diff --git a/Signal/src/ViewControllers/AppSettingsViewController.m b/Signal/src/ViewControllers/AppSettingsViewController.m
index 8774344da..b7fee9fa2 100644
--- a/Signal/src/ViewControllers/AppSettingsViewController.m
+++ b/Signal/src/ViewControllers/AppSettingsViewController.m
@@ -108,10 +108,16 @@
 - (void)updateTableContents
 {
     OWSTableContents *contents = [OWSTableContents new];
-    OWSTableSection *section = [OWSTableSection new];
 
     __weak AppSettingsViewController *weakSelf = self;
 
+#ifdef INTERNAL
+    OWSTableSection *internalSection = [OWSTableSection new];
+    [section addItem:[OWSTableItem softCenterLabelItemWithText:@"Internal Build"]];
+    [contents addSection:internalSection];
+#endif
+
+    OWSTableSection *section = [OWSTableSection new];
     [section addItem:[OWSTableItem itemWithCustomCellBlock:^{
         return [weakSelf profileHeaderCell];
     }
diff --git a/Signal/src/ViewControllers/ConversationView/ConversationViewController.m b/Signal/src/ViewControllers/ConversationView/ConversationViewController.m
index 4ffc5f843..bec4f2a96 100644
--- a/Signal/src/ViewControllers/ConversationView/ConversationViewController.m
+++ b/Signal/src/ViewControllers/ConversationView/ConversationViewController.m
@@ -2834,23 +2834,26 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
     // We need to reload any modified interactions _before_ we call
     // reloadViewItems.
     BOOL hasDeletions = NO;
+    BOOL hasMalformedRowChange = NO;
     for (YapDatabaseViewRowChange *rowChange in rowChanges) {
         switch (rowChange.type) {
             case YapDatabaseViewChangeUpdate: {
                 YapCollectionKey *collectionKey = rowChange.collectionKey;
-                OWSAssert(collectionKey.key.length > 0);
                 if (collectionKey.key) {
                     ConversationViewItem *viewItem = self.viewItemCache[collectionKey.key];
                     [self reloadInteractionForViewItem:viewItem];
+                } else {
+                    hasMalformedRowChange = YES;
                 }
                 break;
             }
             case YapDatabaseViewChangeDelete: {
                 // Discard cached view items after deletes.
                 YapCollectionKey *collectionKey = rowChange.collectionKey;
-                OWSAssert(collectionKey.key.length > 0);
                 if (collectionKey.key) {
                     [self.viewItemCache removeObjectForKey:collectionKey.key];
+                } else {
+                    hasMalformedRowChange = YES;
                 }
                 hasDeletions = YES;
                 break;
@@ -2858,6 +2861,19 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
             default:
                 break;
         }
+        if (hasMalformedRowChange) {
+            break;
+        }
+    }
+
+    if (hasMalformedRowChange) {
+        // These errors seems to be very rare; they can only be reproduced
+        // using the more extreme actions in the debug UI.
+        DDLogError(@"%@ hasMalformedRowChange", self.logTag);
+        [self.collectionView reloadData];
+        [self updateLastVisibleTimestamp];
+        [self cleanUpUnreadIndicatorIfNecessary];
+        return;
     }
 
     NSUInteger oldViewItemCount = self.viewItems.count;
diff --git a/Signal/src/ViewControllers/DebugUI/DebugUIMessages.m b/Signal/src/ViewControllers/DebugUI/DebugUIMessages.m
index 99657f5c6..3f53fbe08 100644
--- a/Signal/src/ViewControllers/DebugUI/DebugUIMessages.m
+++ b/Signal/src/ViewControllers/DebugUI/DebugUIMessages.m
@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
 #import "DebugUIMessages.h"
@@ -124,6 +124,14 @@ NS_ASSUME_NONNULL_BEGIN
                         actionBlock:^{
                             [DebugUIMessages sendFakeMessages:10 * 1000 thread:thread];
                         }],
+        [OWSTableItem itemWithTitle:@"Create 100k fake messages"
+                        actionBlock:^{
+                            [DebugUIMessages sendFakeMessages:100 * 1000 thread:thread];
+                        }],
+        [OWSTableItem itemWithTitle:@"Create 100k fake text messages"
+                        actionBlock:^{
+                            [DebugUIMessages sendFakeMessages:100 * 1000 thread:thread isTextOnly:YES];
+                        }],
         [OWSTableItem itemWithTitle:@"Create 1 fake unread messages"
                         actionBlock:^{
                             [DebugUIMessages createFakeUnreadMessages:1 thread:thread];
@@ -282,9 +290,24 @@ NS_ASSUME_NONNULL_BEGIN
                                              [DebugUIMessages createNewGroups:1000 recipientId:recipientId];
                                          }]];
     }
+    if ([thread isKindOfClass:[TSGroupThread class]]) {
+        TSGroupThread *groupThread = (TSGroupThread *)thread;
+        [items addObject:[OWSTableItem itemWithTitle:@"Send message to all members"
+                                         actionBlock:^{
+                                             [DebugUIMessages sendMessages:1 toAllMembersOfGroup:groupThread];
+                                         }]];
+    }
     return [OWSTableSection sectionWithTitle:self.name items:items];
 }
 
