Aaron Schulz has uploaded a new change for review.
https://gerrit.wikimedia.org/r/255801
Change subject: Make getCacheSetOptions() and WAN cache handle broken
replication
......................................................................
Make getCacheSetOptions() and WAN cache handle broken replication
TTL_LAGGED now triggers if the slave or I/O threads stopped
Change-Id: I5e7bf2d33b8d3a60182ec53a93d65f7e55f02222
---
M includes/db/Database.php
M includes/libs/objectcache/WANObjectCache.php
2 files changed, 8 insertions(+), 4 deletions(-)
git pull ssh://gerrit.wikimedia.org:29418/mediawiki/core
refs/changes/01/255801/1
diff --git a/includes/db/Database.php b/includes/db/Database.php
index c0cf067..68f94b6 100644
--- a/includes/db/Database.php
+++ b/includes/db/Database.php
@@ -3820,7 +3820,7 @@
* @param IDatabase $db1
* @param IDatabase ...
* @return array Map of values:
- * - lag: highest lag of any of the DBs
+ * - lag: highest lag of any of the DBs or false on error (e.g.
replication stopped)
* - since: oldest UNIX timestamp of any of the DB lag estimates
* - pending: whether any of the DBs have uncommitted changes
* @since 1.27
@@ -3830,7 +3830,11 @@
foreach ( func_get_args() as $db ) {
/** @var IDatabase $db */
$status = $db->getSessionLagStatus();
- $res['lag'] = max( $res['lag'], $status['lag'] );
+ if ( $status['lag'] === false ) {
+ $res['lag'] = false;
+ } elseif ( $res['lag'] !== false ) {
+ $res['lag'] = max( $res['lag'], $status['lag']
);
+ }
$res['since'] = min( $res['since'], $status['since'] );
$res['pending'] = $res['pending'] ?:
$db->writesPending();
}
diff --git a/includes/libs/objectcache/WANObjectCache.php
b/includes/libs/objectcache/WANObjectCache.php
index 16e894e..720946a 100644
--- a/includes/libs/objectcache/WANObjectCache.php
+++ b/includes/libs/objectcache/WANObjectCache.php
@@ -378,7 +378,7 @@
$wrapExtra = array(); // additional wrapped value fields
// Check if there's a risk of writing stale data after the
purge tombstone expired
- if ( ( $lag + $age ) > self::MAX_READ_LAG ) {
+ if ( ( $lag + $age ) > self::MAX_READ_LAG || $lag === false ) {
// Case A: read lag with "lockTSE"; save but record
value as stale
if ( $lockTSE >= 0 ) {
$ttl = max( 1, (int)$lockTSE ); // set()
expects seconds
@@ -389,7 +389,7 @@
return true; // no-op the write for being unsafe
// Case C: high replication lag; lower TTL instead of
ignoring all set()s
- } elseif ( $lag > self::MAX_READ_LAG ) {
+ } elseif ( $lag > self::MAX_READ_LAG || $lag === false
) {
$ttl = $ttl ? min( $ttl, self::TTL_LAGGED ) :
self::TTL_LAGGED;
$this->logger->warning( "Lowered set() TTL for
$key due to replication lag." );
// Case D: medium length request with medium
replication lag; ignore this set()
--
To view, visit https://gerrit.wikimedia.org/r/255801
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I5e7bf2d33b8d3a60182ec53a93d65f7e55f02222
Gerrit-PatchSet: 1
Gerrit-Project: mediawiki/core
Gerrit-Branch: master
Gerrit-Owner: Aaron Schulz <asch...@wikimedia.org>
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