【发布时间】：2015-03-21 21:29:30
【问题描述】：
这是一个生产 PHP/MySQL 系统，已经运行了几个月，大部分都没有问题。
非常偶尔，例如每隔几周一次，我会从 MySQL 查询中看到“无法保存结果集”错误。
我知道这可能是由大型结果集引起的，但这里不是这种情况。在最近的例子中，它发生在通常不超过 10 行的小桌子上（行代表活跃的游戏，它们在游戏结束后被删除——很多翻转，但总是很小）。
查询很简单：
SELECT player_1_id, player_2_id FROM minuetServer_games
WHERE ( player_1_id = '1513399' OR player_2_id = '1513399' )
AND last_action_time < SUBTIME( CURRENT_TIMESTAMP, '0 0:01:22.000' )
FOR UPDATE;
此查询的目的是为给定的 user_id（它们可以是 p1 或 p2）找到任何不太陈旧的活动游戏。如果存在，我会在下一个查询中更新他们游戏的 last_action_time（当然，当结果集没有保存时，该更新不会发生）。
我运行了CHECK TABLE，结果还可以。
偶尔出现虚假的“无法保存结果集”警告的原因是什么？有没有办法解决它？有可靠的解决方法吗？
编辑：
一位评论者要求提供有关他的 PHP 配置的更多信息。这是 phpinfo() 输出的直接链接：
http://cordialminuet.com/info.php
编辑2：
这是创建查询的代码：
global $tableNamePrefix;
cm_queryDatabase( "SET AUTOCOMMIT=0" );
global $moveTimeLimit;
$query = "SELECT player_1_id, player_2_id ".
"FROM $tableNamePrefix"."games ".
"WHERE ( player_1_id = '$user_id' OR player_2_id = '$user_id' ) ".
" AND last_action_time < ".
" SUBTIME( CURRENT_TIMESTAMP, '$moveTimeLimit' ) FOR UPDATE;";
// watch for deadlock here and retry
$result = cm_queryDatabase( $query, 0 );
这里是 cm_queryDatabase 的代码：
function cm_queryDatabase( $inQueryString, $inDeadlockFatal=1 ) {
global $cm_mysqlLink;
if( gettype( $cm_mysqlLink ) != "resource" ) {
// not a valid mysql link?
cm_connectToDatabase();
}
$result = mysql_query( $inQueryString, $cm_mysqlLink );
// a bunch of error handling here if $result is FALSE
// ......
// then finally
return $result;
}
这里是 cm_connectToDatabase 的代码：
function cm_connectToDatabase( $inTrackStats = true) {
global $databaseServer,
$databaseUsername, $databasePassword, $databaseName,
$cm_mysqlLink;
$cm_mysqlLink =
mysql_connect( $databaseServer,
$databaseUsername, $databasePassword );
// bunch of error handling if $cm_mysqlLink is false
// ....
}
请注意，“无法保存结果集”是 mysql_query 抛出的警告。此外，该查询每天运行数百次而没有问题。此警告最多每隔几周虚假发生一次。这是几天前的最新堆栈跟踪：
Warning: mysql_query() [<a href='function.mysql-query'>function.mysql-query</a>]: Unable to save result set in /home/jcr14/public_html/gameServer/server.php on line 11248
#0 cm_noticeAndWarningHandler(2, mysql_query() [<a href='function.mysql-query'>function.mysql-query</a>]: Unable to save result set, /home/jcr14/public_html/gameServer/server.php, 11248, Array ([inQueryString] => SELECT player_1_id, player_2_id FROM minuetServer_games WHERE ( player_1_id = '1513399' OR player_2_id = '1513399' ) AND last_action_time < SUBTIME( CURRENT_TIMESTAMP, '0 0:01:22.000' ) FOR UPDATE;,[inDeadlockFatal] => 0,[cm_mysqlLink] => Resource id #4))
#1 mysql_query(SELECT player_1_id, player_2_id FROM minuetServer_games WHERE ( player_1_id = '1513399' OR player_2_id = '1513399' ) AND last_action_time < SUBTIME( CURRENT_TIMESTAMP, '0 0:01:22.000' ) FOR UPDATE;, Resource id #4) called at [/home/jcr14/public_html/gameServer/server.php:11248]
#2 cm_queryDatabase(SELECT player_1_id, player_2_id FROM minuetServer_games WHERE ( player_1_id = '1513399' OR player_2_id = '1513399' ) AND last_action_time < SUBTIME( CURRENT_TIMESTAMP, '0 0:01:22.000' ) FOR UPDATE;, 0) called at [/home/jcr14/public_html/gameServer/server.php:5979]
我将在服务器日志中查找过去几个月的其他示例。
编辑 3：
在过去的 30 天里（我正在刷新旧的日志条目），这种情况发生了五次。其中四次发生在上述查询中。一个不同的查询发生了一次：
SELECT next_magic_square_seed % 4294967296
FROM minuetServer_server_globals FOR UPDATE;
这也被称为每天 100 次没有问题。这是一张只有一行的表格。
周边代码：
function cm_getNewSquare() {
global $tableNamePrefix;
// have it wrap around at the 32-bit unsigned max
// because getMagicSquare6 takes a 32-bit unsigned seed.
// we store it as a BIGINT to keep it from getting stuck on the same
// square after four billion games
$query = "SELECT next_magic_square_seed % 4294967296 ".
