diff --git a/Signal.xcodeproj/project.pbxproj b/Signal.xcodeproj/project.pbxproj
index 8e4efe0979..c8baf27058 100644
--- a/Signal.xcodeproj/project.pbxproj
+++ b/Signal.xcodeproj/project.pbxproj
@@ -302,6 +302,7 @@
 		45360B901F9527DA00FA666C /* SearcherTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45360B8F1F9527DA00FA666C /* SearcherTest.swift */; };
 		45360B911F952AA900FA666C /* MarqueeLabel.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45E5A6981F61E6DD001E4A8A /* MarqueeLabel.swift */; };
 		4539B5861F79348F007141FF /* PushRegistrationManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4539B5851F79348F007141FF /* PushRegistrationManager.swift */; };
+		4542DF52208B82E9007B4E76 /* ThreadModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4542DF51208B82E9007B4E76 /* ThreadModel.swift */; };
 		45464DBC1DFA041F001D3FD6 /* DataChannelMessage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45464DBB1DFA041F001D3FD6 /* DataChannelMessage.swift */; };
 		454A84042059C787008B8C75 /* MediaTileViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 454A84032059C787008B8C75 /* MediaTileViewController.swift */; };
 		454A965A1FD6017E008D2A0E /* SignalAttachment.swift in Sources */ = {isa = PBXBuildFile; fileRef = 34D913491F62D4A500722898 /* SignalAttachment.swift */; };
@@ -919,6 +920,7 @@
 		45360B8F1F9527DA00FA666C /* SearcherTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SearcherTest.swift; sourceTree = "<group>"; };
 		4539B5851F79348F007141FF /* PushRegistrationManager.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = PushRegistrationManager.swift; sourceTree = "<group>"; };
 		453CC0361D08E1A60040EBA3 /* sn */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = sn; path = translations/sn.lproj/Localizable.strings; sourceTree = "<group>"; };
+		4542DF51208B82E9007B4E76 /* ThreadModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ThreadModel.swift; sourceTree = "<group>"; };
 		45464DBB1DFA041F001D3FD6 /* DataChannelMessage.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DataChannelMessage.swift; sourceTree = "<group>"; };
 		454A84032059C787008B8C75 /* MediaTileViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MediaTileViewController.swift; sourceTree = "<group>"; };
 		454A965E1FD60EA2008D2A0E /* OWSFlatButton.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = OWSFlatButton.swift; path = SignalMessaging/Views/OWSFlatButton.swift; sourceTree = SOURCE_ROOT; };
@@ -1898,6 +1900,7 @@
 				45DF5DF11DDB843F00C936C7 /* CompareSafetyNumbersActivity.swift */,
 				458E38351D668EBF0094BD24 /* OWSDeviceProvisioningURLParser.h */,
 				458E38361D668EBF0094BD24 /* OWSDeviceProvisioningURLParser.m */,
+				4542DF51208B82E9007B4E76 /* ThreadModel.swift */,
 			);
 			path = Models;
 			sourceTree = "<group>";
@@ -3199,6 +3202,7 @@
 				34D1F0501F7D45A60066283D /* GifPickerCell.swift in Sources */,
 				34D99C931F2937CC00D284D6 /* OWSAnalytics.swift in Sources */,
 				340FC8B8204DAC8D007AEB0F /* AddToGroupViewController.m in Sources */,
+				4542DF52208B82E9007B4E76 /* ThreadModel.swift in Sources */,
 				341F2C0F1F2B8AE700D07D6B /* DebugUIMisc.m in Sources */,
 				340FC8AF204DAC8D007AEB0F /* OWSLinkDeviceViewController.m in Sources */,
 				34E3EF0D1EFC235B007F6822 /* DebugUIDiskUsage.m in Sources */,
diff --git a/Signal/src/Models/ThreadModel.swift b/Signal/src/Models/ThreadModel.swift
new file mode 100644
index 0000000000..33d73e657d
--- /dev/null
+++ b/Signal/src/Models/ThreadModel.swift
@@ -0,0 +1,40 @@
+//
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//
+
+import Foundation
+
+@objc
+public class ThreadViewModel: NSObject {
+    let hasUnreadMessages: Bool
+    let lastMessageDate: Date
+    let isGroupThread: Bool
+    let threadRecord: TSThread
+    let unreadCount: UInt
+    let contactIdentifier: String?
+    let name: String
+    let isMuted: Bool
+    var isContactThread: Bool {
+        return !isGroupThread
+    }
+
+    let lastMessageText: String?
+
+    init(thread: TSThread, transaction: YapDatabaseReadTransaction) {
+        self.threadRecord = thread
+        self.lastMessageDate = thread.lastMessageDate()
+        self.isGroupThread = thread.isGroupThread()
+        self.name = thread.name()
+        self.isMuted = thread.isMuted
+        self.lastMessageText = thread.lastMessageText(transaction: transaction)
+
+        if let contactThread = thread as? TSContactThread {
+            self.contactIdentifier = contactThread.contactIdentifier()
+        } else {
+            self.contactIdentifier = nil
+        }
+
+        self.unreadCount = thread.unreadMessageCount(transaction: transaction)
+        self.hasUnreadMessages = unreadCount > 0
+    }
+}
diff --git a/Signal/src/ViewControllers/ConversationView/Cells/ConversationViewCell.h b/Signal/src/ViewControllers/ConversationView/Cells/ConversationViewCell.h
index 0f9a586648..097669b620 100644
--- a/Signal/src/ViewControllers/ConversationView/Cells/ConversationViewCell.h
+++ b/Signal/src/ViewControllers/ConversationView/Cells/ConversationViewCell.h
@@ -13,6 +13,7 @@ NS_ASSUME_NONNULL_BEGIN
 @class TSMessage;
 @class TSOutgoingMessage;
 @class TSQuotedMessage;
+@class YapDatabaseReadTransaction;
 
 @protocol ConversationViewCellDelegate <NSObject>
 
@@ -71,7 +72,7 @@ NS_ASSUME_NONNULL_BEGIN
 // The width of the collection view.
 @property (nonatomic) int contentWidth;
 
-- (void)loadForDisplay;
+- (void)loadForDisplayWithTransaction:(YapDatabaseReadTransaction *)transaction;
 
 - (CGSize)cellSizeForViewWidth:(int)viewWidth contentWidth:(int)contentWidth;
 
diff --git a/Signal/src/ViewControllers/ConversationView/Cells/ConversationViewCell.m b/Signal/src/ViewControllers/ConversationView/Cells/ConversationViewCell.m
index 6235989d40..e82863d8cf 100644
--- a/Signal/src/ViewControllers/ConversationView/Cells/ConversationViewCell.m
+++ b/Signal/src/ViewControllers/ConversationView/Cells/ConversationViewCell.m
@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
 #import "ConversationViewCell.h"
@@ -19,7 +19,7 @@ NS_ASSUME_NONNULL_BEGIN
     self.contentWidth = 0;
 }
 
-- (void)loadForDisplay
+- (void)loadForDisplayWithTransaction:(YapDatabaseReadTransaction *)transaction
 {
     OWSFail(@"%@ This method should be overridden.", self.logTag);
 }
diff --git a/Signal/src/ViewControllers/ConversationView/Cells/OWSContactOffersCell.m b/Signal/src/ViewControllers/ConversationView/Cells/OWSContactOffersCell.m
index a86655a7b0..6402fbbf67 100644
--- a/Signal/src/ViewControllers/ConversationView/Cells/OWSContactOffersCell.m
+++ b/Signal/src/ViewControllers/ConversationView/Cells/OWSContactOffersCell.m
@@ -85,7 +85,7 @@ NS_ASSUME_NONNULL_BEGIN
     return NSStringFromClass([self class]);
 }
 
