Unanswered: Significant Performance Difference Between Comparable Boxes
I have several production MySQL servers, but I’m having a strange issue. Both are comparable systems (although not hardware identical) running Ubuntu 8.10 with the exact same software and databae types (and indexes). Both were deployed with apt-get, git, and RoR db migrations, and phpMyAdmin shows indexes match. However one is tasking significantly longer to import data.
Takes under 15 minutes to import 100k records (I do some RoR based validation)
Has more column rows
Server version: 5.0.67-0ubuntu6
Is still chugging along after 5+ hours with a 300k record import
Has fewer column rows
Server version: 5.0.67-0ubuntu6-log
Examining the Processes tab with phpMyAdmin Box B always shows a
SELECT COUNT( * ) AS count_all
IN ( 5 )
AND phone = '44113293XXXX'
Query as its current process (my RoR program FIRST checks for a duplicate, and if none is found, adds it). Doing an explain on this statement at the command line shows that both boxes use the correct index. I cannot figure out why one machine performs the import so well, and the other so poorly. The one item I noticed was the server version. Box B is running 5.0.67-0ubuntu6-log and Box A is running the same version w/o log. What does this mean? I’m out of ideas of how to solve this, so your input would be greatly appreciated.