Lars Steen Lars Steen - 6 months ago 38
Linux Question

Why is import of SQL so slow?

I have an SQL file containing two tables with around 600,000 rows altogether. Yesterday, I tried to import the file into my MySQL database on Fedora 16, and it took over 2 hours to import the file. On my Windows PC it took 7 minutes. My Linux and Windows machines have exactly the same hardware. A couple of my friends tried it too, and they had a similar experience.

The command we were using was:

mysql -u root database_name < sql_file.sql

Why is there such a difference in speed?


My bet is that Fedora 16 is honoring the transaction/sync semantics and Windows is not. If you do the math, 600,000 updates in two hours is 5,000 per minute. That's the same order of magnitude as a disk's rotation rate.

You can try adding SET autocommit=0; to the beginning of your import file and COMMIT; to the end. See this page for more information.