Index: zabbix-3.4.12-1+buster/frontends/php/include/classes/api/managers/CHistoryManager.php
===================================================================
--- zabbix-3.4.12-1+buster.orig/frontends/php/include/classes/api/managers/CHistoryManager.php
+++ zabbix-3.4.12-1+buster/frontends/php/include/classes/api/managers/CHistoryManager.php
@@ -37,6 +37,12 @@ class CHistoryManager {
 		$results = [];
 		$grouped_items = self::getItemsGroupedByStorage($items);
 
+		if (array_key_exists(ZBX_HISTORY_SOURCE_CLICKHOUSE, $grouped_items)) {
+			$results += $this->getLastValuesFromClickHouse($grouped_items[ZBX_HISTORY_SOURCE_CLICKHOUSE], $limit,
+					$period
+			);
+		}
+
 		if (array_key_exists(ZBX_HISTORY_SOURCE_ELASTIC, $grouped_items)) {
 			$results += $this->getLastValuesFromElasticsearch($grouped_items[ZBX_HISTORY_SOURCE_ELASTIC], $limit,
 					$period
@@ -51,6 +57,77 @@ class CHistoryManager {
 	}
 
 	/**
+	 * ClickHouse specific implementation of getLastValues.
+	 *
+	 * @see CHistoryManager::getLastValues
+	 */
+	private function _getLastValuesFromClickHouse($items, $limit, $period) {
+		$results = [];
+
+		foreach ($items as $item) {
+			$endpoints = self::getClickHouseEndpoints($item['value_type']);
+			if ($endpoints) {
+				$query =
+					'SELECT *'.
+					' FROM '.self::getTableName($item['value_type']).
+					' WHERE itemid='.($item['itemid'] + 0).
+						($period ? ' AND clock>'.(time() - $period) : '').
+					' ORDER BY clock DESC';
+
+				if ($limit > 0) $query .= ' LIMIT '.$limit;
+
+				$values = CClickHouseHelper::values('POST', reset($endpoints), $query);
+				if ($values) {
+					$results[$item['itemid']] = $values;
+				}
+			}
+		}
+
+		return $results;
+	}
+
+	/**
+	 * ClickHouse specific implementation of getLastValues.
+	 *
+	 * @see CHistoryManager::getLastValues
+	 */
+	private function getLastValuesFromClickHouse($items, $limit, $period) {
+		$results = [];
+		$type_queries = [];
+
+		foreach ($items as $item) {
+			$query =
+				'SELECT *'.
+				' FROM '.self::getTableName($item['value_type']).
+				' WHERE itemid='.($item['itemid'] + 0).
+					($period ? ' AND clock>'.(time() - $period) : '').
+				' ORDER BY clock DESC';
+
+			if ($limit > 0) $query .= ' LIMIT '.$limit;
+
+			$type_queries[$item['value_type']][] = $query;
+		}
+
+		foreach ($type_queries as $value_type => $queries) {
+			$endpoints = self::getClickHouseEndpoints($value_type);
+			if ($endpoints) {
+				$query =
+					'SELECT *'.
+					' FROM ('.implode(' UNION ALL ', $queries).')';
+
+				$values = CClickHouseHelper::values('POST', reset($endpoints), $query);
+
+				foreach($values as $row) {
+					$itemid = $row['itemid'];
+					$results[$itemid][] = $row;
+				}
+			}
+		}
+
+		return $results;
+	}
+
+	/**
 	 * Elasticsearch specific implementation of getLastValues.
 	 *
 	 * @see CHistoryManager::getLastValues
@@ -172,6 +249,9 @@ class CHistoryManager {
 	 */
 	public function getValueAt($item, $clock, $ns) {
 		switch (self::getDataSourceType($item['value_type'])) {
+			case ZBX_HISTORY_SOURCE_CLICKHOUSE:
+				return $this->getValueAtFromClickHouse($item, $clock, $ns);
+
 			case ZBX_HISTORY_SOURCE_ELASTIC:
 				return $this->getValueAtFromElasticsearch($item, $clock, $ns);
 
