blocks|key|3189256|text|在某种程度上，是的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3189257|当涉及到InnoDB时，可以选择哪些行可以被锁定。它与其说是DB连接的特定设置，不如说是DB连接的特定设置。这是在进行更新之前必须调用的一个特定查询。|3189258|SELECT+...+FOR+UPDATE|unordered-list-item|offset|length|style|CODE|3189259|SELECT+...+LOCK+IN+SHARE+MODE|3189260|这可以根据这些选择的结果集启动独占或共享行锁。|3189261|您可以在MySQL文档中找到有关这方面的更多信息。|3189262|我以前写过关于使用以下内容的文章：|3189263|Aug+08,+2011：InnoDB死锁是否仅用于插入/更新/删除？|3189264|Jan+02,+2012：锁定共享模式|3189265|Mar+18,+2012：选择“更新”使索引列出现错误|3189266|May+09,+2012：更新行时事务锁定超时|3189267|May+13,+2012：无法更新innodb表中的某些行.|3189268|Aug+10,+2012；MySQL中的相似函数NOWAIT|3189269|关于会话和连接|3189270|执行SELECT+...+FOR+UPDATE将启动要更新的行的锁，并且仍然允许读取其他DB连接。|3189271|执行SELECT+...+LOCK+IN+SHARE+MODE本质上执行反向|3189272|锁定行，供您阅读|3189273|允许相同锁定行的选择|3189274|防止连接执行SELECT+...+FOR+UPDATE或直接DML|3189275|3189276|在使用这些SELECT查询时，我看到的唯一优点是防止页面上不必要的死锁。|3189277|希望这能帮上忙！|entityMap|0|LINK|mutability|MUTABLE|url|http://dev.mysql.com/doc/refman/5.5/en/innodb-locking-reads.html|1|https://dba.stackexchange.com/questions/4469/are-innodb-deadlocks-exclusive-to-insert-update-delete/4470#4470|2|https://dba.stackexchange.com/questions/10010/lock-in-share-mode/10017#10017|3|https://dba.stackexchange.com/questions/15208/select-for-update-gives-error-on-indexed-column/15219#15219|4|https://dba.stackexchange.com/questions/17561/transaction-lock-timeouts-when-updating-a-row/17649#17649|5|https://dba.stackexchange.com/questions/17788/cannot-update-certain-rows-in-innodb-tables/17795#17795|6|https://dba.stackexchange.com/questions/22286/similar-function-nowait-in-mysql/22296#22296^0|0|0|0|L|0|0|T|0|0|4|7|0|0|0|0|C|D|M|1|0|0|C|D|6|2|0|0|C|D|E|3|0|0|C|D|A|4|0|0|C|D|H|5|0|0|C|D|H|6|0|0|2|L|0|2|T|1|1|1|6|L|1|0|5|6|0^^$0|@$1|2|3|4|5|6|7|24|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|25|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|26|8|@$G|27|H|28|I|J]]|9|@]|A|$]]|$1|K|3|L|5|F|7|29|8|@$G|2A|H|2B|I|J]]|9|@]|A|$]]|$1|M|3|N|5|6|7|2C|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|2D|8|@]|9|@$G|2E|H|2F|1|2G]]|A|$]]|$1|Q|3|R|5|6|7|2H|8|@]|9|@]|A|$]]|$1|S|3|T|5|F|7|2I|8|@$G|2J|H|2K|I|J]]|9|@$G|2L|H|2M|1|2N]]|A|$]]|$1|U|3|V|5|F|7|2O|8|@$G|2P|H|2Q|I|J]]|9|@$G|2R|H|2S|1|2T]]|A|$]]|$1|W|3|X|5|F|7|2U|8|@$G|2V|H|2W|I|J]]|9|@$G|2X|H|2Y|1|2Z]]|A|$]]|$1|Y|3|Z|5|F|7|30|8|@$G|31|H|32|I|J]]|9|@$G|33|H|34|1|35]]|A|$]]|$1|10|3|11|5|F|7|36|8|@$G|37|H|38|I|J]]|9|@$G|39|H|3A|1|3B]]|A|$]]|$1|12|3|13|5|F|7|3C|8|@$G|3D|H|3E|I|J]]|9|@$G|3F|H|3G|1|3H]]|A|$]]|$1|14|3|15|5|6|7|3I|8|@]|9|@]|A|$]]|$1|16|3|17|5|F|7|3J|8|@$G|3K|H|3L|I|J]]|9|@]|A|$]]|$1|18|3|19|5|F|7|3M|8|@$G|3N|H|3O|I|J]]|9|@]|A|$]]|$1|1A|3|1B|5|F|7|3P|8|@]|9|@]|A|$]]|$1|1C|3|1D|5|F|7|3Q|8|@]|9|@]|A|$]]|$1|1E|3|1F|5|F|7|3R|8|@$G|3S|H|3T|I|J]]|9|@]|A|$]]|$1|1G|3|-4|5|6|7|3U|8|@]|9|@]|A|$]]|$1|1H|3|1I|5|6|7|3V|8|@$G|3W|H|3X|I|J]]|9|@]|A|$]]|$1|1J|3|1K|5|6|7|3Y|8|@]|9|@]|A|$]]]|1L|$1M|$5|1N|1O|1P|A|$1Q|1R]]|1S|$5|1N|1O|1P|A|$1Q|1T]]|1U|$5|1N|1O|1P|A|$1Q|1V]]|1W|$5|1N|1O|1P|A|$1Q|1X]]|1Y|$5|1N|1O|1P|A|$1Q|1Z]]|20|$5|1N|1O|1P|A|$1Q|21]]|22|$5|1N|1O|1P|A|$1Q|23]]]]

