From 5a4d30ed09e44a10cd6fce5f6b03a864d6a253f6 Mon Sep 17 00:00:00 2001
From: Umherirrender <umherirrender_de.wp@web.de>
Date: Wed, 4 Sep 2019 18:11:46 +0200
Subject: [PATCH] Avoid Database::tableName in WikiExporter

Using * in select is not the prefered way.
List all needed columns to make the use visible and to avoid issues when
new fields gets added with big data.
As each column name is unique there is no need to get the table name for
prefixing the columns

The following columns no longer selected:
- log_user_text -> not used due to use of ActorMigration class
- log_actor -> Add by ActorMigration class
- log_comment_id -> Added by CommentStore
- log_page -> Unused in the writer, the ns/title pair is used instead

Move the arrays out of the loop, because there are not depending on
values changing in the loop

Change-Id: I140641b7ed75bc2b8db2e7612020d668f1be663b
---
 includes/export/WikiExporter.php | 38 +++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/includes/export/WikiExporter.php b/includes/export/WikiExporter.php
index ec0b344e3c..c1b35954e8 100644
--- a/includes/export/WikiExporter.php
+++ b/includes/export/WikiExporter.php
@@ -30,6 +30,7 @@
 use MediaWiki\MediaWikiServices as MediaWikiServicesAlias;
 use MediaWiki\Storage\RevisionRecord;
 use Wikimedia\Rdbms\IResultWrapper;
+use Wikimedia\Rdbms\IDatabase;
 
 /**
  * @ingroup SpecialPage Dump
@@ -67,7 +68,7 @@ class WikiExporter {
 	/** @var XmlDumpWriter */
 	private $writer;
 
-	/** @var Database */
+	/** @var IDatabase */
 	protected $db;
 
 	/** @var array|int */
@@ -86,7 +87,7 @@ class WikiExporter {
 	}
 
 	/**
-	 * @param Database $db
+	 * @param IDatabase $db
 	 * @param int|array $history One of WikiExporter::FULL, WikiExporter::CURRENT,
 	 *   WikiExporter::RANGE or WikiExporter::STABLE, or an associative array:
 	 *   - offset: non-inclusive offset at which to start the query
@@ -303,29 +304,36 @@ class WikiExporter {
 		if ( $cond ) {
 			$where[] = $cond;
 		}
-		# Get logging table name for logging.* clause
-		$logging = $this->db->tableName( 'logging' );
-
 		$result = null; // Assuring $result is not undefined, if exception occurs early
 
 		$commentQuery = CommentStore::getStore()->getJoin( 'log_comment' );
 		$actorQuery = ActorMigration::newMigration()->getJoin( 'log_user' );
 
+		$tables = array_merge(
+			[ 'logging' ], $commentQuery['tables'], $actorQuery['tables'], [ 'user' ]
+		);
+		$fields = [
+			'log_id', 'log_type', 'log_action', 'log_timestamp', 'log_namespace',
+			'log_title', 'log_params', 'log_deleted', 'user_name'
+		] + $commentQuery['fields'] + $actorQuery['fields'];
+		$options = [
+			'ORDER BY' => 'log_id',
+			'USE INDEX' => [ 'logging' => 'PRIMARY' ],
+			'LIMIT' => self::BATCH_SIZE,
+		];
+		$joins = [
+			'user' => [ 'JOIN', 'user_id = ' . $actorQuery['fields']['log_user'] ]
+		] + $commentQuery['joins'] + $actorQuery['joins'];
+
 		$lastLogId = 0;
 		while ( true ) {
 			$result = $this->db->select(
-				array_merge( [ 'logging' ], $commentQuery['tables'], $actorQuery['tables'], [ 'user' ] ),
-				[ "{$logging}.*", 'user_name' ] + $commentQuery['fields'] + $actorQuery['fields'],
+				$tables,
+				$fields,
 				array_merge( $where, [ 'log_id > ' . intval( $lastLogId ) ] ),
 				__METHOD__,
-				[
-					'ORDER BY' => 'log_id',
-					'USE INDEX' => [ 'logging' => 'PRIMARY' ],
-					'LIMIT' => self::BATCH_SIZE,
-				],
-				[
-					'user' => [ 'JOIN', 'user_id = ' . $actorQuery['fields']['log_user'] ]
-				] + $commentQuery['joins'] + $actorQuery['joins']
+				$options,
+				$joins
 			);
 
 			if ( !$result->numRows() ) {
-- 
2.20.1