@@ -181,6 +261,74 @@ class CHistoryManager {
 	}
 
 	/**
+	 * ClickHouse specific implementation of getValueAt.
+	 *
+	 * @see CHistoryManager::getValueAt
+	 */
+	private function getValueAtFromClickHouse($item, $clock, $ns) {
+		$value = null;
+		$table = self::getTableName($item['value_type']);
+
+		$endpoints = self::getClickHouseEndpoints($item['value_type']);
+		if ($endpoints) {
+			$url = reset($endpoints);
+
+			$query = 'SELECT value'.
+					' FROM '.$table.
+					' WHERE itemid='.($item['itemid']+0).
+						' AND clock='.($clock+0).
+						' AND ns='.($ns+0).
+					' LIMIT 1';
+			$value = CClickHouseHelper::value('POST', $url, $query);
+			if ($value !== null) {
+				return $value;
+			}
+
+			$query = 'SELECT DISTINCT clock'.
+					' FROM '.$table.
+					' WHERE itemid='.($item['itemid']+0).
+						' AND clock='.($clock+0).
+						' AND ns<'.($ns+0);
+			$max_clock = CClickHouseHelper::value('POST', $url, $query, 'clock');
+
+			if ($max_clock === null) {
+				$query = 'SELECT MAX(clock) AS clock'.
+						' FROM '.$table.
+						' WHERE itemid='.($item['itemid']+0).
+							' AND clock<'.($clock+0).
+							(ZBX_HISTORY_PERIOD ? ' AND clock>='.($clock - ZBX_HISTORY_PERIOD) : '');
+
+				$max_clock = CClickHouseHelper::value('POST', $url, $query, 'clock');
+			}
+
+			if ($max_clock === null) {
+				return $value;
+			}
+
+			if ($clock == $max_clock) {
+				$query = 'SELECT value'.
+						' FROM '.$table.
+						' WHERE itemid='.($item['itemid']+0).
+							' AND clock='.($clock+0).
+							' AND ns<'.($ns+0).
+						' LIMIT 1';
+			}
+			else {
+				$query = 'SELECT value'.
+						' FROM '.$table.
+						' WHERE itemid='.($item['itemid']+0).
+							' AND clock='.($max_clock+0).
+						' ORDER BY itemid, clock, ns DESC'.
+						' LIMIT 1';
+			}
+
+			$value = CClickHouseHelper::value('POST', $url, $query);
+
+		}
+		return $value;
+	}
+
+	/**
 	 * Elasticsearch specific implementation of getValueAt.
 	 *
 	 * @see CHistoryManager::getValueAt
@@ -345,6 +493,12 @@ class CHistoryManager {
 		$grouped_items = self::getItemsGroupedByStorage($items);
 
 		$results = [];
+		if (array_key_exists(ZBX_HISTORY_SOURCE_CLICKHOUSE, $grouped_items)) {
+			$results += $this->getGraphAggregationFromClickHouse($grouped_items[ZBX_HISTORY_SOURCE_CLICKHOUSE],
+					$time_from, $time_to, $width, $size, $delta
+			);
+		}
+
 		if (array_key_exists(ZBX_HISTORY_SOURCE_ELASTIC, $grouped_items)) {
 			$results += $this->getGraphAggregationFromElasticsearch($grouped_items[ZBX_HISTORY_SOURCE_ELASTIC],
 					$time_from, $time_to, $width, $size, $delta
@@ -361,6 +515,114 @@ class CHistoryManager {
 	}
 
