… which do not scale that well. This is why it …are where a lot of work need to be done …clust_rec_for_mysql,row_search_for_mysql,ha_innobase::index_read,…index makes things a lot worse in this workload and innodb_adaptive_hash_index_partitions=16 available for partitioning adaptive hash index does not…
Post: Why Index could refuse to work ?
September 8, 2006 By 13 Comments
…why simple coversion to the string does not work. Interesing enough it works other way around – you can refer to integer column as a string in most cases and MySQL…
Post: Falcon Storage Engine Design Review
January 12, 2007 By 19 Comments
… got them while working for MySQL. These thought base …not if you’re doing something unusual, which people do quite frequently with MySQL 
[+] Compact Indexes Compact Indexes are great. Huge indexes…why Jim does not believe in it. [+/-] Only committed changes go to the disk Innodb modifies data in…
Post: How adding another table to JOIN can improve performance ?
August 1, 2008 By 12 Comments
… from the issue with MySQL optimizer stopping using further index key parts as soon …does not work. The trick however does work if you have just one group_id (and in this case you do not…another table though why it does not work for multiple group remains question to check with MySQL Optimizer team …
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 139 Comments
… system is different in some respect and what works well for Oracle,MS SQL, PostgreSQL may not work well for MySQL and other …or not different selectivity might show benefit from using indexes. In fact even MySQL optimizer currently does not take it into account. For In memory workload index …
Post: Covering index and prefix indexes
November 23, 2006 By 5 Comments
…of experiments to see when exactly it works or does not work: CREATE TABLE `t` ( `i` int(11) …in the index but MySQL does not look at the actual data in this case it only looks at definitions. mysql>…in set (0.00 sec) This example is less obvious – one may think why can’t we read only from the index…
Post: MySQL File System Fragmentation Benchmarks
March 21, 2008 By 28 Comments
…for i in 1 10 100 1000 10000; do ./benchmark.php $i 10000000; mysql -e’drop database test1′; mysql -e…does not work very well. Note: As I checked later contrary to my expectation this filesystem was created without dir_index…again for 10000 tables. I can’t explain why it is a bit worse for 1000 tables…
Post: Reasons for run-away main Innodb Tablespace
June 10, 2010 By 1 Comment
… to be inserted in the index tree and undo …following can be helpful: mysql> select * from innodb_rseg; +———+———-+———-+———+————+———–+ | rseg_…keep up. This however does not work in all cases. If …why Master and Slave may get so much different table space size in…
Post: Database problems in MySQL/PHP Applications
August 11, 2006 By 12 Comments
… but it also might work. Regarding if you use… your data however it does not always bring good performance….not have all these problems with loosing data etc. Read more in my Why MySQL…Not using Join. This is typical error. On other hand in MySQL… do not expect it soon. Use Indexes This item was not in …
Post: MySQL net_write_timeout vs wait_timeout and protocol notes
July 8, 2007 By 1 Comment
…back in multiple pieces and if you’re using mysql_use_result you can do any work …large data sets and large buffers. While indexing Sphinx performs sorts and flushes buffers …MySQL protocol which does not allow client to talk to the server until full result set is fetched. This is also the reason why…
