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Search Results for: kernel_mutex problem

kernel_mutex problem cont. Or triple your throughput

This is to follow up my previous post with kernel_mutex problem. First, I may have an explanation why the performance degrades to significantly and why innodb_sync_spin_loops may fix it. Second, if that is correct ( …


kernel_mutex problem. Or double throughput with single variable

Problem with kernel_mutex in MySQL 5.1 and MySQL 5.5 is known: Bug report. In fact in MySQL 5.6 there are some fixes that suppose to provide a solution, but MySQL 5.6 yet has long way …


Memory allocators: MySQL performance improvements in Percona Server 5.5.30-30.2

In addition to the problem with trx_list scan we discussed in Friday’s post, there is another issue in InnoDB transaction processing that notably affects MySQL performance – for every transaction InnoDB creates a read view …


trx descriptors: MySQL performance improvements in Percona Server 5.5.30-30.2

One major problem in terms of MySQL performance that still stands in the way of InnoDB scalability is the trx_list scan on consistent read view creation. It was originally reported as a part of MySQL …


thread_concurrency doesn’t do what you expect

Over the last months I’ve seen lots of customers trying to tune the thread concurrency inside MySQL with the variable thread_concurrency. Our advice is: stop wasting your time, it does nothing on GNU/Linux Some of …


Three ways that the poor man’s profiler can hurt MySQL

Over the last few years, Domas’s technique of using GDB as a profiler has become a key tool in helping us analyze MySQL when customers are having trouble. We have our own implementation of it …


Tuning for heavy writing workloads

For the my previous post, there was comment to suggest to test db_STRESS benchmark on XtraDB by Dimitri. And I tested and tuned for the benchmark. I will show you the tunings. It should be …