<div>
Hi all
</div><div><br></div><div>I'm wondering if anyone has seen this issue before. Any help would be greatly appreciated. There are a few threads on Stack Overflow, but most of them are marked as duplicates of the supposedly solved thread, which just points to the MySql docs.</div><div><br></div><div>I've removed part of the query, but it's a very straight-forward statement, with a single join. Our db is properly indexed.</div><div><br></div><div>Thanks in advance.</div><div><br></div><div>------</div><div><br></div><div>We're trying to upgrade to Ubuntu 12.04 and we're getting intermittent connection failures. When we upgrade to Ubuntu 12.04, we get this error at seemingly random intervals in the Rails 2.3 app:</div><div><br></div><div><blockquote style="margin: 0px 0px 0px 40px; border: none; padding: 0px; "><div><span style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; ">ActiveRecord::StatementInvalid: Mysql2::Error: Lost connection to MySQL server during query: SELECT <a href="http://users.id" style="color: rgb(0, 106, 227); ">users.id</a>, users.last_login_ip, users.account_id, accounts.account_type_id FROM `users` INNER JOIN `accounts` ON `accounts`.id = `users`.account_id WHERE (...) ORDER BY <a href="http://users.id" style="color: rgb(0, 106, 227); ">users.id</a></span></font></span></div></blockquote><div><span style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; "><br></span></font></span></div><div style="text-align: left; "><b style="line-height: 18px; color: rgb(68, 68, 68); font-family: HelveticaNeueW01-55Roma, 'Helvetica Neue', Helvetica, Arial, Verdana, sans-serif; font-size: large; ">Libraries used in tested apps and OS</b></div><div style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; "><b><br></b></span></font></div><div style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; "><b>Ubuntu 10.04</b></span></font></div><div style="text-align: left; "> mysql-client-5.1 5.1.67-0<br></div><div style="text-align: left; "><div><b><span style="font-size: 12px; line-height: 18px; color: rgb(68, 68, 68); font-family: HelveticaNeueW01-55Roma, 'Helvetica Neue', Helvetica, Arial, Verdana, sans-serif; "><br></span></b></div><div><b><span style="font-size: 12px; line-height: 18px; color: rgb(68, 68, 68); font-family: HelveticaNeueW01-55Roma, 'Helvetica Neue', Helvetica, Arial, Verdana, sans-serif; ">Ubuntu 12.04</span></b></div></div><div> mysql-client-5.5 5.5.28-0<span style="color: rgb(68, 68, 68); font-family: HelveticaNeueW01-55Roma, 'Helvetica Neue', Helvetica, Arial, Verdana, sans-serif; font-size: 12px; line-height: 18px; text-align: left; "><br></span></div><div><span style="color: rgb(68, 68, 68); font-family: HelveticaNeueW01-55Roma, 'Helvetica Neue', Helvetica, Arial, Verdana, sans-serif; font-size: 12px; line-height: 18px; text-align: left; "><b><br></b></span></div><div><span style="color: rgb(68, 68, 68); font-family: HelveticaNeueW01-55Roma, 'Helvetica Neue', Helvetica, Arial, Verdana, sans-serif; font-size: 12px; line-height: 18px; text-align: left; "><b>RDS production database</b></span></div><div><span style="color: rgb(68, 68, 68); font-family: HelveticaNeueW01-55Roma, 'Helvetica Neue', Helvetica, Arial, Verdana, sans-serif; font-size: 12px; line-height: 18px; text-align: left; "> Mysql 5.1.63</span><span style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; "><br></span></font></span></div><div><div style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; "><b><br></b></span></font></div><div style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; "><b>Rails 2.3</b></span></font></div><div style="text-align: left; "> rails (2.3.17)<font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; "><br></span></font></div><div style="text-align: left; "> mysql2 (0.2.18)<font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; "><br></span></font></div><div style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; "><br></span></font></div><div style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; "><b>Rails 3.2</b></span></font></div><div style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; "> </span></font>rails (3.2.12)</div><div style="text-align: left; "> mysql2 (0.3.11)</div><div style="text-align: left; "><br></div><div style="text-align: left; ">Ubuntu 12.04 only comes with Mysql 5.5 packages by they should be 100% compatible (<a href="https://help.ubuntu.com/12.04/serverguide/mysql.html" style="color: rgb(0, 106, 227); ">https://help.ubuntu.com/12.04/serverguide/mysql.html</a>)</div><div style="text-align: left; "><br></div><div style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif" size="4"><span style="line-height: 18px; "><b><br></b></span></font></div><div style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif" size="4"><span style="line-height: 18px; "><b>Debugging</b></span></font></div><div><br></div><div><b>ActiveRecord</b></div></div><div style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; ">I was able to replicate it by executing this query raw from ActiveRecord instance.</span></font></div><div style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; ">Like this:</span></font></div><blockquote style="margin: 0px 0px 0px 40px; border: none; padding: 0px; "><div style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; ">ActiveRecord::Base.connection.execute("</span></font><span style="color: rgb(68, 68, 68); font-family: HelveticaNeueW01-55Roma, 'Helvetica Neue', Helvetica, Arial, Verdana, sans-serif; font-size: 12px; line-height: 18px; ">SELECT <a href="http://users.id" style="color: rgb(0, 106, 227); ">users.id</a>, users.last_login_ip, users.account_id, accounts.account_type_id FROM `users` INNER JOIN `accounts` ON `accounts`.id = `users`.account_id WHERE (...) ORDER BY<a href="http://users.id" style="color: rgb(0, 106, 227); ">users.id</a>")</span></div></blockquote><div style="text-align: left; "><span style="color: rgb(68, 68, 68); font-family: HelveticaNeueW01-55Roma, 'Helvetica Neue', Helvetica, Arial, Verdana, sans-serif; font-size: 12px; line-height: 18px; "><br></span></div><div style="text-align: left; "><span style="color: rgb(68, 68, 68); font-family: HelveticaNeueW01-55Roma, 'Helvetica Neue', Helvetica, Arial, Verdana, sans-serif; font-size: 12px; line-height: 18px; ">Although the problem is that error appears only from time to time.</span></div><div style="text-align: left; "><font color="#444444" face="HelveticaNeueW01-55Roma, Helvetica Neue, Helvetica, Arial, Verdana, sans-serif"><span style="font-size: 12px; line-height: 18px; ">When testing on 2 machines at once I received the error at same time frames. This could mean that the error is dependant on database state ( traffic spikes? ).</span></font></div><div style="text-align: left; "><br></div><div style="text-align: left; "><b>Mysql2 gem</b></div><div style="text-align: left; "><span style="font-size: 12px; line-height: 18px; color: rgb(68, 68, 68); font-family: HelveticaNeueW01-55Roma, 'Helvetica Neue', Helvetica, Arial, Verdana, sans-serif; ">We thought that the Mysql2 gem could be to blame, but we could not replicate the issue when executing query from Mysql2 gem instance (i.e. without Rails environment).</span><br></div><div style="text-align: left; "><br></div><div style="text-align: left; "><b>Query too large</b></div><div style="text-align: left; ">One of the possible causes by the MySQL documentation is:<br></div><div style="text-align: left; "><i>You can also get these errors if you send a query to the server that is incorrect or too large.<br></i></div><div style="text-align: left; "><br></div><div style="text-align: left; ">We tried to shortening the query but got nothing definitive, and this also doesn't explain why our query sometimes succeeds.</div></div>
<div><div><br></div><div>-- </div><div>Ed James</div><div>Sent with <a href="http://www.sparrowmailapp.com/?sig">Sparrow</a></div><div><br></div></div>