--- a/toolkit/components/url-classifier/nsUrlClassifierDBService.cpp
+++ b/toolkit/components/url-classifier/nsUrlClassifierDBService.cpp
@@ -172,16 +172,20 @@ nsUrlClassifierDBServiceWorker::DoLocalL
 
   LOG(("Found %d results.", results->Length()));
   return NS_OK;
 }
 
 static nsresult
 TablesToResponse(const nsACString& tables)
 {
+  if (tables.IsEmpty()) {
+    return NS_OK;
+  }
+
   // We don't check mCheckMalware and friends because BuildTables never
   // includes a table that is not enabled.
   if (FindInReadable(NS_LITERAL_CSTRING("-malware-"), tables)) {
     return NS_ERROR_MALWARE_URI;
   }
   if (FindInReadable(NS_LITERAL_CSTRING("-phish-"), tables)) {
     return NS_ERROR_PHISHING_URI;
   }
@@ -871,20 +875,21 @@ nsUrlClassifierLookupCallback::LookupCom
   }
 
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsUrlClassifierLookupCallback::CompletionFinished(nsresult status)
 {
-  LOG(("nsUrlClassifierLookupCallback::CompletionFinished [%p, %08x]",
-       this, status));
-  if (NS_FAILED(status)) {
-    NS_WARNING("gethash response failed.");
+  if (LOG_ENABLED()) {
+    nsAutoCString errorName;
+    mozilla::GetErrorName(status, errorName);
+    LOG(("nsUrlClassifierLookupCallback::CompletionFinished [%p, %s]",
+         this, errorName.get()));
   }
 
   mPendingCompletions--;
   if (mPendingCompletions == 0) {
     HandleResults();
   }
 
   return NS_OK;
@@ -947,21 +952,23 @@ nsUrlClassifierLookupCallback::HandleRes
   nsTArray<nsCString> tables;
   // Build a stringified list of result tables.
   for (uint32_t i = 0; i < mResults->Length(); i++) {
     LookupResult& result = mResults->ElementAt(i);
 
     // Leave out results that weren't confirmed, as their existence on
     // the list can't be verified.  Also leave out randomly-generated
     // noise.
-    if (!result.Confirmed()) {
-      LOG(("Skipping result from table %s (not confirmed)", result.mTableName.get()));
+    if (result.mNoise) {
+      LOG(("Skipping result %X from table %s (noise)",
+           result.hash.prefix.ToUint32(), result.mTableName.get()));
       continue;
-    } else if (result.mNoise) {
-      LOG(("Skipping result from table %s (noise)", result.mTableName.get()));
+    } else if (!result.Confirmed()) {
+      LOG(("Skipping result %X from table %s (not confirmed)",
+           result.hash.prefix.ToUint32(), result.mTableName.get()));
       continue;
     }
 
     LOG(("Confirmed result %X from table %s",
          result.hash.prefix.ToUint32(), result.mTableName.get()));
 
     if (tables.IndexOf(result.mTableName) == nsTArray<nsCString>::NoIndex) {
       tables.AppendElement(result.mTableName);