 	/**
+	 * ClickHouse specific implementation of getGraphAggregation.
+	 *
+	 * @see CHistoryManager::getGraphAggregation
+	 */
+	private function _getGraphAggregationFromClickHouse(array $items, $time_from, $time_to, $width, $size, $delta) {
+		$group_by = 'itemid';
+		$sql_select_extra = '';
+
+		if ($width !== null && $size !== null && $delta !== null) {
+			$calc_field = 'round('.$width.'*modulo(clock+'.$delta.','.$size.')/('.$size.'),0)';
+
+			$sql_select_extra = ','.$calc_field.' AS i';
+			$group_by .= ','.$calc_field;
+		}
+
+		$results = [];
+
+		foreach ($items as $item) {
+			$endpoints = self::getClickHouseEndpoints($item['value_type']);
+			if ($endpoints) {
+				if ($item['source'] === 'history') {
+					$sql_select = 'COUNT(*) AS count,AVG(value) AS avg,MIN(value) AS min,MAX(value) AS max';
+					$sql_from = ($item['value_type'] == ITEM_VALUE_TYPE_UINT64) ? 'history_uint' : 'history';
+				}
+				else {
+					$sql_select = 'SUM(num) AS count,AVG(value_avg) AS avg,MIN(value_min) AS min,MAX(value_max) AS max';
+					$sql_from = ($item['value_type'] == ITEM_VALUE_TYPE_UINT64) ? 'trends_uint' : 'trends';
+				}
+
+				$query =
+					'SELECT itemid,'.$sql_select.$sql_select_extra.',MAX(clock) AS max_clock'.
+					' FROM '.$sql_from.
+					' WHERE itemid='.($item['itemid']+0).
+						' AND clock>='.($time_from+0).
+						' AND clock<='.($time_to+0).
+					' GROUP BY '.$group_by;
+
+				$values = CClickHouseHelper::values('POST', reset($endpoints), $query, null, ['max_clock' => 'clock']);
+
+				$results[$item['itemid']]['source'] = $item['source'];
+				$results[$item['itemid']]['data'] = $values;
+			}
+		}
+
+		return $results;
+	}
+
+	/**
+	 * ClickHouse specific implementation of getGraphAggregation.
+	 *
+	 * @see CHistoryManager::getGraphAggregation
+	 */
+	private function getGraphAggregationFromClickHouse(array $items, $time_from, $time_to, $width, $size, $delta) {
+		$group_by = 'itemid';
+		$sql_select_extra = '';
+		$query_extra = '';
+
+		if ($width !== null && $size !== null && $delta !== null) {
+			$calc_field = 'round('.$width.'*modulo(clock+'.$delta.','.$size.')/('.$size.'),0)';
+
+			$sql_select_extra = ','.$calc_field.' AS i';
+			$group_by .= ','.$calc_field;
+			$query_extra = ',i';
+		}
+
+		$results = [];
+		$url_queries = [];
+		foreach ($items as $item) {
+			$endpoints = self::getClickHouseEndpoints($item['value_type']);
+			if ($endpoints) {
+				if ($item['source'] === 'history') {
+					$sql_select = 'COUNT(*) AS count,AVG(value) AS avg,MIN(value) AS min,MAX(value) AS max';
+					$sql_from = ($item['value_type'] == ITEM_VALUE_TYPE_UINT64) ? 'history_uint' : 'history';
+				}
+				else {
+					$sql_select = 'SUM(num) AS count,AVG(value_avg) AS avg,MIN(value_min) AS min,MAX(value_max) AS max';
+					$sql_from = ($item['value_type'] == ITEM_VALUE_TYPE_UINT64) ? 'trends_uint' : 'trends';
+				}
+
+				$query =
+					'SELECT itemid,'.$sql_select.$sql_select_extra.',MAX(clock) AS max_clock'.
+					' FROM '.$sql_from.
+					' WHERE itemid='.($item['itemid']+0).
+						' AND clock>='.($time_from+0).
+						' AND clock<='.($time_to+0).
+					' GROUP BY '.$group_by;
+
+				$results[$item['itemid']]['source'] = $item['source'];
+				$url_queries[reset($endpoints)][] = $query;
+			}
+		}
+
+		foreach ($url_queries as $url => $queries) {
+			$query =
+				'SELECT itemid,count,avg,min,max'.$query_extra.',max_clock'.
+				' FROM ('.implode(' UNION ALL ', $queries).')';
+
+			$values = CClickHouseHelper::values('POST', $url, $query, null, ['max_clock' => 'clock']);
+
+			foreach($values as $row) {
+				$results[$row['itemid']]['data'][] = $row;
+			}
+		}
+
+		return $results;
+	}
+
+	/**
 	 * Elasticsearch specific implementation of getGraphAggregation.
 	 *
 	 * @see CHistoryManager::getGraphAggregation
@@ -585,6 +847,9 @@ class CHistoryManager {
 	 */
 	public function getAggregatedValue(array $item, $aggregation, $time_from) {
 		switch (self::getDataSourceType($item['value_type'])) {
+			case ZBX_HISTORY_SOURCE_CLICKHOUSE:
+				return $this->getAggregatedValueFromClickHouse($item, $aggregation, $time_from);
+
 			case ZBX_HISTORY_SOURCE_ELASTIC:
 				return $this->getAggregatedValueFromElasticsearch($item, $aggregation, $time_from);
 
