…average of sum of “r” and “b” columns from VMSTAT. Obviously minimum value…of network IO involved or if there are a lot of locks (table/row… for Disk there are two stages request can be…requests a bit better compared to requests coming one after… same – until you’re able to explore parallel abilities of…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 4 Comments
…same page multiple times. Consider if you have a small buffer pool and a very large number of rows…then, after the selected rows are read from table1, the values of indexed columns that will be …compared to MySQL 5.6. Next interesting thing are the last two columns of the table above and the values…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…values in the date_id column. There will be another blog post about the usage and performance of…of data, so ICE gets over 16:1 compression ratio(compared to Innodb, 8:1 compared…tables yet but since InnoDB compression is not RLE, I doubt it will have the same…
Post: COUNT(*) vs COUNT(col)
April 10, 2007 By 45 Comments
…) | +————-+ | 7340032 | +————-+ 1 row in set (0.00 sec) As this is MYISAM table MySQL has cached number of rows in this table. This is why… val column is not defined as NOT NULL there can be some NULL values in it and so MySQL have to perform table… good job in this case doing full table scan only if it is needed because column can be NULL. Now lets try…
Post: MySQL Performance - eliminating ORDER BY function
October 17, 2007 By 6 Comments
…of the first rules you would learn about MySQL Performance Optimization is to avoid using functions when comparing… Compare those two … column value needs to …row *************************** id: 1 select_type: SIMPLE table: tst type: ref possible_keys: i key: i key_len: 5 ref: const rows… same function…
