the mw.Api instance seems to be for the local wiki.
* After a client performs an action which alters a database that has replica databases,
MediaWiki will wait for the replica databases to synchronize with the master database
- while it renders the HTML output. However, if the output is a redirect, it will instead
- alter the redirect URL to include a ?cpPosTime parameter that triggers the database
- synchronization when the URL is followed by the client.
+ while it renders the HTML output. However, if the output is a redirect to another wiki
+ on the wiki farm with a different domain, MediaWiki will instead alter the redirect
+ URL to include a ?cpPosTime parameter that triggers the database synchronization when
+ the URL is followed by the client. The same-domain case uses a new cpPosTime cookie.
=== External library changes in 1.28 ===
wfDebug( __METHOD__ . ': pre-send deferred updates completed' );
// Decide when clients block on ChronologyProtector DB position writes
- if (
+ $urlDomainDistance = (
$request->wasPosted() &&
$output->getRedirect() &&
- $lbFactory->hasOrMadeRecentMasterChanges( INF ) &&
- self::isWikiClusterURL( $output->getRedirect(), $context )
- ) {
+ $lbFactory->hasOrMadeRecentMasterChanges( INF )
+ ) ? self::getUrlDomainDistance( $output->getRedirect(), $context ) : false;
+
+ if ( $urlDomainDistance === 'local' || $urlDomainDistance === 'remote' ) {
// OutputPage::output() will be fast; $postCommitWork will not be useful for
// masking the latency of syncing DB positions accross all datacenters synchronously.
// Instead, make use of the RTT time of the client follow redirects.
$flags = $lbFactory::SHUTDOWN_CHRONPROT_ASYNC;
+ $cpPosTime = microtime( true );
// Client's next request should see 1+ positions with this DBMasterPos::asOf() time
- $safeUrl = $lbFactory->appendPreShutdownTimeAsQuery(
- $output->getRedirect(),
- microtime( true )
- );
- $output->redirect( $safeUrl );
+ if ( $urlDomainDistance === 'local' ) {
+ // Client will stay on this domain, so set an unobtrusive cookie
+ $expires = time() + ChronologyProtector::POSITION_TTL;
+ $options = [ 'prefix' => '' ];
+ $request->response()->setCookie( 'cpPosTime', $cpPosTime, $expires, $options );
+ } else {
+ // Cookies may not work across wiki domains, so use a URL parameter
+ $safeUrl = $lbFactory->appendPreShutdownTimeAsQuery(
+ $output->getRedirect(),
+ $cpPosTime
+ );
+ $output->redirect( $safeUrl );
+ }
} else {
// OutputPage::output() is fairly slow; run it in $postCommitWork to mask
// the latency of syncing DB positions accross all datacenters synchronously
/**
* @param string $url
* @param IContextSource $context
- * @return bool Whether $url is to something on this wiki farm
+ * @return string|bool Either "local" or "remote" if in the farm, false otherwise
*/
- private function isWikiClusterURL( $url, IContextSource $context ) {
+ private function getUrlDomainDistance( $url, IContextSource $context ) {
static $relevantKeys = [ 'host' => true, 'port' => true ];
$infoCandidate = wfParseUrl( $url );
$context->getConfig()->get( 'LocalVirtualHosts' )
);
- foreach ( $clusterHosts as $clusterHost ) {
+ foreach ( $clusterHosts as $i => $clusterHost ) {
$parseUrl = wfParseUrl( $clusterHost );
if ( !$parseUrl ) {
continue;
}
$infoHost = array_intersect_key( $parseUrl, $relevantKeys );
if ( $infoCandidate === $infoHost ) {
- return true;
+ return ( $i === 0 ) ? 'local' : 'remote';
}
}