-- (void)loadForDisplay
+- (void)loadForDisplayWithTransaction:(YapDatabaseReadTransaction *)transaction
 {
     OWSAssert(self.viewItem);
     OWSAssert([self.viewItem.interaction isKindOfClass:[OWSContactOffersInteraction class]]);
diff --git a/Signal/src/ViewControllers/ConversationView/Cells/OWSMessageCell.m b/Signal/src/ViewControllers/ConversationView/Cells/OWSMessageCell.m
index 49b6b817b5..6c19879c3d 100644
--- a/Signal/src/ViewControllers/ConversationView/Cells/OWSMessageCell.m
+++ b/Signal/src/ViewControllers/ConversationView/Cells/OWSMessageCell.m
@@ -150,7 +150,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 #pragma mark - Load
 
-- (void)loadForDisplay
+- (void)loadForDisplayWithTransaction:(YapDatabaseReadTransaction *)transaction
 {
     OWSAssert(self.viewItem);
     OWSAssert(self.viewItem.interaction);
diff --git a/Signal/src/ViewControllers/ConversationView/Cells/OWSSystemMessageCell.m b/Signal/src/ViewControllers/ConversationView/Cells/OWSSystemMessageCell.m
index d1d6a48b90..4381b6633f 100644
--- a/Signal/src/ViewControllers/ConversationView/Cells/OWSSystemMessageCell.m
+++ b/Signal/src/ViewControllers/ConversationView/Cells/OWSSystemMessageCell.m
@@ -73,7 +73,7 @@ NS_ASSUME_NONNULL_BEGIN
     return NSStringFromClass([self class]);
 }
 
-- (void)loadForDisplay
+- (void)loadForDisplayWithTransaction:(YapDatabaseReadTransaction *)transaction
 {
     OWSAssert(self.viewItem);
 
@@ -83,7 +83,7 @@ NS_ASSUME_NONNULL_BEGIN
     self.imageView.image = [icon imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
     self.imageView.tintColor = [self iconColorForInteraction:interaction];
     self.titleLabel.textColor = [self textColor];
-    [self applyTitleForInteraction:interaction label:self.titleLabel];
+    [self applyTitleForInteraction:interaction label:self.titleLabel transaction:transaction];
 
     [self setNeedsLayout];
 }
@@ -162,7 +162,9 @@ NS_ASSUME_NONNULL_BEGIN
     return result;
 }
 
-- (void)applyTitleForInteraction:(TSInteraction *)interaction label:(UILabel *)label
+- (void)applyTitleForInteraction:(TSInteraction *)interaction
+                           label:(UILabel *)label
+                     transaction:(YapDatabaseReadTransaction *)transaction
 {
     OWSAssert(interaction);
     OWSAssert(label);
@@ -170,22 +172,24 @@ NS_ASSUME_NONNULL_BEGIN
     // TODO: Should we move the copy generation into this view?
 
     if ([interaction isKindOfClass:[TSErrorMessage class]]) {
-        label.text = interaction.description;
+        TSErrorMessage *errorMessage = (TSErrorMessage *)interaction;
+        label.text = [errorMessage previewTextWithTransaction:transaction];
     } else if ([interaction isKindOfClass:[TSInfoMessage class]]) {
-        if ([interaction isKindOfClass:[OWSVerificationStateChangeMessage class]]) {
-            OWSVerificationStateChangeMessage *message = (OWSVerificationStateChangeMessage *)interaction;
-            BOOL isVerified = message.verificationState == OWSVerificationStateVerified;
+        TSInfoMessage *infoMessage = (TSInfoMessage *)interaction;
+        if ([infoMessage isKindOfClass:[OWSVerificationStateChangeMessage class]]) {
+            OWSVerificationStateChangeMessage *verificationMessage = (OWSVerificationStateChangeMessage *)infoMessage;
+            BOOL isVerified = verificationMessage.verificationState == OWSVerificationStateVerified;
             NSString *displayName =
-                [[Environment current].contactsManager displayNameForPhoneIdentifier:message.recipientId];
+                [[Environment current].contactsManager displayNameForPhoneIdentifier:verificationMessage.recipientId];
             NSString *titleFormat = (isVerified
-                    ? (message.isLocalChange
+                    ? (verificationMessage.isLocalChange
                               ? NSLocalizedString(@"VERIFICATION_STATE_CHANGE_FORMAT_VERIFIED_LOCAL",
                                     @"Format for info message indicating that the verification state was verified on "
                                     @"this device. Embeds {{user's name or phone number}}.")
                               : NSLocalizedString(@"VERIFICATION_STATE_CHANGE_FORMAT_VERIFIED_OTHER_DEVICE",
                                     @"Format for info message indicating that the verification state was verified on "
                                     @"another device. Embeds {{user's name or phone number}}."))
-                    : (message.isLocalChange
+                    : (verificationMessage.isLocalChange
                               ? NSLocalizedString(@"VERIFICATION_STATE_CHANGE_FORMAT_NOT_VERIFIED_LOCAL",
                                     @"Format for info message indicating that the verification state was unverified on "
                                     @"this device. Embeds {{user's name or phone number}}.")
@@ -194,10 +198,11 @@ NS_ASSUME_NONNULL_BEGIN
                                     @"another device. Embeds {{user's name or phone number}}.")));
             label.text = [NSString stringWithFormat:titleFormat, displayName];
         } else {
-            label.text = interaction.description;
+            label.text = [infoMessage previewTextWithTransaction:transaction];
         }
     } else if ([interaction isKindOfClass:[TSCall class]]) {
-        label.text = interaction.description;
+        TSCall *call = (TSCall *)interaction;
+        label.text = [call previewTextWithTransaction:transaction];
     } else {
         OWSFail(@"Unknown interaction type: %@", [interaction class]);
         label.text = nil;
@@ -266,7 +271,11 @@ NS_ASSUME_NONNULL_BEGIN
     result.height += self.topVMargin;
     result.height += self.bottomVMargin;
 
-    [self applyTitleForInteraction:interaction label:self.titleLabel];
+    // FIXME pass in transaction from the uiDBConnection.
+    [[TSYapDatabaseObject dbReadConnection] readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
+        [self applyTitleForInteraction:interaction label:self.titleLabel transaction:transaction];
+    }];
+
     CGFloat maxTitleWidth = (viewWidth - ([self hMargin] * 2.f + [self hSpacing] + [self iconSize]));
     CGSize titleSize = [self.titleLabel sizeThatFits:CGSizeMake(maxTitleWidth, CGFLOAT_MAX)];
 
diff --git a/Signal/src/ViewControllers/ConversationView/Cells/OWSUnreadIndicatorCell.m b/Signal/src/ViewControllers/ConversationView/Cells/OWSUnreadIndicatorCell.m
index 88ca54b489..13ceeb8179 100644
--- a/Signal/src/ViewControllers/ConversationView/Cells/OWSUnreadIndicatorCell.m
+++ b/Signal/src/ViewControllers/ConversationView/Cells/OWSUnreadIndicatorCell.m
@@ -84,7 +84,7 @@ NS_ASSUME_NONNULL_BEGIN
     return NSStringFromClass([self class]);
 }
 
-- (void)loadForDisplay
+- (void)loadForDisplayWithTransaction:(YapDatabaseReadTransaction *)transaction
 {
     OWSAssert(self.viewItem);
     OWSAssert([self.viewItem.interaction isKindOfClass:[TSUnreadIndicatorInteraction class]]);
diff --git a/Signal/src/ViewControllers/ConversationView/ConversationViewController.m b/Signal/src/ViewControllers/ConversationView/ConversationViewController.m
index 9c7bdb86d6..6531cc68fd 100644
--- a/Signal/src/ViewControllers/ConversationView/ConversationViewController.m
+++ b/Signal/src/ViewControllers/ConversationView/ConversationViewController.m
@@ -4757,7 +4757,9 @@ typedef enum : NSUInteger {
     }
     cell.contentWidth = self.layout.contentWidth;
 
