From: Aaron Schulz <aschulz@wikimedia.org>
Date: Thu, 29 Mar 2018 23:14:37 +0000 (-0700)
Subject: rdbms: update IDatabase::getLag comments
X-Git-Tag: 1.31.0-rc.0~237^2~1
X-Git-Url: https://git.heureux-cyclage.org/?p=lhc%2Fweb%2Fwiklou.git;a=commitdiff_plain;h=4255b4fa6dd303f2c2db65ff67f02c2c561e4821

rdbms: update IDatabase::getLag comments

Also add missing __METHOD__ to getLagFromPtHeartbeat()

Change-Id: I4257b1d47a88779b47d807a881561c331ff3aa30
---

diff --git a/includes/libs/rdbms/database/DatabaseMysqlBase.php b/includes/libs/rdbms/database/DatabaseMysqlBase.php
index 286d65881e..315c9eb0ec 100644
--- a/includes/libs/rdbms/database/DatabaseMysqlBase.php
+++ b/includes/libs/rdbms/database/DatabaseMysqlBase.php
@@ -749,6 +749,7 @@ abstract class DatabaseMysqlBase extends Database {
 	protected function getLagFromSlaveStatus() {
 		$res = $this->query( 'SHOW SLAVE STATUS', __METHOD__ );
 		$row = $res ? $res->fetchObject() : false;
+		// If the server is not replicating, there will be no row
 		if ( $row && strval( $row->Seconds_Behind_Master ) !== '' ) {
 			return intval( $row->Seconds_Behind_Master );
 		}
@@ -856,7 +857,8 @@ abstract class DatabaseMysqlBase extends Database {
 			// Note: this would use "TIMESTAMPDIFF(MICROSECOND,ts,UTC_TIMESTAMP(6))" but the
 			// percision field is not supported in MySQL <= 5.5.
 			$res = $this->query(
-				"SELECT ts FROM heartbeat.heartbeat WHERE $whereSQL ORDER BY ts DESC LIMIT 1"
+				"SELECT ts FROM heartbeat.heartbeat WHERE $whereSQL ORDER BY ts DESC LIMIT 1",
+				__METHOD__
 			);
 			$row = $res ? $res->fetchObject() : false;
 		} finally {
diff --git a/includes/libs/rdbms/database/IDatabase.php b/includes/libs/rdbms/database/IDatabase.php
index 07f1e2336f..545c8e36f7 100644
--- a/includes/libs/rdbms/database/IDatabase.php
+++ b/includes/libs/rdbms/database/IDatabase.php
@@ -1752,11 +1752,9 @@ interface IDatabase {
 	public function ping( &$rtt = null );
 
 	/**
-	 * Get replica DB lag. Currently supported only by MySQL.
+	 * Get the amount of replication lag for this database server
 	 *
-	 * Note that this function will generate a fatal error on many
-	 * installations. Most callers should use LoadBalancer::safeGetLag()
-	 * instead.
+	 * Callers should avoid using this method while a transaction is active
 	 *
 	 * @return int|bool Database replication lag in seconds or false on error
 	 * @throws DBError