Index: branches/5.2.x/core/install/install_data.sql
===================================================================
diff -u -N -r16754 -r16770
--- branches/5.2.x/core/install/install_data.sql	(.../install_data.sql)	(revision 16754)
+++ branches/5.2.x/core/install/install_data.sql	(.../install_data.sql)	(revision 16770)
@@ -100,6 +100,7 @@
 INSERT INTO SystemSettings VALUES(DEFAULT, 'Backup_Path', '/home/alex/web/in-portal.rc/system/backupdata', 'In-Portal', 'in-portal:configure_advanced', 'la_section_SettingsSystem', 'la_config_backup_path', 'text', '', '', 60.07, 0, 1, NULL);
 INSERT INTO SystemSettings VALUES(DEFAULT, 'SystemTagCache', '0', 'In-Portal', 'in-portal:configure_advanced', 'la_section_SettingsSystem', 'la_prompt_syscache_enable', 'checkbox', NULL, NULL, 60.08, 0, 0, NULL);
 INSERT INTO SystemSettings VALUES(DEFAULT, 'SocketBlockingMode', '0', 'In-Portal', 'in-portal:configure_advanced', 'la_section_SettingsSystem', 'la_prompt_socket_blocking_mode', 'checkbox', NULL, NULL, 60.09, 0, 0, NULL);
+INSERT INTO SystemSettings VALUES(DEFAULT, 'SemaphoreLifetimeInSeconds', '300', 'In-Portal', 'in-portal:configure_advanced', 'la_section_SettingsSystem', 'la_config_SemaphoreLifetimeInSeconds', 'text', '', 'style=\"width: 50px;\"', 60.1, 0, 1, 'hint:la_config_SemaphoreLifetimeInSeconds');
 INSERT INTO SystemSettings VALUES(DEFAULT, 'EnableEmailLog', '1', 'In-Portal', 'in-portal:configure_advanced', 'la_section_SettingsLogs', 'la_config_EnableEmailLog', 'radio', NULL, '1=la_Yes||0=la_No', 65.01, 0, 1, 'hint:la_config_EnableEmailLog');
 INSERT INTO SystemSettings VALUES(DEFAULT, 'EmailLogRotationInterval', '2419200', 'In-Portal', 'in-portal:configure_advanced', 'la_section_SettingsLogs', 'la_config_EmailLogRotationInterval', 'select', NULL, '86400=la_opt_OneDay||604800=la_opt_OneWeek||1209600=la_opt_TwoWeeks||2419200=la_opt_OneMonth||7257600=la_opt_ThreeMonths||29030400=la_opt_OneYear||-1=la_opt_EmailLogKeepForever', 65.02, 0, 0, 'hint:la_config_EmailLogRotationInterval');
 INSERT INTO SystemSettings VALUES(DEFAULT, 'SystemLogRotationInterval', '2419200', 'In-Portal', 'in-portal:configure_advanced', 'la_section_SettingsLogs', 'la_config_SystemLogRotationInterval', 'select', NULL, '86400=la_opt_OneDay||604800=la_opt_OneWeek||1209600=la_opt_TwoWeeks||2419200=la_opt_OneMonth||7257600=la_opt_ThreeMonths||29030400=la_opt_OneYear||-1=la_opt_SystemLogKeepForever', 65.03, 0, 1, 'hint:la_config_SystemLogRotationInterval');
Index: branches/5.2.x/core/install/install_schema.sql
===================================================================
diff -u -N -r16754 -r16770
--- branches/5.2.x/core/install/install_schema.sql	(.../install_schema.sql)	(revision 16754)
+++ branches/5.2.x/core/install/install_schema.sql	(.../install_schema.sql)	(revision 16770)
@@ -1282,15 +1282,20 @@
 );
 
 CREATE TABLE Semaphores (
-  SemaphoreId int(11) NOT NULL AUTO_INCREMENT,
-  SessionKey int(10) unsigned NOT NULL DEFAULT '0',
+  `SemaphoreId` int(11) NOT NULL AUTO_INCREMENT,
+  `SessionKey` int(10) unsigned NOT NULL DEFAULT '0',
   `Timestamp` int(10) unsigned NOT NULL DEFAULT '0',
-  MainPrefix varchar(255) NOT NULL DEFAULT '',
-  MainIDs text,
-  PRIMARY KEY (SemaphoreId),
-  KEY SessionKey (SessionKey),
+  `MainPrefix` varchar(255) NOT NULL DEFAULT '',
+  `MainIDs` text,
+  `UserId` int(11) DEFAULT NULL,
+  `IpAddress` varchar(15) NOT NULL DEFAULT '',
+  `Hostname` varchar(255) NOT NULL DEFAULT '',
+  `RequestURI` varchar(255) NOT NULL DEFAULT '',
+  `Backtrace` longtext,
+  PRIMARY KEY (`SemaphoreId`),
+  KEY `SessionKey` (`SessionKey`),
   KEY `Timestamp` (`Timestamp`),
-  KEY MainPrefix (MainPrefix)
+  KEY `MainPrefix` (`MainPrefix`)
 );
 
