Re-use databases in the most obvious (single function) cases

These cases don't involve any threading so this should speed things
up a little without any risk.

23 files changed, 165 insertions, 115 deletions

diff --git a/plugins/backend/bazqux/bazquxAPI.vala b/plugins/backend/bazqux/bazquxAPI.vala
index 9a16e1ae..8b203ab7 100644
--- a/plugins/backend/bazqux/bazquxAPI.vala
+++ b/plugins/backend/bazqux/bazquxAPI.vala
@@ -162,6 +162,7 @@ public bool getCategoriesAndTags(Gee.List<Feed> feeds, Gee.List<Category> catego
 	uint length = array.get_length();
 	int orderID = 0;
 
+	var db = DataBase.readOnly();
 	for (uint i = 0; i < length; i++)
 	{
 		Json.Object object = array.get_object_element(i);
@@ -191,7 +192,7 @@ public bool getCategoriesAndTags(Gee.List<Feed> feeds, Gee.List<Category> catego
 					new Tag(
 						id,
 						title,
-						DataBase.readOnly().getTagColor()
+						db.getTagColor()
 						)
 					);
 			}
@@ -323,6 +324,7 @@ public string? getArticles(Gee.List<Article> articles, int count, ArticleStatus
 	var array = root.get_array_member("items");
 	uint length = array.get_length();
 
+	var db = DataBase.readOnly();
 	for (uint i = 0; i < length; i++)
 	{
 		Json.Object object = array.get_object_element(i);
@@ -341,7 +343,7 @@ public string? getArticles(Gee.List<Article> articles, int count, ArticleStatus
 				marked = true;
 			else if(cat.has_suffix("com.google/read"))
 				read = true;
-			else if(cat.contains("/label/") && DataBase.readOnly().getTagName(cat) != null)
+			else if(cat.contains("/label/") && db.getTagName(cat) != null)
 				tags.add(cat);
 		}
 
diff --git a/plugins/backend/bazqux/bazquxInterface.vala b/plugins/backend/bazqux/bazquxInterface.vala
index 708fc8de..479c12c5 100644
--- a/plugins/backend/bazqux/bazquxInterface.vala
+++ b/plugins/backend/bazqux/bazquxInterface.vala
@@ -257,13 +257,14 @@ public void setCategoryRead(string catID)
 
 public void markAllItemsRead()
 {
-	var categories = DataBase.readOnly().read_categories();
+	var db = DataBase.readOnly();
+	var categories = db.read_categories();
 	foreach(Category cat in categories)
 	{
 		m_api.markAsRead(cat.getCatID());
 	}
 
-	var feeds = DataBase.readOnly().read_feeds_without_cat();
+	var feeds = db.read_feeds_without_cat();
 	foreach(Feed feed in feeds)
 	{
 		m_api.markAsRead(feed.getFeedID());
diff --git a/plugins/backend/decsync/decsyncInterface.vala b/plugins/backend/decsync/decsyncInterface.vala
index baa406c9..23303f1e 100644
--- a/plugins/backend/decsync/decsyncInterface.vala
+++ b/plugins/backend/decsync/decsyncInterface.vala
@@ -302,9 +302,10 @@ public void setArticleIsRead(string articleIDs, ArticleStatus readStatus)
 	var read = readStatus == ArticleStatus.READ;
 	Logger.debug("Mark " + articleIDs + " as " + (read ? "read" : "unread"));
 	var entries = new Gee.ArrayList<Decsync.EntryWithPath>();
+	var db = DataBase.readOnly();
 	foreach (var articleID in articleIDs.split(","))
 	{
-		Article? article = DataBase.readOnly().read_article(articleID);
+		Article? article = db.read_article(articleID);
 		if (article != null)
 		{
 			var path = articleToPath(article, "read");
@@ -380,12 +381,13 @@ public bool addFeed(string feedURL, string? catID, string? newCatName, out strin
 
 public bool addFeedWithDecsync(string feedURL, string? catID, string? newCatName, out string feedID, out string errmsg, bool updateDecsync = true)
 {
+	var db = DataBase.writeAccess();
 	var catIDs = new Gee.ArrayList<string>();
 	if(catID == null && newCatName != null)
 	{
 		string cID = createCategory(newCatName, null);
 		var cat = new Category(cID, newCatName, 0, 99, CategoryID.MASTER.to_string(), 1);
-		DataBase.writeAccess().write_categories(ListUtils.single(cat));
+		db.write_categories(ListUtils.single(cat));
 		catIDs.add(cID);
 	}
 	else if(catID != null && newCatName == null)
@@ -404,8 +406,8 @@ public bool addFeedWithDecsync(string feedURL, string? catID, string? newCatName
 
 	if(feed != null)
 	{
-		if(!DataBase.readOnly().feed_exists(feed.getURL())) {
-			DataBase.writeAccess().write_feeds(ListUtils.single(feed));
+		if(!db.feed_exists(feed.getURL())) {
+			db.write_feeds(ListUtils.single(feed));
 
 			if (updateDecsync)
 			{
@@ -455,8 +457,9 @@ public void moveFeed(string feedID, string newCatID, string? currentCatID)
 
 public string createCategory(string title, string? parentID)
 {
-	string? catID = DataBase.readOnly().getCategoryID(title);
-	while (catID == null || DataBase.readOnly().read_category(catID) != null)
+	var db = DataBase.readOnly();
+	string? catID = db.getCategoryID(title);
+	while (catID == null || db.read_category(catID) != null)
 	{
 		catID = "catID%05d".printf(Random.int_range(0, 100000));
 	}
@@ -561,6 +564,7 @@ public void getArticles(int count, ArticleStatus whatToGet, DateTime? since, str
 
 				Logger.debug("Got %u articles".printf(doc.get_items().length()));
 				var newArticles = new Gee.ArrayList<Article>();
+				var db = DataBase.readOnly();
 				foreach(Rss.Item item in doc.get_items())
 				{
 				        string? articleID = item.guid;
@@ -576,9 +580,9 @@ public void getArticles(int count, ArticleStatus whatToGet, DateTime? since, str
 				                articleID = item.link;
 					}
 
