…the amazing MySQL manual, especially the option and variable… print_defaultsblogpercona.commanual profilingblogpercona.commanual profiling_history_sizeblogpercona.commanual protocol_versionblogpercona….commanual shared_memoryblogpercona.commanual shared_memory_base_nameblogpercona.commanual show_slave…
Post: Wanted: Better memory profiling for MySQL
May 18, 2008 By 4 Comments
… MySQL using too much memory. I would look at memory consumed by Innodb (it is often higher than innodb_buffer_pool_size) substract memory… see amount of memory allocated for current thread in addition to global memory allocation. As MySQL is progressing the problem of memory allocation transparency…
Post: Three ways that the poor man's profiler can hurt MySQL
December 2, 2011 By 19 Comments
… technique of using GDB as a profiler has become a key tool in helping us analyze MySQL when customers are having trouble… of seconds, but on big servers with a lot of memory and many threads, it can take much longer (I’ve… they can be. Of course, I’m really waiting for MySQL 5.6 and the improved Performance Schema that will be…
Post: Getting MySQL Core file on Linux
August 26, 2011 By 1 Comment
… and restart time. The core file will dump all MySQL Server memory content including buffer pool which can be tens on even…, you may be looking at many times the amount of memory MySQL consumes worth of disk space. You have to do couple… if you expect to do any MySQL profiling or dealing with crashes. It does not slow MySQL performance yet it is very helpful…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
… query execution time, the number of tmp tables created in memory vs on-disk, percentage of queries that needed full scan… these pages in memory. What it says though is that, if this query would run on a cold MySQL instance, then it… next part of the output produced by pt-query-digest. # Profile # Rank Query ID Response time Calls R/Call Apdx V…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…box’s hardware, including RAID controllers, installed memory, and so on in the boot output….mysql –user=mysql –pid-file=/var/run/mysqld/mysqld.pid –skip-external-locking –port=3306 –socket=/var/db/mysql/mysql…, and can completely change the performance profile and workload of a server, so …
Post: Predicting Performance improvements from memory increase
August 7, 2008 By 6 Comments
… much IO bound anyway. Interesting enough because of MySQL scaling issues it is also possible to see …do not expect to gain much by increasing the memory. This however have to be watched carefully. Performance …couple of ideas how to do global working set profiling but it should wait for now. At this …
Post: MySQL Performance on Memory Appliance
March 31, 2008 By 23 Comments
… MySQL Performance on “Memory Appliance” by Violin Memory which can be used as extremely high speed storage system. I helped Violin Memory to optimize MySQL for customer workload and Violin memory… out other storage engines and other workloads or get some profiling results.
Post: Read Buffers, mmap, malloc and MySQL Performance
September 12, 2007 By 8 Comments
… see from this post is – o_profile (often together with strace) are great tools for MySQL Performance analyses. Too many people end…. Indeed allocating with mmap is much slower than allocating from memory memory pool which process already “owns” and in real life it… 10 times slow down over time as memory becomes fragmented with 50.000+ of memory areas mapped. As the gap in the…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 27 Comments
… is a problem for my application. I have profiled it with SHOW STATUS and I know it …big and forget it. If you have enough memory, who cares. The memory isn’t allocated until it’s used … the results to your IO system’s capabilities. MySQL doesn’t have good instrumentation for scientifically choosing …
