Hi there!

I'm working on a project using the Catalyst framework. The db access is done by DBIx::Class. All works fine until the queries get too complicated and take too long to run.

Therefore I wrote a test script to find out if there is a fix amount of time after which the db crashes and the answer is yes. If a query takes longer than 50 seconds then we get the error msg:

DBI Exception: DBD::mysql::st execute failed: Lost connection to MySQL server during query

For testing I use the query "SELECT SLEEP(n);" which does nothing but to sleep for n seconds and then returns.
Here is my test code:

use encs;
my $sto     = encs->model("DB::Exset")->new({})->result_source->schema
+->storage;
printf("start\n");
foreach my $i (49,50,51,52,53,49) {
    print("wait $i seconds:\n");
    my $t1 = time;
    my $t2 = undef;
    eval {
        $sto->dbh_do(
              sub {
                my ($storage, $dbh, @cols) = @_;
                $t2 = time;
                my $sth = $dbh->prepare("Select sleep($i)") or die $db
+h->errstr;
                $sth->execute or die $sth->errstr;
                my $data = $sth->fetchrow_hashref;
              }  
        );
    };
    if ( $@ ) {
        printf("ERROR: %s (%d, %d)\n", $@, time - $t1, time - $t2);   
+ 
    } 
    else {
        printf("Ok: (%d, %d)\n", time - $t1, time - $t2);    
    }  
}
printf("end\n");
exit;

[download]
A typical run: 
start
wait 49 seconds:
Ok: (92, 49)
wait 50 seconds:
Ok: (86, 50)
wait 51 seconds:
ERROR: {UNKNOWN}: DBI Exception: DBD::mysql::st execute failed: Lost c
+onnection to MySQL server during query [for Statement "Select sleep(5
+1)"] at ./script/encs_wetest.pl line 32 (86, 51)
wait 52 seconds:
ERROR: {UNKNOWN}: DBI Exception: DBD::mysql::st execute failed: Lost c
+onnection to MySQL server during query [for Statement "Select sleep(5
+2)"] at ./script/encs_wetest.pl line 32 (51, 51)
wait 53 seconds:
ERROR: {UNKNOWN}: DBI Exception: DBD::mysql::st execute failed: Lost c
+onnection to MySQL server during query [for Statement "Select sleep(5
+3)"] at ./script/encs_wetest.pl line 32 (51, 51)
wait 49 seconds:
Ok: (49, 49)
end

[download]

"encs" is my Catalyst class. 50 seconds are running through and 51 seconds are failing. Interestingly the query breaks everey time after 51 seconds, but it's not the mysql server that ends the connection. There ist no error message at the mysql server. If I setup a DBI connection on my own, without Catalyst, then it runs as long as it takes. Therefore I think it's an Catalyst/DBIx issue.

My Catalyst YAML config for db:

Model::DB:
      schema_class: encs::Schema::DB
      connect_info:
          dsn: dbi:mysql:encs01_test:encsdb
          user: uu
          password: xxxxx
          options:
              mysql_connect_timeout: 600
              net_read_timeout: 600
              net_write_timeout: 600

[download]

Does anybody have an idea what is the problem? How I could configure Catalyst to avoid this timeout?

Thx, Lars

In reply to DBIx or Catalyst problem: Lost connection to MySQL server during query by Largo

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