-				        if (DataBase.readOnly().read_article(articleID) != null)
-				        {
-				                continue;
+					if (db.read_article(articleID) != null)
+					{
+						continue;
 					}
 
 				        var date = Rfc822.parseDate(item.pub_date);
diff --git a/plugins/backend/decsync/decsyncListeners.vala b/plugins/backend/decsync/decsyncListeners.vala
index 98006cd4..c907d240 100644
--- a/plugins/backend/decsync/decsyncListeners.vala
+++ b/plugins/backend/decsync/decsyncListeners.vala
@@ -50,7 +50,8 @@ public override void onSubdirEntryUpdate(Gee.List<string> path, Decsync.Entry en
 	{
 		Logger.debug((added ? "mark " : "unmark ") + articleID);
 	}
-	Article? article = DataBase.readOnly().read_article(articleID);
+	var db = DataBase.writeAccess();
+	Article? article = db.read_article(articleID);
 	if (article == null)
 	{
 		Logger.info("Unkown article " + articleID);
@@ -64,7 +65,7 @@ public override void onSubdirEntryUpdate(Gee.List<string> path, Decsync.Entry en
 	{
 		article.setMarked(added ? ArticleStatus.MARKED : ArticleStatus.UNMARKED);
 	}
-	DataBase.writeAccess().update_article(article);
+	db.update_article(article);
 }
 }
 
@@ -163,7 +164,8 @@ public override void onSubfileEntryUpdate(Decsync.Entry entry, Unit extra)
 		Logger.warning("Invalid feedID " + Json.to_string(entry.key, false));
 		return;
 	}
-	var feed = DataBase.readOnly().read_feed(feedID);
+	var db = DataBase.writeAccess();
+	var feed = db.read_feed(feedID);
 	if (feed == null) return;
 	var currentCatID = feed.getCatString();
 	string newCatID;
@@ -181,7 +183,7 @@ public override void onSubfileEntryUpdate(Decsync.Entry entry, Unit extra)
 		return;
 	}
 	addCategory(m_plugin, newCatID);
-	DataBase.writeAccess().move_feed(feedID, currentCatID, newCatID);
+	db.move_feed(feedID, currentCatID, newCatID);
 }
 }
 
diff --git a/plugins/backend/feedbin/feedbinInterface.vala b/plugins/backend/feedbin/feedbinInterface.vala
index 519ae931..cc6fc685 100644
--- a/plugins/backend/feedbin/feedbinInterface.vala
+++ b/plugins/backend/feedbin/feedbinInterface.vala
@@ -285,9 +285,10 @@ private void setRead(string id, FeedListType type)
 {
 	const int count = 1000;
 	int num_articles = 1;         // set to any value > 0
+	var db = DataBase.readOnly();
 	for(var offset = 0; num_articles > 0; offset += count)
 	{
-		var articles = DataBase.readOnly().read_articles(id, type, ArticleListState.ALL, "", count, offset);
+		var articles = db.read_articles(id, type, ArticleListState.ALL, "", count, offset);
 		var entry_ids = new Gee.ArrayList<int64?>();
 		foreach(var article in articles)
 		{
@@ -643,6 +644,7 @@ requires (count >= 0)
 {
 	try
 	{
+		var db = DataBase.readOnly();
 		int64? feed_id = null;
 		if(!is_tag_id && feed_id_str != null)
 			feed_id = int64.parse(feed_id_str);
@@ -683,7 +685,7 @@ requires (count >= 0)
 			for(var offset = 0, c = 1000; ; offset += c)
 			{
 				var articles = new Gee.ArrayList<Article>();
-				var existing_articles = DataBase.readOnly().read_articles(search_feed_id, search_type, ArticleListState.ALL, "", c, offset);
+				var existing_articles = db.read_articles(search_feed_id, search_type, ArticleListState.ALL, "", c, offset);
 				if(existing_articles.size == 0)
 					break;
 
diff --git a/plugins/backend/feedhq/feedhqInterface.vala b/plugins/backend/feedhq/feedhqInterface.vala
index 0057e365..cf8363a3 100644
--- a/plugins/backend/feedhq/feedhqInterface.vala
+++ b/plugins/backend/feedhq/feedhqInterface.vala
@@ -259,13 +259,14 @@ public void setCategoryRead(string catID)
 
 public void markAllItemsRead()
 {
-	var categories = DataBase.readOnly().read_categories();
+	var db = DataBase.readOnly();
+	var categories = db.read_categories();
 	foreach(Category cat in categories)
 	{
 		m_api.markAsRead(cat.getCatID());
 	}
 
-	var feeds = DataBase.readOnly().read_feeds_without_cat();
+	var feeds = db.read_feeds_without_cat();
 	foreach(Feed feed in feeds)
 	{
 		m_api.markAsRead(feed.getFeedID());
diff --git a/plugins/backend/feedly/feedlyAPI.vala b/plugins/backend/feedly/feedlyAPI.vala
index 74123013..35c26609 100644
--- a/plugins/backend/feedly/feedlyAPI.vala
+++ b/plugins/backend/feedly/feedlyAPI.vala
@@ -271,6 +271,7 @@ public bool getTags(Gee.List<Tag> tags)
 	Json.Array array = parser.get_root().get_array ();
 	uint length = array.get_length();
 
+	var db = DataBase.readOnly();
 	for (uint i = 0; i < length; i++) {
 		Json.Object object = array.get_object_element(i);
 
@@ -278,7 +279,7 @@ public bool getTags(Gee.List<Tag> tags)
 			new Tag(
 				object.get_string_member("id"),
 				object.has_member("label") ? object.get_string_member("label") : "",
-				DataBase.readOnly().getTagColor()
+				db.getTagColor()
 				)
 			);
 	}
@@ -595,9 +596,10 @@ public bool addSubscription(string feedURL, string? title = null, string? catIDs
 		var catArray = catIDs.split(",");
 		Json.Array cats = new Json.Array();
 
