… tuned system you have if you put too heavy of concurrent load on it the response times will increase and user… to use. Do push concurrency too high Many developers will test script with multiple level of concurrency and find out doing work… to serve other users too you typically need to reduce concurrency to where it does not overload the system. Unless it…
Post: Benchmarking single-row insert performance on Amazon EC2
May 16, 2012 By 11 Comments
… used: ## InnoDB options innodb_buffer_pool_size = 55G innodb_log_file_size = 1G innodb_log_files_in_group = 4 innodb_buffer_pool_instances = 4 innodb_adaptive…) ENGINE = InnoDB, PARTITION p10 VALUES LESS THAN MAXVALUE ENGINE = InnoDB) */ Also, I ran 5 instances of iiBench simultaneously to simulate 5 concurrent connections…
Post: InnoDB's gap locks
March 27, 2012 By 14 Comments
… of the most important features of InnoDB is the row level locking. This feature provides better concurrency under heavy write load but…? Is possible to detect those gap locks using SHOW ENGINE INNODB STATUS: —TRANSACTION 72C, ACTIVE 755 sec 4 lock struct(s… have lot of gaps locks in your transactions affecting the concurrency and the performance you can disable them in two different…
Comment: InnoDB thread concurrency
March 19, 2012 By 4 Comments
… i ask you quesiton? i issue the command ‘show engine innodb status’, is shows there are 10 io threads(4 are… that the value of the innodb_thread_concurrency is 8. so, what is wrong with this sitution? what the innodb_thread_concurrency real meaning?
Comment: InnoDB's gap locks
April 4, 2012 By 14 Comments
Andy, With READ COMMITTED InnoDB doesn’t take additional locks on the gap, improving the concurrence. You would avoid all “Lock wait… locks on the gap, so no wait timeout and more concurrence.
Comment: Should you move from MyISAM to Innodb ?
March 10, 2012 By 53 Comments
… that is) and that if not using InnoDB you aren’t too smart. However, InnoDB brings a lot of cons to the… not use MyISAM. If you have a huge number of concurrent writes and selects and query performance must be consistently fast… your problems. In fact there are other engines better than InnoDB for certain usage patterns – if you go down this path…
Post: Tuning InnoDB Concurrency Tickets
May 24, 2010 By 4 Comments
… innodb_concurrency_tickets that seems widely misunderstood. From the docs: “The number of threads that can enter InnoDB concurrently is determined by the innodb_thread_concurrency variable. A thread is placed in a queue when it tries to enter InnoDB if…
Post: InnoDB thread concurrency
June 5, 2006 By 4 Comments
…_to_enter_innodb–; ENTER; } retry: if (entered_thread < innodb_thread_concurrency) { entered_threads++; thread->n_tickets_to_enter_innodb = innodb_concurrency_tickets; ENTER; } if (innodb_thread_sleep_delay > 0) { thread_sleep(innodb_thread_sleep…
Post: MySQL/Innodb scalability tests after fix
January 3, 2007 By 1 Comment
… still have massive scalability drop with increasing concurrency – going from 10 to 20 concurrent connections drops performance from about 620 to 450… nasty surprise. It may be possible to improve it with innodb concurrency settings though – I do not know, this requires some extra… MySQL scalability problem with high number of CPUs and high concurrency is elevated but it is far from being completely eliminated…
Post: kernel_mutex problem cont. Or triple your throughput
December 2, 2011 By 10 Comments
… with innodb_thread_concurrency also may help. So I ran some benchmarks with innodb_thread_concurrency. My explanation on the performance degradation is following: InnoDB… innodb_thread_concurrency=8. So now let’s compare results for innodb_thread_concurrency= 0 vs 8 for all range of threads: Threads innodb concurrency=0 innodb concurrency…