-    [cell loadForDisplay];
+    [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
+        [cell loadForDisplayWithTransaction:transaction];
+    }];
 
     return cell;
 }
diff --git a/Signal/src/ViewControllers/DebugUI/DebugUIMessages.m b/Signal/src/ViewControllers/DebugUI/DebugUIMessages.m
index b050f9e8b4..ef3ffc1dda 100644
--- a/Signal/src/ViewControllers/DebugUI/DebugUIMessages.m
+++ b/Signal/src/ViewControllers/DebugUI/DebugUIMessages.m
@@ -3223,7 +3223,7 @@ NS_ASSUME_NONNULL_BEGIN
 
                   TSContactThread *contactThread = [TSContactThread getOrCreateThreadWithContactId:phoneNumber.toE164];
                   [self sendFakeMessages:messageCount thread:contactThread];
-                  DDLogError(@"Create fake thread: %@, interactions: %zd",
+                  DDLogError(@"Create fake thread: %@, interactions: %tu",
                       phoneNumber.toE164,
                       contactThread.numberOfInteractions);
               }];
@@ -3251,7 +3251,7 @@ NS_ASSUME_NONNULL_BEGIN
                         [self sendFakeMessages:batchSize thread:thread isTextOnly:isTextOnly transaction:transaction];
                     }];
                 remainder -= batchSize;
-                DDLogInfo(@"%@ sendFakeMessages %zd / %zd", self.logTag, counter - remainder, counter);
+                DDLogInfo(@"%@ sendFakeMessages %td / %tu", self.logTag, counter - remainder, counter);
             }
         });
     }
@@ -3263,7 +3263,7 @@ NS_ASSUME_NONNULL_BEGIN
               isTextOnly:(BOOL)isTextOnly
              transaction:(YapDatabaseReadWriteTransaction *)transaction
 {
-    DDLogInfo(@"%@ sendFakeMessages: %zd", self.logTag, counter);
+    DDLogInfo(@"%@ sendFakeMessages: %tu", self.logTag, counter);
 
     for (NSUInteger i = 0; i < counter; i++) {
         NSString *randomText = [self randomText];
@@ -3411,7 +3411,7 @@ NS_ASSUME_NONNULL_BEGIN
 {
     OWSAssert(thread);
 
-    DDLogInfo(@"%@ injectIncomingMessageInThread: %zd", self.logTag, counter);
+    DDLogInfo(@"%@ injectIncomingMessageInThread: %tu", self.logTag, counter);
 
     NSString *randomText = [self randomText];
     NSString *text = [[[@(counter) description] stringByAppendingString:@" "] stringByAppendingString:randomText];
diff --git a/Signal/src/ViewControllers/HomeView/HomeViewCell.h b/Signal/src/ViewControllers/HomeView/HomeViewCell.h
index 4e51d15fc6..054b9fcb5f 100644
--- a/Signal/src/ViewControllers/HomeView/HomeViewCell.h
+++ b/Signal/src/ViewControllers/HomeView/HomeViewCell.h
@@ -5,7 +5,8 @@
 NS_ASSUME_NONNULL_BEGIN
 
 @class OWSContactsManager;
-@class TSThread;
+@class ThreadViewModel;
+@class YapDatabaseReadTransaction;
 
 @interface HomeViewCell : UITableViewCell
 
@@ -13,7 +14,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 + (NSString *)cellReuseIdentifier;
 
-- (void)configureWithThread:(TSThread *)thread
+- (void)configureWithThread:(ThreadViewModel *)thread
             contactsManager:(OWSContactsManager *)contactsManager
       blockedPhoneNumberSet:(NSSet<NSString *> *)blockedPhoneNumberSet;
 
diff --git a/Signal/src/ViewControllers/HomeView/HomeViewCell.m b/Signal/src/ViewControllers/HomeView/HomeViewCell.m
index 7281b65b25..785c4cfc5e 100644
--- a/Signal/src/ViewControllers/HomeView/HomeViewCell.m
+++ b/Signal/src/ViewControllers/HomeView/HomeViewCell.m
@@ -12,7 +12,6 @@
 #import <SignalServiceKit/OWSMessageManager.h>
 #import <SignalServiceKit/TSContactThread.h>
 #import <SignalServiceKit/TSGroupThread.h>
-#import <SignalServiceKit/TSThread.h>
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -27,7 +26,7 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic) UIView *unreadBadge;
 @property (nonatomic) UILabel *unreadLabel;
 
-@property (nonatomic, nullable) TSThread *thread;
+@property (nonatomic, nullable) ThreadViewModel *thread;
 @property (nonatomic, nullable) OWSContactsManager *contactsManager;
 
 @property (nonatomic, readonly) NSMutableArray<NSLayoutConstraint *> *viewConstraints;
@@ -143,9 +142,9 @@ NS_ASSUME_NONNULL_BEGIN
     return NSStringFromClass(self.class);
 }
 
-- (void)configureWithThread:(TSThread *)thread
-              contactsManager:(OWSContactsManager *)contactsManager
-        blockedPhoneNumberSet:(NSSet<NSString *> *)blockedPhoneNumberSet
+- (void)configureWithThread:(ThreadViewModel *)thread
+            contactsManager:(OWSContactsManager *)contactsManager
+      blockedPhoneNumberSet:(NSSet<NSString *> *)blockedPhoneNumberSet
 {
     OWSAssertIsOnMainThread();
     OWSAssert(thread);
@@ -183,7 +182,7 @@ NS_ASSUME_NONNULL_BEGIN
         self.dateTimeLabel.font = self.unreadFont;
     }
 
-    NSUInteger unreadCount = [[OWSMessageUtils sharedManager] unreadMessagesInThread:thread];
+    NSUInteger unreadCount = thread.unreadCount;
     if (unreadCount == 0) {
         [self.viewConstraints addObject:[self.payloadView autoPinTrailingToSuperviewMargin]];
     } else {
@@ -240,18 +239,19 @@ NS_ASSUME_NONNULL_BEGIN
         return;
     }
 
-    TSThread *thread = self.thread;
+    ThreadViewModel *thread = self.thread;
     if (thread == nil) {
         OWSFail(@"%@ thread should not be nil", self.logTag);
         self.avatarView.image = nil;
         return;
     }
 
-    self.avatarView.image =
-        [OWSAvatarBuilder buildImageForThread:thread diameter:self.avatarSize contactsManager:contactsManager];
+    self.avatarView.image = [OWSAvatarBuilder buildImageForThread:thread.threadRecord
+                                                         diameter:self.avatarSize
+                                                  contactsManager:contactsManager];
 }
 
-- (NSAttributedString *)attributedSnippetForThread:(TSThread *)thread
+- (NSAttributedString *)attributedSnippetForThread:(ThreadViewModel *)thread
                              blockedPhoneNumberSet:(NSSet<NSString *> *)blockedPhoneNumberSet
 {
     OWSAssert(thread);
@@ -285,7 +285,7 @@ NS_ASSUME_NONNULL_BEGIN
                                                                     : [UIColor lightGrayColor]),
                                                         }]];
         }
-        NSString *displayableText = thread.lastMessageLabel.filterStringForDisplay;
+        NSString *displayableText = thread.lastMessageText;
         if (displayableText) {
             [snippetText appendAttributedString:[[NSAttributedString alloc]
                                                     initWithString:displayableText
@@ -447,7 +447,7 @@ NS_ASSUME_NONNULL_BEGIN
 
     self.nameLabel.font = self.nameFont;
 
-    TSThread *thread = self.thread;
+    ThreadViewModel *thread = self.thread;
     if (thread == nil) {
         OWSFail(@"%@ thread should not be nil", self.logTag);
         self.nameLabel.attributedText = nil;
diff --git a/Signal/src/ViewControllers/HomeView/HomeViewController.m b/Signal/src/ViewControllers/HomeView/HomeViewController.m
index fec4651188..1d507f74c5 100644
--- a/Signal/src/ViewControllers/HomeView/HomeViewController.m
+++ b/Signal/src/ViewControllers/HomeView/HomeViewController.m
@@ -47,7 +47,7 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
 @property (nonatomic) UISegmentedControl *segmentedControl;
 @property (nonatomic) id previewingContext;
 @property (nonatomic) NSSet<NSString *> *blockedPhoneNumberSet;
-
+@property (nonatomic, readonly) NSCache<NSString *, ThreadViewModel *> *threadViewModelCache;
 @property (nonatomic) BOOL isViewVisible;
 @property (nonatomic) BOOL isAppInBackground;
 @property (nonatomic) BOOL shouldObserveDBModifications;
@@ -108,6 +108,7 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
     _messageSender = [Environment current].messageSender;
     _blockingManager = [OWSBlockingManager sharedManager];
     _blockedPhoneNumberSet = [NSSet setWithArray:[_blockingManager blockedPhoneNumbers]];
+    _threadViewModelCache = [NSCache new];
 
