Shulou(Shulou.com)05/31 Report--

What this article shares to you is about the expression of several new parameters of mysql5.5, the editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

The new parameter item the old parameter indicates that innodb_read_io_threads innodb_write_io_threadsinnodb_file_io_threads (default is 4) needs to enable asynchronous IO, otherwise it doesn't make any sense. Online tests are set to 2 for the best performance. No more than 4. Therefore, it has a great impact on high-speed devices such as ssd, while traditional hard drives have less impact. Can be set to Barracuda format, can be set to dynaic and compressed format. MySQL uses this parameter to evaluate the io capacity of your disk, which is valid only in independent tablespaces. The default 200page is for general SAS disks. In the case of high disk performance, you can set a larger number of innodb_rollback_segments rollback segments. The default is whether the 128innodb_support_xa parameter setting supports distributed transactions. The default value is ON or 1, which means distributed transactions are supported. If you confirm that distributed transactions are not needed in the application, you can turn this parameter off to reduce the number of disk refreshes and achieve better InnoDB performance

S

Multi-instance bp, provided that the buffer_pool_size is greater than 1G, and a maximum of 64 instances are supported. In the past, only the default insert cache was used, but now it includes delete,purge. The default is all.

Innodb_purge_batch_size

Whether to enable independent threads to clear undo pages. Default is 0. The number of pages deleted each time is controlled by Innodb_purge_batch_size. Default is 20skip-external-lockingskip-lockingdefault-character-setlog_bin_trust_routine_creators.

Setting the format of data rows

The file format supports Antelope (antelope) Compact [tight cluster] default format for blog, and the rest of the overflow Redundant [redundancy] is 20 bytes for Barracuda (barracuda) Compressed [compression] for IO performance before the previous version 5.0. the rest is completely overflowed.

In 5. 5, three tables about locks (MEMORY engine) have been added to the information_schema library:

Innodb_trx # # all currently running transactions

Innodb_locks # # current locks

Innodb_lock_waits # # correspondence of lock waiting

The above is the representation of several new parameters of mysql5.5, and the editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.