@@ -594,6 +859,27 @@ class CHistoryManager {
 	}
 
 	/**
+	 * ClickHouse specific implementation of getAggregatedValue.
+	 *
+	 * @see CHistoryManager::getAggregatedValue
+	 */
+	private function getAggregatedValueFromClickHouse(array $item, $aggregation, $time_from) {
+		$value = null;
+		$endpoints = self::getClickHouseEndpoints($item['value_type']);
+		if ($endpoints) {
+			$query =
+				'SELECT '.$aggregation.'(value) AS value'.
+				' FROM '.self::getTableName($item['value_type']).
+				' WHERE clock>'.$time_from.
+				' AND itemid='.($item['itemid']+0).
+				' HAVING COUNT(*)>0';
+
+			$value = CClickHouseHelper::value('POST', reset($endpoints), $query);
+		}
+		return $value;
+	}
+
+	/**
 	 * Elasticsearch specific implementation of getAggregatedValue.
 	 *
 	 * @see CHistoryManager::getAggregatedValue
@@ -718,6 +1004,10 @@ class CHistoryManager {
 
 		$min_clock = [];
 
+		if (array_key_exists(ZBX_HISTORY_SOURCE_CLICKHOUSE, $storage_items)) {
+			$min_clock[] = $this->getMinClockFromClickHouse($storage_items[ZBX_HISTORY_SOURCE_CLICKHOUSE], $source);
+		}
+
 		if (array_key_exists(ZBX_HISTORY_SOURCE_ELASTIC, $storage_items)) {
 			$min_clock[] = $this->getMinClockFromElasticsearch($storage_items[ZBX_HISTORY_SOURCE_ELASTIC]);
 		}
@@ -750,6 +1040,66 @@ class CHistoryManager {
 	}
 
 	/**
+	 * ClickHouse specific implementation of getMinClock.
+	 *
+	 * @see CHistoryManager::getMinClock
+	 */
+	private function getMinClockFromClickHouse(array $items, $source) {
+		$url_queries = [];
+		$endpoints = self::getClickHouseEndpoints(array_keys($items));
+		foreach ($items as $type => $itemids) {
+			if (!$itemids) {
+				continue;
+			}
+
+			if (!array_key_exists($type, $endpoints)) {
+				continue;
+			}
+
+			$url = $endpoints[$type];
+
+			switch ($type) {
+				case ITEM_VALUE_TYPE_FLOAT:
+					$sql_from = $source;
+					break;
+				case ITEM_VALUE_TYPE_STR:
+					$sql_from = 'history_str';
+					break;
+				case ITEM_VALUE_TYPE_LOG:
+					$sql_from = 'history_log';
+					break;
+				case ITEM_VALUE_TYPE_UINT64:
+					$sql_from = $source.'_uint';
+					break;
+				case ITEM_VALUE_TYPE_TEXT:
+					$sql_from = 'history_text';
+					break;
+				default:
+					$sql_from = 'history';
+			}
+
+			$url_queries[$url][] =
+				'SELECT MIN(clock) AS min_clock'.
+				' FROM '.$sql_from.
+				' WHERE itemid IN ('.implode(',', $itemids).')';
+		}
+
+		$min_clock = [];
+		foreach ($url_queries as $url => $queries) {
+			$query =
+				'SELECT MIN(min_clock) AS min'.
+				' FROM ('.implode(' UNION ALL ', $queries).')';
+
+			$clock = CClickHouseHelper::value('POST', $url, $query, 'min');
+			if ($clock !== null) {
+				$min_clock[] = $clock;
+			}
+		}
+
+		return min($min_clock);
+	}
+
+	/**
 	 * Elasticsearch specific implementation of getMinClock.
 	 *
 	 * @see CHistoryManager::getMinClock
@@ -836,6 +1186,7 @@ class CHistoryManager {
 
 	/**
 	 * Clear item history and trends by provided item IDs. History is deleted from both SQL and Elasticsearch.
+	 * ClickHouse does not support delete rows.
 	 *
 	 * @param array $itemids    item ids to delete history for
 	 *
@@ -943,7 +1294,7 @@ class CHistoryManager {
 	}
 