++ (void)sendMessages:(int)counter toAllMembersOfGroup:(TSGroupThread *)groupThread
+{
+    for (NSString *recipientId in groupThread.groupModel.groupMemberIds) {
+        TSContactThread *contactThread = [TSContactThread getOrCreateThreadWithContactId:recipientId];
+        [DebugUIMessages sendTextMessages:counter thread:contactThread];
+    }
+}
+
 + (void)sendTextMessageInThread:(TSThread *)thread counter:(int)counter
 {
     DDLogInfo(@"%@ sendTextMessageInThread: %d", self.logTag, counter);
@@ -964,20 +987,42 @@ NS_ASSUME_NONNULL_BEGIN
 
 + (void)sendFakeMessages:(NSUInteger)counter thread:(TSThread *)thread
 {
-    [TSStorageManager.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
-        [self sendFakeMessages:counter thread:thread transaction:transaction];
-    }];
+    [self sendFakeMessages:counter thread:thread isTextOnly:NO];
+}
+
++ (void)sendFakeMessages:(NSUInteger)counter thread:(TSThread *)thread isTextOnly:(BOOL)isTextOnly
+{
+    const NSUInteger kMaxBatchSize = 2500;
+    if (counter < kMaxBatchSize) {
+        [TSStorageManager.dbReadWriteConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+            [self sendFakeMessages:counter thread:thread isTextOnly:isTextOnly transaction:transaction];
+        }];
+    } else {
+        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
+            NSUInteger remainder = counter;
+            while (remainder > 0) {
+                NSUInteger batchSize = MIN(kMaxBatchSize, remainder);
+                [TSStorageManager.dbReadWriteConnection
+                    readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+                        [self sendFakeMessages:batchSize thread:thread isTextOnly:isTextOnly transaction:transaction];
+                    }];
+                remainder -= batchSize;
+                DDLogInfo(@"%@ sendFakeMessages %zd / %zd", self.logTag, counter - remainder, counter);
+            }
+        });
+    }
 }
 
 + (void)sendFakeMessages:(NSUInteger)counter
                   thread:(TSThread *)thread
+              isTextOnly:(BOOL)isTextOnly
              transaction:(YapDatabaseReadWriteTransaction *)transaction
 {
     DDLogInfo(@"%@ sendFakeMessages: %zd", self.logTag, counter);
 
     for (NSUInteger i = 0; i < counter; i++) {
         NSString *randomText = [self randomText];
-        switch (arc4random_uniform(4)) {
+        switch (arc4random_uniform(isTextOnly ? 2 : 4)) {
             case 0: {
                 TSIncomingMessage *message =
                     [[TSIncomingMessage alloc] initWithTimestamp:[NSDate ows_millisecondTimeStamp]
@@ -985,7 +1030,6 @@ NS_ASSUME_NONNULL_BEGIN
                                                         authorId:@"+19174054215"
                                                   sourceDeviceId:0
                                                      messageBody:randomText];
-                DDLogError(@"%@ sendFakeMessages incoming timestamp: %llu.", self.logTag, message.timestamp);
                 [message markAsReadWithTransaction:transaction sendReadReceipt:NO updateExpiration:NO];
                 break;
             }
@@ -994,8 +1038,8 @@ NS_ASSUME_NONNULL_BEGIN
                     [[TSOutgoingMessage alloc] initWithTimestamp:[NSDate ows_millisecondTimeStamp]
                                                         inThread:thread
                                                      messageBody:randomText];
-                DDLogError(@"%@ sendFakeMessages outgoing timestamp: %llu.", self.logTag, message.timestamp);
                 [message saveWithTransaction:transaction];
+                [message updateWithMessageState:TSOutgoingMessageStateUnsent transaction:transaction];
                 break;
             }
             case 2: {
@@ -1009,6 +1053,7 @@ NS_ASSUME_NONNULL_BEGIN
                                                             relay:@""
                                                    sourceFilename:@"test.mp3"
                                                    attachmentType:TSAttachmentTypeDefault];
+                pointer.state = TSAttachmentPointerStateFailed;
                 [pointer saveWithTransaction:transaction];
                 TSIncomingMessage *message =
                     [[TSIncomingMessage alloc] initWithTimestamp:[NSDate ows_millisecondTimeStamp]
@@ -1020,7 +1065,6 @@ NS_ASSUME_NONNULL_BEGIN
                                                        pointer.uniqueId,
                                                    ]
                                                 expiresInSeconds:0];
-                DDLogError(@"%@ sendFakeMessages incoming attachment timestamp: %llu.", self.logTag, message.timestamp);
                 [message markAsReadWithTransaction:transaction sendReadReceipt:NO updateExpiration:NO];
                 break;
             }
@@ -1031,7 +1075,6 @@ NS_ASSUME_NONNULL_BEGIN
                                                      messageBody:nil
                                                   isVoiceMessage:NO
                                                 expiresInSeconds:0];
-                DDLogError(@"%@ sendFakeMessages outgoing attachment timestamp: %llu.", self.logTag, message.timestamp);
 
