mySQL Temporary Table is Full -

i trying create , load temporary mysql table memory using following syntax running "table full" error:

create temporary table if not exists tmphistory engine=memory select * history order date asc; 

my original history innodb table has 3m rows , 300mb. i've increased both of following server variables 16mb default values:

max_heap_table_size = 536870912

tmp_table_size = 536870912

i'm running mysql on aws r3.xlarge 4-core box 30.5gb of ram.

i've reviewed this guidance still running table full error. i'm new using memory engine, suggestions appreciated.

max_heap_table_size, not tmp_table_size controls maximum size of subsequent memory table.

memory has several quirks. perhaps 1 bit you: varchars turned chars. varchar(255) takes 765 bytes each row if character set utf8.

why want copy innodb table memory table? avoid disk hits? no... if innodb_buffer_pool_size big enough, innodb table live in ram. speed things up? not necessarily, because innodb has row locks memory has table locks.

please provide show create table; there may other things argue against doing and/or explain why got error.