 	/**
-	 * Get data source (SQL or Elasticsearch) type based on value type id.
+	 * Get data source (SQL, Clickhouse or Elasticsearch) type based on value type id.
 	 *
 	 * @param int $value_type    value type id
 	 *
@@ -955,9 +1306,12 @@ class CHistoryManager {
 		if (!array_key_exists($value_type, $cache)) {
 			global $HISTORY;
 
-			if (is_array($HISTORY) && array_key_exists('types', $HISTORY) && is_array($HISTORY['types'])) {
-				$cache[$value_type] = in_array(self::getTypeNameByTypeId($value_type), $HISTORY['types'])
-						? ZBX_HISTORY_SOURCE_ELASTIC : ZBX_HISTORY_SOURCE_SQL;
+			$type_name = self::getTypeNameByTypeId($value_type);
+
+			if (is_array($HISTORY) && array_key_exists('types', $HISTORY)
+				&& is_array($HISTORY['types']) && array_key_exists($type_name, $HISTORY['types'])) {
+				// Special data source.
+				$cache[$value_type] = $HISTORY['types'][$type_name];
 			}
 			else {
 				// SQL is a fallback data source.
@@ -968,6 +1322,51 @@ class CHistoryManager {
 		return $cache[$value_type];
 	}
 
+	private static function getClickHouseUrl($value_name) {
+		static $urls = [];
+		static $invalid = [];
+
+		// Additional check to limit error count produced by invalid configuration.
+		if (array_key_exists($value_name, $invalid)) {
+			return null;
+		}
+
+		if (!array_key_exists($value_name, $urls)) {
+			global $HISTORY;
+
+			$urls[$value_name] = $HISTORY['url'][$value_name];
+		}
+
+		return $urls[$value_name];
+	}
+
+	/**
+	 * Get endpoints for ClickHouse requests.
+	 *
+	 * @param mixed $value_types    value type(s)
+	 *
+	 * @return array    ClickHouse query endpoints
+	 */
+	public static function getClickHouseEndpoints($value_types) {
+		if (!is_array($value_types)) {
+			$value_types = [$value_types];
+		}
+
+		$endpoints = [];
+
+		foreach (array_unique($value_types) as $type) {
+			if (self::getDataSourceType($type) === ZBX_HISTORY_SOURCE_CLICKHOUSE) {
+				$index = self::getTypeNameByTypeId($type);
+
+				if (($url = self::getClickHouseUrl($index)) !== null) {
+					$endpoints[$type] = $url;
+				}
+			}
+		}
+
+		return $endpoints;
+	}
+
 	private static function getElasticsearchUrl($value_name) {
 		static $urls = [];
 		static $invalid = [];
Index: zabbix-3.4.12-1+buster/frontends/php/include/classes/api/services/CHistory.php
===================================================================
--- zabbix-3.4.12-1+buster.orig/frontends/php/include/classes/api/services/CHistory.php
+++ zabbix-3.4.12-1+buster/frontends/php/include/classes/api/services/CHistory.php
@@ -118,6 +118,9 @@ class CHistory extends CApiService {
 		]);
 
 		switch (CHistoryManager::getDataSourceType($options['history'])) {
+			case ZBX_HISTORY_SOURCE_CLICKHOUSE:
+				return $this->getFromClickHouse($options);
+
 			case ZBX_HISTORY_SOURCE_ELASTIC:
 				return $this->getFromElasticsearch($options);
 