     // Ensure ExperienceUpgradeFinder has been initialized.
     [ExperienceUpgradeFinder sharedManager];
@@ -155,14 +156,14 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
 
     _blockedPhoneNumberSet = [NSSet setWithArray:[_blockingManager blockedPhoneNumbers]];
 
-    [self.tableView reloadData];
+    [self reloadTableViewData];
 }
 
 - (void)signalAccountsDidChange:(id)notification
 {
     OWSAssertIsOnMainThread();
 
-    [self.tableView reloadData];
+    [self reloadTableViewData];
 }
 
 #pragma mark - View Life Cycle
@@ -395,7 +396,11 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
 - (void)viewWillAppear:(BOOL)animated
 {
     [super viewWillAppear:animated];
-    if ([TSThread numberOfKeysInCollection] > 0) {
+    __block BOOL hasAnyMessages;
+    [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction * _Nonnull transaction) {
+        hasAnyMessages = [self hasAnyMessagesWithTransaction:transaction];
+    }];
+    if (hasAnyMessages) {
         [self.contactsManager requestSystemContactsOnceWithCompletion:^(NSError *_Nullable error) {
             dispatch_async(dispatch_get_main_queue(), ^{
                 [self updateReminderViews];
@@ -468,6 +473,13 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
     }
 }
 
+- (void)reloadTableViewData
+{
+    // PERF: come up with a more nuanced cache clearing scheme
+    [self.threadViewModelCache removeAllObjects];
+    [self.tableView reloadData];
+}
+
 - (void)resetMappings
 {
     // If we're entering "active" mode (e.g. view is visible and app is in foreground),
@@ -484,13 +496,18 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
         }];
     }
 
-    [[self tableView] reloadData];
+    [self reloadTableViewData];
+
     [self checkIfEmptyView];
     [self updateInboxCountLabel];
 
     // If the user hasn't already granted contact access
     // we don't want to request until they receive a message.
-    if ([TSThread numberOfKeysInCollection] > 0) {
+    __block BOOL hasAnyMessages;
+    [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction * _Nonnull transaction) {
+        hasAnyMessages = [self hasAnyMessagesWithTransaction:transaction];
+    }];
+    if (hasAnyMessages) {
         [self.contactsManager requestSystemContactsOnce];
     }
 }
@@ -506,11 +523,21 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
     self.isAppInBackground = YES;
 }
 
+- (BOOL)hasAnyMessagesWithTransaction:(YapDatabaseReadTransaction *)transaction
+{
+    return [TSThread numberOfKeysInCollectionWithTransaction:transaction] > 0;
+}
+
 - (void)applicationDidBecomeActive:(NSNotification *)notification
 {
     // It's possible a thread was created while we where in the background. But since we don't honor contact
     // requests unless the app is in the foregrond, we must check again here upon becoming active.
-    if ([TSThread numberOfKeysInCollection] > 0) {
+    __block BOOL hasAnyMessages;
+    [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction * _Nonnull transaction) {
+        hasAnyMessages = [self hasAnyMessagesWithTransaction:transaction];
+    }];
+    
+    if (hasAnyMessages) {
         [self.contactsManager requestSystemContactsOnceWithCompletion:^(NSError *_Nullable error) {
             dispatch_async(dispatch_get_main_queue(), ^{
                 [self updateReminderViews];
@@ -577,13 +604,29 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
     return (NSInteger)[self.threadMappings numberOfItemsInSection:(NSUInteger)section];
 }
 
+- (ThreadViewModel *)threadViewModelForIndexPath:(NSIndexPath *)indexPath
+{
+    TSThread *threadRecord = [self threadForIndexPath:indexPath];
+
+    ThreadViewModel *_Nullable cachedThreadViewModel = [self.threadViewModelCache objectForKey:threadRecord.uniqueId];
+    if (cachedThreadViewModel) {
+        return cachedThreadViewModel;
+    }
+
+    __block ThreadViewModel *_Nullable newThreadViewModel;
+    [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
+        newThreadViewModel = [[ThreadViewModel alloc] initWithThread:threadRecord transaction:transaction];
+    }];
+    [self.threadViewModelCache setObject:newThreadViewModel forKey:threadRecord.uniqueId];
+    return newThreadViewModel;
+}
+
 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
 {
     HomeViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:HomeViewCell.cellReuseIdentifier];
     OWSAssert(cell);
 
-    TSThread *thread = [self threadForIndexPath:indexPath];
-
+    ThreadViewModel *thread = [self threadViewModelForIndexPath:indexPath];
     [cell configureWithThread:thread
               contactsManager:self.contactsManager
         blockedPhoneNumberSet:self.blockedPhoneNumberSet];
@@ -891,7 +934,7 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
 
     [self resetMappings];
 
-    [[self tableView] reloadData];
+    [self reloadTableViewData];
     [self checkIfEmptyView];
     [self updateReminderViews];
 }
@@ -904,6 +947,8 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
 
     if (!_uiDatabaseConnection) {
         _uiDatabaseConnection = [OWSPrimaryStorage.sharedManager newDatabaseConnection];
+        // default is 250
+        _uiDatabaseConnection.objectCacheLimit = 500;
         [_uiDatabaseConnection beginLongLivedReadTransaction];
     }
     return _uiDatabaseConnection;
@@ -948,7 +993,12 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
 
     // If the user hasn't already granted contact access
     // we don't want to request until they receive a message.
-    if ([TSThread numberOfKeysInCollection] > 0) {
+    __block BOOL hasAnyMessages;
+    [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
+        hasAnyMessages = [self hasAnyMessagesWithTransaction:transaction];
+    }];
+
+    if (hasAnyMessages) {
         [self.contactsManager requestSystemContactsOnce];
     }
 
@@ -989,6 +1039,10 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
     }
 
     for (YapDatabaseViewRowChange *rowChange in rowChanges) {
+        NSString *key = rowChange.collectionKey.key;
+        OWSAssert(key);
+        [self.threadViewModelCache removeObjectForKey:key];
+
         switch (rowChange.type) {
             case YapDatabaseViewChangeDelete: {
                 [self.tableView deleteRowsAtIndexPaths:@[ rowChange.indexPath ]
diff --git a/Signal/src/environment/NotificationsManager.m b/Signal/src/environment/NotificationsManager.m
index a09ab3b657..1bd2f6f740 100644
--- a/Signal/src/environment/NotificationsManager.m
+++ b/Signal/src/environment/NotificationsManager.m
@@ -18,6 +18,7 @@
 #import <SignalServiceKit/TSIncomingMessage.h>
 #import <SignalServiceKit/TextSecureKitEnv.h>
 #import <SignalServiceKit/Threading.h>
+#import <YapDatabase/YapDatabaseTransaction.h>
 
 @interface NotificationsManager ()
 
@@ -200,51 +201,56 @@
 
 #pragma mark - Signal Messages
 
-- (void)notifyUserForErrorMessage:(TSErrorMessage *)message inThread:(TSThread *)thread {
+- (void)notifyUserForErrorMessage:(TSErrorMessage *)message
+                           thread:(TSThread *)thread
+                      transaction:(YapDatabaseReadWriteTransaction *)transaction
+{
     OWSAssert(message);
     OWSAssert(thread);
 
-    dispatch_async(dispatch_get_main_queue(), ^{
-        if (thread.isMuted) {
-            return;
-        }
+    NSString *messageText = [message previewTextWithTransaction:transaction];
 