+		var db = DataBase.readOnly();
 		foreach(string catID in catArray)
 		{
-			string catName = DataBase.readOnly().getCategoryName(catID);
+			string catName = db.getCategoryName(catID);
 			Json.Object catObject = new Json.Object();
 			catObject.set_string_member("id", catID);
 			catObject.set_string_member("label", catName);
@@ -617,7 +619,8 @@ public bool addSubscription(string feedURL, string? title = null, string? catIDs
 
 public void moveSubscription(string feedID, string newCatID, string? oldCatID = null)
 {
-	var Feed = DataBase.readOnly().read_feed(feedID);
+	var db = DataBase.readOnly();
+	var Feed = db.read_feed(feedID);
 
 	Json.Object object = new Json.Object();
 	object.set_string_member("id", feedID);
@@ -631,7 +634,7 @@ public void moveSubscription(string feedID, string newCatID, string? oldCatID =
 	{
 		if(catID != oldCatID)
 		{
-			string catName = DataBase.readOnly().getCategoryName(catID);
+			string catName = db.getCategoryName(catID);
 			Json.Object catObject = new Json.Object();
 			catObject.set_string_member("id", catID);
 			catObject.set_string_member("label", catName);
@@ -639,7 +642,7 @@ public void moveSubscription(string feedID, string newCatID, string? oldCatID =
 		}
 	}
 
-	string newCatName = DataBase.readOnly().getCategoryName(newCatID);
+	string newCatName = db.getCategoryName(newCatID);
 	Json.Object catObject = new Json.Object();
 	catObject.set_string_member("id", newCatID);
 	catObject.set_string_member("label", newCatName);
diff --git a/plugins/backend/feedly/feedlyInterface.vala b/plugins/backend/feedly/feedlyInterface.vala
index d4391bc5..ec96fd7a 100644
--- a/plugins/backend/feedly/feedlyInterface.vala
+++ b/plugins/backend/feedly/feedlyInterface.vala
@@ -218,8 +218,9 @@ public void markAllItemsRead()
 	string catArray = "";
 	string feedArray = "";
 
-	var categories = DataBase.readOnly().read_categories();
-	var feeds = DataBase.readOnly().read_feeds_without_cat();
+	var db = DataBase.readOnly();
+	var categories = db.read_categories();
+	var feeds = db.read_feeds_without_cat();
 
 	foreach(Category cat in categories)
 	{
diff --git a/plugins/backend/inoreader/InoReaderAPI.vala b/plugins/backend/inoreader/InoReaderAPI.vala
index b179973d..7919d147 100644
--- a/plugins/backend/inoreader/InoReaderAPI.vala
+++ b/plugins/backend/inoreader/InoReaderAPI.vala
@@ -162,6 +162,7 @@ public bool getCategoriesAndTags(Gee.List<Feed> feeds, Gee.List<Category> catego
 	uint length = array.get_length();
 	int orderID = 0;
 
+	var db = DataBase.readOnly();
 	for (uint i = 0; i < length; i++)
 	{
 		Json.Object object = array.get_object_element(i);
@@ -190,7 +191,7 @@ public bool getCategoriesAndTags(Gee.List<Feed> feeds, Gee.List<Category> catego
 					new Tag(
 						id,
 						title,
-						DataBase.readOnly().getTagColor()
+						db.getTagColor()
 						)
 					);
 			}
@@ -318,6 +319,7 @@ public string? getArticles(Gee.List<Article> articles, int count, ArticleStatus
 	var array = root.get_array_member("items");
 	uint length = array.get_length();
 
+	var db = DataBase.readOnly();
 	for (uint i = 0; i < length; i++)
 	{
 		Json.Object object = array.get_object_element(i);
@@ -336,7 +338,7 @@ public string? getArticles(Gee.List<Article> articles, int count, ArticleStatus
 				marked = true;
 			else if(cat.has_suffix("com.google/read"))
 				read = true;
-			else if(cat.contains("/label/") && DataBase.readOnly().getTagName(cat) != null)
+			else if(cat.contains("/label/") && db.getTagName(cat) != null)
 				tags.add(cat);
 		}
 
diff --git a/plugins/backend/inoreader/InoReaderInterface.vala b/plugins/backend/inoreader/InoReaderInterface.vala
index 23ea916a..ca176530 100644
--- a/plugins/backend/inoreader/InoReaderInterface.vala
+++ b/plugins/backend/inoreader/InoReaderInterface.vala
@@ -232,13 +232,14 @@ public void setCategoryRead(string catID)
 
 public void markAllItemsRead()
 {
-	var categories = DataBase.readOnly().read_categories();
+	var db = DataBase.readOnly();
+	var categories = db.read_categories();
 	foreach(Category cat in categories)
 	{
 		m_api.markAsRead(cat.getCatID());
 	}
 
-	var feeds = DataBase.readOnly().read_feeds_without_cat();
+	var feeds = db.read_feeds_without_cat();
 	foreach(Feed feed in feeds)
 	{
 		m_api.markAsRead(feed.getFeedID());
diff --git a/plugins/backend/local/localInterface.vala b/plugins/backend/local/localInterface.vala
index c322af6a..7eb801ed 100644
--- a/plugins/backend/local/localInterface.vala
+++ b/plugins/backend/local/localInterface.vala
@@ -365,8 +365,9 @@ public string createTag(string caption)
 {
 	string tagID = "1";
 
-	if(!DataBase.readOnly().isTableEmpty("tags"))
-		tagID = (int.parse(DataBase.readOnly().getMaxID("tags", "tagID")) + 1).to_string();
+	var db = DataBase.readOnly();
+	if(!db.isTableEmpty("tags"))
+		tagID = (int.parse(db.getMaxID("tags", "tagID")) + 1).to_string();
 
