I'm trying to do some analysis on data stored in a largish MySQL database. I have 2 tables with 130mio and 600'000 entries respectively and I want to run the following query:
select hashes.hash, hashes.hash LIKE 'block%' as block, min(timestamp) as min, max(timestamp) as max, max(timestamp)-min(timestamp) as diff from timings left join hashes on (id=timings.hash) group by timings.hash
but after a random amount of time (varying between 1 and 18 minutes) I get the following:
$ time mysql timings -e "<query>" > diff2.tsv ERROR 2013 (HY000) at line 1: Lost connection to MySQL server during query real 7m34.158s user 0m0.004s sys 0m0.000s
And I get absolutely no message in the log. Any ideas why this might happen?