Bartosz Dziewoński has uploaded a new change for review.
https://gerrit.wikimedia.org/r/290142
Change subject: populateRevisionLength: Read from slaves when possible
......................................................................
populateRevisionLength: Read from slaves when possible
The references to revision content stored in 'revision' and 'archive'
tables are immutable (outside of other maintenance scripts), so we can
safely query them from slave databases.
Also:
* Avoid transactions with no operations inside them
* Improve documentation
Bug: T135414
Change-Id: I3e1407e18e09cf01f105c1cae6d6c23bfde747e6
---
M maintenance/populateRevisionLength.php
1 file changed, 23 insertions(+), 20 deletions(-)
git pull ssh://gerrit.wikimedia.org:29418/mediawiki/core
refs/changes/42/290142/1
diff --git a/maintenance/populateRevisionLength.php
b/maintenance/populateRevisionLength.php
index 10408ec..dcb9933 100644
--- a/maintenance/populateRevisionLength.php
+++ b/maintenance/populateRevisionLength.php
@@ -1,7 +1,6 @@
<?php
/**
- * Populates the rev_len and ar_len fields for old revisions created
- * before MW 1.10.
+ * Populates the rev_len and ar_len fields when they are NULL.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@@ -25,8 +24,9 @@
require_once __DIR__ . '/Maintenance.php';
/**
- * Maintenance script that populates the rev_len and ar_len fields
- * for old revisions created before MW 1.10.
+ * Maintenance script that populates the rev_len and ar_len fields when they
are NULL.
+ * This is the case for all revisions created before MW 1.10, as well as those
affected
+ * by T18748 (MW 1.10-1.13) and those affected by T135414 (MW 1.21-1.24).
*
* @ingroup Maintenance
*/
@@ -42,12 +42,12 @@
}
public function doDBUpdates() {
- $db = $this->getDB( DB_MASTER );
- if ( !$db->tableExists( 'revision' ) ) {
+ $dbw = $this->getDB( DB_MASTER );
+ if ( !$dbw->tableExists( 'revision' ) ) {
$this->error( "revision table does not exist", true );
- } elseif ( !$db->tableExists( 'archive' ) ) {
+ } elseif ( !$dbw->tableExists( 'archive' ) ) {
$this->error( "archive table does not exist", true );
- } elseif ( !$db->fieldExists( 'revision', 'rev_len', __METHOD__
) ) {
+ } elseif ( !$dbw->fieldExists( 'revision', 'rev_len',
__METHOD__ ) ) {
$this->output( "rev_len column does not exist\n\n",
true );
return false;
@@ -73,9 +73,10 @@
* @return int
*/
protected function doLenUpdates( $table, $idCol, $prefix, $fields ) {
- $db = $this->getDB( DB_MASTER );
- $start = $db->selectField( $table, "MIN($idCol)", false,
__METHOD__ );
- $end = $db->selectField( $table, "MAX($idCol)", false,
__METHOD__ );
+ $dbr = $this->getDB( DB_SLAVE );
+ $dbw = $this->getDB( DB_MASTER );
+ $start = $dbw->selectField( $table, "MIN($idCol)", false,
__METHOD__ );
+ $end = $dbw->selectField( $table, "MAX($idCol)", false,
__METHOD__ );
if ( !$start || !$end ) {
$this->output( "...$table table seems to be empty.\n" );
@@ -89,7 +90,7 @@
while ( $blockStart <= $end ) {
$this->output( "...doing $idCol from $blockStart to
$blockEnd\n" );
- $res = $db->select(
+ $res = $dbr->select(
$table,
$fields,
[
@@ -100,14 +101,16 @@
__METHOD__
);
- $this->beginTransaction( $db, __METHOD__ );
- # Go through and update rev_len from these rows.
- foreach ( $res as $row ) {
- if ( $this->upgradeRow( $row, $table, $idCol,
$prefix ) ) {
- $count++;
+ if ( $res->numRows() > 0 ) {
+ $this->beginTransaction( $dbw, __METHOD__ );
+ # Go through and update rev_len from these rows.
+ foreach ( $res as $row ) {
+ if ( $this->upgradeRow( $row, $table,
$idCol, $prefix ) ) {
+ $count++;
+ }
}
+ $this->commitTransaction( $dbw, __METHOD__ );
}
- $this->commitTransaction( $db, __METHOD__ );
$blockStart += $this->mBatchSize;
$blockEnd += $this->mBatchSize;
@@ -125,7 +128,7 @@
* @return bool
*/
protected function upgradeRow( $row, $table, $idCol, $prefix ) {
- $db = $this->getDB( DB_MASTER );
+ $dbw = $this->getDB( DB_MASTER );
$rev = ( $table === 'archive' )
? Revision::newFromArchiveRow( $row )
@@ -141,7 +144,7 @@
}
# Update the row...
- $db->update( $table,
+ $dbw->update( $table,
[ "{$prefix}_len" => $content->getSize() ],
[ $idCol => $row->$idCol ],
__METHOD__
--
To view, visit https://gerrit.wikimedia.org/r/290142
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I3e1407e18e09cf01f105c1cae6d6c23bfde747e6
Gerrit-PatchSet: 1
Gerrit-Project: mediawiki/core
Gerrit-Branch: master
Gerrit-Owner: Bartosz Dziewoński <[email protected]>
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