-        BOOL shouldPlaySound = [self shouldPlaySoundForNotification];
+    [transaction
+        addCompletionQueue:nil
+           completionBlock:^() {
+               if (thread.isMuted) {
+                   return;
+               }
 
-        NSString *messageDescription = message.description;
+               BOOL shouldPlaySound = [self shouldPlaySoundForNotification];
 
-        if (([UIApplication sharedApplication].applicationState != UIApplicationStateActive) && messageDescription) {
-            UILocalNotification *notification = [[UILocalNotification alloc] init];
-            notification.userInfo = @{ Signal_Thread_UserInfo_Key : thread.uniqueId };
-            if (shouldPlaySound) {
-                OWSSound sound = [OWSSounds notificationSoundForThread:thread];
-                notification.soundName = [OWSSounds filenameForSound:sound];
-            }
+               if (([UIApplication sharedApplication].applicationState != UIApplicationStateActive) && messageText) {
+                   UILocalNotification *notification = [[UILocalNotification alloc] init];
+                   notification.userInfo = @{ Signal_Thread_UserInfo_Key : thread.uniqueId };
+                   if (shouldPlaySound) {
+                       OWSSound sound = [OWSSounds notificationSoundForThread:thread];
+                       notification.soundName = [OWSSounds filenameForSound:sound];
+                   }
 
-            NSString *alertBodyString = @"";
+                   NSString *alertBodyString = @"";
 
-            NSString *authorName = [thread name];
-            switch (self.notificationPreviewType) {
-                case NotificationNamePreview:
-                case NotificationNameNoPreview:
-                    alertBodyString = [NSString stringWithFormat:@"%@: %@", authorName, messageDescription];
-                    break;
-                case NotificationNoNameNoPreview:
-                    alertBodyString = messageDescription;
-                    break;
-            }
-            notification.alertBody = alertBodyString;
+                   NSString *authorName = [thread name];
+                   switch (self.notificationPreviewType) {
+                       case NotificationNamePreview:
+                       case NotificationNameNoPreview:
+                           alertBodyString = [NSString stringWithFormat:@"%@: %@", authorName, messageText];
+                           break;
+                       case NotificationNoNameNoPreview:
+                           alertBodyString = messageText;
+                           break;
+                   }
+                   notification.alertBody = alertBodyString;
 
-            [[PushManager sharedManager] presentNotification:notification checkForCancel:NO];
-        } else {
-            if (shouldPlaySound && [Environment.preferences soundInForeground]) {
-                OWSSound sound = [OWSSounds notificationSoundForThread:thread];
-                SystemSoundID soundId = [OWSSounds systemSoundIDForSound:sound quiet:YES];
-                // Vibrate, respect silent switch, respect "Alert" volume, not media volume.
-                AudioServicesPlayAlertSound(soundId);
-            }
-        }
-    });
+                   [[PushManager sharedManager] presentNotification:notification checkForCancel:NO];
+               } else {
+                   if (shouldPlaySound && [Environment.preferences soundInForeground]) {
+                       OWSSound sound = [OWSSounds notificationSoundForThread:thread];
+                       SystemSoundID soundId = [OWSSounds systemSoundIDForSound:sound quiet:YES];
+                       // Vibrate, respect silent switch, respect "Alert" volume, not media volume.
+                       AudioServicesPlayAlertSound(soundId);
+                   }
+               }
+           }];
 }
 
 - (void)notifyUserForIncomingMessage:(TSIncomingMessage *)message
diff --git a/SignalMessaging/contacts/OWSContactsManager.m b/SignalMessaging/contacts/OWSContactsManager.m
index 5d6ef6deb9..96a3dc6b23 100644
--- a/SignalMessaging/contacts/OWSContactsManager.m
+++ b/SignalMessaging/contacts/OWSContactsManager.m
@@ -371,9 +371,15 @@ NSString *const OWSContactsManagerSignalAccountsDidChangeNotification
 {
     OWSAssert(recipientId.length > 0);
 
-    SignalAccount *signalAccount = [self signalAccountForRecipientId:recipientId];
+    SignalAccount *_Nullable signalAccount = [self signalAccountForRecipientId:recipientId];
     if (!signalAccount) {
-        return nil;
+        // search system contacts for no-longer-registered signal users, for which there will be no SignalAccount
+        DDLogDebug(@"%@ no signal account", self.logTag);
+        Contact *_Nullable nonSignalContact = self.allContactsMap[recipientId];
+        if (!nonSignalContact) {
+            return nil;
+        }
+        return nonSignalContact.fullName;
     }
 
     NSString *fullName = signalAccount.contactFullName;
diff --git a/SignalMessaging/environment/NoopNotificationsManager.swift b/SignalMessaging/environment/NoopNotificationsManager.swift
index 865e47c98f..a801a7d8d2 100644
--- a/SignalMessaging/environment/NoopNotificationsManager.swift
+++ b/SignalMessaging/environment/NoopNotificationsManager.swift
@@ -7,11 +7,11 @@ import SignalServiceKit
 @objc
 public class NoopNotificationsManager: NSObject, NotificationsProtocol {
 
-    public func notifyUser(for incomingMessage: TSIncomingMessage!, in thread: TSThread!, contactsManager: ContactsManagerProtocol!, transaction: YapDatabaseReadTransaction!) {
+    public func notifyUser(for incomingMessage: TSIncomingMessage, in thread: TSThread, contactsManager: ContactsManagerProtocol, transaction: YapDatabaseReadTransaction) {
         owsFail("\(self.logTag) in \(#function).")
     }
 
-    public func notifyUser(for error: TSErrorMessage!, in thread: TSThread!) {
+    public func notifyUser(for error: TSErrorMessage, thread: TSThread, transaction: YapDatabaseReadWriteTransaction) {
         Logger.warn("\(self.logTag) in \(#function), skipping notification for: \(error.description)")
     }
 }
diff --git a/SignalServiceKit/src/Contacts/TSThread.h b/SignalServiceKit/src/Contacts/TSThread.h
index 8ed22a61fd..07b795bd98 100644
--- a/SignalServiceKit/src/Contacts/TSThread.h
+++ b/SignalServiceKit/src/Contacts/TSThread.h
@@ -65,12 +65,8 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (NSArray<TSInvalidIdentityKeyReceivingErrorMessage *> *)receivedMessagesForInvalidKey:(NSData *)key;
 
-/**
- *  Returns whether or not the thread has unread messages.
- *
- *  @return YES if it has unread TSIncomingMessages, NO otherwise.
- */
-- (BOOL)hasUnreadMessages;
+- (NSUInteger)unreadMessageCountWithTransaction:(YapDatabaseReadTransaction *)transaction
+    NS_SWIFT_NAME(unreadMessageCount(transaction:));
 
 - (BOOL)hasSafetyNumbers;
 
@@ -90,7 +86,8 @@ NS_ASSUME_NONNULL_BEGIN
  *
  *  @return Thread preview string.
  */
-- (NSString *)lastMessageLabel;
+- (NSString *)lastMessageTextWithTransaction:(YapDatabaseReadTransaction *)transaction
+    NS_SWIFT_NAME(lastMessageText(transaction:));
 
 /**
  *  Updates the thread's caches of the latest interaction.
diff --git a/SignalServiceKit/src/Contacts/TSThread.m b/SignalServiceKit/src/Contacts/TSThread.m
index f9cc5fe4ce..074dc7c0d1 100644
--- a/SignalServiceKit/src/Contacts/TSThread.m
+++ b/SignalServiceKit/src/Contacts/TSThread.m
@@ -4,6 +4,7 @@
 
 #import "TSThread.h"
 #import "NSDate+OWS.h"
+#import "NSString+SSK.h"
 #import "OWSPrimaryStorage.h"
 #import "OWSReadTracking.h"
 #import "TSDatabaseView.h"
@@ -24,7 +25,7 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic, copy) NSString *messageDraft;
 @property (atomic, nullable) NSDate *mutedUntilDate;
 
