Some queries stays "statistics" state for long time in my Google Cloud SQL Database. (MySQL 5.5)
After this post, I changed optimizer_search_depth to 0. But some queries still have long statistics time.
> select @@optimizer_search_depth;
+--------------------------+
| @@optimizer_search_depth |
+--------------------------+
| 0 |
+--------------------------+
> show processlist;
+----+------+-----------+------+---------+------+------------+-----------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------+------+---------+------+------------+-----------------+
| 4 | root | localhost | mydb | Query | 84 | statistics | SELECT * FROM ..|
Table and count is as below.
> describe mytable;
+----------+---------------+------+-----+---------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+----------+---------------+------+-----+---------------------+-----------------------------+
| col1 | varchar(50) | NO | PRI | NULL | |
| col2 | varchar(50) | NO | PRI | NULL | |
| col3 | decimal(15,4) | NO | | NULL | |
| col4 | decimal(15,4) | NO | | NULL | |
| col5 | decimal(15,4) | NO | | NULL | |
| col6 | decimal(15,4) | NO | | NULL | |
| col7 | varchar(50) | YES | | NULL | |
| col8 | decimal(15,4) | NO | | NULL | |
| col9 | decimal(15,4) | NO | | NULL | |
| col10 | varchar(8) | NO | | NULL | |
| col11 | varchar(30) | NO | | NULL | |
| col12 | timestamp | NO | | 0000-00-00 00:00:00 | |
| col13 | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| col14 | int(11) | NO | | NULL | |
+----------+---------------+------+-----+---------------------+-----------------------------+
> select count(*) from mytable;
+----------+
| count(*) |
+----------+
| 852304 |
+----------+
Query is like this.
SELECT * FROM mytable WHERE
((col1 = 'FFP60003' AND col2 = '360' ) OR
(col1 = 'FIU51001' AND col2 = '210' ) OR
(col1 = 'FIU51003' AND col2 = '360' ) OR
(col1 = 'FPC60001' AND col2 = '240' ) OR
(col1 = 'SLU50006' AND col2 = '360' ) OR
... (about 2000-3000 and/or) ...
(col1 = '89969' AND col2 = '270' ) ) AND col14 > 0
As shown above, query is very long. I think this is the cause of long statistics state, but my app needs this type of query.
How can I avoid long statistics issue?
[Update]
SHOW CREATE TABLE and SHOW VARIABLES LIKE '%buffer%' are as belows.
> show create table mytableG
*************************** 1. row ***************************
Table: mytable
Create Table: CREATE TABLE `mytable` (
`col1` varchar(50) NOT NULL COMMENT 'col1',
`col2` varchar(50) NOT NULL COMMENT 'col2',
`col3` decimal(15,4) NOT NULL COMMENT 'col3',
`col4` decimal(15,4) NOT NULL COMMENT 'col4',
`col5` decimal(15,4) NOT NULL COMMENT 'col5',
`col6` decimal(15,4) NOT NULL COMMENT 'col6',
`col7` varchar(50) DEFAULT NULL COMMENT 'col7',
`col8` decimal(15,4) NOT NULL COMMENT 'col8',
`col9` decimal(15,4) NOT NULL COMMENT 'col9',
`col10` varchar(8) NOT NULL COMMENT 'col10',
`col11` varchar(30) NOT NULL COMMENT 'col11',
`col12` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00' COMMENT 'col12',
`col13` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT 'col13',
`col14` int(11) NOT NULL COMMENT 'col14',
PRIMARY KEY (`col1`,`col2`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
> SHOW VARIABLES LIKE '%buffer%';
+------------------------------+-----------+
| Variable_name | Value |
+------------------------------+-----------+
| bulk_insert_buffer_size | 8388608 |
| innodb_buffer_pool_instances | 1 |
| innodb_buffer_pool_size | 805306368 |
| innodb_change_buffering | all |
| innodb_log_buffer_size | 8388608 |
| join_buffer_size | 131072 |
| key_buffer_size | 8388608 |
| myisam_sort_buffer_size | 8388608 |
| net_buffer_length | 16384 |
| preload_buffer_size | 32768 |
| read_buffer_size | 131072 |
| read_rnd_buffer_size | 262144 |
| sort_buffer_size | 2097152 |
| sql_buffer_result | OFF |
+------------------------------+-----------+
See Question&Answers more detail:
os 
