script for watching mysqld. r=endico@mozilla.org

diff --git a/mysqld-watcher.pl b/mysqld-watcher.pl
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+#!/usr/bonsaitools/bin/perl -w
+#
+# The contents of this file are subject to the Mozilla Public
+# License Version 1.1 (the "License"); you may not use this file
+# except in compliance with the License. You may obtain a copy of
+# the License at http://www.mozilla.org/MPL/
+# 
+# Software distributed under the License is distributed on an "AS
+# IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
+# implied. See the License for the specific language governing
+# rights and limitations under the License.
+# 
+# The Original Code is the Bugzilla Bug Tracking System.
+# 
+# The Initial Developer of the Original Code is Netscape Communications
+# Corporation. Portions created by Netscape are
+# Copyright (C) 2000 Netscape Communications Corporation.  All
+# Rights Reserved.
+# 
+# Contributor(s): Dan Mosedale <dmose@mozilla.org>
+#
+
+# mysqld-watcher.pl - a script that watches the running instance of
+# mysqld and kills off any long-running SELECTs against the shadow_db
+# 
+use diagnostics;
+use strict;
+
+require "globals.pl";
+
+# some configurables: 
+
+# length of time before a thread is eligible to be killed, in seconds
+#
+my $long_query_time = 600;
+#
+# the From header for any messages sent out
+#
+my $mail_from = "root\@lounge.mozilla.org";
+#
+# mail transfer agent.  this should probably really be converted to a Param().
+#
+my $mta_program = "/usr/lib/sendmail -t -ODeliveryMode=deferred";
+
+# and STDIN is where we get the info about running threads
+#
+close(STDIN);
+open(STDIN, "/usr/bonsaitools/bin/mysqladmin processlist |");
+
+# iterate through the running threads
+#
+my @LONGEST = (0,0,0,0,0,0,0,0,0);
+while ( <STDIN> ) { 
+    my @F = split(/\|/);
+
+    # if this line is not the correct number of fields, or if the thread-id
+    # field contains Id, skip this line.  both these cases indicate that this
+    # line contains pretty-printing gunk and not thread info.
+    #
+    next if ( $#F != 9 || $F[1] =~ /Id/); 
+
+    if ( $F[4] =~ /shadow_bugs/             # shadowbugs database in use
+         && $F[5] =~ /Query/                # this is actually a query
+         && $F[6] > $long_query_time        # this query has taken too long
+         && $F[8] =~ /(select|SELECT)/      # only kill a select
+         && $F[6] > $LONGEST[6] ) {         # the longest running query seen
+        @LONGEST = @F;
+    }
+}
+
+# if we found anything, kill the database thread and send mail about it
+#
+if ($LONGEST[6] != 0) {
+
+    system ("/usr/bonsaitools/bin/mysqladmin", "kill", $LONGEST[1]);
+
+    # fire off an email telling the maintainer that we had to kill a thread
+    #
+    sendEmail($mail_from, Param("maintainer"), 
+            "long running MySQL thread killed",
+            join(" ", @LONGEST) . "\n");
+}
+
+# send an email message
+#
+# should perhaps be moved to somewhere more global for use in bugzilla as a 
+# whole; should also do more error-checking
+#
+sub sendEmail($$$$) {
+    ($#_ == 3) || die("sendEmail: invalid number of arguments");
+    my ($from, $to, $subject, $body) = @_;
+
+    open(MTA, "|$mta_program");
+    print MTA "From: $from\n";
+    print MTA "To: $to\n";
+    print MTA "Subject: $subject\n";
+    print MTA "\n";
+    print MTA $body;
+    print MTA "\n";
+    close(MTA);
+   
+}