                 NSString *filename = @"test.mp3";
                 UInt32 filesize = 16;
@@ -1050,6 +1093,7 @@ NS_ASSUME_NONNULL_BEGIN
                     message.attachmentFilenameMap[attachmentStream.uniqueId] = filename;
                 }
                 [message saveWithTransaction:transaction];
+                [message updateWithMessageState:TSOutgoingMessageStateUnsent transaction:transaction];
                 break;
             }
         }
@@ -1248,7 +1292,7 @@ NS_ASSUME_NONNULL_BEGIN
         },
         ^(YapDatabaseReadWriteTransaction *transaction) {
             NSUInteger messageCount = (NSUInteger)(1 + arc4random_uniform(4));
-            [self sendFakeMessages:messageCount thread:thread transaction:transaction];
+            [self sendFakeMessages:messageCount thread:thread isTextOnly:NO transaction:transaction];
         },
         ^(YapDatabaseReadWriteTransaction *transaction) {
             NSUInteger messageCount = (NSUInteger)(1 + arc4random_uniform(4));
diff --git a/SignalServiceKit/src/Storage/TSStorageManager.m b/SignalServiceKit/src/Storage/TSStorageManager.m
index f77ebec86..23b1c3295 100644
--- a/SignalServiceKit/src/Storage/TSStorageManager.m
+++ b/SignalServiceKit/src/Storage/TSStorageManager.m
@@ -141,6 +141,10 @@ void runAsyncRegistrationsForStorage(OWSStorage *storage)
 
 + (void)protectFiles
 {
+    DDLogInfo(@"%@ Database file size: %@", self.logTag, [OWSFileSystem fileSizeOfPath:self.legacyDatabaseFilePath]);
+    DDLogInfo(@"%@ \t SHM file size: %@", self.logTag, [OWSFileSystem fileSizeOfPath:self.legacyDatabaseFilePath_SHM]);
+    DDLogInfo(@"%@ \t WAL file size: %@", self.logTag, [OWSFileSystem fileSizeOfPath:self.legacyDatabaseFilePath_WAL]);
+
     // The old database location was in the Document directory,
     // so protect the database files individually.
     [OWSFileSystem protectFileOrFolderAtPath:self.legacyDatabaseFilePath];
diff --git a/SignalServiceKit/src/Util/OWSFileSystem.h b/SignalServiceKit/src/Util/OWSFileSystem.h
index cf6f091ce..d81d94fb3 100644
--- a/SignalServiceKit/src/Util/OWSFileSystem.h
+++ b/SignalServiceKit/src/Util/OWSFileSystem.h
@@ -35,6 +35,8 @@ NS_ASSUME_NONNULL_BEGIN
 // Returns nil on failure.
 + (nullable NSString *)writeDataToTemporaryFile:(NSData *)data fileExtension:(NSString *_Nullable)fileExtension;
 
++ (nullable NSNumber *)fileSizeOfPath:(NSString *)filePath;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/SignalServiceKit/src/Util/OWSFileSystem.m b/SignalServiceKit/src/Util/OWSFileSystem.m
index bd089cca6..a95ae4395 100644
--- a/SignalServiceKit/src/Util/OWSFileSystem.m
+++ b/SignalServiceKit/src/Util/OWSFileSystem.m
@@ -200,6 +200,20 @@ NS_ASSUME_NONNULL_BEGIN
     return tempFilePath;
 }
 
++ (nullable NSNumber *)fileSizeOfPath:(NSString *)filePath
+{
+    NSFileManager *fileManager = [NSFileManager defaultManager];
+    NSError *_Nullable error;
+    unsigned long long fileSize =
+        [[fileManager attributesOfItemAtPath:filePath error:&error][NSFileSize] unsignedLongLongValue];
+    if (error) {
+        DDLogError(@"%@ Couldn't fetch file size[%@]: %@", self.logTag, filePath, error);
+        return nil;
+    } else {
+        return @(fileSize);
+    }
+}
+
 @end
 
 NS_ASSUME_NONNULL_END