 CREATE TABLE CachedUrls (
Index: branches/5.2.x/core/kernel/utility/temp_handler.php
===================================================================
diff -u -N -r16733 -r16770
--- branches/5.2.x/core/kernel/utility/temp_handler.php	(.../temp_handler.php)	(revision 16733)
+++ branches/5.2.x/core/kernel/utility/temp_handler.php	(.../temp_handler.php)	(revision 16770)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: temp_handler.php 16733 2022-09-16 14:22:19Z alex $
+* @version	$Id: temp_handler.php 16770 2023-11-21 09:05:59Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -988,24 +988,24 @@
 		} while ($another_coping_active && ($sleep_count <= 30));
 
 		if ($sleep_count > 30) {
-			// another coping process failed to finished in 30 seconds
+			// Another coping process failed to finished in 30 seconds.
 			$error_message = $this->Application->Phrase('la_error_TemporaryTableCopyingFailed');
 			$this->Application->SetVar('_temp_table_message', $error_message);
 
+			$log = $this->Application->log('Parallel item saving attempt detected');
+			$log->addTrace();
+			$log->setLogLevel(kLogger::LL_ERROR);
+			$log->write();
+
 			return false;
 		}
 
-		// mark, that we are coping from temp to live right now, so other similar attempt (from another script) will fail
-		$fields_hash = Array (
-			'SessionKey' => $this->Application->GetSID(),
-			'Timestamp' => adodb_mktime(),
-			'MainPrefix' => $this->Tables['Prefix'],
-			'MainIDs' => implode(',', $master_ids),
-		);
+		/*
+		 * Mark, that we are coping from temp to live right now,
+		 * so other similar attempt (from another script) will fail.
+		 */
+		$semaphore_id = $this->createSemaphore($conn, $master_ids);
 
-		$conn->doInsert($fields_hash, TABLE_PREFIX.'Semaphores');
-		$semaphore_id = $conn->getInsertID();
-
 		// unlock table now to prevent permanent lock in case, when coping will end with SQL error in the middle
 		$conn->ChangeQuery('UNLOCK TABLES');
 