@@ -127,6 +130,139 @@ class CHistory extends CApiService {
 	}
 
 	/**
+	 * ClickHouse specific implementation of get.
+	 *
+	 * @see CHistory::get
+	 */
+	private function getFromClickHouse($options) {
+		$result = [];
+		$sql_parts = [
+			'select'	=> ['history' => 'h.itemid'],
+			'from'		=> [],
+			'where'		=> [],
+			'group'		=> [],
+			'order'		=> [],
+			'limit'		=> null
+		];
+
+		if (!$table_name = CHistoryManager::getTableName($options['history'])) {
+			$table_name = 'history';
+		}
+
+		$endpoints = CHistoryManager::getClickHouseEndpoints($options['history']);
+		if (!$endpoints) {
+			return $result;
+		}
+		$url = reset($endpoints);
+
+		$sql_parts['from']['history'] = $table_name.' h';
+
+		// itemids
+		if ($options['itemids'] !== null) {
+			$sql_parts['where']['itemid'] = dbConditionInt('h.itemid', $options['itemids'], false, true, false);
+		}
+
+		// time_from
+		if ($options['time_from'] !== null) {
+			$sql_parts['where']['clock_from'] = 'h.clock>='.($options['time_from']+0);
+		}
+
+		// time_till
+		if ($options['time_till'] !== null) {
+			$sql_parts['where']['clock_till'] = 'h.clock<='.($options['time_till']+0);
+		}
+
+		// filter
+		if (is_array($options['filter'])) {
+			$this->dbFilter($sql_parts['from']['history'], $options, $sql_parts);
+		}
+
+		// search
+		if (is_array($options['search'])) {
+			zbx_db_search($sql_parts['from']['history'], $options, $sql_parts);
+		}
+
+		// output
+		if ($options['output'] == API_OUTPUT_EXTEND) {
+			unset($sql_parts['select']['clock']);
+			$sql_parts['select']['history'] = 'h.*';
+		}
+		elseif ($options['output'] != API_OUTPUT_COUNT) {
+			unset($sql_parts['select']['clock']);
+			$sql_parts['select']['history'] = implode(',', $options['output']);
+		}
+
+		// countOutput
+		if ($options['countOutput']) {
+			$options['sortfield'] = '';
+			$sql_parts['select'] = ['count(*) as rowscount'];
+
+			// groupCount
+			if ($options['groupCount']) {
+				foreach ($sql_parts['group'] as $key => $fields) {
+					$sql_parts['select'][$key] = $fields;
+				}
+			}
+		}
+
+		// sorting
+		$sql_parts = $this->applyQuerySortOptions($table_name, $this->tableAlias(), $options, $sql_parts);
+
+		// limit
+		if (zbx_ctype_digit($options['limit']) && $options['limit']) {
+			$sql_parts['limit'] = $options['limit'];
+		}
+
+		$sql_parts['select'] = array_unique($sql_parts['select']);
+		$sql_parts['from'] = array_unique($sql_parts['from']);
+		$sql_parts['where'] = array_unique($sql_parts['where']);
+		$sql_parts['order'] = array_unique($sql_parts['order']);
+
+		$sql_select = '';
+		$sql_from = '';
+		$sql_order = '';
+
+		if ($sql_parts['select']) {
+			$sql_select .= implode(',', $sql_parts['select']);
+		}
+
+		if ($sql_parts['from']) {
+			$sql_from .= implode(',', $sql_parts['from']);
+		}
+
+		$sql_where = $sql_parts['where'] ? ' WHERE '.implode(' AND ', $sql_parts['where']) : '';
+
+		if ($sql_parts['order']) {
+			$sql_order .= ' ORDER BY '.implode(',', $sql_parts['order']);
+		}
+
+		if ($sql_parts['limit'] > 0) {
+			$sql_limit = ' LIMIT '.$sql_parts['limit'];
+		}
+		$query = 'SELECT '.$sql_select.
+				' FROM '.$sql_from.
+				$sql_where.
+				$sql_order.
+				$sql_limit;
+
+		$values = CClickHouseHelper::values('POST', $url, $query);
+		foreach ($values as $row) {
+			if ($options['countOutput']) {
+				$result = $row;
+			}
+			else {
+				$result[] = $row;
+			}
+		}
+
+		if (!$options['preservekeys']) {
+			$result = zbx_cleanHashes($result);
+		}
+
+		return $result;
+	}
+
+	/**
 	 * SQL specific implementation of get.
 	 *
 	 * @see CHistory::get
Index: zabbix-3.4.12-1+buster/frontends/php/include/classes/api/services/CTrend.php
===================================================================
--- zabbix-3.4.12-1+buster.orig/frontends/php/include/classes/api/services/CTrend.php
+++ zabbix-3.4.12-1+buster/frontends/php/include/classes/api/services/CTrend.php
@@ -71,11 +71,15 @@ class CTrend extends CApiService {
 			}
 		}
 
