php - 使用 HandlerSockets 时，我可以指定要从查询中接收哪些字段吗？

Question

我可以在使用 HandlerSockets 时指定我想从查询中接收哪些字段吗？ ？

这是我的示例表

CREATE TABLE pushed_media
(
    user_id BINARY(12) NOT NULL,
    story_id BINARY(12) NOT NULL,
    sent_date TIMESTAMP DEFAULT CURRENT_TIMESTAMP NOT NULL,
    PRIMARY KEY ( user_id, story_id )
);

下面是查询它的php代码

$hs = new HandlerSocket($host, $port);
if (!($hs->openIndex(1, $dbname, $table, HandlerSocket::PRIMARY, 'user_id,story_id,sent_date')))
{
    echo $hs->getError(), PHP_EOL;
    die();
}

$user_id = pack('H*', substr(md5('ruslan'), 0, 24));
$story_id = pack('H*', substr(md5('story1'), 0, 24));

$retval = $hs->executeSingle(1, '=', array($user_id, $story_id), 1, 0);

我只需要 sent_date 因为我已经知道另外两个值。是否可以不再通过网络传输它们？

Answer 1

您可以通过简单地在 openIndex 的 field 参数中指定您希望从查询中接收的字段来指定它们方法。
如您所见here ，这段代码:

<?php
$hs->openIndex(1, 'db', 'table', 'PRIMARY', 'k,v');
$ret = $hs->executeSingle(1, '>=', array('K1'));
var_dump($ret);
?>

相当于下面的SQL语句:

SELECT k,v FROM table WHERE k >= 'K1' LIMIT 1

回到您的示例，如果您只想读取 sent_date 字段值:

$hs = new HandlerSocket($host, $port);
if (!$hs->openIndex(1, $dbname, $table, myHandlerSocket::PRIMARY, 'sent_date')) {
    die($hs->getError());
}

$user_id  = pack('H*', substr(md5('ruslan'), 0, 24));
$story_id = pack('H*', substr(md5('story1'), 0, 24));

$retval = $hs->executeSingle(1, '=', array($user_id, $story_id), 1, 0);
die("<pre>".print_r($retval,true)."</pre>");

结果输出应该是这样的:

Array
(
    [0] => 0
    [1] => 1
    [2] => 2013-02-01 22:18:39
)

HandlerSocket protocol documentation状态:

Once an 'open_index' request is issued, the HandlerSocket plugin opens the specified index and keep it open until the client connection is closed. Each open index is identified by <indexid>. If <indexid> is already open, the old open index is closed. You can open the same combination of <dbname> <tablename> <indexname> multple times, possibly with different <columns>. For efficiency, keep <indexid> small as far as possible.