@@ -1023,6 +1023,33 @@
 		return $ids;
 	}
 
+	/**
+	 * Creates a semaphore.
+	 *
+	 * @param IDBConnection $conn       Database connection.
+	 * @param array         $master_ids Master record IDs.
+	 *
+	 * @return integer
+	 */
+	protected function createSemaphore(IDBConnection $conn, array $master_ids)
+	{
+		$fields_hash = array(
+			'SessionKey' => $this->Application->GetSID(),
+			'Timestamp' => adodb_mktime(),
+			'MainPrefix' => $this->Tables['Prefix'],
+			'MainIDs' => implode(',', $master_ids),
+			'UserId' => $this->Application->RecallVar('user_id'),
+			'IPAddress' => $this->Application->getClientIp(),
+			'Hostname' => $_SERVER['HTTP_HOST'],
+			'RequestURI' => $_SERVER['REQUEST_URI'],
+			'Backtrace' => serialize(debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS)),
+		);
+
+		$conn->doInsert($fields_hash, TABLE_PREFIX . 'Semaphores');
+
+		return $conn->getInsertID();
+	}
+
 	function CancelEdit($master=null)
 	{
 		if (!isset($master)) $master = $this->Tables;
Index: branches/5.2.x/core/install/english.lang
===================================================================
diff -u -N -r16754 -r16770
--- branches/5.2.x/core/install/english.lang	(.../english.lang)	(revision 16754)
+++ branches/5.2.x/core/install/english.lang	(.../english.lang)	(revision 16770)
@@ -204,6 +204,7 @@
 			<PHRASE Label="la_config_require_ssl" Module="Core" Type="1">UmVxdWlyZSBTU0wgZm9yIGxvZ2luICYgY2hlY2tvdXQ=</PHRASE>
 			<PHRASE Label="la_config_ResizableFrames" Module="Core" Type="1">RnJhbWVzIGluIGFkbWluaXN0cmF0aXZlIGNvbnNvbGUgYXJlIHJlc2l6YWJsZQ==</PHRASE>
 			<PHRASE Label="la_config_Search_MinKeyword_Length" Module="Core" Type="1">TWluaW1hbCBTZWFyY2ggS2V5d29yZCBMZW5ndGg=</PHRASE>
+			<PHRASE Label="la_config_SemaphoreLifetimeInSeconds" Module="Core" Type="1">RGVsZXRlIFN0dWNrIFNlbWFwaG9yZXMgYWZ0ZXI=</PHRASE>
 			<PHRASE Label="la_config_SessionBrowserSignatureCheck" Module="Core" Type="1">U2Vzc2lvbiBTZWN1cml0eSBDaGVjayBiYXNlZCBvbiBCcm93c2VyIFNpZ25hdHVyZQ==</PHRASE>
 			<PHRASE Label="la_config_SessionCookieDomains" Module="Core" Type="1">U2Vzc2lvbiBDb29raWUgRG9tYWlucyAoc2luZ2xlIGRvbWFpbiBwZXIgbGluZSk=</PHRASE>
 			<PHRASE Label="la_config_SessionIPAddressCheck" Module="Core" Type="1">U2Vzc2lvbiBTZWN1cml0eSBDaGVjayBiYXNlZCBvbiBJUA==</PHRASE>
@@ -1380,6 +1381,7 @@
 			<PHRASE Label="la_Text_Reviews" Module="Core" Type="1">Q29tbWVudHM=</PHRASE>
 			<PHRASE Label="la_Text_RootCategory" Module="Core" Type="1">TW9kdWxlIFJvb3QgU2VjdGlvbg==</PHRASE>
 			<PHRASE Label="la_text_Save" Module="Core" Type="1">U2F2ZQ==</PHRASE>
+			<PHRASE Label="la_text_seconds" Module="Core" Type="1">c2Vjb25kcw==</PHRASE>
 			<PHRASE Label="la_Text_Select" Module="Core" Type="1">U2VsZWN0</PHRASE>
 			<PHRASE Label="la_text_sess_expired" Module="Core" Type="1">U2Vzc2lvbiBFeHBpcmVk</PHRASE>
 			<PHRASE Label="la_Text_Simple" Module="Core" Type="1">U2ltcGxl</PHRASE>
Index: branches/5.2.x/core/install/upgrades.sql
===================================================================
diff -u -N -r16754 -r16770
--- branches/5.2.x/core/install/upgrades.sql	(.../upgrades.sql)	(revision 16754)
+++ branches/5.2.x/core/install/upgrades.sql	(.../upgrades.sql)	(revision 16770)
@@ -2964,3 +2964,11 @@
     ADD COLUMN `LogCodeFragment` longtext NULL AFTER `LogSourceFileLine`,
 	ADD COLUMN `LogCodeFragmentsRotated` tinyint(4) NOT NULL DEFAULT '0' AFTER `LogCodeFragment`;
 ALTER TABLE SystemLog ADD INDEX `TIMESTAMP_CODE_FRAGMENTS_ROTATED` (`LogTimestamp`,`LogCodeFragmentsRotated`) USING BTREE;
+
+ALTER TABLE Semaphores
+	ADD COLUMN `UserId` int(11) NULL,
+	ADD COLUMN `IpAddress` varchar(15) NOT NULL DEFAULT '',
+	ADD COLUMN `Hostname` varchar(255) NOT NULL DEFAULT '',
+	ADD COLUMN `RequestURI` varchar(255) NOT NULL DEFAULT '',
+	ADD COLUMN `Backtrace` longtext NULL;
+INSERT INTO SystemSettings VALUES(DEFAULT, 'SemaphoreLifetimeInSeconds', '300', 'In-Portal', 'in-portal:configure_advanced', 'la_section_SettingsSystem', 'la_config_SemaphoreLifetimeInSeconds', 'text', '', 'style=\"width: 50px;\"', 60.1, 0, 1, 'hint:la_config_SemaphoreLifetimeInSeconds');
Index: branches/5.2.x/core/units/admin/admin_events_handler.php
===================================================================
diff -u -N -r16664 -r16770
--- branches/5.2.x/core/units/admin/admin_events_handler.php	(.../admin_events_handler.php)	(revision 16664)
+++ branches/5.2.x/core/units/admin/admin_events_handler.php	(.../admin_events_handler.php)	(revision 16770)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: admin_events_handler.php 16664 2021-01-11 08:51:24Z alex $
+* @version	$Id: admin_events_handler.php 16770 2023-11-21 09:05:59Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -1265,6 +1265,57 @@
 		}
 	}
 