-- (TSInteraction *)lastInteraction;
+- (TSInteraction *)lastInteractionWithTranscation:(YapDatabaseReadTransaction *)transaction;
 
 @end
 
@@ -199,17 +200,6 @@ NS_ASSUME_NONNULL_BEGIN
     return count;
 }
 
-- (BOOL)hasUnreadMessages {
-    TSInteraction *interaction = self.lastInteraction;
-    BOOL hasUnread = NO;
-
-    if ([interaction isKindOfClass:[TSIncomingMessage class]]) {
-        hasUnread = ![(TSIncomingMessage *)interaction wasRead];
-    }
-
-    return hasUnread;
-}
-
 - (NSArray<id<OWSReadTracking>> *)unseenMessagesWithTransaction:(YapDatabaseReadTransaction *)transaction
 {
     NSMutableArray<id<OWSReadTracking>> *messages = [NSMutableArray new];
@@ -228,6 +218,11 @@ NS_ASSUME_NONNULL_BEGIN
     return [messages copy];
 }
 
+- (NSUInteger)unreadMessageCountWithTransaction:(YapDatabaseReadTransaction *)transaction
+{
+    return [[transaction ext:TSUnreadDatabaseViewExtensionName] numberOfItemsInGroup:self.uniqueId];
+}
+
 - (void)markAllAsReadWithTransaction:(YapDatabaseReadWriteTransaction *)transaction
 {
     for (id<OWSReadTracking> message in [self unseenMessagesWithTransaction:transaction]) {
@@ -238,34 +233,34 @@ NS_ASSUME_NONNULL_BEGIN
     OWSAssert([self unseenMessagesWithTransaction:transaction].count < 1);
 }
 
-- (TSInteraction *) lastInteraction {
-    __block TSInteraction *last;
-    [OWSPrimaryStorage.dbReadConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-        last = [[transaction ext:TSMessageDatabaseViewExtensionName] lastObjectInGroup:self.uniqueId];
-    }];
-    return last;
-}
-
-- (TSInteraction *)lastInteractionForInbox
+- (TSInteraction *)lastInteractionForInboxWithTransaction:(YapDatabaseReadTransaction *)transaction
 {
+    __block NSUInteger missedCount = 0;
     __block TSInteraction *last = nil;
-    [OWSPrimaryStorage.dbReadConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-        [[transaction ext:TSMessageDatabaseViewExtensionName]
-            enumerateRowsInGroup:self.uniqueId
-                     withOptions:NSEnumerationReverse
-                      usingBlock:^(
-                          NSString *collection, NSString *key, id object, id metadata, NSUInteger index, BOOL *stop) {
+    [[transaction ext:TSMessageDatabaseViewExtensionName]
+     enumerateRowsInGroup:self.uniqueId
+     withOptions:NSEnumerationReverse
+     usingBlock:^(
+                  NSString *collection, NSString *key, id object, id metadata, NSUInteger index, BOOL *stop) {
+         
+         OWSAssert([object isKindOfClass:[TSInteraction class]]);
 
-                          OWSAssert([object isKindOfClass:[TSInteraction class]]);
+         missedCount++;
+         TSInteraction *interaction = (TSInteraction *)object;
+         
+         if ([TSThread shouldInteractionAppearInInbox:interaction]) {
+             last = interaction;
 
-                          TSInteraction *interaction = (TSInteraction *)object;
-
-                          if ([TSThread shouldInteractionAppearInInbox:interaction]) {
-                              last = interaction;
-                              *stop = YES;
-                          }
-                      }];
-    }];
+             // For long ignored threads, with lots of SN changes this can get really slow.
+             // I see this in development because I have a lot of long forgotten threads with members
+             // who's test devices are constantly reinstalled. We could add a purpose-built DB view,
+             // but I think in the real world this is rare to be a hotspot.
+             if (missedCount > 50) {
+                 DDLogWarn(@"%@ found last interaction for inbox after skipping %tu items", self.logTag, missedCount);
+             }
+             *stop = YES;
+         }
+     }];
     return last;
 }
 
@@ -277,12 +272,14 @@ NS_ASSUME_NONNULL_BEGIN
     }
 }
 
-- (NSString *)lastMessageLabel {
-    TSInteraction *interaction = self.lastInteractionForInbox;
-    if (interaction == nil) {
-        return @"";
+- (NSString *)lastMessageTextWithTransaction:(YapDatabaseReadTransaction *)transaction
+{
+    TSInteraction *interaction = [self lastInteractionForInboxWithTransaction:transaction];
+    if ([interaction conformsToProtocol:@protocol(OWSPreviewText)]) {
+        id<OWSPreviewText> previewable = (id<OWSPreviewText>)interaction;
+        return [previewable previewTextWithTransaction:transaction].filterStringForDisplay;
     } else {
-        return interaction.description;
+        return @"";
     }
 }
 
diff --git a/SignalServiceKit/src/Contacts/Threads/TSContactThread.m b/SignalServiceKit/src/Contacts/Threads/TSContactThread.m
index 599ea92022..9b4de20ed2 100644
--- a/SignalServiceKit/src/Contacts/Threads/TSContactThread.m
+++ b/SignalServiceKit/src/Contacts/Threads/TSContactThread.m
@@ -114,6 +114,7 @@ NS_ASSUME_NONNULL_BEGIN
     return !![[OWSIdentityManager sharedManager] identityKeyForRecipientId:self.contactIdentifier];
 }
 
+// TODO deprecate this? seems weird to access the displayName in the DB model
 - (NSString *)name
 {
     return [[TextSecureKitEnv sharedEnv].contactsManager displayNameForPhoneIdentifier:self.contactIdentifier];
diff --git a/SignalServiceKit/src/Messages/Interactions/OWSDisappearingConfigurationUpdateInfoMessage.m b/SignalServiceKit/src/Messages/Interactions/OWSDisappearingConfigurationUpdateInfoMessage.m
index 1391aa271a..8ae97209dc 100644
--- a/SignalServiceKit/src/Messages/Interactions/OWSDisappearingConfigurationUpdateInfoMessage.m
+++ b/SignalServiceKit/src/Messages/Interactions/OWSDisappearingConfigurationUpdateInfoMessage.m
@@ -56,7 +56,7 @@ NS_ASSUME_NONNULL_BEGIN
     return NO;
 }
 
-- (NSString *)description
+-(NSString *)previewTextWithTransaction:(YapDatabaseReadTransaction *)transaction
 {
     if (self.createdByRemoteName) {
         if (self.configurationIsEnabled && self.configurationDurationSeconds > 0) {
diff --git a/SignalServiceKit/src/Messages/Interactions/TSErrorMessage.m b/SignalServiceKit/src/Messages/Interactions/TSErrorMessage.m
index 363605a73b..1f130877a7 100644
--- a/SignalServiceKit/src/Messages/Interactions/TSErrorMessage.m
+++ b/SignalServiceKit/src/Messages/Interactions/TSErrorMessage.m
@@ -97,7 +97,8 @@ NSUInteger TSErrorMessageSchemaVersion = 1;
     return OWSInteractionType_Error;
 }
 
-- (NSString *)description {
+- (NSString *)previewTextWithTransaction:(YapDatabaseReadTransaction *)transaction
+{
     switch (_errorType) {
         case TSErrorMessageNoSession:
             return NSLocalizedString(@"ERROR_MESSAGE_NO_SESSION", @"");
diff --git a/SignalServiceKit/src/Messages/Interactions/TSInfoMessage.m b/SignalServiceKit/src/Messages/Interactions/TSInfoMessage.m
index 10abeb18b5..5e19dd4468 100644
--- a/SignalServiceKit/src/Messages/Interactions/TSInfoMessage.m
+++ b/SignalServiceKit/src/Messages/Interactions/TSInfoMessage.m
@@ -91,7 +91,8 @@ NSUInteger TSInfoMessageSchemaVersion = 1;
     return OWSInteractionType_Info;
 }
 
