Added: script simulating a slow MySQL server

Author: patrickallaert

README.md

@@ -41,4 +41,16 @@ using red in reverse video.
 
 Same as debug.lua, but without shell colors.
 
+### slow.lua
+
+Simulates a server being slow because of huge traffic.
+
+The *sleep* command accepting a float as argument is required to make this
+script works out of the box.
+
+The slowdowns can be configured to make all requests longer by a factor or by
+a fixed amount of time (or both).
+
+By default, requests are made twice slower with an additional overhead of 0.1s.
+
 [mysql-proxy]: http://forge.mysql.com/wiki/MySQL_Proxy

slow.lua

@@ -0,0 +1,40 @@
+-- MySQL Proxy script for simulating a slow server
+--
+-- Written by Patrick Allaert <[email protected]>
+-- Copyright © 2009-2011 Libereco Technologies
+-- 
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+-- Requirements: the sleep command accepting a float value as parameter
+-- See http://lua-users.org/wiki/SleepFunction for alternatives
+
+-- Factor of slowness, how many times slower every requests should be
+factor = 2
+
+-- In addition to a factor of slowness you can set a fixed amount of additional
+-- time every request should take (in seconds).
+additionalTime = 0.1
+
+function read_query( packet )
+  if packet:byte() ~= proxy.COM_QUERY then
+    return
+  end
+  proxy.queries:append(1, string.char(proxy.COM_QUERY) .. packet:sub(2))
+
+  return proxy.PROXY_SEND_QUERY
+end
+
+function read_query_result (inj)
+  os.execute( "sleep " .. ( ( (factor - 1) * inj.response_time / 1e6 ) + additionalTime ) )
+end