11) | NO | | 1 | |
+-----------+-------------+------+-----+---------+----------------+
radusergroup table Index
+--------------+------------+-------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+--------------+------------+-------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| radusergroup | 0 | PRIMARY | 1 | id | A | 11292 | NULL | NULL | | BTREE | | |
| radusergroup | 1 | username | 1 | username | A | NULL | NULL | NULL | | BTREE | | |
| radusergroup | 1 | groupname | 1 | groupname | A | NULL | NULL | NULL | | BTREE | | |
| radusergroup | 1 | indexradusergroup | 1 | username | A | NULL | NULL | NULL | | BTREE | | |
| radusergroup | 1 | indexradusergroup | 2 | groupname | A | NULL | NULL | NULL | | BTREE | | |
Table : userinfo
---------------------+------------------+------+-----+---------------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------------------+------------------+------+-----+---------------------+----------------+
| id | int(11) unsigned | NO | PRI | NULL | auto_increment |
| username | varchar(128) | YES | MUL | NULL | |
| firstname | varchar(200) | YES | | NULL | |
| lastname | varchar(200) | YES | | NULL | |
| email | varchar(200) | YES | | NULL | |
| workphone | varchar(200) | YES | | NULL | |
| homephone | varchar(200) | YES | | NULL | |
| mobilephone | varchar(200) | YES | | NULL | |
| address | varchar(200) | YES | | NULL | |
| zone | varchar(20) | YES | | NULL | |
| account_state | varchar(10) | YES | | active | |
| change_commit | tinyint(1) | YES | | NULL | |
| link_type | varchar(8) | YES | | NULL | |
| account_type | varchar(255) | YES | | NULL | |
| device_owner | varchar(255) | YES | | NULL | |
| account_name | varchar(255) | YES | | NULL | |
| account_email | varchar(255) | YES | | NULL | |
| account_mobile | varchar(255) | YES | | NULL | |
| groupname | varchar(255) | YES | | NULL | |
+---------------------+------------------+------+-----+---------------------+----------------+
Indexes on userinfo
----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| userinfo | 0 | PRIMARY | 1 | id | A | 11282 | NULL | NULL | | BTREE | | |
| userinfo | 1 | username | 1 | username | A | NULL | NULL | NULL | YES | BTREE | | |
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
Table: Radcheck
+-----------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+------------------+------+-----+---------+----------------+
| id | int(11) unsigned | NO | PRI | NULL | auto_increment |
| username | varchar(64) | NO | MUL | | |
| attribute | varchar(32) | NO | MUL | | |
| op | char(2) | NO | | == | |
| value | varchar(253) | NO | MUL | | |
+-----------+------------------+------+-----+---------+----------------+
indexes on radcheck
+----------+------------+---------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+----------+------------+---------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| radcheck | 0 | PRIMARY | 1 | id | A | 33425 | NULL | NULL | | BTREE | | |
| radcheck | 1 | username | 1 | username | A | NULL | NULL | NULL | | BTREE | | |
| radcheck | 1 | value | 1 | value | A | NULL | NULL | NULL | | BTREE | | |
| radcheck | 1 | attribute | 1 | attribute | A | NULL | NULL | NULL | | BTREE | | |
The function invalidates the use of the index. Despite your cardinality showing 11k rows, the table scan ensues and it takes 13 seconds.
Though you have a join between Radcheck and userinfo, it is the STR_TO_DATE function in the where clause that kills the index use.
I have a sql statement that looks like this:
SELECT colID
FROM tableName
WHERE ColDateStart <='$lowerDate'
AND ColDateStart>='$upperDate'
AND ColVcamID='$id1'
AND ColVlviID='$id2'
AND ColSomeID='$id3';
All the columns in the WHERE statment are indexed columns.
When I run this it takes over a second. However when I run this without other Id3, the performance is considerably improved (0.03 seconds).
When I run explain, with otherId3, it uses an index merge using otherId1 and otherId3. However when I remove the otherId3, it uses the single index of otherId2.
