Thanks to all, Best Regards, Geetanjali Mehra Senior Oracle and MySQL DBA Corporate Trainer and Database Security Specialist
On Fri, Aug 29, 2014 at 11:59 AM, Hartmut Holzgraefe <hart...@skysql.com> wrote: > On 08/29/2014 08:15 AM, geetanjali mehra wrote: > > But after doing *optimize table*, the value inside > > data_free is still the same. If there is no change in the value of > > data_free, then what *optimize table* does here? > > Without seeing actual values I can only give an educated > guess: > > * If you are not using innodb_file_per_table then > data_free is for the whole table space, not just > the individual table you're looking at. > > Even if that table was fragmented before running > OPTIMIZE the overall unallocated storage space > within the table space won't change much ... > > * If you have innodb_file_per_table=1 and you are > seeing data_free values round about 4MB what > you're seeing is simply pre-allocated space. > > See also the last paragraph on > > > http://dev.mysql.com/doc/refman/5.6/en/innodb-multiple-tablespaces.html > > File-per-table tablespace files are auto-extending regardless > of the value of innodb_autoextend_increment. The initial extensions > are by small amounts, after which extensions occur in increments > of 4MB. > > So unless you have innodb_file_per_table set and > see data_free values substantially larger than 4MB > there's nothing to worry about ... > > -- > Hartmut Holzgraefe, Principal Support Engineer (EMEA) > SkySQL - The MariaDB Company | http://www.skysql.com/ > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/mysql > >
