private bool LoadEntitiesFromLocalDbLocked(bool onStartup, BPlusTree <int, ContentNodeKit> localDb, ContentStore store, string entityType)
{
var kits = localDb.Select(x => x.Value)
.OrderBy(x => x.Node.Level)
.ThenBy(x => x.Node.ParentContentId)
.ThenBy(x => x.Node.SortOrder) // IMPORTANT sort by level + parentId + sortOrder
.ToList();
if (kits.Count == 0)
{
// If there's nothing in the local cache file, we should return false? YES even though the site legitately might be empty.
// Is it possible that the cache file is empty but the database is not? YES... (well, it used to be possible)
// * A new file is created when one doesn't exist, this will only be done when MainDom is acquired
// * The new file will be populated as soon as LoadCachesOnStartup is called
// * If the appdomain is going down the moment after MainDom was acquired and we've created an empty cache file,
// then the MainDom release callback is triggered from on a different thread, which will close the file and
// set the cache file reference to null. At this moment, it is possible that the file is closed and the
// reference is set to null BEFORE LoadCachesOnStartup which would mean that the current appdomain would load
// in the in-mem cache via DB calls, BUT this now means that there is an empty cache file which will be
// loaded by the next appdomain and it won't check if it's empty, it just assumes that since the cache
// file is there, that is correct.
// Update: We will still return false here even though the above mentioned race condition has been fixed since we now
// lock the entire operation of creating/populating the cache file with the same lock as releasing/closing the cache file
_logger.LogInformation("Tried to load {entityType} from the local cache file but it was empty.", entityType);
return(false);
}
return(onStartup ? store.SetAllFastSortedLocked(kits, false) : store.SetAllLocked(kits));
}
private bool LoadMediaFromDatabaseLocked(bool onStartup)
{
// locks & notes: see content
var mediaTypes = _serviceContext.MediaTypeService.GetAll()
.Select(x => _publishedContentTypeFactory.CreateContentType(x));
_mediaStore.SetAllContentTypesLocked(mediaTypes);
using (_profilingLogger.TraceDuration <PublishedSnapshotService>("Loading media from database"))
{
// beware! at that point the cache is inconsistent,
// assuming we are going to SetAll content items!
_localMediaDb?.Clear();
_logger.LogDebug("Loading media from database...");
// IMPORTANT GetAllMediaSources sorts kits by level + parentId + sortOrder
var kits = _publishedContentService.GetAllMediaSources();
return(onStartup ? _mediaStore.SetAllFastSortedLocked(kits, true) : _mediaStore.SetAllLocked(kits));
}
}
private bool LoadContentFromDatabaseLocked(bool onStartup)
{
// locks:
// contentStore is wlocked (1 thread)
// content (and types) are read-locked
var contentTypes = _serviceContext.ContentTypeService.GetAll().ToList();
_contentStore.SetAllContentTypesLocked(contentTypes.Select(x => _publishedContentTypeFactory.CreateContentType(x)));
using (_profilingLogger.TraceDuration <PublishedSnapshotService>("Loading content from database"))
{
// beware! at that point the cache is inconsistent,
// assuming we are going to SetAll content items!
_localContentDb?.Clear();
// IMPORTANT GetAllContentSources sorts kits by level + parentId + sortOrder
var kits = _publishedContentService.GetAllContentSources();
return(onStartup ? _contentStore.SetAllFastSortedLocked(kits, true) : _contentStore.SetAllLocked(kits));
}
}
