当模式在其名称中包含连字符（“-”）时，MySQL 5.5.9 查询缓存不起作用

Question

我正在运行从 mysql.com 下载的 MySQL 5.5.9 x86_64 RPM。在 CentOS 5.5 Xen DomU 上运行。

我启用了 Query_cache 但是 MySQL 从不使用它。我所有的表都是 InnoDB。为什么 Qcache 从不命中？

更新 2：我发现这仅限于名称中带有 - 的模式。创建一个新架构，例如 new-db，查询缓存失败。不幸的是，我有 148 个现有的 Schama，它们的名字中都带有“-”。

更新这似乎仅限于从以前版本的 MySQL (5.0.32) 转储和导入的模式 创建新模式并在此查询缓存中查询表按预期工作。

这是我的 Qc 工作和不工作的设置和示例。

mysql> SHOW VARIABLES LIKE '%query_cache%';
+------------------------------+-----------+
| Variable_name                | Value     |
+------------------------------+-----------+
| have_query_cache             | YES       |
| query_cache_limit            | 2097152   |
| query_cache_min_res_unit     | 4096      |
| query_cache_size             | 536870912 |
| query_cache_type             | ON        |
| query_cache_wlock_invalidate | OFF       |
+------------------------------+-----------+
6 rows in set (0.00 sec)


mysql> USE `existing-schema`;
Database changed

mysql> CREATE TABLE test (
    ->  `uid` INT AUTO_INCREMENT PRIMARY KEY,
    ->  `str` VARCHAR(255) NOT NULL
        -> ) ENGINE=InnoDB;
    Query OK, 0 rows affected (0.01 sec)

mysql> SHOW CREATE TABLE test;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                                                                              |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| test  | CREATE TABLE `test` (
  `uid` int(11) NOT NULL AUTO_INCREMENT,
  `str` varchar(255) NOT NULL,
  PRIMARY KEY (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8 |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> INSERT INTO test (str) VALUES ('one'),('two'),('three'),('four');
Query OK, 4 rows affected (0.00 sec)
Records: 4  Duplicates: 0  Warnings: 0

mysql> SHOW GLOBAL STATUS LIKE 'Qcache%';

+-------------------------+-----------+
| Variable_name           | Value     |
+-------------------------+-----------+
| Qcache_free_blocks      | 1         |
| Qcache_free_memory      | 536852824 |
| Qcache_hits             | 0         |
| Qcache_inserts          | 0         |
| Qcache_lowmem_prunes    | 0         |
| Qcache_not_cached       | 56725     |
| Qcache_queries_in_cache | 0         |
| Qcache_total_blocks     | 1         |
+-------------------------+-----------+
8 rows in set (0.00 sec)

mysql> SELECT * FROM test;
+-----+-------+
| uid | str   |
+-----+-------+
|   1 | one   |
|   2 | two   |
|   3 | three |
|   4 | four  |
+-----+-------+
4 rows in set (0.00 sec)

mysql> SHOW GLOBAL STATUS LIKE 'Qcache%';
+-------------------------+-----------+
| Variable_name           | Value     |
+-------------------------+-----------+
| Qcache_free_blocks      | 1         |
| Qcache_free_memory      | 536852824 |
| Qcache_hits             | 0         |
| Qcache_inserts          | 0         |
| Qcache_lowmem_prunes    | 0         |
| Qcache_not_cached       | 89824     |
| Qcache_queries_in_cache | 0         |
| Qcache_total_blocks     | 1         |
+-------------------------+-----------+
8 rows in set (0.00 sec)

mysql> CREATE DATABASE new;
Query OK, 1 row affected (0.00 sec)

mysql> USE new;
Database changed
mysql> CREATE TABLE test (
    ->  `uid` INT AUTO_INCREMENT PRIMARY KEY,
    ->  `str` VARCHAR(255) NOT NULL
    -> ) ENGINE=InnoDB;
    Query OK, 0 rows affected (0.01 sec)

mysql> SHOW CREATE TABLE test;
+-------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                                                                                |
+-------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| test  | CREATE TABLE `test` (
  `uid` int(11) NOT NULL AUTO_INCREMENT,
  `str` varchar(255) NOT NULL,
  PRIMARY KEY (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1 |
+-------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)


    mysql> INSERT INTO test (str) VALUES ('one'),('two'),('three'),('four');
    Query OK, 4 rows affected (0.00 sec)

