diff --git a/SignalServiceKit/src/Messages/DeviceSyncing/OWSSyncGroupsMessage.h b/SignalServiceKit/src/Messages/DeviceSyncing/OWSSyncGroupsMessage.h
index 530997f53..212d3051b 100644
--- a/SignalServiceKit/src/Messages/DeviceSyncing/OWSSyncGroupsMessage.h
+++ b/SignalServiceKit/src/Messages/DeviceSyncing/OWSSyncGroupsMessage.h
@@ -1,12 +1,16 @@
-//  Copyright © 2016 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "OWSOutgoingSyncMessage.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
+@class YapDatabaseReadTransaction;
+
 @interface OWSSyncGroupsMessage : OWSOutgoingSyncMessage
 
-- (NSData *)buildPlainTextAttachmentData;
+- (NSData *)buildPlainTextAttachmentDataWithTransaction:(YapDatabaseReadTransaction *)transaction;
 
 @end
 
diff --git a/SignalServiceKit/src/Messages/DeviceSyncing/OWSSyncGroupsMessage.m b/SignalServiceKit/src/Messages/DeviceSyncing/OWSSyncGroupsMessage.m
index 575f3d9eb..651a7edb7 100644
--- a/SignalServiceKit/src/Messages/DeviceSyncing/OWSSyncGroupsMessage.m
+++ b/SignalServiceKit/src/Messages/DeviceSyncing/OWSSyncGroupsMessage.m
@@ -40,7 +40,7 @@ NS_ASSUME_NONNULL_BEGIN
     return syncMessageBuilder;
 }
 
-- (NSData *)buildPlainTextAttachmentData
+- (NSData *)buildPlainTextAttachmentDataWithTransaction:(YapDatabaseReadTransaction *)transaction
 {
     // TODO use temp file stream to avoid loading everything into memory at once
     // First though, we need to re-engineer our attachment process to accept streams (encrypting with stream,
@@ -49,14 +49,16 @@ NS_ASSUME_NONNULL_BEGIN
     [dataOutputStream open];
     OWSGroupsOutputStream *groupsOutputStream = [OWSGroupsOutputStream streamWithOutputStream:dataOutputStream];
 
-    [TSGroupThread enumerateCollectionObjectsUsingBlock:^(id obj, BOOL *stop) {
-        if (![obj isKindOfClass:[TSGroupThread class]]) {
-            DDLogVerbose(@"Ignoring non group thread in thread collection: %@", obj);
-            return;
-        }
-        TSGroupModel *group = ((TSGroupThread *)obj).groupModel;
-        [groupsOutputStream writeGroup:group];
-    }];
+    [TSGroupThread
+        enumerateCollectionObjectsWithTransaction:transaction
+                                       usingBlock:^(id obj, BOOL *stop) {
+                                           if (![obj isKindOfClass:[TSGroupThread class]]) {
+                                               DDLogVerbose(@"Ignoring non group thread in thread collection: %@", obj);
+                                               return;
+                                           }
+                                           TSGroupModel *group = ((TSGroupThread *)obj).groupModel;
+                                           [groupsOutputStream writeGroup:group];
+                                       }];
 
     [groupsOutputStream flush];
     [dataOutputStream close];
diff --git a/SignalServiceKit/src/Messages/OWSMessageManager.m b/SignalServiceKit/src/Messages/OWSMessageManager.m
index 4b146b86b..5eb9e024b 100644
--- a/SignalServiceKit/src/Messages/OWSMessageManager.m
+++ b/SignalServiceKit/src/Messages/OWSMessageManager.m
@@ -615,8 +615,8 @@ NS_ASSUME_NONNULL_BEGIN
                 }];
         } else if (syncMessage.request.type == OWSSignalServiceProtosSyncMessageRequestTypeGroups) {
             OWSSyncGroupsMessage *syncGroupsMessage = [[OWSSyncGroupsMessage alloc] init];
-            DataSource *dataSource =
-                [DataSourceValue dataSourceWithSyncMessage:[syncGroupsMessage buildPlainTextAttachmentData]];
+            DataSource *dataSource = [DataSourceValue
+                dataSourceWithSyncMessage:[syncGroupsMessage buildPlainTextAttachmentDataWithTransaction:transaction]];
             [self.messageSender sendTemporaryAttachmentData:dataSource
                 contentType:OWSMimeTypeApplicationOctetStream
                 inMessage:syncGroupsMessage
diff --git a/SignalServiceKit/src/Network/API/OWSUploadingService.m b/SignalServiceKit/src/Network/API/OWSUploadingService.m
index 97127bdb2..3cc067802 100644
--- a/SignalServiceKit/src/Network/API/OWSUploadingService.m
+++ b/SignalServiceKit/src/Network/API/OWSUploadingService.m
@@ -107,9 +107,7 @@ static const CGFloat kAttachmentUploadProgressTheta = 0.001f;
                                          DDLogInfo(@"%@ Uploaded attachment: %p.", self.tag, attachmentStream);
                                          attachmentStream.serverId = serverId;
                                          attachmentStream.isUploaded = YES;
-                                         [attachmentStream save];
-
-                                         successHandlerWrapper();
+                                         [attachmentStream saveAsyncWithCompletionBlock:successHandlerWrapper];
                                      }
                                      failure:failureHandlerWrapper];
 
diff --git a/SignalServiceKit/src/Storage/TSYapDatabaseObject.h b/SignalServiceKit/src/Storage/TSYapDatabaseObject.h
index 07dbcc6f8..cb68f9496 100644
--- a/SignalServiceKit/src/Storage/TSYapDatabaseObject.h
+++ b/SignalServiceKit/src/Storage/TSYapDatabaseObject.h
@@ -81,10 +81,22 @@
 + (instancetype)fetchObjectWithUniqueID:(NSString *)uniqueID NS_SWIFT_NAME(fetch(uniqueId:));
 
 /**
- *  Saves the object with a new YapDatabaseConnection
+ * Saves the object with the shared readWrite connection.
+ *
+ * This method will block if another readWrite transaction is open.
  */
 - (void)save;
 
+/**
+ * Saves the object with the shared readWrite connection - does not block.
+ *
+ * Be mindful that this method may clobber other changes persisted
+ * while waiting to open the readWrite transaction.
+ *
+ * @param completionBlock is called on the main thread
+ */
+- (void)saveAsyncWithCompletionBlock:(void (^_Nullable)(void))completionBlock;
+
 /**
  *  Saves the object with the provided transaction
  *
diff --git a/SignalServiceKit/src/Storage/TSYapDatabaseObject.m b/SignalServiceKit/src/Storage/TSYapDatabaseObject.m
index 032d55b48..ec392ccde 100644
--- a/SignalServiceKit/src/Storage/TSYapDatabaseObject.m
+++ b/SignalServiceKit/src/Storage/TSYapDatabaseObject.m
@@ -37,6 +37,14 @@
     }];
 }
 
+- (void)saveAsyncWithCompletionBlock:(void (^_Nullable)(void))completionBlock
+{
+    [[self dbReadWriteConnection] asyncReadWriteWithBlock:^(YapDatabaseReadWriteTransaction *_Nonnull transaction) {
+        [self saveWithTransaction:transaction];
+    }
+                                          completionBlock:completionBlock];
+}
+
 - (void)touchWithTransaction:(YapDatabaseReadWriteTransaction *)transaction
 {
     [transaction touchObjectForKey:self.uniqueId inCollection:[self.class collection]];