-		foreach ([ZBX_HISTORY_SOURCE_ELASTIC, ZBX_HISTORY_SOURCE_SQL] as $source) {
+		foreach ([ZBX_HISTORY_SOURCE_CLICKHOUSE, ZBX_HISTORY_SOURCE_ELASTIC, ZBX_HISTORY_SOURCE_SQL] as $source) {
 			if (array_key_exists($source, $storage_items)) {
 				$options['itemids'] = $storage_items[$source];
 
 				switch ($source) {
+					case ZBX_HISTORY_SOURCE_CLICKHOUSE:
+						$data = $this->getFromClickHouse($options);
+						break;
+
 					case ZBX_HISTORY_SOURCE_ELASTIC:
 						$data = $this->getFromElasticsearch($options);
 						break;
@@ -92,6 +96,103 @@ class CTrend extends CApiService {
 				}
 			}
 		}
+
+		return $result;
+	}
+
+	/**
+	 * ClickHouse specific implementation of get.
+	 *
+	 * @see CTrend::get
+	 */
+	private function getFromClickHouse($options) {
+		$sql_where = [];
+
+		if ($options['time_from'] !== null) {
+			$sql_where['clock_from'] = 't.clock>='.($options['time_from']+0);
+		}
+
+		if ($options['time_till'] !== null) {
+			$sql_where['clock_till'] = 't.clock<='.($options['time_till']+0);
+		}
+
+		if (!$options['countOutput']) {
+			$sql_limit = ($options['limit'] && zbx_ctype_digit($options['limit'])) ? $options['limit'] : null;
+
+			$sql_fields = [];
+
+			if (is_array($options['output'])) {
+				foreach ($options['output'] as $field) {
+					if ($this->hasField($field, 'trends') && $this->hasField($field, 'trends_uint')) {
+						$sql_fields[] = 't.'.$field;
+					}
+				}
+			}
+			elseif ($options['output'] == API_OUTPUT_EXTEND) {
+				$sql_fields[] = 't.*';
+			}
+
+			// An empty field set or invalid output method (string). Select only "itemid" instead of everything.
+			if (!$sql_fields) {
+				$sql_fields[] = 't.itemid';
+			}
+
+			$result = [];
+
+			foreach ([ITEM_VALUE_TYPE_FLOAT, ITEM_VALUE_TYPE_UINT64] as $value_type) {
+				$endpoints = CHistoryManager::getClickHouseEndpoints($value_type);
+				if (!$endpoints) {
+	 				continue;
+				}
+
+				if ($sql_limit !== null && $sql_limit <= 0) {
+					break;
+				}
+
+				$sql_from = ($value_type == ITEM_VALUE_TYPE_FLOAT) ? 'trends' : 'trends_uint';
+
+				if ($options['itemids'][$value_type]) {
+					$sql_where['itemid'] = dbConditionInt('t.itemid', array_keys($options['itemids'][$value_type]), false, true, false);
+
+					$query = 'SELECT '.implode(',', $sql_fields).
+							' FROM '.$sql_from.' t'.
+							' WHERE '.implode(' AND ', $sql_where);
+
+					if ($sql_limit > 0) $query .= ' LIMIT '.$sql_limit;
+
+					$values = CClickHouseHelper::values('POST', reset($endpoints), $query);
+
+					if ($sql_limit !== null) {
+						$sql_limit -= count($values);
+					}
+
+					$result = array_merge($result, $values);
+				}
+			}
+
+			$result = $this->unsetExtraFields($result, ['itemid'], $options['output']);
+		}
+		else {
+			$result = 0;
+
+			foreach ([ITEM_VALUE_TYPE_FLOAT, ITEM_VALUE_TYPE_UINT64] as $value_type) {
+				if ($options['itemids'][$value_type]) {
+					$endpoints = CHistoryManager::getClickHouseEndpoints($value_type);
+					if (!$endpoints) {
+	 					continue;
+					}
+
+					$sql_from = ($value_type == ITEM_VALUE_TYPE_FLOAT) ? 'trends' : 'trends_uint';
+					$sql_where['itemid'] = dbConditionInt('t.itemid', array_keys($options['itemids'][$value_type]), false, true, false);
+
+					$query = 'SELECT COUNT(*) AS rowcount'.
+							' FROM '.$sql_from.' t'.
+							' WHERE '.implode(' AND ', $sql_where);
+
+					$result += CClickHouseHelper::value('POST', reset($endpoints), $query, 'rowcount');
+				}
+			}
+		}
 
