When syncing, update the database by articleIDs rather than by feeds — this means *far* fewer fetches and much less data pulled from the database. It should help app responsiveness dramatically during sync, and especially during an initial sync.

Frameworks/Account/Account.swift

@@ -573,12 +573,40 @@ public final class Account: DisplayNameProvider, UnreadCountProvider, Container,
 	}
 
 	func update(_ feed: Feed, with parsedFeed: ParsedFeed, _ completion: @escaping (() -> Void)) {
+		// Used only by an On My Mac account.
 		feed.takeSettings(from: parsedFeed)
-		update(feed, parsedItems: parsedFeed.items, completion)
+		let feedIDsAndItems = [feed.feedID: parsedFeed.items]
+		update(feedIDsAndItems: feedIDsAndItems, defaultRead: false, completion: completion)
 	}
-	
+
+	func update(feedIDsAndItems: [String: Set<ParsedItem>], defaultRead: Bool, completion: @escaping (() -> Void)) {
+		guard !feedIDsAndItems.isEmpty else {
+			completion()
+			return
+		}
+		database.update(feedIDsAndItems: feedIDsAndItems, defaultRead: defaultRead) { (newArticles, updatedArticles) in
+			var userInfo = [String: Any]()
+			let feeds = Set(feedIDsAndItems.compactMap { (key, _) -> Feed? in
+				self.existingFeed(withFeedID: key)
+			})
+			if let newArticles = newArticles, !newArticles.isEmpty {
+				self.updateUnreadCounts(for: feeds)
+				userInfo[UserInfoKey.newArticles] = newArticles
+			}
+			if let updatedArticles = updatedArticles, !updatedArticles.isEmpty {
+				userInfo[UserInfoKey.updatedArticles] = updatedArticles
+			}
+			userInfo[UserInfoKey.feeds] = feeds
+
+			completion()
+
+			NotificationCenter.default.post(name: .AccountDidDownloadArticles, object: self, userInfo: userInfo)
+		}
+	}
+
 	func update(_ feed: Feed, parsedItems: Set<ParsedItem>, defaultRead: Bool = false, _ completion: @escaping (() -> Void)) {
-		database.update(feedID: feed.feedID, parsedItems: parsedItems, defaultRead: defaultRead) { (newArticles, updatedArticles) in
+		let feedIDsAndItems = [feed.feedID: parsedItems]
+		database.update(feedIDsAndItems: feedIDsAndItems, defaultRead: defaultRead) { (newArticles, updatedArticles) in
 			var userInfo = [String: Any]()
 			if let newArticles = newArticles, !newArticles.isEmpty {
 				self.updateUnreadCounts(for: Set([feed]))

Frameworks/Account/Feedbin/FeedbinAccountDelegate.swift

@@ -1054,7 +1054,6 @@ private extension FeedbinAccountDelegate {
 	}
 
 	func refreshArticles(_ account: Account, page: String?, completion: @escaping (() -> Void)) {
-		
 		guard let page = page else {
 			completion()
 			return
@@ -1074,42 +1073,16 @@ private extension FeedbinAccountDelegate {
 				os_log(.error, log: self.log, "Refresh articles for additional pages failed: %@.", error.localizedDescription)
 				completion()
 			}
-			
 		}
-		
 	}
 	
 	func processEntries(account: Account, entries: [FeedbinEntry]?, completion: @escaping (() -> Void)) {
-		
 		let parsedItems = mapEntriesToParsedItems(entries: entries)
-		let parsedMap = Dictionary(grouping: parsedItems, by: { item in item.feedURL } )
-		
-		let group = DispatchGroup()
-		
-		for (feedID, mapItems) in parsedMap {
-			
-			group.enter()
-			
-			if let feed = account.existingFeed(withFeedID: feedID) {
-				DispatchQueue.main.async {
-					account.update(feed, parsedItems: Set(mapItems), defaultRead: true) {
-						group.leave()
-					}
-				}
-			} else {
-				group.leave()
-			}
-			
-		}
-		
-		group.notify(queue: DispatchQueue.main) {
-			completion()
-		}
-
+		let feedIDsAndItems = Dictionary(grouping: parsedItems, by: { item in item.feedURL } ).mapValues { Set($0) }
+		account.update(feedIDsAndItems: feedIDsAndItems, defaultRead: true, completion: completion)
 	}
 	
