Aaron Schulz has uploaded a new change for review.
https://gerrit.wikimedia.org/r/88761
Change subject: Fixed trx isolation bug that could cause text not to be found
......................................................................
Fixed trx isolation bug that could cause text not to be found
* Also added some logging for when revision text is not found
bug: 55418
Change-Id: I0993e8f49d36771cc526fd4afef67455209b8e3a
---
M includes/Revision.php
1 file changed, 23 insertions(+), 5 deletions(-)
git pull ssh://gerrit.wikimedia.org:29418/mediawiki/core
refs/changes/61/88761/1
diff --git a/includes/Revision.php b/includes/Revision.php
index c09af74..305c8ff 100644
--- a/includes/Revision.php
+++ b/includes/Revision.php
@@ -61,6 +61,11 @@
*/
protected $mContentHandler;
+ /**
+ * @var int
+ */
+ protected $mQueryFlags = 0;
+
// Revision deletion constants
const DELETED_TEXT = 1;
const DELETED_COMMENT = 2;
@@ -297,6 +302,9 @@
$dbw = wfGetDB( DB_MASTER );
$rev = self::loadFromConds( $dbw, $conditions,
$flags );
}
+ }
+ if ( $rev ) {
+ $rev->mQueryFlags = $flags;
}
return $rev;
}
@@ -1477,20 +1485,30 @@
$dbr = wfGetDB( DB_SLAVE );
$row = $dbr->selectRow( 'text',
array( 'old_text', 'old_flags' ),
- array( 'old_id' => $this->getTextId() ),
+ array( 'old_id' => $textId ),
__METHOD__ );
}
- if ( !$row && wfGetLB()->getServerCount() > 1 ) {
- // Possible slave lag!
+ // Fallback to the master in case of slave lag. Also use FOR
UPDATE if it was
+ // used to fetch this revision to avoid missing the row due to
REPEATABLE-READ.
+ $forUpdate = ( $this->mQueryFlags & self::READ_LOCKING ==
self::READ_LOCKING );
+ if ( !$row && ( $forUpdate || wfGetLB()->getServerCount() > 1 )
) {
$dbw = wfGetDB( DB_MASTER );
$row = $dbw->selectRow( 'text',
array( 'old_text', 'old_flags' ),
- array( 'old_id' => $this->getTextId() ),
- __METHOD__ );
+ array( 'old_id' => $textId ),
+ __METHOD__,
+ $forUpdate ? array( 'FOR UPDATE' ) : array() );
+ }
+
+ if ( !$row ) {
+ wfDebugLog( 'Revision', "No text row with ID '$textId'
(revision {$this->getId()})." );
}
$text = self::getRevisionText( $row );
+ if ( $row && $text === false ) {
+ wfDebugLog( 'Revision', "No blob for text row '$textId'
(revision {$this->getId()})." );
+ }
# No negative caching -- negative hits on text rows may be due
to corrupted slave servers
if ( $wgRevisionCacheExpiry && $text !== false ) {
--
To view, visit https://gerrit.wikimedia.org/r/88761
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I0993e8f49d36771cc526fd4afef67455209b8e3a
Gerrit-PatchSet: 1
Gerrit-Project: mediawiki/core
Gerrit-Branch: master
Gerrit-Owner: Aaron Schulz <[email protected]>
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