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# Bug#21476: Lost Database Connection During Query
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# When the amount of stack space we think we need to report an error is
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# actually too small, then we can get SEGVs. But, we don't want to reserve
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# space that we could use to get real work done. So, we want the reserved
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# space small, and this test verifies that the reservation is not too small.
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CREATE TABLE `t_bug21476` (
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`ID_BOARD` int(5) NOT NULL default '0',
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`ID_MEMBER` mediumint(8) NOT NULL default '0',
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`logTime` int(10) NOT NULL default '0',
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`ID_MSG` mediumint(8) NOT NULL default '0',
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PRIMARY KEY (`ID_MEMBER`,`ID_BOARD`),
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KEY `logTime` (`logTime`)
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) ENGINE=MyISAM DEFAULT CHARSET=cp1251 COLLATE=cp1251_bulgarian_ci;
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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);
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let $query_head=UPDATE t_bug21476 SET ID_MSG = IF(logTime BETWEEN 1 AND 1101770053, 2, //
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let $query_tail =) WHERE logTime BETWEEN 1 AND 1104091539 AND ID_MSG = 0//
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# Scan over the possible stack heights, trying to recurse to exactly that
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# depth. Eventually, we will reach our imposed limit on height and try to
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# raise an error. If the remaining stack space is enough to raise that error,
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# we will get an error-number of 1436 and quit the loop. If it's not enough
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# space, we should get a SEGV
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# Well more than enough recursions to find the end of our stack.
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# If we SEGV because the min stack size is exceeded, this would return error
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eval $query_head 0 $query_tail//
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if ($mysql_errno != 1436)
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# We reached the place where we reported an error about the stack limit,
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# and we successfully returned the error. That means that at the stack
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# limit, we still have enough space reserved to report an error.
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# Multiplying by three stack frames should be fine enough resolution.
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# Trading exactness for speed.
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# go one more level deep
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let $query_head = $query_head IF(logTime <= 1104091$i, $i, //
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let $query_tail =) $query_tail//
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# go one more level deep
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let $query_head = $query_head IF(logTime <= 1105091$i, $i, //
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let $query_tail =) $query_tail//
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# go one more level deep
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let $query_head = $query_head IF(logTime <= 1106091$i, $i, //
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let $query_tail =) $query_tail//
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echo Assertion: mysql_errno 1436 == $mysql_errno//
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DROP TABLE `t_bug21476`;
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--echo End of 5.0 tests.