 	Logger.info("createTag: ID = " + tagID);
 	return tagID;
@@ -385,11 +386,12 @@ public void renameTag(string tagID, string title)
 public bool addFeed(string feedURL, string? catID, string? newCatName, out string feedID, out string errmsg)
 {
 	var catIDs = new Gee.ArrayList<string>();
+	var db = DataBase.writeAccess();
 	if(catID == null && newCatName != null)
 	{
 		string cID = createCategory(newCatName, null);
 		var cat = new Category(cID, newCatName, 0, 99, CategoryID.MASTER.to_string(), 1);
-		DataBase.writeAccess().write_categories(ListUtils.single(cat));
+		db.write_categories(ListUtils.single(cat));
 		catIDs.add(cID);
 	}
 	else if(catID != null && newCatName == null)
@@ -408,8 +410,8 @@ public bool addFeed(string feedURL, string? catID, string? newCatName, out strin
 
 	if(feed != null)
 	{
-		if(!DataBase.readOnly().feed_exists(feed.getURL())) {
-			DataBase.writeAccess().write_feeds(ListUtils.single(feed));
+		if(!db.feed_exists(feed.getURL())) {
+			db.write_feeds(ListUtils.single(feed));
 			return true;
 		}
 	}
@@ -520,7 +522,8 @@ public int getUnreadCount()
 
 public void getArticles(int count, ArticleStatus whatToGet, DateTime? since, string? feedID, bool isTagID, GLib.Cancellable? cancellable = null)
 {
-	var feeds = DataBase.readOnly().read_feeds();
+	var db = DataBase.writeAccess();
+	var feeds = db.read_feeds();
 	var articles = new Gee.ArrayList<Article>();
 	GLib.Mutex mutex = GLib.Mutex();
 
@@ -665,7 +668,7 @@ public void getArticles(int count, ArticleStatus whatToGet, DateTime? since, str
 
 	if(articles.size > 0)
 	{
-		DataBase.writeAccess().write_articles(articles);
+		db.write_articles(articles);
 		Logger.debug("localInterface: %i articles written".printf(articles.size));
 		refreshFeedListCounter();
 		updateArticleList();
diff --git a/plugins/backend/oldreader/oldreaderAPI.vala b/plugins/backend/oldreader/oldreaderAPI.vala
index 48724ae6..a25b6bd2 100644
--- a/plugins/backend/oldreader/oldreaderAPI.vala
+++ b/plugins/backend/oldreader/oldreaderAPI.vala
@@ -300,6 +300,7 @@ public string? getArticles(Gee.List<Article> articles, int count, ArticleStatus
 	var array = root.get_array_member("items");
 	uint length = array.get_length();
 
+	var db = DataBase.readOnly();
 	for (uint i = 0; i < length; i++)
 	{
 		Json.Object object = array.get_object_element(i);
@@ -318,7 +319,7 @@ public string? getArticles(Gee.List<Article> articles, int count, ArticleStatus
 				marked = true;
 			else if(cat.has_suffix("com.google/read"))
 				read = true;
-			else if(cat.contains("/label/") && DataBase.readOnly().getTagName(cat) != null)
+			else if(cat.contains("/label/") && db.getTagName(cat) != null)
 				tags.add(cat);
 		}
 
diff --git a/plugins/backend/oldreader/oldreaderInterface.vala b/plugins/backend/oldreader/oldreaderInterface.vala
index 0567fd6e..5993f55b 100644
--- a/plugins/backend/oldreader/oldreaderInterface.vala
+++ b/plugins/backend/oldreader/oldreaderInterface.vala
@@ -258,13 +258,14 @@ public void setCategoryRead(string catID)
 
 public void markAllItemsRead()
 {
-	var categories = DataBase.readOnly().read_categories();
+	var db = DataBase.readOnly();
+	var categories = db.read_categories();
 	foreach(Category cat in categories)
 	{
 		m_api.markAsRead(cat.getCatID());
 	}
 
-	var feeds = DataBase.readOnly().read_feeds_without_cat();
+	var feeds = db.read_feeds_without_cat();
 	foreach(Feed feed in feeds)
 	{
 		m_api.markAsRead(feed.getFeedID());
diff --git a/plugins/backend/ttrss/ttrssAPI.vala b/plugins/backend/ttrss/ttrssAPI.vala
index b5e26aab..8a2f31c6 100644
--- a/plugins/backend/ttrss/ttrssAPI.vala
+++ b/plugins/backend/ttrss/ttrssAPI.vala
@@ -298,6 +298,7 @@ public bool getTags(Gee.List<Tag> tags)
 		var response = message.get_response_array();
 		var tag_count = response.get_length();
 
+		var db = DataBase.readOnly();
 		for(uint i = 0; i < tag_count; ++i)
 		{
 			var tag_node = response.get_object_element(i);
@@ -305,7 +306,7 @@ public bool getTags(Gee.List<Tag> tags)
 				new Tag(
 					tag_node.get_int_member("id").to_string(),
 					tag_node.get_string_member("caption"),
-					DataBase.readOnly().getTagColor()
+					db.getTagColor()
 					)
 				);
 		}
diff --git a/plugins/backend/ttrss/ttrssInterface.vala b/plugins/backend/ttrss/ttrssInterface.vala
index 1e1c1d7d..fb226416 100644
--- a/plugins/backend/ttrss/ttrssInterface.vala
+++ b/plugins/backend/ttrss/ttrssInterface.vala
@@ -468,12 +468,13 @@ public void getArticles(int count, ArticleStatus whatToGet, DateTime? since, str
 	if(cancellable != null && cancellable.is_cancelled())
 		return;
 
+	var db = DataBase.writeAccess();
 	if(unreadIDs != null && whatToGet == ArticleStatus.ALL)
 	{
 		Logger.debug("getArticles: newsplus plugin active");
 		var markedIDs = m_api.NewsPlus(ArticleStatus.MARKED, settings_general.get_int("max-articles"));
-		DataBase.writeAccess().updateArticlesByID(unreadIDs, "unread");
-		DataBase.writeAccess().updateArticlesByID(markedIDs, "marked");
+		db.updateArticlesByID(unreadIDs, "unread");
+		db.updateArticlesByID(markedIDs, "marked");
 		//updateArticleList();
 	}
 