Records: 4  Duplicates: 0  Warnings: 0

mysql> SHOW GLOBAL STATUS LIKE 'Qcache%';
+-------------------------+-----------+
| Variable_name           | Value     |
+-------------------------+-----------+
| Qcache_free_blocks      | 1         |
| Qcache_free_memory      | 536852824 |
| Qcache_hits             | 0         |
| Qcache_inserts          | 0         |
| Qcache_lowmem_prunes    | 0         |
| Qcache_not_cached       | 89824     |
| Qcache_queries_in_cache | 0         |
| Qcache_total_blocks     | 1         |
+-------------------------+-----------+
8 rows in set (0.00 sec)

mysql> SELECT * FROM test;
+-----+-------+
| uid | str   |
+-----+-------+
|   1 | one   |
|   2 | two   |
|   3 | three |
|   4 | four  |
+-----+-------+
4 rows in set (0.00 sec)

mysql> SHOW GLOBAL STATUS LIKE 'Qcache%';
+-------------------------+-----------+
| Variable_name           | Value     |
+-------------------------+-----------+
| Qcache_free_blocks      | 1         |
| Qcache_free_memory      | 536851288 |
| Qcache_hits             | 0         |
| Qcache_inserts          | 1         |
| Qcache_lowmem_prunes    | 0         |
| Qcache_not_cached       | 109528    |
| Qcache_queries_in_cache | 1         |
| Qcache_total_blocks     | 4         |
+-------------------------+-----------+
8 rows in set (0.00 sec)

mysql> SELECT * FROM test;
+-----+-------+
| uid | str   |
+-----+-------+
|   1 | one   |
|   2 | two   |
|   3 | three |
|   4 | four  |
+-----+-------+
4 rows in set (0.00 sec)

mysql> SHOW GLOBAL STATUS LIKE 'Qcache%';
+-------------------------+-----------+
| Variable_name           | Value     |
+-------------------------+-----------+
| Qcache_free_blocks      | 1         |
| Qcache_free_memory      | 536851288 |
| Qcache_hits             | 1         |
| Qcache_inserts          | 1         |
| Qcache_lowmem_prunes    | 0         |
| Qcache_not_cached       | 126100    |
| Qcache_queries_in_cache | 1         |
| Qcache_total_blocks     | 4         |
+-------------------------+-----------+
8 rows in set (0.00 sec)

mysql> SHOW CREATE DATABASE new;
+----------+----------------------------------------------------------------+
| Database | Create Database                                                |
+----------+----------------------------------------------------------------+
| new      | CREATE DATABASE `new` /*!40100 DEFAULT CHARACTER SET latin1 */ |
+----------+----------------------------------------------------------------+
1 row in set (0.01 sec)

mysql> SHOW CREATE DATABASE `existing-schema`;
+------------------+---------------------------------------------------------------------------+
| Database         | Create Database                                                           |
+------------------+---------------------------------------------------------------------------+
| ezlead-live-data | CREATE DATABASE `existing-schema` /*!40100 DEFAULT CHARACTER SET utf8 */ |
+------------------+---------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> SHOW GRANTS FOR 'root'@'localhost';
+----------------------------------------------------------------------------------------------------------------------------------------+
| Grants for root@localhost                                                                                                              |
+----------------------------------------------------------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY PASSWORD '[REMOVED]' WITH GRANT OPTION |
| GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION                                                                           |
+----------------------------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)

Answer 1

这是MySQL 中的一个错误。我想目前唯一的解决方案是重命名我的数据库架构，以便它们不包含连字符。