"FROM $tableNamePrefix".
"server_globals FOR UPDATE;";
$result = cm_queryDatabase( $query );
编辑 4：
表结构：
mysql> describe minuetServer_games;
+-----------------------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------------------+---------------------+------+-----+---------+----------------+
| game_id | bigint(20) unsigned | NO | PRI | NULL | auto_increment |
| creation_time | datetime | NO | | NULL | |
| last_action_time | datetime | NO | | NULL | |
| player_1_id | int(10) unsigned | NO | MUL | NULL | |
| player_2_id | int(10) unsigned | NO | MUL | NULL | |
| dollar_amount | decimal(11,2) | NO | MUL | NULL | |
| amulet_game | tinyint(3) unsigned | NO | MUL | NULL | |
| amulet_game_wait_time | datetime | NO | MUL | NULL | |
| started | tinyint(3) unsigned | NO | | NULL | |
| round_number | int(10) unsigned | NO | | NULL | |
| game_square | char(125) | NO | | NULL | |
| player_1_got_start | tinyint(4) | NO | | NULL | |
| player_2_got_start | tinyint(4) | NO | | NULL | |
| player_1_moves | char(13) | NO | | NULL | |
| player_2_moves | char(13) | NO | | NULL | |
| player_1_bet_made | tinyint(3) unsigned | NO | | NULL | |
| player_2_bet_made | tinyint(3) unsigned | NO | | NULL | |
| player_1_ended_round | tinyint(3) unsigned | NO | | NULL | |
| player_2_ended_round | tinyint(3) unsigned | NO | | NULL | |
| move_deadline | datetime | NO | | NULL | |
| player_1_coins | tinyint(3) unsigned | NO | | NULL | |
| player_2_coins | tinyint(3) unsigned | NO | | NULL | |
| player_1_pot_coins | tinyint(3) unsigned | NO | | NULL | |
| player_2_pot_coins | tinyint(3) unsigned | NO | | NULL | |
| settled_pot_coins | tinyint(3) unsigned | NO | | NULL | |
| semaphore_key | int(10) unsigned | NO | | NULL | |
+-----------------------+---------------------+------+-----+---------+----------------+
26 rows in set (0.00 sec)
CREATE 语句：
"CREATE TABLE $tableName(" .
"game_id BIGINT UNSIGNED NOT NULL PRIMARY KEY AUTO_INCREMENT," .
"creation_time DATETIME NOT NULL,".
"last_action_time DATETIME NOT NULL,".
"player_1_id INT UNSIGNED NOT NULL," .
"INDEX( player_1_id )," .
"player_2_id INT UNSIGNED NOT NULL," .
"INDEX( player_2_id )," .
"dollar_amount DECIMAL(11, 2) NOT NULL,".
"INDEX( dollar_amount )," .
"amulet_game TINYINT UNSIGNED NOT NULL,".
"INDEX( amulet_game ),".
// wait for a random amount of time before
// settling on an opponent for an amulet game
"amulet_game_wait_time DATETIME NOT NULL,".
"INDEX( amulet_game_wait_time ),".
"started TINYINT UNSIGNED NOT NULL,".
"round_number INT UNSIGNED NOT NULL," .
// 36-cell square, numbers from 1 to 36, separated by #
// character
"game_square CHAR(125) NOT NULL,".
// flag set when each player requests the very first game
// state. This indicates that both are aware that the game
// has started, so leave penalties can be assessed
"player_1_got_start TINYINT NOT NULL,".
"player_2_got_start TINYINT NOT NULL,".
"player_1_moves CHAR(13) NOT NULL,".
"player_2_moves CHAR(13) NOT NULL,".
"player_1_bet_made TINYINT UNSIGNED NOT NULL,".
"player_2_bet_made TINYINT UNSIGNED NOT NULL,".
"player_1_ended_round TINYINT UNSIGNED NOT NULL,".
"player_2_ended_round TINYINT UNSIGNED NOT NULL,".
"move_deadline DATETIME NOT NULL,".
"player_1_coins TINYINT UNSIGNED NOT NULL, ".
"player_2_coins TINYINT UNSIGNED NOT NULL, ".
"player_1_pot_coins TINYINT UNSIGNED NOT NULL, ".
"player_2_pot_coins TINYINT UNSIGNED NOT NULL, ".
// coins in both pots that are common knowledge to both players
// (coins that have been matched by opponent to move on
// to next turn)
"settled_pot_coins TINYINT UNSIGNED NOT NULL, ".
"semaphore_key INT UNSIGNED NOT NULL ) ENGINE = INNODB;"
【问题讨论】：
-
这是一个 PHP 错误，而不是 MySQL 错误。要确定问题，您需要提供有关执行此命令的 PHP 上下文的更多信息。
-
不，不是 phpinfo - ！生成和应用更新的 php 代码。
-
首先 - 停止使用
mysql扩展，因为它已弃用。尝试重写您的代码以改用mysqli或pdo。 -
@PaulTomkiel：对于一个拥有大量现有代码库的大型现有项目来说，目前这可能不是一个非常有用的建议......
-
@FélixGagnon-Grenier：MySQL 文档清楚地说明了可能发生此故障的情况，这不是由于锁冲突（通常只会导致一个查询排队等待这些锁被释放，可能会超时——除非出现死锁，在这种情况下会引发错误）。