Repair by Sort not working

Question

I am trying to import a .sql file which has MyISAM engine, about 51 million rows with 18 columns. The file has 1 primary and 1 unique key. I have after lurking around this site and reading mysql manual learned about how to import by using repair by sort. This however started my problem. Although show processlist shows Repair by sort I cant see the tmp tables that it supposedly creates for the process not to mention when I check the /mysql/data directory .myd and .myi files totals the .sql file but the process does not end. I have left the process open for 2 days without any change at which time I killed it.

Could this be because the computer I have to use as mysql server is wamp or cause of the hardware limitations which has 2.gen i5 with 4GB Ram and 1 500GB HDD with 2 partitions or could the dump I have been given is corrupted?

Thnx in advance for any nudge in the right direction to this newbie about mysql and well databases in general. (Below is the parts of the my.ini with the help of percona config tool)

tmpdir = D:/temp
key_buffer_size = 2344M
myisam_file_sort_size = 80G
myisam_max_sort_file_size = 80G
myisam_sort_buffer_size=164M
join_buffer=1M
record_buffer=1M
sort_buffer_size=2M
read_buffer_size=2M
query_cache_size=132M
table_cache=1024
thread_cache_size=256
max_allowed_packet=156M

Answer 1

The tmp tables won't be in /mysql/data, but rather in the subdirectory corresponding to the database. Or maybe in the tmpdir directory.

key_buffer_size = 2344M -- that is just for indexes. In a 4GB machine, that does not leave enough room for data. Change it to 700M.

thread_cache_size -- 0 is better for Windows.

query_cache_size=132M -- too big; drop to 50M

max_allowed_packet=156M -- Probably too high. Suggest 32M.

None of those necessarily explain the symptoms you have. Can you tell if mysql is "swapping"? If it is, that would be deadly, and my suggestions would probably prevent swapping.

Is the "repair" because of a crash? If so, you should seriously consider switching to InnoDB. At least put it on your roadmap. But be aware that the disk footprint with be 2-3 times as big.

"Repair by sorting" would, I think, proceed as follows:

1. Load all the data into the #sql...MYD file. Meanwhile the .MYI file would be 1K or empty.
2. Read the data, sort it, and load it into the .MYI for one index.
3. Ditto for second index.

I do not know if having two unique index complicates things, and necessitates use of the key_buffer.