Merge "Make DBAccessBase use DBConnRef, rename $wiki, and hide getLoadBalancer()"

[lhc/web/wiklou.git] / includes / libs / rdbms / ChronologyProtector.php

diff --git a/includes/libs/rdbms/ChronologyProtector.php b/includes/libs/rdbms/ChronologyProtector.php
index 8615cfc..e1398b8 100644 (file)
--- a/includes/libs/rdbms/ChronologyProtector.php
+++ b/includes/libs/rdbms/ChronologyProtector.php
@@ -224,10 +224,9 @@ class ChronologyProtector implements LoggerAwareInterface {
                        implode( ', ', array_keys( $this->shutdownPositions ) ) . "\n"
                );
 
-               // CP-protected writes should overwhelmingly go to the master datacenter, so use a
-               // DC-local lock to merge the values. Use a DC-local get() and a synchronous all-DC
-               // set(). This makes it possible for the BagOStuff class to write in parallel to all
-               // DCs with one RTT. The use of WRITE_SYNC avoids needing READ_LATEST for the get().
+               // CP-protected writes should overwhelmingly go to the master datacenter, so merge the
+               // positions with a DC-local lock, a DC-local get(), and an all-DC set() with WRITE_SYNC.
+               // If set() returns success, then any get() should be able to see the new positions.
                if ( $store->lock( $this->key, 3 ) ) {
                        if ( $workCallback ) {
                                // Let the store run the work before blocking on a replication sync barrier.