…performing the lookup, and then there are other possibilities like InnoDB doing read_ahead by noticing the sequential …equi-join, then the way hash join algorithm will operate is that first a hash table will be …this that the query on MariaDB 5.5 is slow as compared to MySQL 5.6. Next interesting …
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 3 Comments
… STATUS and look for memory information block, which can use like this: ———————- BUFFER POOL AND MEMORY ———————- Total memory allocated 132183490560; in… total any more as Innodb has moved allocating memory from operation system directly not from addition memory pool (hence 0). Such… rather complicated as good tools to detect memory leaks like valgrind are too slow to run in production. So the best thing…
Post: MySQL Slow query log in the table
May 31, 2007 By Leave a Comment
As of MySQL 5.1 get MySQL slow query log logged in mysql.slow_log table instead of the file as you… already looked at using LIKE statement. As default table format for slow_log is CSV with no indexes typical operations like finding how many… over and over again you can create stored procedure, something like LAST_SLOW_QUERIES and use it instead, just remember unless you…
Post: InnoDB Flushing: a lot of memory and slow disk
March 31, 2011 By 57 Comments
… time (and that is an important factor with slow disks); and 3) MySQL does not support innodb… extent, but remember that hard disks love sequential operations, and your throughput in this case may turn… may vary a lot, like EC2 systems, or is affected by periodic tasks like backup or heavy background …
Post: Solving INFORMATION_SCHEMA slowness
December 23, 2011 By 16 Comments
… much space innodb tables are using and things like it. Besides being just slow accessing information_schema can often impact server performance dramatically. The cause of majority of this slowness is not opening and closing tables, which can be solved… query information_schema. Most likely you do not want it anyway. This will not make Innodb to operate without statistics at all…
Post: Tuning for heavy writing workloads
October 14, 2009 By 9 Comments
… workloads. At first,
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 139 Comments
… other hand it is well known with customers like Google, Yahoo, LiveJournal,Technocarati MySQL has installations … which is completely disk bound can be very slow. One of the reasons elevating this problem … and table design you can build applications operating with very large data sets based on…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… what the operating parameters are. Can… by line, like this: +———————————–+———————-+———————-+ | Variable_name | Value | Value | +———————————–+———————-+———————-+ |…mysqlsla -lt slow /path/to/slow.log …
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 27 Comments
…that occur, because we know that disks are very slow relative to other parts of the computer. And …hit, maybe. What else? Maybe this physical I/O operation is randomly positioned, which is a worst-case …a performance problem. I know what I’d like: I’d like to ask the disk itself how much random…
Comment: How to find wrong indexing with glance view
March 8, 2010 By 27 Comments
… support. Going from any of those systems to MySQL is like switching from a driving modern automobile to one from the… useless they’re detrimental. Not only do these indexes slow down insert operations, the MySQL optimizer sometimes appears to become rather overwhelmed… key(currency_id) references items(currency_id), foreign key(operator_id) references items(operator_id) ); create index order_date_idx on orders…
