# In embedded server we don't really have a control over stack usage
-- source include/not_embedded.inc

#
# Bug#21476: Lost Database Connection During Query
#
# When the amount of stack space we think we need to report an error is
# actually too small, then we can get SEGVs.  But, we don't want to reserve
# space that we could use to get real work done.  So, we want the reserved
# space small, and this test verifies that the reservation is not too small.

CREATE TABLE `t_bug21476` (
  `ID_BOARD` smallint(5) unsigned NOT NULL default '0',
  `ID_MEMBER` mediumint(8) unsigned NOT NULL default '0',
  `logTime` int(10) unsigned NOT NULL default '0',
  `ID_MSG` mediumint(8) unsigned NOT NULL default '0',
  PRIMARY KEY  (`ID_MEMBER`,`ID_BOARD`),
  KEY `logTime` (`logTime`)
) ENGINE=MyISAM DEFAULT CHARSET=cp1251 COLLATE=cp1251_bulgarian_ci;

INSERT INTO `t_bug21476` VALUES (2,2,1154870939,0),(1,2,1154870957,0),(2,183,1154941362,0),(2,84,1154904301,0),(1,84,1154905867,0),(2,13,1154947484,10271),(3,84,1154880549,0),(1,6,1154892183,0),(2,25,1154947581,10271),(3,25,1154904760,0),(1,25,1154947373,10271),(1,179,1154899992,0),(2,179,1154899410,0),(5,25,1154901666,0),(2,329,1154902026,0),(3,329,1154902040,0),(1,329,1154902058,0),(1,13,1154930841,0),(3,85,1154904987,0),(1,183,1154929665,0),(3,13,1154931268,0),(1,85,1154936888,0),(1,169,1154937959,0),(2,169,1154941717,0),(3,183,1154939810,0),(3,169,1154941734,0);

delimiter //;
let $query_head=UPDATE t_bug21476 SET ID_MSG = IF(logTime BETWEEN 1 AND 1101770053, 2, //
let $query_tail =) WHERE logTime BETWEEN 1 AND 1104091539 AND ID_MSG = 0//

# Scan over the possible stack heights, trying to recurse to exactly that
# depth.  Eventually, we will reach our imposed limit on height and try to
# raise an error.  If the remaining stack space is enough to raise that error,
# we will get an error-number of 1436 and quit the loop.  If it's not enough
# space, we should get a SEGV

# Well more than enough recursions to find the end of our stack.
let $i = 100000//
disable_query_log//
disable_result_log//
while ($i)
{
  # If we SEGV because the min stack size is exceeded, this would return error
  # 2013 .
  error 0,1436 //
  eval $query_head 0 $query_tail//

  if ($mysql_errno)
  {
    # We reached the place where we reported an error about the stack limit,
    # and we successfully returned the error.  That means that at the stack
    # limit, we still have enough space reserved to report an error.
    let $i = 1//

    # Check that mysql_errno is 1436
    if (`select $mysql_errno != 1436`)
    {
      die Wrong error triggered, expected 1436 but got $mysql_errno//
    }

  }

  # Multiplying by three stack frames should be fine enough resolution.
  # Trading exactness for speed.

  # go one more level deep
  let $query_head = $query_head IF(logTime <= 1104091$i, $i, //
  let $query_tail =) $query_tail//

  # go one more level deep
  let $query_head = $query_head IF(logTime <= 1105091$i, $i, //
  let $query_tail =) $query_tail//

  # go one more level deep
  let $query_head = $query_head IF(logTime <= 1106091$i, $i, //
  let $query_tail =) $query_tail//

  dec $i//
}
enable_result_log//
enable_query_log//

echo Assertion: mysql_errno 1436 == $mysql_errno//

delimiter ;//
DROP TABLE `t_bug21476`;

--echo End of 5.0 tests.