@@ -505,14 +506,14 @@ public void getArticles(int count, ArticleStatus whatToGet, DateTime? since, str
 		// only update article states if they haven't been updated by the newsPlus-plugin
 		if(unreadIDs == null || whatToGet != ArticleStatus.ALL)
 		{
-			DataBase.writeAccess().update_articles(articles);
+			db.update_articles(articles);
 			updateArticleList();
 		}
 
 		foreach(Article article in articles)
 		{
 			var id = article.getArticleID();
-			if(!DataBase.readOnly().article_exists(id))
+			if(!db.article_exists(id))
 			{
 				articleIDs += id + ",";
 			}
@@ -536,7 +537,7 @@ public void getArticles(int count, ArticleStatus whatToGet, DateTime? since, str
 
 	if(articles.size > 0)
 	{
-		DataBase.writeAccess().write_articles(articles);
+		db.write_articles(articles);
 		refreshFeedListCounter();
 		updateArticleList();
 	}
diff --git a/src/ActionCache.vala b/src/ActionCache.vala
index aa892014..36413376 100644
--- a/src/ActionCache.vala
+++ b/src/ActionCache.vala
@@ -119,12 +119,15 @@ private void removeOpposite(CachedAction action)
 
 private void removeForFeed(string feedID)
 {
+	DataBaseReadOnly db = null;
 	foreach(CachedAction a in m_list)
 	{
 		if(a.getType() == CachedActions.MARK_READ
 		   || a.getType() == CachedActions.MARK_UNREAD)
 		{
-			if(feedID == DataBase.readOnly().getFeedIDofArticle(a.getID()))
+			if (db == null)
+				db = DataBase.readOnly();
+			if(feedID == db.getFeedIDofArticle(a.getID()))
 			{
 				m_list.remove(a);
 			}
@@ -204,6 +207,7 @@ public ArticleStatus checkRead(Article a)
 	}
 	else if(a.getUnread() == ArticleStatus.UNREAD)
 	{
+		DataBaseReadOnly db = null;
 		foreach(CachedAction action in m_list)
 		{
 			switch(action.getType())
@@ -217,7 +221,9 @@ public ArticleStatus checkRead(Article a)
 				break;
 
 			case CachedActions.MARK_READ_CATEGORY:
-				var feedIDs = DataBase.readOnly().getFeedIDofCategorie(a.getArticleID());
+				if (db == null)
+					db = DataBase.readOnly();
+				var feedIDs = db.getFeedIDofCategorie(a.getArticleID());
 				foreach(string feedID in feedIDs)
 				{
 					if(feedID == a.getFeedID())
diff --git a/src/Backend/Backend.vala b/src/Backend/Backend.vala
index 4f426963..a60197f7 100644
--- a/src/Backend/Backend.vala
+++ b/src/Backend/Backend.vala
@@ -437,15 +437,16 @@ public void tagArticle(Article article, Tag tag, bool add)
 		article.removeTag(tag.getTagID());
 	}
 
-	DataBase.writeAccess().update_article(article);
+	var db = DataBase.writeAccess();
+	db.update_article(article);
 
-	if(!add && !DataBase.readOnly().tag_still_used(tag))
+	if(!add && !db.tag_still_used(tag))
 	{
 		Logger.debug("backend: remove tag completely");
 		asyncPayload pl2 = () => { FeedServer.get_default().deleteTag(tag.getTagID()); };
 		callAsync.begin((owned)pl2, (obj, res) => { callAsync.end(res); });
 
-		asyncPayload pl3 = () => { DataBase.writeAccess().dropTag(tag); };
+		asyncPayload pl3 = () => { db.dropTag(tag); };
 		callAsync.begin((owned)pl3, (obj, res) => {
 					callAsync.end(res);
 					newFeedList();
@@ -494,8 +495,9 @@ public void updateTagColor(Tag tag)
 
 public void resetDB()
 {
-	DataBase.writeAccess().resetDB();
-	DataBase.writeAccess().init();
+	var db = DataBase.writeAccess();
+	db.resetDB();
+	db.init();
 }
 
 public void resetAccount()
@@ -642,7 +644,8 @@ public void markAllItemsRead()
 
 public void removeCategory(string catID)
 {
-	var feeds = DataBase.readOnly().read_feeds();
+	var db = DataBase.writeAccess();
+	var feeds = db.read_feeds();
 	foreach(Feed feed in feeds)
 	{
 		if(feed.hasCat(catID))
@@ -651,7 +654,7 @@ public void removeCategory(string catID)
 		}
 	}
 
-	var cats = DataBase.readOnly().read_categories(feeds);
+	var cats = db.read_categories(feeds);
 	foreach(var cat in cats)
 	{
 		if(cat.getParent() == catID)
@@ -663,7 +666,7 @@ public void removeCategory(string catID)
 	asyncPayload pl = () => { FeedServer.get_default().deleteCategory(catID); };
 	callAsync.begin((owned)pl, (obj, res) => { callAsync.end(res); });
 
