Question

The current way I am loading the file is:

   load data local infile 'file_name' into table tableA  
fields terminated by ',' enclosed by '"' lines terminated by '\n';

Is the optimal way to load in a table in a unix machine. Does it create the optimal table size? I want a table that takes up the smallest space.

Answer 1

MyISAM

If the table is MyISAM, you should do the following:

set bulk_insert_buffer_size = 1024 * 1024 * 256;
alter table tableA disable keys;
load data local infile 'file_name' into table tableA  
fields terminated by ',' enclosed by '"' lines terminated by '\n';
alter table tableA enable keys;

InnoDB

If the table is InnoDB, you should do the following:

set bulk_insert_buffer_size = 1024 * 1024 * 256;
load data local infile 'file_name' into table tableA  
fields terminated by ',' enclosed by '"' lines terminated by '\n';

No only will this take up the least space (loading an empty table), but the rows will be buffered in a treelike structure in memory based on the bulk_insert_buffer_size for caching the data quicker during the reload.

If you are worried about ibdata1 exploding, you need to convert all InnoDB tables to use innodb_file_per_table. Please use my InnoDB Cleanup Steps : Howto: Clean a mysql InnoDB storage engine?