Why does adding otherId3 make an impact on the performance?
Table Structure:
+----------------------+-------------+------+-----+---------------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------------------+-------------+------+-----+---------------------+----------------+
| ColID | int(11) | NO | PRI | NULL | auto_increment |
| ColCustID | int(11) | NO | MUL | 0 | |
| ColCarrID | int(11) | NO | MUL | NULL | |
| ColTariID | int(11) | NO | MUL | 0 | |
| ColCarrierRef | varchar(30) | NO | MUL | | |
| ColNumbID | int(11) | NO | MUL | 0 | |
| ColVlviID | int(11) | NO | MUL | NULL | |
| ColVcamID | int(11) | NO | MUL | NULL | |
| ColSomeID | int(11) | NO | MUL | NULL | |
| ColVlnsID | int(11) | NO | MUL | NULL | |
| ColNGNumber | varchar(12) | NO | | | |
| ColOrigNumber | varchar(16) | NO | MUL | NULL | |
| ColCLIRestrictedFlag | int(2) | NO | | NULL | |
| ColOrigLocality | varchar(11) | NO | MUL | | |
| ColOrigAreaCode | varchar(11) | NO | MUL | | |
| ColTermNumber | varchar(16) | NO | MUL | NULL | |
| ColBatchNumber | varchar(10) | NO | | | |
| ColDateStart | date | NO | MUL | 0000-00-00 | |
| ColDateClear | date | NO | | 0000-00-00 | |
| ColTimeStart | time | NO | | 00:00:00 | |
| ColTimeClear | time | NO | | 00:00:00 | |
| ColCallLength | time | NO | | 00:00:00 | |
| ColRingLength | time | NO | | 00:00:00 | |
| ColEffectiveFlag | smallint(1) | NO | MUL | NULL | |
| ColUnansweredFlag | smallint(1) | NO | MUL | NULL | |
| ColEngagedFlag | smallint(1) | NO | | NULL | |
| ColRecID | int(11) | NO | MUL | NULL | |
| ColCreatedUserID | int(11) | NO | | 0 | |
| ColCreatedDatetime | datetime | NO | MUL | 0000-00-00 00:00:00 | |
| ColDirection | int(1) | NO | MUL | NULL | |
+----------------------+-------------+------+-----+---------------------+----------------+
Indexes
+-------+------------+-------------------------------+--------------+---------------------+-----------+-------------+----------+--------+------+------------+---------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+-------+------------+-------------------------------+--------------+---------------------+-----------+-------------+----------+--------+------+------------+---------+
| tableName | 0 | PRIMARY | 1 | ColID | A | 18031283 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_ColCustID | 1 | ColCustID | A | 1339 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_ColNumbID | 1 | ColNumbID | A | 24366 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colOrigNumber | 1 | colOrigNumber | A | 4507820 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colOrigLocality | 1 | colOrigLocality | A | 36873 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colOrigAreaCode | 1 | colOrigAreaCode | A | 696 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colTermNumber | 1 | colTermNumber | A | 137643 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colDateStart | 1 | colDateStart | A | 3639 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colEffectiveFlag | 1 | colEffectiveFlag | A | 2 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colUnansweredFlag | 1 | colUnansweredFlag | A | 2 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colEngagedFlag | 1 | colUnansweredFlag | A | 2 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colTariID | 1 | colTariID | A | 91 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_CustID_DateStart | 1 | colCustID | A | 1339 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_CustID_DateStart | 2 | colDateStart | A | 693510 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_NumbID_DateStart | 1 | colNumbID | A | 24366 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_NumbID_DateStart | 2 | colDateStart | A | 4507820 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colRecID | 1 | colRecID | A | 214658 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colCarrierRef | 1 | colCarrierRef | A | 6010427 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colCustID_colTermNumber | 1 | colCustID | A | 1339 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colCustID_colTermNumber | 2 | colTermNumber | A | 143105 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colCreatedDatetime | 1 | colCreatedDatetime | A | 474507 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colDirection | 1 | colDirection | A | 2 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colVlviID | 1 | colVlviID | A | 4133 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colSomeID | 1 | colSomeID | A | 10 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colVcamID | 1 | colVcamID | A | 7 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colVlnsID | 1 | colVlnsID | A | 18 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_colCarrID | 1 | colCarrID | A | 4 | NULL | NULL | | BTREE | |
+-------+------------+-------------------------------+--------------+---------------------+-----------+-------------+----------+--------+------+------------+---------+
First up, you have far too may indexes. Most of those indexes are likely pointless. If you aren't using a specific index for WHERE criteria, JOINs, or ORDERing, then remove it as it just slows things down.