 	func mapEntriesToParsedItems(entries: [FeedbinEntry]?) -> Set<ParsedItem> {
-		
 		guard let entries = entries else {
 			return Set<ParsedItem>()
 		}

Frameworks/ArticlesDatabase/ArticlesDatabase.swift

@@ -18,7 +18,7 @@ import Articles
 
 public typealias UnreadCountDictionary = [String: Int] // feedID: unreadCount
 public typealias UnreadCountCompletionBlock = (UnreadCountDictionary) -> Void
-public typealias UpdateArticlesWithFeedCompletionBlock = (Set<Article>?, Set<Article>?) -> Void //newArticles, updatedArticles
+public typealias UpdateArticlesCompletionBlock = (Set<Article>?, Set<Article>?) -> Void //newArticles, updatedArticles
 
 public final class ArticlesDatabase {
 
@@ -118,10 +118,11 @@ public final class ArticlesDatabase {
 
 	// MARK: - Saving and Updating Articles
 
-	public func update(feedID: String, parsedItems: Set<ParsedItem>, defaultRead: Bool, completion: @escaping UpdateArticlesWithFeedCompletionBlock) {
-		return articlesTable.update(feedID, parsedItems, defaultRead, completion)
+	/// Update articles and save new ones. The key for feedIDsAndItems is feedID.
+	public func update(feedIDsAndItems: [String: Set<ParsedItem>], defaultRead: Bool, completion: @escaping UpdateArticlesCompletionBlock) {
+		articlesTable.update(feedIDsAndItems, defaultRead, completion)
 	}
-	
+
 	public func ensureStatuses(_ articleIDs: Set<String>, _ defaultRead: Bool, _ statusKey: ArticleStatus.Key, _ flag: Bool) {
 		articlesTable.ensureStatuses(articleIDs, defaultRead, statusKey, flag)
 	}

Frameworks/ArticlesDatabase/ArticlesTable.swift

@@ -208,9 +208,9 @@ final class ArticlesTable: DatabaseTable {
 	}
 
 	// MARK: - Updating
-	
-	func update(_ feedID: String, _ parsedItems: Set<ParsedItem>, _ read: Bool, _ completion: @escaping UpdateArticlesWithFeedCompletionBlock) {
-		if parsedItems.isEmpty {
+
+	func update(_ feedIDsAndItems: [String: Set<ParsedItem>], _ read: Bool, _ completion: @escaping UpdateArticlesCompletionBlock) {
+		if feedIDsAndItems.isEmpty {
 			completion(nil, nil)
 			return
 		}
@@ -224,30 +224,34 @@ final class ArticlesTable: DatabaseTable {
 		// 7. Call back with new and updated Articles.
 		// 8. Update search index.
 
-		let articleIDs = Set(parsedItems.map { $0.articleID })
-		
+		var articleIDs = Set<String>()
+		for (_, parsedItems) in feedIDsAndItems {
+			articleIDs.formUnion(parsedItems.articleIDs())
+		}
+
 		self.queue.update { (database) in
 			let statusesDictionary = self.statusesTable.ensureStatusesForArticleIDs(articleIDs, read, database) //1
 			assert(statusesDictionary.count == articleIDs.count)
-			
-			let allIncomingArticles = Article.articlesWithParsedItems(parsedItems, self.accountID, feedID, statusesDictionary) //2
+
+			let allIncomingArticles = Article.articlesWithFeedIDsAndItems(feedIDsAndItems, self.accountID, statusesDictionary) //2
 			if allIncomingArticles.isEmpty {
 				self.callUpdateArticlesCompletionBlock(nil, nil, completion)
 				return
 			}
-			
+
 			let incomingArticles = self.filterIncomingArticles(allIncomingArticles) //3
 			if incomingArticles.isEmpty {
 				self.callUpdateArticlesCompletionBlock(nil, nil, completion)
 				return
 			}
 
