mysql query cache size

. subcategory = c. idGroup by c. idHaving count (*)> 2000;-- Choose one of the results, thenSelect * from subcategory where id = ????-- Result: category = 14I got a suitable value of 14, which will be used in the following queries. This is the statement used to query subcategory where the number of all items in category 14 is greater than 2000:[SQL]Copy codeThe Code is as follows:Select c. idFrom subcategory as cInner join item as I on I. subcategory

Count MySQL data table size bitsCN.com How can I query the size of each table in the MySQL database? MySQL has a database named information_schema, which has a TABLES Table. The main fields of this table are: TABLE_SCHEMA: data

|+ ------------------------- + ------- +3 rows in set (0.00 sec) Created_tmp_tables is increased each time a temporary table is used, and Created_tmp_disk_tables is increased for a disk-based table. There are no strict rules for this ratio, because it depends on the involved query. After a long period of observation, Created_tmp_disk_tables will display the ratio of the created disk table. You can determine the efficiency of the settings. Both tmp_ta

How to use commands to view the Mysql database size bitsCN.com How to use commands to view the Mysql database size 1. enter the specified schema database (storing the information of other databases) 1 Use information_schema 2. query the

script execution time'Mysql _ version' => $ this-> _ mysql_version (),'Mysql _ size' => $ this-> _ mysql_db_size (),);$ This-> display ();}Private function _ mysql_version (){$ Model = self: _ model ();$ Version = $ Model-> query ("select version () as ver ");Return $ version [0] ['ver '];}Private function _ mysql_db_size (){$ Model = self: _ model ();$ SQL = "S

Library. These extension libraries are directly oriented to programmers, and their underlying implementation is the mysql connection engine (such as mysqlnd and libmysql) (refer to http://bbs.chinaunix.net/thread-3679393-1-1.html, http://blog.csdn.net/treesky/article/details/7286098 ). Mysqlnd and libmysql are the database connection driver for PHP clients. Libmysql is a general database connection engine, while mysqlnd is a connection engine develop

of the calculation as key, query results as value 3, the MySQL query cache is case-sensitive, so use SQL as far as possible to use the same style will not be cached statements 1, indeterminate data, not cached, such as now (), Current_time () 2, If the query SQL contains

Query_cache_min_res_unit: query the minimum block size (in bytes) allocated by the cache) Query_alloc_block_size: QueryDuring analysis and executionMemory block size allocated to the created objectQcache_free_blocks indicates the number of free memory blocks, reflecting the memory fragmentation. =====================

say, the block will be used in three places: Table information, SQL text, and query results. Show global status like 'com _ select': You can view the number of queries without cache, including read/write queries. The total number of SELECT queries is equivalent: Com_select + Qcache_hits + queries with errors found by parser The value of Com_select is equivalent: Qcache_inserts + Qcache_not_cached + queries

considered to be different queries and are cached separately. 2. Query cache related parametersMySQL>like'%query_cache%'; 3. A simple example:MySQL> use zzlp; MySQL> show Tables; MySQL>Selectcount(*fromuser; #Qcache_hits表示sql查询在缓存中命中的累计次数, is the cumulative value of mysql