Next up, for your query you specify 3 columns that are always in the query comprising 1x DATE and 2x INT columns. The DATE column should be first as a date range is pretty fast on an index, and then the two INTs. This gives a starting point of the following 3-column index
CREATE INDEX searchIndex
ON tableName (ColDateStart,ColVlviID,ColVcamID)
USING BTREE;
More information on that available here : http://dev.mysql.com/doc/refman/5.0/en/multiple-column-indexes.html
I ordered the columns that way intentionally. ColDateStart for the date range filtering, followed by the other columns in decreasing order of cardinality. I selected ColVlviID as a second column as it has a cardinality of 4133 compared to ColVcamID having a cardinality of 7. This will allow MySQL to more efficiently reduce the matching rows.
Now, assuming colSomeID is the last column, I might instead do the following
CREATE INDEX searchIndex_someID
ON tableName (ColDateStart,ColVlviID,ColVcamID,ColSomeID)
USING BTREE;
This 3-column index will help MySQL get down to the applicable dataset before checking for that last ID. Optioanlly you could add a 4th column to that index at the end, if you are commonly filtering in another particular INT column.
As an aside, you may want to consider the following instead of the dateCol criteria
SELECT colID
FROM tableName
WHERE ColDateStart BETWEEN DATE('$lowerDate') AND DATE('$upperDate')
AND ColVcamID=$id1
AND ColVlviID=$id2
AND ColSomeID=$id3
The above all of course assumes that you are sanitising the variables before executing the query. I have removed the quotes from the $idx variables, as they should be numeric and therefore do not need to be entered as strings.
SELECT id
FROM tableName FORCE INDEX(`idx_otherId2`)
WHERE dateCol <='$lowerDate'
AND dateCol>='$upperDate'
AND otherId1='$id1'
AND otherId2='$id2'
AND otherId3='$id3';
I'm trying to run the following query:
SELECT formatted_journeys.*, MAX(speed)
FROM formatted_journeys
JOIN tracker.g_log
ON imeiid = vehicle
AND g_logid BETWEEN start_g_log AND end_g_log
GROUP BY id
however, it seems to be extremely slow. Here's the explain for that query.