-- (NSString *)description {
+- (NSString *)previewTextWithTransaction:(YapDatabaseReadTransaction *)transaction
+{
     switch (_messageType) {
         case TSInfoMessageTypeSessionDidEnd:
             return NSLocalizedString(@"SECURE_SESSION_RESET", nil);
diff --git a/SignalServiceKit/src/Messages/Interactions/TSInteraction.h b/SignalServiceKit/src/Messages/Interactions/TSInteraction.h
index 67044af1fc..a6088803d7 100644
--- a/SignalServiceKit/src/Messages/Interactions/TSInteraction.h
+++ b/SignalServiceKit/src/Messages/Interactions/TSInteraction.h
@@ -19,6 +19,12 @@ typedef NS_ENUM(NSInteger, OWSInteractionType) {
     OWSInteractionType_Offer,
 };
 
+@protocol OWSPreviewText
+
+- (NSString *)previewTextWithTransaction:(YapDatabaseReadTransaction *)transaction;
+
+@end
+
 @interface TSInteraction : TSYapDatabaseObject
 
 - (instancetype)initInteractionWithTimestamp:(uint64_t)timestamp inThread:(TSThread *)thread;
diff --git a/SignalServiceKit/src/Messages/Interactions/TSInteraction.m b/SignalServiceKit/src/Messages/Interactions/TSInteraction.m
index b5319d9d0d..bd6a53662e 100644
--- a/SignalServiceKit/src/Messages/Interactions/TSInteraction.m
+++ b/SignalServiceKit/src/Messages/Interactions/TSInteraction.m
@@ -127,8 +127,10 @@ NS_ASSUME_NONNULL_BEGIN
     return OWSInteractionType_Unknown;
 }
 
-- (NSString *)description {
-    return @"Interaction description";
+- (NSString *)description
+{
+    return [NSString
+        stringWithFormat:@"%@ in thread: %@ timestamp: %tu", [super description], self.uniqueThreadId, self.timestamp];
 }
 
 - (void)saveWithTransaction:(YapDatabaseReadWriteTransaction *)transaction {
diff --git a/SignalServiceKit/src/Messages/Interactions/TSMessage.h b/SignalServiceKit/src/Messages/Interactions/TSMessage.h
index f08f13acfb..66c3598043 100644
--- a/SignalServiceKit/src/Messages/Interactions/TSMessage.h
+++ b/SignalServiceKit/src/Messages/Interactions/TSMessage.h
@@ -15,7 +15,7 @@ NS_ASSUME_NONNULL_BEGIN
 @class TSQuotedMessage;
 @class YapDatabaseReadWriteTransaction;
 
-@interface TSMessage : TSInteraction
+@interface TSMessage : TSInteraction <OWSPreviewText>
 
 @property (nonatomic, readonly) NSMutableArray<NSString *> *attachmentIds;
 @property (nonatomic, readonly, nullable) NSString *body;
@@ -39,7 +39,6 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (BOOL)hasAttachments;
 - (nullable TSAttachment *)attachmentWithTransaction:(YapDatabaseReadTransaction *)transaction;
-- (NSString *)previewTextWithTransaction:(YapDatabaseReadTransaction *)transaction;
 - (void)setQuotedMessageThumbnailAttachmentStream:(TSAttachmentStream *)attachmentStream;
 
 - (BOOL)shouldStartExpireTimer;
diff --git a/SignalServiceKit/src/Messages/Interactions/TSMessage.m b/SignalServiceKit/src/Messages/Interactions/TSMessage.m
index 558af46131..071aada166 100644
--- a/SignalServiceKit/src/Messages/Interactions/TSMessage.m
+++ b/SignalServiceKit/src/Messages/Interactions/TSMessage.m
@@ -265,16 +265,6 @@ static const NSUInteger OWSMessageSchemaVersion = 4;
     }
 }
 
-// TODO deprecate this and implement something like previewTextWithTransaction: for all TSInteractions
-- (NSString *)description
-{
-    __block NSString *result;
-    [self.dbReadConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-        result = [self previewTextWithTransaction:transaction];
-    }];
-    return result;
-}
-
 - (void)removeWithTransaction:(YapDatabaseReadWriteTransaction *)transaction
 {
     [super removeWithTransaction:transaction];
diff --git a/SignalServiceKit/src/Messages/Interactions/TSOutgoingMessage.m b/SignalServiceKit/src/Messages/Interactions/TSOutgoingMessage.m
index a98b39491a..0e95c93af1 100644
--- a/SignalServiceKit/src/Messages/Interactions/TSOutgoingMessage.m
+++ b/SignalServiceKit/src/Messages/Interactions/TSOutgoingMessage.m
@@ -437,7 +437,7 @@ NSString *const kTSOutgoingMessageSentRecipientAll = @"kTSOutgoingMessageSentRec
         [builder setBody:self.body];
     } else {
         OWSFail(@"%@ message body length too long.", self.logTag);
-        NSMutableString *truncatedBody = [self.body mutableCopy];
+        NSString *truncatedBody = self.body;
         while ([truncatedBody lengthOfBytesUsingEncoding:NSUTF8StringEncoding] > kOversizeTextMessageSizeThreshold) {
             DDLogError(@"%@ truncating body which is too long: %tu",
                 self.logTag,
diff --git a/SignalServiceKit/src/Messages/OWSIdentityManager.m b/SignalServiceKit/src/Messages/OWSIdentityManager.m
index ed76aa21c0..78e0b60eb0 100644
--- a/SignalServiceKit/src/Messages/OWSIdentityManager.m
+++ b/SignalServiceKit/src/Messages/OWSIdentityManager.m
@@ -545,7 +545,9 @@ NSString *const kNSNotificationName_IdentityStateDidChange = @"kNSNotificationNa
         [message saveWithTransaction:transaction];
     }
 
-    [[TextSecureKitEnv sharedEnv].notificationsManager notifyUserForErrorMessage:errorMessage inThread:contactThread];
+    [[TextSecureKitEnv sharedEnv].notificationsManager notifyUserForErrorMessage:errorMessage
+                                                                          thread:contactThread
+                                                                     transaction:transaction];
 }
 
 - (void)enqueueSyncMessageForVerificationStateForRecipientId:(NSString *)recipientId
diff --git a/SignalServiceKit/src/Messages/OWSMessageDecrypter.m b/SignalServiceKit/src/Messages/OWSMessageDecrypter.m
index 220b36983f..dffbad90ed 100644
--- a/SignalServiceKit/src/Messages/OWSMessageDecrypter.m
+++ b/SignalServiceKit/src/Messages/OWSMessageDecrypter.m
@@ -269,8 +269,10 @@ NS_ASSUME_NONNULL_BEGIN
         exception.name,
         exception.reason);
 
-    __block TSErrorMessage *errorMessage;
+
     [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+        TSErrorMessage *errorMessage;
+
         if ([exception.name isEqualToString:NoSessionException]) {
             OWSProdErrorWEnvelope([OWSAnalyticsEvents messageManagerErrorNoSession], envelope);
             errorMessage = [TSErrorMessage missingSessionWithEnvelope:envelope withTransaction:transaction];
@@ -298,18 +300,21 @@ NS_ASSUME_NONNULL_BEGIN
         }
 
         OWSAssert(errorMessage);
-        [errorMessage saveWithTransaction:transaction];
+        if (errorMessage != nil) {
+            [errorMessage saveWithTransaction:transaction];
+            [self notifyUserForErrorMessage:errorMessage envelope:envelope transaction:transaction];
+        }
     }];
-
-    if (errorMessage != nil) {
-        [self notifyForErrorMessage:errorMessage withEnvelope:envelope];
-    }
 }
 