+	/**
+	 * Deletes stuck semaphore records.
+	 *
+	 * @param kEvent $event Event.
+	 *
+	 * @return void
+	 */
+	protected function OnDeleteStuckSemaphoresScheduledTask(kEvent $event)
+	{
+		$semaphore_lifetime = $this->Application->ConfigValue('SemaphoreLifetimeInSeconds');
+
+		$sql = 'SELECT *
+				FROM ' . TABLE_PREFIX . 'Semaphores
+				WHERE Timestamp < ' . strtotime('-' . $semaphore_lifetime . ' seconds');
+		$stuck_semaphores = $this->Conn->Query($sql, 'SemaphoreId');
+
+		if ( !$stuck_semaphores ) {
+			return;
+		}
+
+		/** @var LanguagesItem $language */
+		$language = $this->Application->recallObject('lang.current', null, array('skip_autoload' => true));
+		$date_format = $language->GetDBField('DateFormat') . ' ' . $language->GetDBField('TimeFormat');
+
+		foreach ( $stuck_semaphores as $semaphore_id => $semaphore_data ) {
+			$log = $this->Application->log('Stuck semaphore detected (unit: ' . $semaphore_data['MainPrefix'] . ')');
+			$log->setLogLevel(kLogger::LL_ERROR);
+			$log->addTrace(unserialize($semaphore_data['Backtrace']));
+			$log->setUserData(implode(PHP_EOL, array(
+				'Main Prefix: ' . $semaphore_data['MainPrefix'],
+				'Main IDs: ' . $semaphore_data['MainIDs'],
+				'Created On: ' . date($date_format, $semaphore_data['Timestamp']),
+				'Deleted On: ' . date($date_format),
+			)));
+
+			$log->setLogField('LogHostname', $semaphore_data['Hostname']);
+			$log->setLogField('LogRequestSource', 1); // Web.
+			$log->setLogField('LogInterface', kLogger::LI_ADMIN);
+			$log->setLogField('LogRequestURI', $semaphore_data['RequestURI']);
+			$log->setLogField('LogUserId', $semaphore_data['UserId']);
+			$log->setLogField('IpAddress', $semaphore_data['IpAddress']);
+			$log->setLogField('LogSessionKey', $semaphore_data['SessionKey']);
+
+			$log->write();
+
+			$sql = 'DELETE FROM ' . TABLE_PREFIX . 'Semaphores
+					WHERE SemaphoreId = ' . $semaphore_id;
+			$this->Conn->Query($sql);
+		}
+	}
+
 }
 
 
Index: branches/5.2.x/core/admin_templates/config/custom_variables.tpl
===================================================================
diff -u -N -r15608 -r16770
--- branches/5.2.x/core/admin_templates/config/custom_variables.tpl	(.../custom_variables.tpl)	(revision 15608)
+++ branches/5.2.x/core/admin_templates/config/custom_variables.tpl	(.../custom_variables.tpl)	(revision 16770)
@@ -143,4 +143,8 @@
 
 <inp2:m_DefineElement name="cf_AllowAdminConsoleInterfaceChange_value">
 	<inp2:m_RenderElement name="cf_default_value" pass_params="1"/> <label for="_cb_<inp2:InputName name='VariableValue'/>"><inp2:m_Phrase name="la_AllowChangingAdminConsoleInterface"/></label>
-</inp2:m_DefineElement>
\ No newline at end of file
+</inp2:m_DefineElement>
+
+<inp2:m_DefineElement name="cf_SemaphoreLifetimeInSeconds_value">
+	<inp2:m_RenderElement name="cf_default_value" pass_params="1"/> <inp2:m_Phrase name="la_text_seconds"/>
+</inp2:m_DefineElement>
Index: branches/5.2.x/core/units/admin/admin_config.php
===================================================================
diff -u -N -r16664 -r16770
--- branches/5.2.x/core/units/admin/admin_config.php	(.../admin_config.php)	(revision 16664)
+++ branches/5.2.x/core/units/admin/admin_config.php	(.../admin_config.php)	(revision 16770)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: admin_config.php 16664 2021-01-11 08:51:24Z alex $
+* @version	$Id: admin_config.php 16770 2023-11-21 09:05:59Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -32,6 +32,7 @@
 		'optimize_performance' => Array ('EventName' => 'OnOptimizePerformance', 'RunSchedule' => '0 0 * * *'),
 		'purge_expired_database_cache' => Array ('EventName' => 'OnPurgeExpiredDatabaseCacheScheduledTask', 'RunSchedule' => '0 0,12 * * *'),
 		'populate_url_unit_cache' => array('EventName' => 'OnPopulateUrlUnitCacheScheduledTask', 'RunSchedule' => '0 * * * *'),
+		'delete_stuck_semaphores' => array('EventName' => 'OnDeleteStuckSemaphoresScheduledTask', 'RunSchedule' => '*/5 * * * *'),
 	),
 
 	'TitlePresets' => Array (