To some extent, yes.

When it comes to InnoDB, you can choose what rows can get locked. It is not so much a particular setting for the DB Connection. It is a specific query you have to call before doing UPDATEs.

<ul>
<li><code>SELECT ... FOR UPDATE</code></li>
<li><code>SELECT ... LOCK IN SHARE MODE</code></li>
</ul>

This can initiate exclusive or shared row locks based on the result set of those SELECTs.

You can find more information on this in the <a href="http://dev.mysql.com/doc/refman/5.5/en/innodb-locking-reads.html" rel="nofollow noreferrer">MySQL Documentation</a>.

I wrote earlier posts on using these:

<ul>
<li><code>Aug 08, 2011</code> : <a href="https://dba.stackexchange.com/questions/4469/are-innodb-deadlocks-exclusive-to-insert-update-delete/4470#4470">Are InnoDB Deadlocks exclusive to INSERT/UPDATE/DELETE?</a></li>
<li><code>Jan 02, 2012</code> : <a href="https://dba.stackexchange.com/questions/10010/lock-in-share-mode/10017#10017">LOCK IN SHARE MODE</a></li>
<li><code>Mar 18, 2012</code> : <a href="https://dba.stackexchange.com/questions/15208/select-for-update-gives-error-on-indexed-column/15219#15219">select for update gives error on indexed column</a></li>
<li><code>May 09, 2012</code> : <a href="https://dba.stackexchange.com/questions/17561/transaction-lock-timeouts-when-updating-a-row/17649#17649">Transaction Lock Timeouts When Updating a Row</a></li>
<li><code>May 13, 2012</code> : <a href="https://dba.stackexchange.com/questions/17788/cannot-update-certain-rows-in-innodb-tables/17795#17795">Cannot update certain rows in innodb tables</a></li>
<li><code>Aug 10, 2012</code> ; <a href="https://dba.stackexchange.com/questions/22286/similar-function-nowait-in-mysql/22296#22296">Similar function NOWAIT in MySQL</a></li>
</ul>

With regard to sessions and connections

<ul>
<li>Performing <code>SELECT ... FOR UPDATE</code> will initiate locks on rows you intend to update and still permit other DB Connections to read.</li>
<li>Performing <code>SELECT ... LOCK IN SHARE MODE</code> essentially does the reverse

<ul>
<li>lock rows for you to read</li>
<li>allow SELECTs of the same locked rows</li>
<li>prevent connections from doing <code>SELECT ... FOR UPDATE</code> or direct DML</li>
</ul></li>
</ul>

The only advantage I see in using these <code>SELECT</code> queries is preventing needless deadlocks on pages.

I hope this helps !!!

I've heard of page- and row-level locks, but never heard them used with regards to sessions and connections. Today, our (MySQL) DBA was talking about row locks and implied that their scope can be set at the connection or session level. Is this true, or did I misunderstand him?

I didn't realize that locks could be set when a connection is made (or when a session is started) and then released when that connection/session ends. If this is true, what benefits does this have over row-/page-level locks? Thanks in advance.

How are DB locks tied to connections and sessions?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我听说过页面和行级别的锁，但从未听说过用于会话和连接的锁。今天，我们的(MySQL) DBA讨论了行锁，并暗示它们的作用域可以在连接或会话级别上设置。这是真的，还是我误解了他？我没有意识到，当连接建立(或会话启动时)时可以设置锁，然后在连接/会话结束时释放锁。如果这是真的，这对行/页级别的锁有什么好处？提前谢谢。

问DB锁是如何绑定到连接和会话的？
EN

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问DB锁是如何绑定到连接和会话的？EN