diff --git a/app/sql.js b/app/sql.js
index a448be12a..64cec5cb0 100644
--- a/app/sql.js
+++ b/app/sql.js
@@ -394,9 +394,8 @@ async function updateToSchemaVersion6(currentVersion, instance) {
 
   await instance.run(
     `CREATE TABLE seenMessages(
-      id STRING PRIMARY KEY ASC,
-      expiresAt INTEGER,
-      hash STRING
+      hash STRING PRIMARY KEY,
+      expiresAt INTEGER
     );`
   );
 
@@ -1256,15 +1255,12 @@ async function saveSeenMessageHash(data) {
   } = data;
   await db.run(
     `INSERT INTO seenMessages (
-      id,
       expiresAt,
       hash
     ) values (
-      $id,
       $expiresAt,
       $hash
     );`, {
-      $id: generateUUID(),
       $expiresAt: expiresAt,
       $hash: hash,
     }
diff --git a/libtextsecure/http-resources.js b/libtextsecure/http-resources.js
index 08934dc39..576ae98d9 100644
--- a/libtextsecure/http-resources.js
+++ b/libtextsecure/http-resources.js
@@ -40,6 +40,17 @@
     };
   };
 
+  const filterIncomingMessages = async function filterIncomingMessages(messages) {
+      const incomingHashes = messages.map(m => m.hash);
+      const dupHashes = await window.Signal.Data.getSeenMessagesByHashList(incomingHashes);
+      const newMessages = messages.filter(m => !dupHashes.includes(m.hash));
+      const newHashes = newMessages.map(m => ({
+        expiresAt: m.expiration,
+        hash: m.hash,
+      }));
+      await window.Signal.Data.saveSeenMessageHashes(newHashes);
+      return newMessages;
+  };
 
   window.HttpResource = function HttpResource(_server, opts = {}) {
     server = _server;
@@ -68,19 +79,8 @@
         setTimeout(() => { pollServer(callBack); }, 5000);
         return;
       }
-      const incomingHashes = result.messages.map(m => m.hash);
-      const dupHashes = await window.Signal.Data.getSeenMessagesByHashList(incomingHashes);
-      if (incomingHashes.length === dupHashes.length) {
-        setTimeout(() => { pollServer(callBack); }, 5000);
-        return;
-      }
-      const NewMessages = result.messages.filter(m => !dupHashes.includes(m.hash));
-      const NewHashes = NewMessages.map(m => ({
-        expiresAt: m.expiration,
-        hash: m.hash,
-      }));
-      await window.Signal.Data.saveMessageHashes(NewHashes);
-      NewMessages.forEach(async message => {
+      const newMessages = await filterIncomingMessages(result.messages);
+      newMessages.forEach(async message => {
         const { data } = message;
         const dataPlaintext = stringToArrayBufferBase64(data);
         const messageBuf = textsecure.protobuf.WebSocketMessage.decode(dataPlaintext);