…memory insertion in the simple table and table with long rows and bunch of indexes will see lower numbers. So what’s the deal ? First MySQL…
Post: The new cool MySQL patch has landed! Check your queries performance!
October 31, 2007 By 16 Comments
…THE REPLICATED STATEMENTS Normally MySQL will not …indexes. If a temporary table is required for query execution Tmp_table will be set. Sometimes that table must be created on disk instead of in memory, in such case Disk_tmp_table… chance for hash collisions. In …
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…MySQL. My goal was to simulate as much IO as possible so I use Sysbench to get 300Mil rows table…. Disabling adaptive hash index could take …
Post: MySQL 5.6: Improvements in the Nutshell
January 27, 2013 By 16 Comments
…in MySQL …Memory Fragmentation – Reduced Locking for Partitioned tables – Reduced Contention for LOCK_open – Support for multiple table…index for Innodb – Microsecond TIME precision – Precise spatial operations in GIS Security – Password hashes instead of plain passwords in Query Logs – SHA256 hashing…
Post: UNION vs UNION ALL Performance
October 5, 2007 By 15 Comments
When I was comparing performance of UNION vs MySQL 5.0 index merge algorithm Sinisa pointed out I should be using UNION… table without such index. This also explains why difference becomes larger when on disk table is required (as in this case) – Hash indexes used by MEMORY table…
Post: Percona build7 with latest patches
November 14, 2008 By 26 Comments
… MySQL 5.0.67 build 7 which … names are Innodb_scan_* | | userstatsv2.patch | SHOW USER/TABLE/INDEX statistics | V2 | Google | GPL | Added INFORMATION_SCHEMA.*_STATISTICS…) | | innodb_show_hashed_memory.patch | Adds additional information of InnoDB internal hash table memories in SHOW INNODB STATUS |…
Post: Using CHAR keys for joins, how much is the overhead ?
June 18, 2007 By 18 Comments
…. The results below are for MySQL 5.1.18 using MyISAM and Innodb tables. This time unlike other … so I replaced all numbers with their sha1() hashes which still made eq join to run the … for in memory tables, for IO bound workload results are likely to be different as longer indexes expected to …
Post: Percona Server 5.5.13-20.4 Stable Release
July 1, 2011 By 3 Comments
… the Percona Software Repositories). Based on MySQL 5.5.13, Percona Server Percona … provided the ability to use a shared memory segment for the buffer pool to …tables (e.g. 350G) using the Expand Table Import feature due to a timeout. Bug Fix: #684829 (Y. Kinoshita). Partitioning adaptive hash index…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
…hash index is hash index Innodb builds for some pages to speed up row lookup replacing btree search with hash search. This section shows hash table…memory usage. You can see total memory allocated by Innodb (sometimes it is higher than you anticipated), amount of memory allocated in additional memory…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
…hash indexes require that the prefix is stored in every record R. An adaptive hash index…tables, everything can reside within a single extent. For big tables, a secondary index reserves different extents from the clustered index…€™s memory the kernel can decide (incorrectly) to swap out MySQL. There …
