double-cache to get newer items

darcs-hash:20081122124151-84dde-3e942c9ab172444bd28afb84a452b8bfb5e3574a.gz
This commit is contained in:
Evan Prodromou 2008-11-22 07:41:51 -05:00
parent a730ad708c
commit 3a82ff2860

View File

@ -299,6 +299,9 @@ class Notice extends Memcached_DataObject
return $notice;
}
# XXX: this is pretty long and should probably be broken up into
# some helper functions
static function getCachedStream($qry, $cachekey, $offset, $limit, $order) {
# If outside our cache window, just go to the DB
@ -326,6 +329,46 @@ class Notice extends Memcached_DataObject
return $wrapper;
}
# If the cache was invalidated because of new data being
# added, we can try and just get the new stuff. We keep an additional
# copy of the data at the key + ';last'
# No cache hit. Try to get the *last* cached version
$last_notices = $cache->get(common_cache_key($cachekey) . ';last');
if ($last_notices) {
# Reverse-chron order, so last ID is last.
$last_id = $last_notices[0]->id;
# XXX: this assumes monotonically increasing IDs; a fair
# bet with our DB.
$new_notice = Notice::getStreamDirect($qry, 0, NOTICE_CACHE_WINDOW,
$last_id, NULL, $order);
if ($new_notice) {
$new_notices = array();
while ($new_notice->fetch()) {
$new_notices[] = clone($new_notice);
}
$new_notice->free();
$notices = array_slice(array_merge($new_notices, $last_notices),
0, NOTICE_CACHE_WINDOW);
# Store the array in the cache for next time
$result = $cache->set(common_cache_key($cachekey), $notices);
$result = $cache->set(common_cache_key($cachekey) . ';last', $notices);
# return a wrapper of the array for use now
return new NoticeWrapper(array_slice($notices, $offset, $limit));
}
}
# Otherwise, get the full cache window out of the DB
$notice = Notice::getStreamDirect($qry, 0, NOTICE_CACHE_WINDOW, NULL, NULL, $order);
@ -344,9 +387,12 @@ class Notice extends Memcached_DataObject
$notices[] = clone($notice);
}
$notice->free();
# Store the array in the cache for next time
$result = $cache->set(common_cache_key($cachekey), $notices);
$result = $cache->set(common_cache_key($cachekey) . ';last', $notices);
# return a wrapper of the array for use now