table cache mysql

1. View Data Table Structure 1) view the basic table structure statement DESCRIBE syntax: DESCRIBE table name; example: mysqlDESCRIBEproduct; + ---------------- + ------------ + ------ + ----- + --------- + ---------------- + | Field 1. view the data table structure 1) view the basic

). Indicates whether the page is readable, writable, or read-only. However, r/w bit-to-page write protection only works when the processor is at the user privilege level.When the processor is at the system privilege level, the R/W bit is ignored, which can always be read, written, or executed. -U/S (2)-User/Administrator bit (user/supervisor). Indicates that the page is available to the user layer (privilege Layer 3) and the administrator layer, and only to programs that can be used by the admin

the safe side, please try not to use dynamic annotations. In PHP's MySQL extensions, SQL annotations are not removed. That is, three of SQL is stored in three different caches, although their results are the same.SELECT * from people where name= ' surfchen ';SELECT * from people where/*hey~*/name= ' surfchen ';SELECT * from people where name= ' surfchen '; Currently only SELECT statements will be cache, o

Reprinted: mysql status view QPSTPS cache hit rate view Reprinted: http://blog.163.com/ji_1006/blog/static/106123412013101421530142/ View the running mysql status Monitor running mysql. one of the following methods is to view the running status of mysql.(1) QPS (queries per

Reprint to Http://www.server110.com/mysql/201311/2991.htmlThe global shared memory is mostly MySQL Instance (MySQLD process) and the underlying storage engine is used to stage various global operations and shareable staging information, such as query cache to store queries cached, thread cache for the connection thread

The cache mechanism simply caches the SQL text and query results. If the same SQL statement is run, the server directly retrieves the results from the cache without parsing and executing the SQL statement. If the table is changed, all cache queries using this table will no l

(not explicitly stating that the query cache is not allowed, or if you have explicitly declared that you need to use query cache), MySQL will hash the received SELECT statement as a string directly based on a pre-set hash algorithm, and then go directly to the query cache to find out if it is already cached. That is,

whether the function is enabled. have_query_cache indicates whether the function is enabled, and query_cache_limit indicates the buffer size that can be used by a single query. The default value is 1 M. query_cache_min_res_unit indicates the minimum size of Cache, the default value is 4 kb. Setting a large value is good for big data queries. However, if you query small data queries, memory fragmentation and waste may occur; query_cache_size and query

If a Cache clause is specified when a table is created or modified, the table will be added to the database Cache for a long time when the data in the table is accessed for the first time, If a Cache clause is specified when a

Table replication in MySQL: create table like and create table as select, tables in mysql Copy codeThe Code is as follows:CREATE TABLE A LIKE B In this way, when table B is copied to

is inserted, all SQL caches related to the table will be cleared.Query OK, 1 row affected (0.00 sec)Records: 1 Duplicates: 0 Warnings: 0 Mysql> select count (*) from animals;+ ---------- +| Count (*) |+ ---------- +| 7 |+ ---------- +1 row in set (0.00 sec) Mysql> show status like 'qcache _ hits ';+ --------------- + ------- +| Variable_name | Value |+ ---------

Tags: style blog color using data sp div problem cWith the long-term use of MySQL, there will certainly be some problems, in general, the MySQL table can not be accessed, it is possible to repair the table, optimized to reduce disk space, convenient backup. Table table_name

. Therefore, do not use dynamic comments if possible. In the mysql extension of PHP, SQL comments are not removed. That is, three sqls will be stored in three different caches, although their results are the same.Select * FROM people where name = 'surfchen ';Select * FROM people where/* hey ~ */Name = 'surfchen ';SELECT * FROM people where name = 'surfchen '; Currently, only select statements are cached. Other statements similar to show and use statem

| | qcache_not_cached | 2 | | Qcache_free_memory | 20932976 | | Qcache_free_blocks | 1 | | Qcache_total_blocks | 6 | +-------------------------+----------+ The query has not made to the cache-in fact, MySQL has inserted query in the another The problem is this is this MySQL ' s query cache is case-sensitive (in fact

next mysql-log, found that the query table is constantly inserting data, according to the PV number of the site can be judged by someone in the frequent use of the search function, this feature is not configured Sphinx Full-text indexing, but directly read the database, and real-time statistics user input keywords. However, the frequent insertion of new data by people will cause the

-level variables or local variables in the stored procedure;The lock in share mode and for update statements are used IN the query statement.The query statement is similar to SELECT... INTO statement for data export;When the transaction isolation level is Serializable, all query statements cannot be cached;Query temporary tables;Query statement with warning information;Query statements that do not involve any tables or views;A user can only query statements with column-level permissions; Advanta

cache is typically used only during table scans. It is like a read-ahead buffer that retrieves one chunk at a time, reducing the number of disk accesses during the scan. in general, fewer disk accesses mean higher performance. Interestingly, MySQL also uses the record cache when writing data sequentially: Write the ne

MYSQL Tutorial: my. cnf cache optimization 1. check the machine configuration, which refers to three major parts: cpu, memory, and hard disk 2. check mysql configuration parameters. 3. check the mysql row status. you can use the mysqlreport tool to view the status. 4. View mysql