-	asyncPayload pl2 = () => { DataBase.writeAccess().delete_category(catID); };
+	asyncPayload pl2 = () => { db.delete_category(catID); };
 	callAsync.begin((owned)pl2, (obj, res) => {
 				callAsync.end(res);
 				newFeedList();
@@ -691,20 +694,21 @@ public string addCategory(string title, string? parentID = null, bool createLoca
 	{
 		string? parent = parentID;
 		int level = 1;
+		var db = DataBase.writeAccess();
 		if(parentID == null || parentID == "")
 		{
 			parent = CategoryID.MASTER.to_string();
 		}
 		else
 		{
-			var parentCat = DataBase.readOnly().read_category(parentID);
+			var parentCat = db.read_category(parentID);
 			level = parentCat.getLevel()+1;
 		}
 
 		var cat = new Category(catID, title, 0, 99, parent, level);
 		var list = new Gee.LinkedList<Category>();
 		list.add(cat);
-		DataBase.writeAccess().write_categories(list);
+		db.write_categories(list);
 	}
 
 	return catID;
@@ -712,10 +716,11 @@ public string addCategory(string title, string? parentID = null, bool createLoca
 
 public void removeCategoryWithChildren(string catID)
 {
-	var feeds = DataBase.readOnly().read_feeds();
+	var db = DataBase.readOnly();
+	var feeds = db.read_feeds();
 	deleteFeedsInCategory(catID, feeds);
 
-	var cats = DataBase.readOnly().read_categories(feeds);
+	var cats = db.read_categories(feeds);
 	foreach(var cat in cats)
 	{
 		if(cat.getParent() == catID)
diff --git a/src/Backend/FeedServer.vala b/src/Backend/FeedServer.vala
index 2ee30bae..58ef831e 100644
--- a/src/Backend/FeedServer.vala
+++ b/src/Backend/FeedServer.vala
@@ -174,6 +174,7 @@ public void syncContent(GLib.Cancellable? cancellable = null)
 		return;
 	}
 
+	var db = DataBase.writeAccess();
 	if(syncFeedsAndCategories())
 	{
 		var categories = new Gee.LinkedList<Category>();
@@ -198,21 +199,21 @@ public void syncContent(GLib.Cancellable? cancellable = null)
 			return;
 
 		// write categories
-		DataBase.writeAccess().reset_exists_flag();
-		DataBase.writeAccess().write_categories(categories);
-		DataBase.writeAccess().delete_nonexisting_categories();
+		db.reset_exists_flag();
+		db.write_categories(categories);
+		db.delete_nonexisting_categories();
 
 		// write feeds
-		DataBase.writeAccess().reset_subscribed_flag();
-		DataBase.writeAccess().write_feeds(feeds);
-		DataBase.writeAccess().delete_articles_without_feed();
-		DataBase.writeAccess().delete_unsubscribed_feeds();
+		db.reset_subscribed_flag();
+		db.write_feeds(feeds);
+		db.delete_articles_without_feed();
+		db.delete_unsubscribed_feeds();
 
 		// write tags
-		DataBase.writeAccess().reset_exists_tag();
-		DataBase.writeAccess().write_tags(tags);
-		DataBase.writeAccess().update_tags(tags);
-		DataBase.writeAccess().delete_nonexisting_tags();
+		db.reset_exists_tag();
+		db.write_tags(tags);
+		db.update_tags(tags);
+		db.delete_nonexisting_tags();
 
 		FeedReaderBackend.get_default().newFeedList();
 	}
@@ -222,7 +223,7 @@ public void syncContent(GLib.Cancellable? cancellable = null)
 
 	var drop_articles = (DropArticles)Settings.general().get_enum("drop-articles-after");
 	DateTime? since = drop_articles.to_start_date();
-	if(!DataBase.readOnly().isTableEmpty("articles"))
+	if(!db.isTableEmpty("articles"))
 	{
 		var last_sync = new DateTime.from_unix_utc(Settings.state().get_int("last-sync"));
 		if(since == null || last_sync.to_unix() > since.to_unix())
@@ -236,7 +237,7 @@ public void syncContent(GLib.Cancellable? cancellable = null)
 
 
 	syncProgress(_("Getting articles"));
-	string row_id = DataBase.readOnly().getMaxID("articles", "rowid");
+	string row_id = db.getMaxID("articles", "rowid");
 	int before = row_id != null ? int.parse(row_id) : 0;
 
 	if(unread > max && useMaxArticles())
@@ -253,10 +254,10 @@ public void syncContent(GLib.Cancellable? cancellable = null)
 		return;
 
 	//update fulltext table
-	DataBase.writeAccess().updateFTS();
+	db.updateFTS();
 
-	int new_and_unread = DataBase.readOnly().get_new_unread_count(row_id != null ? int.parse(row_id) : 0);
-	row_id = DataBase.readOnly().getMaxID("articles", "rowid");
+	int new_and_unread = db.get_new_unread_count(row_id != null ? int.parse(row_id) : 0);
+	row_id = db.getMaxID("articles", "rowid");
 	int after = row_id != null ? int.parse(row_id) : 0;
 	int newArticles = after-before;
 	if(newArticles > 0)
@@ -266,12 +267,12 @@ public void syncContent(GLib.Cancellable? cancellable = null)
 
 	var drop_weeks = drop_articles.to_weeks();
 	if(drop_weeks != null)
-		DataBase.writeAccess().dropOldArticles(-(int)drop_weeks);
+		db.dropOldArticles(-(int)drop_weeks);
 
 	var now = new DateTime.now_local();
 	Settings.state().set_int("last-sync", (int)now.to_unix());
 
-	DataBase.writeAccess().checkpoint();
+	db.checkpoint();
 	FeedReaderBackend.get_default().newFeedList();
 	return;
 }
@@ -280,6 +281,7 @@ public void InitSyncContent(GLib.Cancellable? cancellable = null)
 {
 	Logger.debug("FeedServer: initial sync");
 
+	var db = DataBase.writeAccess();
 	if(syncFeedsAndCategories())
 	{
 		var categories = new Gee.LinkedList<Category>();
@@ -297,13 +299,13 @@ public void InitSyncContent(GLib.Cancellable? cancellable = null)
 			return;
 
 		// write categories
-		DataBase.writeAccess().write_categories(categories);
+		db.write_categories(categories);
 
 		// write feeds
-		DataBase.writeAccess().write_feeds(feeds);
+		db.write_feeds(feeds);
 
 		// write tags
-		DataBase.writeAccess().write_tags(tags);
+		db.write_tags(tags);
 
