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first turn off the transaction and then insert, so the speed is fastMySQL supports the two main table storage format Myisam,innodb, last month to do a project, the first use of InnoDB, the result is particularly slow, 1 seconds can only insert 10. Later into the MyISAM format, one second to insert tens of thousands of bars. It was decided that the performance of the two tables was too different. Later, I g
single table: The most common database design, for example, a user table is placed in database db, all users can be found in the DB Library in the Use table2) Library Multi-table: As the number of users increased, the user table data volume is more and more large, when the amount of data to a certain extent, the User
The MySQL system creates temporary tables in memory (MEMORY) and disks (MyISAM), how do you know how many temporary tables are built on disk, and how many temporary tables are built in memory? You can learn from the following commands: Mysql> show GLOBAL STATUS like ' created_tmp%tables '; +-------------------------+----------+ | Variable_name | Value | +-------------------------+----------+ |
query has no performance problems, we look at 10, 100, 1000, 10000 to start the paging execution time (20 per page), as follows: SELECT * FROM Product limit 10, 20 0.016 secondsSELECT * FROM product limit 100, 20 0.016 secondsSELECT * FROM product limit 1000, 20 0.047 secondsSELECT * FROM Product limit 10000, 20 0.094 seconds We have seen that as the start record increases, the time also increases, which means that the paging statement limit is very
of the limit statement is proportional to the position of the starting record2) MySQL limit statement is very convenient, but for many records of the table is not suitable for direct use.2. Performance optimization approach to limit paging problemSpeed up paged queries with table overlay indexesAs we all know, if you
After the data found that MySQL can use variable tmp_table_size and max_heap_table_size to control the upper limit of memory table size, if more than the upper limit will write data to disk, which will have physical disk read and write operations, resulting in performance impact.We can improve performance by adjusting
High Performance MySQL Reading Notes-query performance optimization, high performance mysql For high-performance database operations, it is not enough to design the optimal database table
Label:Today, database operations are increasingly becoming a performance bottleneck for the entire application, which is especially noticeable for web applications. It's not just about the performance of the database that DBAs need to worry about, it's something that our programmers need to focus on. When we design the database table structure, we need to pay att
updated. Nature,The amount of Binary Log is large. Especially when statements such as alter table are executed, the log volume generated is astonishing. Because MySQL processes DDL change statements such as alter table by recreating all data in the entire TABLE, that is, every record in the
the database, and all kinds of constraints are actually a very consuming resource for the database. Therefore, for the performance-based database schema design, we can not completely take the canonical paradigm theory as the only guidance. In the design process, should start from the actual demand, performance improvement as the fundamental goal to carry out the design work, many times in order to maximize
‘max_connections‘;+—————–+——-+| Variable_name | Value |+—————–+——-+| max_connections | 256 |+—————–+——-+ The maximum number of connections on this MySQL server is 256, and then query the maximum number of connections on the server response:Mysql> show global status like 'max _ used_connections ';In the past, the maximum number of connections on the MySQL server was 245, but the maximum number of conne
obtain the required data (query) in the desired format ). Complex applications can have complex modes and queries. If you want the performance and scalability required by the application, you cannot simply rely on intuition to understand how to execute the query. You should learn how to use the EXPLAIN command instead of making guesses and imagination at will. This command shows how to execute a query and shows you the expected
Mysql database performance optimization 1. mysql Performance Optimization Today, database operations are increasingly becoming the performance bottleneck of the entire application, especially for Web applications. Concerning the database
|| Handler_read_rnd | 219230406 || Handler_read_rnd_next | 344713226172 |+-----------------------+--------------+7 rows in set (0.00 sec) Handler_read_first: Number of times the index is used for scanning. This value is not clear about big novels. the system performance is good or bad. Handler_read_key: number of queries by key. A greater value indicates better system performance. Handler_read_next: Th
MYSQL Performance Tuning and architecture design-instance analysis of factors affecting MYSQL Performance Requirement overview A simple discussion zone system requires users, user groups, and group discussion areas. Brief analysis 1) tables that need to store user data; 2) tables that need to store group information an
consider increasing the load on distributed reads from the server, in another case, the value of max_connections In the mysql configuration file is too small: mysql> show variables like 'max_connections';+-----------------+-------+| variable_name | value |+-----------------+-------+| max_connections | 256 |+-----------------+-------+ The maximum number of connections on this
speed is 100 times times more, Io from 100% to less than 1%Test on SSD machine, optimize before 7s, optimize the first 0.3s, second 0.1s, optimized execution speed is 10 times times more, Io from 100% to less than 1%As you can see, pre-optimization disk IO is a performance bottleneck, the SSD is significantly faster than SATA, the disk is no longer a bottleneck after optimization, and SSD and SATA performance
association query, and there is no appropriate index, perhaps one of the sub-query created a temporary table, and then make a union query with other tables, and the temporary table used to hold the results of the subquery is not indexed.? Note, however, that using show status itself creates a temporary table and also accesses the temporary
default tablespace has a negative impact on performance. Define a default temporary tablespace named TEMP for all users. This prevents users from allocating SYSTEM tablespace as the default temporary tablespace. Creating a user who uses SYSTEM as the default temporary tablespace has a negative impact on the performance, because this will cause resource competiti
not null) ENGINE = InnoDB; Change the UPDATE and query SQL statement to mysql> UPDATE hit_counter SET cnt = cnt + 1 WHERE slot = RAND () * 100; mysql> SELECT SUM (cnt) FROM hit_counter; Ps: If you need to refresh the counter every day, add the Time column: create table daily_hit_counter (day date not null, slot tinyint unsigned not null primary key, cnt int uns
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