title: mysql workbench "Lost connection to mysql server"
body: <p>First I need to indicate that I ran the sql file for the Wikipedia dump on my machine, and to be able to run that I needed to update many settings regarding the index size available on memory and some other settings. I just want to mention that those large sql queries were run successfully and I didn't have any problem regarding memory or time out.</p>
  
  <p>Now I have a table pagelinks (pl_from, pl_title) that shows the links that appears in each wikipedia page, for example the data can be (1, "title1"), (1,"title2"), (2, "title3"), (2, "title1"). I want to create a table that concat the titles group by pl_from. For that this is my sql query (I am using workbench):</p>
  
  <pre><code>SET @@group_concat_max_len=150000;
  create table concatpagelinks 
  (SELECT pl_from, GROUP_CONCAT(pl_title , ' ') as links FROM pagelinks GROUP BY pl_from)
  </code></pre>
  
  <p>Running this query I got the error : "Lost connection to mysql server during query" and the system asked me again for the password. So I search and found <a href="http://dev.mysql.com/doc/refman/5.0/en/error-lost-connection.html" rel="noreferrer">this</a>. Therefore I changed net_read_timeout to 1000 and connect_timeout to 60. It didn't solve the problem, SO I changed the query to :</p>
  
  <pre><code>SET @@group_concat_max_len=150000;
  create table concatpagelinks 
  (SELECT pl_from, GROUP_CONCAT(pl_title , ' ') as links FROM pagelinks GROUP BY pl_from limit 0,1000)
  </code></pre>
  
  <p>Still the same problem, and the amazing thing is that every time the query is run for 600.495 sec and the error happens.</p>