-			let fetchedArticles = self.fetchArticlesForFeedID(feedID, withLimits: false, database) //4
+			let incomingArticleIDs = incomingArticles.articleIDs()
+			let fetchedArticles = self.fetchArticles(articleIDs: incomingArticleIDs, database) //4
 			let fetchedArticlesDictionary = fetchedArticles.dictionary()
-			
+
 			let newArticles = self.findAndSaveNewArticles(incomingArticles, fetchedArticlesDictionary, database) //5
 			let updatedArticles = self.findAndSaveUpdatedArticles(incomingArticles, fetchedArticlesDictionary, database) //6
-			
+
 			self.callUpdateArticlesCompletionBlock(newArticles, updatedArticles, completion) //7
 
 			// 8. Update search index.
@@ -258,16 +262,75 @@ final class ArticlesTable: DatabaseTable {
 			if let updatedArticles = updatedArticles {
 				articlesToIndex.formUnion(updatedArticles)
 			}
-			let articleIDs = articlesToIndex.articleIDs()
-			if articleIDs.isEmpty {
+			let articleIDsToIndex = articlesToIndex.articleIDs()
+			if articleIDsToIndex.isEmpty {
 				return
 			}
 			DispatchQueue.main.async {
-				self.searchTable.ensureIndexedArticles(for: articleIDs)
+				self.searchTable.ensureIndexedArticles(for: articleIDsToIndex)
 			}
 		}
 	}
 
+//	func update(_ feedID: String, _ parsedItems: Set<ParsedItem>, _ read: Bool, _ completion: @escaping UpdateArticlesCompletionBlock) {
+//		if parsedItems.isEmpty {
+//			completion(nil, nil)
+//			return
+//		}
+//
+//		// 1. Ensure statuses for all the incoming articles.
+//		// 2. Create incoming articles with parsedItems.
+//		// 3. Ignore incoming articles that are userDeleted || (!starred and really old)
+//		// 4. Fetch all articles for the feed.
+//		// 5. Create array of Articles not in database and save them.
+//		// 6. Create array of updated Articles and save what’s changed.
+//		// 7. Call back with new and updated Articles.
+//		// 8. Update search index.
+//
+//		let articleIDs = Set(parsedItems.map { $0.articleID })
+//
+//		self.queue.update { (database) in
+//			let statusesDictionary = self.statusesTable.ensureStatusesForArticleIDs(articleIDs, read, database) //1
+//			assert(statusesDictionary.count == articleIDs.count)
+//
+//			let allIncomingArticles = Article.articlesWithParsedItems(parsedItems, self.accountID, feedID, statusesDictionary) //2
+//			if allIncomingArticles.isEmpty {
+//				self.callUpdateArticlesCompletionBlock(nil, nil, completion)
+//				return
+//			}
+//
+//			let incomingArticles = self.filterIncomingArticles(allIncomingArticles) //3
+//			if incomingArticles.isEmpty {
+//				self.callUpdateArticlesCompletionBlock(nil, nil, completion)
+//				return
+//			}
+//
+//			let fetchedArticles = self.fetchArticlesForFeedID(feedID, withLimits: false, database) //4
+//			let fetchedArticlesDictionary = fetchedArticles.dictionary()
+//
+//			let newArticles = self.findAndSaveNewArticles(incomingArticles, fetchedArticlesDictionary, database) //5
+//			let updatedArticles = self.findAndSaveUpdatedArticles(incomingArticles, fetchedArticlesDictionary, database) //6
+//
+//			self.callUpdateArticlesCompletionBlock(newArticles, updatedArticles, completion) //7
+//
+//			// 8. Update search index.
+//			var articlesToIndex = Set<Article>()
+//			if let newArticles = newArticles {
+//				articlesToIndex.formUnion(newArticles)
+//			}
+//			if let updatedArticles = updatedArticles {
+//				articlesToIndex.formUnion(updatedArticles)
+//			}
+//			let articleIDs = articlesToIndex.articleIDs()
+//			if articleIDs.isEmpty {
+//				return
+//			}
+//			DispatchQueue.main.async {
+//				self.searchTable.ensureIndexedArticles(for: articleIDs)
+//			}
+//		}
+//	}
+
 	func ensureStatuses(_ articleIDs: Set<String>, _ defaultRead: Bool, _ statusKey: ArticleStatus.Key, _ flag: Bool) {
 		self.queue.update { (database) in
 			let statusesDictionary = self.statusesTable.ensureStatusesForArticleIDs(articleIDs, defaultRead, database)
@@ -596,7 +659,7 @@ private extension ArticlesTable {
 