 		FeedReaderBackend.get_default().newFeedList();
 	}
@@ -323,7 +325,7 @@ public void InitSyncContent(GLib.Cancellable? cancellable = null)
 
 	// get articles for each tag
 	syncProgress(_("Getting tagged articles"));
-	foreach(var tag_item in DataBase.readOnly().read_tags())
+	foreach(var tag_item in db.read_tags())
 	{
 		getArticles((Settings.general().get_int("max-articles")/8), ArticleStatus.ALL, since, tag_item.getTagID(), true, cancellable);
 		if(cancellable != null && cancellable.is_cancelled())
@@ -347,7 +349,7 @@ public void InitSyncContent(GLib.Cancellable? cancellable = null)
 		return;
 
 	//update fulltext table
-	DataBase.writeAccess().updateFTS();
+	db.updateFTS();
 
 	Settings.general().reset("content-grabber");
 
@@ -361,7 +363,8 @@ private void writeArticles(Gee.List<Article> articles)
 {
 	if(articles.size > 0)
 	{
-		DataBase.writeAccess().update_articles(articles);
+		var db = DataBase.writeAccess();
+		db.update_articles(articles);
 
 		// Reverse the list
 		var new_articles = new Gee.ArrayList<Article>();
@@ -370,7 +373,7 @@ private void writeArticles(Gee.List<Article> articles)
 			new_articles.insert(0, article);
 		}
 
-		DataBase.writeAccess().write_articles(new_articles);
+		db.write_articles(new_articles);
 		FeedReaderBackend.get_default().refreshFeedListCounter();
 		FeedReaderBackend.get_default().updateArticleList();
 	}
@@ -383,7 +386,8 @@ public async void grabContent(GLib.Cancellable? cancellable = null)
 		return;
 
 	Logger.debug("FeedServer: grabContent");
-	var articles = DataBase.readOnly().readUnfetchedArticles();
+	var db = DataBase.writeAccess();
+	var articles = db.readUnfetchedArticles();
 	int size = articles.size;
 	int i = 0;
 	var new_article_content = new Gee.ArrayList<Article>();
@@ -466,14 +470,14 @@ public async void grabContent(GLib.Cancellable? cancellable = null)
 		{
 			if (cancellable != null && cancellable.is_cancelled())
 				return;
-			DataBase.writeAccess().writeContent(content);
+			db.writeContent(content);
 		}
 
 		if (cancellable != null && cancellable.is_cancelled())
 			return;
 
 		//update fulltext table
-		DataBase.writeAccess().updateFTS();
+		db.updateFTS();
 	}
 }
 
diff --git a/src/CachedActionManager.vala b/src/CachedActionManager.vala
index 098e3dae..edfe0c7f 100644
--- a/src/CachedActionManager.vala
+++ b/src/CachedActionManager.vala
@@ -74,19 +74,21 @@ public void markAllRead()
 
 private void addAction(CachedAction action)
 {
-	if(DataBase.writeAccess().cachedActionNecessary(action))
+	var db = DataBase.writeAccess();
+	if(db.cachedActionNecessary(action))
 	{
-		DataBase.writeAccess().addCachedAction(action.getType(), action.getID());
+		db.addCachedAction(action.getType(), action.getID());
 	}
 	else
 	{
-		DataBase.writeAccess().deleteOppositeCachedAction(action);
+		db.deleteOppositeCachedAction(action);
 	}
 }
 
 public void executeActions()
 {
-	if(DataBase.readOnly().isTableEmpty("CachedActions"))
+	var db = DataBase.writeAccess();
+	if(db.isTableEmpty("CachedActions"))
 	{
 		Logger.debug("CachedActionManager - executeActions: no actions to perform");
 		return;
@@ -95,7 +97,7 @@ public void executeActions()
 
 	Logger.debug("CachedActionManager: executeActions");
 
-	var actions = DataBase.writeAccess().readCachedActions();
+	var actions = db.readCachedActions();
 
 	foreach(CachedAction action in actions)
 	{
@@ -141,7 +143,7 @@ public void executeActions()
 		execute(m_ids.substring(1), m_lastAction);
 	}
 
-	DataBase.writeAccess().resetCachedActions();
+	db.resetCachedActions();
 }
 
 private void execute(string ids, CachedActions action)
diff --git a/src/Utils.vala b/src/Utils.vala
index 3716728d..b463299c 100644
--- a/src/Utils.vala
+++ b/src/Utils.vala
@@ -33,15 +33,16 @@ public static Soup.Session getSession()
 public static void generatePreviews(Gee.List<Article> articles)
 {
 	string noPreview = _("No Preview Available");
+	var db = DataBase.readOnly();
 	foreach(var Article in articles)
 	{
-		if(!DataBase.readOnly().article_exists(Article.getArticleID()))
+		if(!db.article_exists(Article.getArticleID()))
 		{
 			if(Article.getPreview() != null && Article.getPreview() != "")
 			{
 				continue;
 			}
-			if(!DataBase.readOnly().preview_empty(Article.getArticleID()))
+			if(!db.preview_empty(Article.getArticleID()))
 			{
 				continue;
 			}
@@ -85,9 +86,10 @@ public static void generatePreviews(Gee.List<Article> articles)
 
 public static void checkHTML(Gee.List<Article> articles)
 {
+	var db = DataBase.readOnly();
 	foreach(var Article in articles)
 	{
-		if(!DataBase.readOnly().article_exists(Article.getArticleID()))
+		if(!db.article_exists(Article.getArticleID()))
 		{
 			string modified_html = _("No Text available for this article :(");
 			if(Article.getHTML() != "")
@@ -770,9 +772,10 @@ public static bool onlyShowFeeds()
 	if(Settings.general().get_boolean("only-feeds"))
 		return true;
 
