diff --git a/src/gxs/rsdataservice.cc b/src/gxs/rsdataservice.cc
index 1db2f77c2..022704740 100644
--- a/src/gxs/rsdataservice.cc
+++ b/src/gxs/rsdataservice.cc
@@ -47,6 +47,11 @@
 
 #define MSG_INDEX_GRPID std::string("INDEX_MESSAGES_GRPID")
 
+// Maximum number of message ids packed into a single "IN (...)" clause. Keeps
+// the generated SQL and sqlite's expression tree to a sane size while making
+// the per-statement preparation cost negligible.
+static const uint32_t MAX_MSG_IDS_PER_QUERY = 500;
+
 // generic
 #define KEY_NXS_DATA        std::string("nxsData")
 #define KEY_NXS_DATA_LEN    std::string("nxsDataLen")
@@ -1205,14 +1210,28 @@ int RsDataService::retrieveNxsMsgs(const GxsMsgReq &reqIds, GxsMsgResult &msg,
 		{
 			RS_STACK_MUTEX(mDbMutex);
 
-            // request each grp
-			for( std::set<RsGxsMessageId>::const_iterator sit = msgIdV.begin();
-			     sit!=msgIdV.end();++sit )
-			{
-                const RsGxsMessageId& msgId = *sit;
+            // Retrieve the requested messages in batches, using a single
+            // "msgId IN (...)" clause per batch. Preparing one statement per
+            // message dominates the cost as soon as a request covers more than
+            // a handful of them (a channel post and its comments, a forum
+            // thread, a filtered group request).
 
-                RetroCursor* c = mDb->sqlQuery(MSG_TABLE_NAME, withMeta ? mMsgColumnsWithMeta : mMsgColumns, KEY_GRP_ID+ "='" + grpId.toStdString()
-                                               + "' AND " + KEY_MSG_ID + "='" + msgId.toStdString() + "'", "");
+            const std::string selection_prefix = KEY_GRP_ID + "='" + grpId.toStdString()
+                                               + "' AND " + KEY_MSG_ID + " IN (";
+
+            for(auto sit = msgIdV.begin(); sit != msgIdV.end(); )
+            {
+                std::string selection = selection_prefix;
+
+                for(uint32_t i=0; i<MAX_MSG_IDS_PER_QUERY && sit!=msgIdV.end(); ++i,++sit)
+                {
+                    if(i > 0) selection += ",";
+                    selection += "'" + sit->toStdString() + "'";
+                }
+
+                selection += ")";
+
+                RetroCursor* c = mDb->sqlQuery(MSG_TABLE_NAME, withMeta ? mMsgColumnsWithMeta : mMsgColumns, selection, "");
                 ++prof_queries;
 
                 if(c)