 		return $result;
 	}
Index: zabbix-3.4.12-1+buster/frontends/php/include/classes/helpers/CClickHouseHelper.php
===================================================================
--- /dev/null
+++ zabbix-3.4.12-1+buster/frontends/php/include/classes/helpers/CClickHouseHelper.php
@@ -0,0 +1,76 @@
+<?php
+
+/**
+ * A helper class for working with ClickHouse.
+ */
+class CClickHouseHelper {
+
+	/**
+	 * Perform request to ClickHouse.
+	 *
+	 * @param string $method      HTTP method to be used to perform request
+	 * @param string $endpoint    requested url
+	 * @param mixed  $request     data to be sent
+	 *
+	 * @return string    result
+	 */
+	private static function request($method, $endpoint, $query) {
+		$options = [
+			'http' => [
+				'header'  => "Content-Type: application/json; charset=UTF-8",
+				'method'  => $method,
+				'ignore_errors' => true // To get error messages from ClickHouse.
+			]
+		];
+
+		$query .= ' FORMAT JSONCompact';
+		$options['http']['content'] = $query;
+
+		try {
+			$response = file_get_contents($endpoint, false, stream_context_create($options));
+		}
+		catch (Exception $e) {
+			error($e->getMessage());
+		}
+
+		return json_decode($response, true);
+	}
+
+	public static function values($method, $endpoint, $query = null, $columns = null, $map = null) {
+		#file_put_contents('/var/log/nginx/chartlog.log', "$query\n\n", FILE_APPEND);
+		$response = self::request($method, $endpoint, $query);
+
+		$values = [];
+		foreach ($response['data'] as $row) {
+			$value = [];
+			for($i = 0; $i < count($row); $i++)
+			{
+				if ($columns) {
+					$column = $columns[$i];
+				} else {
+					$column = $response['meta'][$i]['name'];
+				}
+
+				if ($map && array_key_exists($column, $map))
+				{
+					$column = $map[$column];
+				}
+
+				$value[$column] = $row[$i];
+			}
+			$values[] = $value;
+		}
+		#$json = json_encode($values, true);
+		#file_put_contents('/var/log/nginx/chartlog.log', "$json\n", FILE_APPEND);
+		return $values;
+	}
+
+	public static function value($method, $endpoint, $query = null, $column = 'value') {
+		$values = self::values($method, $endpoint, $query, [$column]);
+
+		if ((count($values) > 0) && array_key_exists($column, $values[0])) {
+			return $values[0][$column];
+		}
+		return null;
+	}
+}
Index: zabbix-3.4.12-1+buster/frontends/php/include/defines.inc.php
===================================================================
--- zabbix-3.4.12-1+buster.orig/frontends/php/include/defines.inc.php
+++ zabbix-3.4.12-1+buster/frontends/php/include/defines.inc.php
@@ -41,6 +41,7 @@ define('ZBX_PERIOD_DEFAULT',	3600); // 1
 // by default set to 86400 seconds (24 hours)
 define('ZBX_HISTORY_PERIOD', 86400);
 
+define('ZBX_HISTORY_SOURCE_CLICKHOUSE',	'clickhouse');
 define('ZBX_HISTORY_SOURCE_ELASTIC',	'elastic');
 define('ZBX_HISTORY_SOURCE_SQL',		'sql');
 
Index: zabbix-3.4.12-1+buster/frontends/php/conf/zabbix.conf.php.example
===================================================================
--- zabbix-3.4.12-1+buster.orig/frontends/php/conf/zabbix.conf.php.example
+++ zabbix-3.4.12-1+buster/frontends/php/conf/zabbix.conf.php.example
@@ -17,10 +17,13 @@ $ZBX_SERVER_NAME		= '';
 
 $IMAGE_FORMAT_DEFAULT	= IMAGE_FORMAT_PNG;
 
-// Elasticsearch url (can be string if same url is used for all types).
+// Elasticsearch or ClickHouse url.
 $HISTORY['url']   = [
-		'uint' => 'http://localhost:9200',
+		'uint' => 'http://login:password@localhost:8123/?database=zabbix',
 		'text' => 'http://localhost:9200'
 ];
-// Value types stored in Elasticsearch.
-$HISTORY['types'] = ['uint', 'text'];
+// Value types stored in Elasticsearch or ClickHouse.
+$HISTORY['types'] = [
+		'uint' => 'clickhouse',
+		'text' => 'elastic'
+];