-	if(!DataBase.readOnly().haveCategories()
+	var db = DataBase.readOnly();
+	if(!db.haveCategories()
 	   && !FeedReaderBackend.get_default().supportTags()
-	   && !DataBase.readOnly().haveFeedsWithoutCat())
+	   && !db.haveFeedsWithoutCat())
 		return true;
 
 	return false;
diff --git a/src/Widgets/FeedList.vala b/src/Widgets/FeedList.vala
index 1f9efbf3..bf0cff7e 100644
--- a/src/Widgets/FeedList.vala
+++ b/src/Widgets/FeedList.vala
@@ -465,7 +465,8 @@ private void addTagCategory(int length)
 
 private void createCategories(ref Gee.List<Feed> feeds, bool masterCat, ArticleListState state)
 {
-	int maxCatLevel = DataBase.readOnly().getMaxCatLevel();
+	var db = DataBase.readOnly();
+	int maxCatLevel = db.getMaxCatLevel();
 	int length = (int)m_list.get_children().length();
 	bool supportTags = false;
 	bool supportCategories = true;
@@ -478,7 +479,7 @@ private void createCategories(ref Gee.List<Feed> feeds, bool masterCat, ArticleL
 	supportMultiLevelCategories = FeedReaderBackend.get_default().supportMultiLevelCategories();
 
 	if((supportTags
-	    && !DataBase.readOnly().isTableEmpty("tags"))
+	    && !db.isTableEmpty("tags"))
 	   || masterCat)
 	{
 		addMasterCategory(length, _("Categories"));
@@ -497,16 +498,16 @@ private void createCategories(ref Gee.List<Feed> feeds, bool masterCat, ArticleL
 
 	for(int i = 1; i <= maxCatLevel; i++)
 	{
-		var categories = DataBase.readOnly().read_categories_level(i, feeds);
+		var categories = db.read_categories_level(i, feeds);
 
-		if(DataBase.readOnly().haveFeedsWithoutCat())
+		if(db.haveFeedsWithoutCat())
 		{
 			categories.insert(
 				0,
 				new Category(
 					uncategorizedID,
 					_("Uncategorized"),
-					(int)DataBase.readOnly().get_unread_uncategorized(),
+					(int)db.get_unread_uncategorized(),
 					(int)(categories.size + 10),
 					CategoryID.MASTER.to_string(),
 					1
@@ -592,9 +593,10 @@ private void createTags()
 
 public void refreshCounters(ArticleListState state)
 {
-	uint allCount = (state == ArticleListState.MARKED) ? DataBase.readOnly().get_marked_total() : DataBase.readOnly().get_unread_total();
-	var feeds = DataBase.readOnly().read_feeds((state == ArticleListState.MARKED) ? true : false);
-	var categories = DataBase.readOnly().read_categories(feeds);
+	var db = DataBase.readOnly();
+	uint allCount = (state == ArticleListState.MARKED) ? db.get_marked_total() : db.get_unread_total();
+	var feeds = db.read_feeds((state == ArticleListState.MARKED) ? true : false);
+	var categories = db.read_categories(feeds);
 
 	// double-check
 	uint feedCount = 0;
@@ -674,7 +676,7 @@ public void refreshCounters(ArticleListState state)
 		}
 	}
 
-	if(DataBase.readOnly().haveFeedsWithoutCat())
+	if(db.haveFeedsWithoutCat())
 	{
 		foreach(Gtk.Widget row in FeedChildList)
 		{
@@ -683,12 +685,12 @@ public void refreshCounters(ArticleListState state)
 			{
 				if(state == ArticleListState.MARKED)
 				{
-					tmpCatRow.set_unread_count(DataBase.readOnly().get_marked_uncategorized());
+					tmpCatRow.set_unread_count(db.get_marked_uncategorized());
 					tmpCatRow.activateUnreadEventbox(false);
 				}
 				else
 				{
-					tmpCatRow.set_unread_count(DataBase.readOnly().get_unread_uncategorized());
+					tmpCatRow.set_unread_count(db.get_unread_uncategorized());
 					tmpCatRow.activateUnreadEventbox(true);
 				}
 				if(Settings.general().get_boolean("feedlist-only-show-unread") && tmpCatRow.getUnreadCount() != 0)
diff --git a/src/Widgets/MainWindow.vala b/src/Widgets/MainWindow.vala
index e29105ef..76901972 100644
--- a/src/Widgets/MainWindow.vala
+++ b/src/Widgets/MainWindow.vala
@@ -476,14 +476,15 @@ private void markSelectedRead()
 	{
 		if(selectedRow[1] == FeedID.ALL.to_string())
 		{
-			var categories = DataBase.readOnly().read_categories();
+			var db = DataBase.readOnly();
+			var categories = db.read_categories();
 			foreach(Category cat in categories)
 			{
 				FeedReaderBackend.get_default().markFeedAsRead(cat.getCatID(), true);
 				Logger.debug("MainWindow: mark all articles as read cat: %s".printf(cat.getTitle()));
 			}
 
-			var feeds = DataBase.readOnly().read_feeds_without_cat();
+			var feeds = db.read_feeds_without_cat();
 			foreach(Feed feed in feeds)
 			{
 				FeedReaderBackend.get_default().markFeedAsRead(feed.getFeedID(), false);
diff --git a/src/Widgets/TagPopover.vala b/src/Widgets/TagPopover.vala
index e33ef6db..bbba5981 100644
--- a/src/Widgets/TagPopover.vala
+++ b/src/Widgets/TagPopover.vala
@@ -29,12 +29,13 @@ public TagPopover(Gtk.Widget widget)
 	m_availableTags = new Gee.ArrayList<Tag>();
 	m_tags = new Gee.ArrayList<Tag>();
 	Article? selectedArticle = ColumnView.get_default().getSelectedArticle();
+	var db = DataBase.readOnly();
 	if(selectedArticle != null)
 	{
 		Gee.List<string> tagIDs = selectedArticle.getTagIDs();
 		foreach(string tagID in tagIDs)
 		{
-			m_tags.add(DataBase.readOnly().read_tag(tagID));
+			m_tags.add(db.read_tag(tagID));
 		}
 	}