 	// MARK: - Saving Parsed Items
 	
-	func callUpdateArticlesCompletionBlock(_ newArticles: Set<Article>?, _ updatedArticles: Set<Article>?, _ completion: @escaping UpdateArticlesWithFeedCompletionBlock) {
+	func callUpdateArticlesCompletionBlock(_ newArticles: Set<Article>?, _ updatedArticles: Set<Article>?, _ completion: @escaping UpdateArticlesCompletionBlock) {
 		DispatchQueue.main.async {
 			completion(newArticles, updatedArticles)
 		}
@@ -728,3 +791,8 @@ private extension ArticlesTable {
 	}
 }
 
+private extension Set where Element == ParsedItem {
+	func articleIDs() -> Set<String> {
+		return Set<String>(map { $0.articleID })
+	}
+}

Frameworks/ArticlesDatabase/Extensions/Article+Database.swift

@@ -79,11 +79,20 @@ extension Article {
 		return d.count < 1 ? nil : d
 	}
 
-	static func articlesWithParsedItems(_ parsedItems: Set<ParsedItem>, _ accountID: String, _ feedID: String, _ statusesDictionary: [String: ArticleStatus]) -> Set<Article> {
+//	static func articlesWithParsedItems(_ parsedItems: Set<ParsedItem>, _ accountID: String, _ feedID: String, _ statusesDictionary: [String: ArticleStatus]) -> Set<Article> {
+//		let maximumDateAllowed = Date().addingTimeInterval(60 * 60 * 24) // Allow dates up to about 24 hours ahead of now
+//		return Set(parsedItems.map{ Article(parsedItem: $0, maximumDateAllowed: maximumDateAllowed, accountID: accountID, feedID: feedID, status: statusesDictionary[$0.articleID]!) })
+//	}
+
+	static func articlesWithFeedIDsAndItems(_ feedIDsAndItems: [String: Set<ParsedItem>], _ accountID: String, _ statusesDictionary: [String: ArticleStatus]) -> Set<Article> {
 		let maximumDateAllowed = Date().addingTimeInterval(60 * 60 * 24) // Allow dates up to about 24 hours ahead of now
-		return Set(parsedItems.map{ Article(parsedItem: $0, maximumDateAllowed: maximumDateAllowed, accountID: accountID, feedID: feedID, status: statusesDictionary[$0.articleID]!) })
+		var articles = Set<Article>()
+		for (feedID, parsedItems) in feedIDsAndItems {
+			let feedArticles = Set(parsedItems.map{ Article(parsedItem: $0, maximumDateAllowed: maximumDateAllowed, accountID: accountID, feedID: feedID, status: statusesDictionary[$0.articleID]!) })
+			articles.formUnion(feedArticles)
+		}
+		return articles
 	}
-	
 }
 
 extension Article: DatabaseObject {