+----+-------------+--------------------+------+-------------------------------+-------+---------+-----------------------------------+------+----------+---------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+--------------------+------+-------------------------------+-------+---------+-----------------------------------+------+----------+---------------------------------+
| 1 | SIMPLE | formatted_journeys | ALL | vehicle,start_g_log,end_g_log | NULL | NULL | NULL | 824 | 100.00 | Using temporary; Using filesort |
| 1 | SIMPLE | g_log | ref | PRIMARY,Dupes | Dupes | 4 | motrak.formatted_journeys.vehicle | 1985 | 100.00 | Using where |
+----+-------------+--------------------+------+-------------------------------+-------+---------+-----------------------------------+------+----------+---------------------------------+
2 rows in set, 1 warning (0.02 sec)
The tables are as follows:
formatted_journeys:
+-----------------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------------+------------------+------+-----+---------+----------------+
| id | int(11) unsigned | NO | PRI | NULL | auto_increment |
| start_g_log | int(11) | YES | MUL | NULL | |
| end_g_log | int(11) | YES | MUL | NULL | |
| start_latitude | decimal(18,12) | YES | | NULL | |
| start_longitude | decimal(18,12) | YES | | NULL | |
| end_latitude | decimal(18,12) | YES | | NULL | |
| end_longitude | decimal(18,12) | YES | | NULL | |
| start_location | text | YES | | NULL | |
| end_location | text | YES | | NULL | |
| distance | decimal(10,5) | YES | | NULL | |
| start_date | datetime | YES | | NULL | |
| end_date | datetime | YES | | NULL | |
| vehicle | int(11) | YES | MUL | NULL | |
| private | bit(1) | NO | | b'0' | |
+-----------------+------------------+------+-----+---------+----------------+
Indices:
+--------------------+------------+-------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+--------------------+------------+-------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| formatted_journeys | 0 | PRIMARY | 1 | id | A | 830 | NULL | NULL | | BTREE | |
| formatted_journeys | 1 | vehicle | 1 | vehicle | A | 4 | NULL | NULL | YES | BTREE | |
| formatted_journeys | 1 | start_g_log | 1 | start_g_log | A | 830 | NULL | NULL | YES | BTREE | |
| formatted_journeys | 1 | end_g_log | 1 | end_g_log | A | 830 | NULL | NULL | YES | BTREE | |
+--------------------+------------+-------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
tracker.g_log:
+-----------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+------------------+------+-----+---------+----------------+
| g_logid | int(10) unsigned | NO | PRI | NULL | auto_increment |
| imeiid | int(10) unsigned | NO | MUL | NULL | |
| latitude | decimal(18,12) | YES | | NULL | |
| longitude | decimal(18,12) | YES | | NULL | |
| speed | int(4) | YES | MUL | NULL | |
| bearing | int(4) | YES | | NULL | |
| distance | decimal(10,5) | YES | | NULL | |
| eventcode | int(10) | YES | | NULL | |
| status | int(10) | YES | | NULL | |
| date | datetime | YES | | NULL | |
+-----------+------------------+------+-----+---------+----------------+
Indices:
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| g_log | 0 | PRIMARY | 1 | g_logid | A | 31760 | NULL | NULL | | BTREE | |
| g_log | 0 | Dupes | 1 | imeiid | A | 16 | NULL | NULL | | BTREE | |
| g_log | 0 | Dupes | 2 | date | A | 31760 | NULL | NULL | YES | BTREE | |
| g_log | 0 | Dupes | 3 | eventcode | A | 31760 | NULL | NULL | YES | BTREE | |
| g_log | 1 | speed | 1 | speed | A | 423 | NULL | NULL | YES | BTREE | |
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
Now I know that the filesort isn't a good thing but how would I get rid of it?
You will hardly get rid of Using temporary; Using filesort, but the query might be faster.
First, try to rewrite the query as:
SELECT *
FROM (
SELECT id, MAX(speed) as max_speed
FROM formatted_journeys
JOIN tracker.g_log
ON imeiid = vehicle
AND g_logid BETWEEN start_g_log AND end_g_log
GROUP BY id) as maxspeeds
JOIN formatted_journeys USING (id);
Then, you can try to force the query to use a coverage index, though that is not easy for the query.
