Fetch all unread counts at startup. This is done with a single SQL call, and it’s done in the background, so performance hit should not be noticeable. Fix #138.

Frameworks/Account/Account.swift

@@ -140,6 +140,7 @@ public final class Account: DisplayNameProvider, UnreadCountProvider, Container,
 		
 		DispatchQueue.main.async {
 			self.updateUnreadCount()
+			self.fetchAllUnreadCounts()
 		}
 	}
 	
@@ -622,6 +623,28 @@ private extension Account {
         
         NotificationCenter.default.post(name: .StatusesDidChange, object: self, userInfo: [UserInfoKey.statuses: statuses, UserInfoKey.articles: articles, UserInfoKey.feeds: feeds])
     }
+
+	func fetchAllUnreadCounts() {
+
+		database.fetchAllNonZeroUnreadCounts { (unreadCountDictionary) in
+
+			if unreadCountDictionary.isEmpty {
+				return
+			}
+
+			self.flattenedFeeds().forEach{ (feed) in
+
+				// When the unread count is zero, it won’t appear in unreadCountDictionary.
+
+				if let unreadCount = unreadCountDictionary[feed] {
+					feed.unreadCount = unreadCount
+				}
+				else {
+					feed.unreadCount = 0
+				}
+			}
+		}
+	}
 }
 
 // MARK: - Container Overrides

Frameworks/Database/ArticlesTable.swift

@@ -174,6 +174,37 @@ final class ArticlesTable: DatabaseTable {
 		}
 	}
 
+	func fetchAllUnreadCounts(_ completion: @escaping UnreadCountCompletionBlock) {
+
+		// Returns only where unreadCount > 0.
+
+		let cutoffDate = articleCutoffDate
+
+		queue.fetch { (database) in
+
+			let sql = "select distinct feedID, count(*) from articles natural join statuses where read=0 and userDeleted=0 and (starred=1 or dateArrived>?) group by feedID;"
+
+			guard let resultSet = database.executeQuery(sql, withArgumentsIn: [cutoffDate]) else {
+				DispatchQueue.main.async() {
+					completion(UnreadCountDictionary())
+				}
+				return
+			}
+
+			var d = UnreadCountDictionary()
+			while resultSet.next() {
+				let unreadCount = resultSet.long(forColumnIndex: 1)
+				if let feedID = resultSet.string(forColumnIndex: 0) {
+					d[feedID] = unreadCount
+				}
+			}
+
+			DispatchQueue.main.async() {
+				completion(d)
+			}
+		}
+	}
+
 	func fetchStarredAndUnreadCount(_ feeds: Set<Feed>, _ callback: @escaping (Int) -> Void) {
 
 		if feeds.isEmpty {

Frameworks/Database/Database.swift

@@ -71,6 +71,11 @@ public final class Database {
 		articlesTable.fetchStarredAndUnreadCount(feeds, callback)
 	}
 
+	public func fetchAllNonZeroUnreadCounts(_ completion: @escaping UnreadCountCompletionBlock) {
+
+		articlesTable.fetchAllUnreadCounts(completion)
+	}
+
 	// MARK: - Saving and Updating Articles
 
 	public func update(feed: Feed, parsedFeed: ParsedFeed, completion: @escaping UpdateArticlesWithFeedCompletionBlock) {

Frameworks/Database/UnreadCountDictionary.swift

@@ -13,6 +13,10 @@ public struct UnreadCountDictionary {
 	
 	private var dictionary = [String: Int]()
 
+	public var isEmpty: Bool {
+		return dictionary.count < 1
+	}
+	
 	subscript(_ feedID: String) -> Int? {
 		get {
 			return dictionary[feedID]