…MySQL 3.23 when there would only handful of places where memory could be allocated but it is a lot larger problems with MySQL…for Table Cache Related Allocations There are cases when MySQL will allocate a lot of memory for table cache, especially if you’re using large… valgrind are too slow to run in …
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 2 Comments
… you could be reading the same page multiple times. Consider if you have a small buffer pool and a very large number of rows from table2 that do not fit into the buffer pool, then worst case you could be reading… is slow as compared to MySQL 5.6. Next interesting thing are the last two columns of the table above and the values for…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 139 Comments
… number of index lookups which could be random accesses. This problem exists for all kinds of applications, however for OLTP applications with queries examining… join of few large tables, which is completely disk bound can be very slow. One of the reasons elevating this problem in MySQL is lack…
Post: Database problems in MySQL/PHP Applications
August 11, 2006 By 12 Comments
…, your ALTER TABLE or OPTIMIZE TABLE now locks small table for few seconds rather than giant 100GB table for few hours so can be done pretty much…. Read more in my Why MySQL Could be slow with Large Tables article. 5. The n+1 pattern This probably should rather be called Not using Join…
Comment: Database problems in MySQL/PHP Applications
August 11, 2006 By 12 Comments
…, your ALTER TABLE or OPTIMIZE TABLE > now locks small table for few seconds rather than giant 100GB table > for few hours so can be done pretty much… lookup table however so you do > not have all these problems with loosing data etc. Read more in my > Why MySQL Could be slow with Large Tables…
Post: Slow DROP TABLE
June 16, 2009 By 21 Comments
…mysql> drop table large_table; Query OK, 0 rows affected (0.29 sec) A better solution through MySQL internals could be to simulate the table…
Post: MySQL: what read_buffer_size value is optimal ?
September 17, 2007 By 25 Comments
… for large table you should set this variable to some high value. Sample my.cnf values on large memory sizes recommend 1M settings and MySQL…. It could be OS has to split large requests into multiple ones submitting them to device which slows things down or it could be something else…
Post: MySQL Server Variables - SQL layer or Storage Engine specific.
June 8, 2006 By 14 Comments
…and could be used by something else. True in theory but in practice for years…tables in MyISAM format in “mysql” database. Plus HEAP/MEMORY tables are used for temporary tables which may become MyISAM if they are large… slow query log or general log. flush, flush_time Flushing (closing) of tables …
Post: Read Buffers, mmap, malloc and MySQL Performance
September 12, 2007 By 8 Comments
…for MySQL Performance analyses. Too many people end tuning on plans and indexes while there well could be… times slow …large pages. These already can be used for Innodb Buffer Pool and Key Buffer but could be used for other large…table or LIMIT 10 in full table scan query you well may not need large…
Post: MySQL extensions for hosting
April 24, 2008 By 11 Comments
…being used at all and could be candidates for dropping. All the patch features will surely be a great help for…mysql> SHOW TABLE_STATISTICS LIKE ‘hosting2%’; +——————————–+———–+————–+————————-+ | Table…