First try: add a composite index (vehicle, start_g_log, end_g_log) and look in explain whether it is used (you should see "Using index" there)
I am trying to optimize a MySQL select request:
SELECT * FROM `sales`
WHERE ((sales.private = false AND (sales.buyer_id IS NULL OR NOT sales.buyer_id=142)
AND (sales.merchand_id IS NULL OR NOT sales.merchand_id=142)
AND (sales.private_item = false) )
AND ((sales.buyer_id=32 OR sales.merchand_id=32)
AND (sales.admin=0 AND NOT sales.type IN ('book'))))
ORDER BY sales.created_at DESC, sales.id DESC LIMIT 0, 10;
The schema of the table is
mysql> SHOW columns from sales;
+------------------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------------------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| type | varchar(255) | YES | MUL | NULL | |
| buyer_id | int(11) | YES | MUL | NULL | |
| merchand_id | int(11) | YES | MUL | NULL | |
| private | tinyint(1) | YES | | 0 | |
| admin | tinyint(1) | YES | | 0 | |
| created_at | datetime | YES | | NULL | |
| updated_at | datetime | YES | | NULL | |
| country_id | int(11) | YES | MUL | 0 | |
| private_item | tinyint(1) | YES | | 0 | |
+------------------------+--------------+------+-----+---------+----------------+
The indexes are:
mysql> show indexes from sales;
+-----------------+------------+--------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+-----------------+------------+--------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| sales | 0 | PRIMARY | 1 | id | A | 286509 | NULL | NULL | | BTREE | |
| sales | 1 | index_sales_on_type | 1 | type | A | 123 | NULL | NULL | YES | BTREE | |
| sales | 1 | index_sales_on_buyer_id | 1 | buyer_id | A | 40929 | NULL | NULL | YES | BTREE | |
| sales | 1 | index_sales_on_merchand_id | 1 | merchand_id | A | 40929 | NULL | NULL | YES | BTREE | |
| sales | 1 | index_sales_on_country_id | 1 | country_id | A | 6 | NULL | NULL | YES | BTREE | |
| sales | 1 | index_sales_on_type_and_country_id | 1 | type | A | 151 | NULL | NULL | YES | BTREE | |
| sales | 1 | index_sales_on_type_and_country_id | 2 | country_id | A | 428 | NULL | NULL | YES | BTREE | |
| sales | 1 | index_sales_viewed | 1 | buyer_id | A | 35813 | NULL | NULL | YES | BTREE | |
| sales | 1 | index_sales_viewed | 2 | merchand_id | A | 286509 | NULL | NULL | YES | BTREE | |
| sales | 1 | index_sales_viewed | 3 | private_item| A | 285009 | NULL | NULL | YES | BTREE | |
| sales | 1 | index_sales_viewed | 4 | admin | A | 285009 | NULL | NULL | YES | BTREE | |
| sales | 1 | index_sales_viewed | 5 | type | A | 285009 | NULL | NULL | YES | BTREE | |
| sales | 1 | index_sales_viewed | 6 | private | A | 285009 | NULL | NULL | YES | BTREE | |
| sales | 1 | index_sales_viewed | 7 | created_at | A | 285009 | NULL | NULL | YES | BTREE | |
+-------+------------+------------------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
When doing the query it uses the index_sales_on_type_and_country_id even if there is no country_id in the query...
The query takes 2.5 seconds with this index.
But when I use USE INDEX(index_sales_viewed) it goes down to 0.2 seconds.
Here is the EXPLAIN of the query:
+----+-------------+-----------------+------+----------------------------------------------+------+---------+------+--------+---------------------
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-----------------+------+----------------------------------------------+------+---------+------+--------+---------------------
| 1 | SIMPLE | sales | range | see bellow | index_sales_on_type_and_country_id | 258 | NULL | 208725 | Using where; Using filesort |
+----+-------------+-----------------+------+----------------------------------------------+------+---------+------+--------+---------------------
the possible keys are :
index_sales_on_type,
index_sales_on_buyer_id,
index_sales_on_merchand_id,
index_sales_on_type_and_country_id,
index_sales_public_recent_activity
Why doesn't MySQL use index_sales_viewed by default? Could there be a better index?
Thank you!
This is wrong use on NULL, please change all the column used in the index to be NOT NULL
refer this When to use NULL in MySQL tables
official documentation
If this column is NULL, there are no relevant indexes. In this case, you may be able to improve the performance of your query by examining the WHERE clause to check whether it refers to some column or columns that would be suitable for indexing. If so, create an appropriate index and check the query with EXPLAIN again
Mysql chosen index index_sales_on_type_and_country_id because you are not compare with NULL value