CollectionFind::lockShared

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CollectionFind::lockShared — Execute operation with SHARED LOCK

Description

public mysql_xdevapi\CollectionFind::lockShared(int $lock_waiting_option = ?): mysql_xdevapi\CollectionFind

Allows to share the documents between multiple transactions which are locking in shared mode.

Other sessions can read the rows, but cannot modify them until your transaction commits.

If any of these rows were changed by another transaction that has not yet committed,

your query waits until that transaction ends and then uses the latest values.

Parameters

lock_waiting_option

Optional waiting option. By default it is MYSQLX_LOCK_DEFAULT. Valid values are these constants:

  • MYSQLX_LOCK_DEFAULT

  • MYSQLX_LOCK_NOWAIT

  • MYSQLX_LOCK_SKIP_LOCKED

Return Values

A CollectionFind object that can be used for further processing

Examples

Example #1 mysql_xdevapi\CollectionFind::lockShared() example

<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");

$schema     = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");

$session->startTransaction();

$result = $collection
  ->find("age > 50")
  ->lockShared()
  ->execute();

// ... read the object in shared mode

// Complete the transaction and unlock the document
$session->commit();
?>