-- (void)notifyForErrorMessage:(TSErrorMessage *)errorMessage withEnvelope:(OWSSignalServiceProtosEnvelope *)envelope
+- (void)notifyUserForErrorMessage:(TSErrorMessage *)errorMessage
+                         envelope:(OWSSignalServiceProtosEnvelope *)envelope
+                      transaction:(YapDatabaseReadWriteTransaction *)transaction
 {
-    TSThread *contactThread = [TSContactThread getOrCreateThreadWithContactId:envelope.source];
-    [[TextSecureKitEnv sharedEnv].notificationsManager notifyUserForErrorMessage:errorMessage inThread:contactThread];
+    TSThread *contactThread = [TSContactThread getOrCreateThreadWithContactId:envelope.source transaction:transaction];
+    [[TextSecureKitEnv sharedEnv].notificationsManager notifyUserForErrorMessage:errorMessage
+                                                                          thread:contactThread
+                                                                     transaction:transaction];
 }
 
 @end
diff --git a/SignalServiceKit/src/Messages/OWSMessageUtils.h b/SignalServiceKit/src/Messages/OWSMessageUtils.h
index 5c136eebef..031e7fc98d 100644
--- a/SignalServiceKit/src/Messages/OWSMessageUtils.h
+++ b/SignalServiceKit/src/Messages/OWSMessageUtils.h
@@ -15,7 +15,6 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (NSUInteger)unreadMessagesCount;
 - (NSUInteger)unreadMessagesCountExcept:(TSThread *)thread;
-- (NSUInteger)unreadMessagesInThread:(TSThread *)thread;
 
 - (void)updateApplicationBadgeCount;
 
diff --git a/SignalServiceKit/src/Messages/OWSMessageUtils.m b/SignalServiceKit/src/Messages/OWSMessageUtils.m
index 79c72df0c7..165e11f677 100644
--- a/SignalServiceKit/src/Messages/OWSMessageUtils.m
+++ b/SignalServiceKit/src/Messages/OWSMessageUtils.m
@@ -95,14 +95,6 @@ NS_ASSUME_NONNULL_BEGIN
     [CurrentAppContext() setMainAppBadgeNumber:numberOfItems];
 }
 
-- (NSUInteger)unreadMessagesInThread:(TSThread *)thread
-{
-    __block NSUInteger numberOfItems;
-    [self.dbConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-        numberOfItems = [[transaction ext:TSUnreadDatabaseViewExtensionName] numberOfItemsInGroup:thread.uniqueId];
-    }];
-    return numberOfItems;
-}
 
 @end
 
diff --git a/SignalServiceKit/src/Messages/TSCall.h b/SignalServiceKit/src/Messages/TSCall.h
index bcadbaf8b9..fdca7d4d12 100644
--- a/SignalServiceKit/src/Messages/TSCall.h
+++ b/SignalServiceKit/src/Messages/TSCall.h
@@ -20,7 +20,7 @@ typedef enum {
     RPRecentCallTypeIncomingDeclined
 } RPRecentCallType;
 
-@interface TSCall : TSInteraction <OWSReadTracking>
+@interface TSCall : TSInteraction <OWSReadTracking, OWSPreviewText>
 
 @property (nonatomic, readonly) RPRecentCallType callType;
 
diff --git a/SignalServiceKit/src/Messages/TSCall.m b/SignalServiceKit/src/Messages/TSCall.m
index 7b37efb3a2..20d805c09f 100644
--- a/SignalServiceKit/src/Messages/TSCall.m
+++ b/SignalServiceKit/src/Messages/TSCall.m
@@ -67,7 +67,9 @@ NSUInteger TSCallCurrentSchemaVersion = 1;
     return OWSInteractionType_Call;
 }
 
-- (NSString *)description {
+- (NSString *)previewTextWithTransaction:(YapDatabaseReadTransaction *)transaction
+{
+    // We don't actually use the `transaction` but other sibling classes do.
     switch (_callType) {
         case RPRecentCallTypeIncoming:
             return NSLocalizedString(@"INCOMING_CALL", @"");
@@ -83,7 +85,7 @@ NSUInteger TSCallCurrentSchemaVersion = 1;
             return NSLocalizedString(@"INFO_MESSAGE_MISSED_CALL_DUE_TO_CHANGED_IDENITY", @"info message text shown in conversation view");
         case RPRecentCallTypeIncomingDeclined:
             return NSLocalizedString(@"INCOMING_DECLINED_CALL",
-                @"info message recorded in conversation history when local user declined a call");
+                                     @"info message recorded in conversation history when local user declined a call");
     }
 }
 
diff --git a/SignalServiceKit/src/Protocols/NotificationsProtocol.h b/SignalServiceKit/src/Protocols/NotificationsProtocol.h
index 183cec0781..892c80eed6 100644
--- a/SignalServiceKit/src/Protocols/NotificationsProtocol.h
+++ b/SignalServiceKit/src/Protocols/NotificationsProtocol.h
@@ -1,11 +1,14 @@
 //
-//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
+NS_ASSUME_NONNULL_BEGIN
+
 @class TSErrorMessage;
 @class TSIncomingMessage;
 @class TSThread;
 @class YapDatabaseReadTransaction;
+
 @protocol ContactsManagerProtocol;
 
 @protocol NotificationsProtocol <NSObject>
@@ -15,6 +18,10 @@
                      contactsManager:(id<ContactsManagerProtocol>)contactsManager
                          transaction:(YapDatabaseReadTransaction *)transaction;
 
-- (void)notifyUserForErrorMessage:(TSErrorMessage *)error inThread:(TSThread *)thread;
+- (void)notifyUserForErrorMessage:(TSErrorMessage *)error
+                           thread:(TSThread *)thread
+                      transaction:(YapDatabaseReadWriteTransaction *)transaction;
 
 @end
+
+NS_ASSUME_NONNULL_END
diff --git a/SignalServiceKit/src/Storage/TSYapDatabaseObject.m b/SignalServiceKit/src/Storage/TSYapDatabaseObject.m
index f9eafec5f6..4317e8b7a5 100644
--- a/SignalServiceKit/src/Storage/TSYapDatabaseObject.m
+++ b/SignalServiceKit/src/Storage/TSYapDatabaseObject.m
@@ -109,17 +109,20 @@ NS_ASSUME_NONNULL_BEGIN
 
 + (YapDatabaseConnection *)dbReadConnection
 {
+    OWSJanksUI();
+
     // We use TSYapDatabaseObject's dbReadWriteConnection (not OWSPrimaryStorage's
     // dbReadConnection) for consistency, since we tend to [TSYapDatabaseObject
     // save] and want to write to the same connection we read from.  To get true
     // consistency, we'd want to update entities by reading & writing from within
     // the same transaction, but that'll be a big refactor.
-
     return self.dbReadWriteConnection;
 }
 
 + (YapDatabaseConnection *)dbReadWriteConnection
 {
+    OWSJanksUI();
+
     // Use a dedicated connection for model reads & writes.
     static YapDatabaseConnection *dbReadWriteConnection = nil;
     static dispatch_once_t onceToken;
diff --git a/SignalServiceKit/src/Util/OWSAsserts.h b/SignalServiceKit/src/Util/OWSAsserts.h
index c9f34a660b..84be8e747e 100755
--- a/SignalServiceKit/src/Util/OWSAsserts.h
+++ b/SignalServiceKit/src/Util/OWSAsserts.h
@@ -150,4 +150,26 @@ void SwiftAssertIsOnMainThread(NSString *functionName);
                                      userInfo:userInfoParam];                                                          \
     }
 
+
+// UI JANK
+//
+// In pursuit of smooth UI, we want to continue moving blocking operations off the main thread.
+// Add `OWSJanksUI` in code paths that shouldn't be called on the main thread.
+// Because we have pervasively broken this tenant, enabling it by default would be too disruptive
+// but it's helpful while unjanking and maybe someday we can have it enabled by default.
+//#define DEBUG_UI_JANK 1
+
+#ifdef DEBUG
+#ifdef DEBUG_UI_JANK
+#define OWSJanksUI()                                                                                                   \
+    do {                                                                                                               \
+        OWSAssert(![NSThread isMainThread])                                                                            \
+    } while (NO)
+#endif
+#endif
+
+#ifndef OWSJanksUI
+#define OWSJanksUI()
+#endif
+
 NS_ASSUME_NONNULL_END