diff --git a/roxie/ccd/ccd.hpp b/roxie/ccd/ccd.hpp
index 7da23b7d033..af0d00649eb 100644
--- a/roxie/ccd/ccd.hpp
+++ b/roxie/ccd/ccd.hpp
@@ -314,6 +314,8 @@ extern bool blockedLocalAgent;
 extern bool acknowledgeAllRequests;
 extern unsigned packetAcknowledgeTimeout;
 extern cycle_t dynPriorityAdjustCycles;
+extern bool traceThreadStartDelay;
+extern int adjustBGThreadNiceValue;
 extern bool alwaysTrustFormatCrcs;
 extern bool allFilesDynamic;
 extern bool lockSuperFiles;
diff --git a/roxie/ccd/ccdmain.cpp b/roxie/ccd/ccdmain.cpp
index 92db1614993..0c00c4f98b2 100644
--- a/roxie/ccd/ccdmain.cpp
+++ b/roxie/ccd/ccdmain.cpp
@@ -76,6 +76,8 @@ bool blockedLocalAgent = true;
 bool acknowledgeAllRequests = true;
 unsigned packetAcknowledgeTimeout = 100;
 cycle_t dynPriorityAdjustCycles = 0;   // default off (0)
+bool traceThreadStartDelay = true;
+int adjustBGThreadNiceValue = 5;
 unsigned ccdMulticastPort;
 bool enableHeartBeat = true;
 unsigned parallelLoopFlowLimit = 100;
@@ -1010,6 +1012,12 @@ int CCD_API roxie_main(int argc, const char *argv[], const char * defaultYaml)
         unsigned dynAdjustMsec = topology->getPropInt("@dynPriorityAdjustTime", 0);
         if (dynAdjustMsec)
             dynPriorityAdjustCycles = dynAdjustMsec * (queryOneSecCycles() / 1000ULL);
+        traceThreadStartDelay = topology->getPropBool("@traceThreadStartDelay", traceThreadStartDelay);
+        adjustBGThreadNiceValue = topology->getPropInt("@adjustBGThreadNiceValue", adjustBGThreadNiceValue);
+        if (adjustBGThreadNiceValue < 0)
+            adjustBGThreadNiceValue = 0;
+        if (adjustBGThreadNiceValue > 19)
+            adjustBGThreadNiceValue = 19;
         ccdMulticastPort = topology->getPropInt("@multicastPort", CCD_MULTICAST_PORT);
         statsExpiryTime = topology->getPropInt("@statsExpiryTime", 3600);
         roxiemem::setMemTraceSizeLimit((memsize_t) topology->getPropInt64("@memTraceSizeLimit", 0));
diff --git a/roxie/ccd/ccdqueue.cpp b/roxie/ccd/ccdqueue.cpp
index 0918f6df969..7046420cc08 100644
--- a/roxie/ccd/ccdqueue.cpp
+++ b/roxie/ccd/ccdqueue.cpp
@@ -1188,6 +1188,13 @@ class RoxieQueue : public CInterface, implements IThreadFactory
         if (qname && *qname)
             tname.appendf(" (%s)", qname);
         workers.setown(createThreadPool(tname.str(), this, false, nullptr, numWorkers));
+        if (traceThreadStartDelay)
+            workers->setStartDelayTracing(60);
+        if (qname && *qname)
+        {
+            if (streq(qname, "BG"))
+                workers->setNiceValue(adjustBGThreadNiceValue);
+        }
         started = 0;
         idle = 0;
         if (IBYTIbufferSize)
@@ -1893,7 +1900,7 @@ class RoxieReceiverBase : implements IRoxieOutputQueueManager, public CInterface
 public:
     IMPLEMENT_IINTERFACE;
 
-    RoxieReceiverBase(unsigned _numWorkers) : slaQueue(_numWorkers, "SLA"), hiQueue(_numWorkers, "HIGH"), loQueue(_numWorkers, "LOW"), bgQueue(_numWorkers/2 + 1, "BG"), numWorkers(_numWorkers)
+    RoxieReceiverBase(unsigned _numWorkers) : slaQueue(_numWorkers, "SLA"), hiQueue(_numWorkers, "HIGH"), loQueue(_numWorkers, "LOW"), bgQueue(_numWorkers, "BG"), numWorkers(_numWorkers)
     {
     }
 
@@ -1902,7 +1909,7 @@ class RoxieReceiverBase : implements IRoxieOutputQueueManager, public CInterface
         loQueue.start();
         hiQueue.start();
         slaQueue.start();
-        bgQueue.start(); // consider nice(+3) BG threads
+        bgQueue.start(); // NB BG thread priority can be adjusted
     }
 
     virtual void stop() 
diff --git a/roxie/ccd/ccdserver.cpp b/roxie/ccd/ccdserver.cpp
index a4d611da13f..c17b2ecd5e7 100644
--- a/roxie/ccd/ccdserver.cpp
+++ b/roxie/ccd/ccdserver.cpp
@@ -4611,6 +4611,7 @@ class CRemoteResultAdaptor : implements IEngineRowStream, implements IFinalRoxie
                 ctx->queryOptions().dynPriority = QUERY_BG_PRIORITY_VALUE;
                 unsigned dynAdjustMsec = (dynPriorityAdjustCycles * 1000ULL) / queryOneSecCycles();
                 UWARNLOG("WARNING: %d msec dynamic adjustment threshold reached, shifting query to BG queue", dynAdjustMsec);
+                p->queryHeader().activityId &= ~ROXIE_PRIORITY_MASK;
                 p->queryHeader().activityId |= ROXIE_BG_PRIORITY;
                 // TODO: what to do about still running activities' continuation/ack priorities ?
             }
diff --git a/system/jlib/jthread.cpp b/system/jlib/jthread.cpp
index 8545d2bd641..769f04e9595 100644
--- a/system/jlib/jthread.cpp
+++ b/system/jlib/jthread.cpp
@@ -995,6 +995,7 @@ class CThreadPool: public CThreadPoolBase, implements IThreadPool, public CInter
     unsigned stacksize;
     unsigned timeoutOnRelease;
     unsigned traceStartDelayPeriod = 0;
+    int niceValue = 0;
     unsigned startsInPeriod = 0;
     cycle_t startDelayInPeriod = 0;
     CCycleTimer overAllTimer;
@@ -1114,6 +1115,8 @@ class CThreadPool: public CThreadPoolBase, implements IThreadPool, public CInter
         CPooledThreadWrapper &ret = *new CPooledThreadWrapper(*this,newid,factory->createNew());
         if (stacksize)
             ret.setStackSize(stacksize);
+        if (niceValue)
+            ret.setNice(niceValue);
         ret.start(false);
         threadwrappers.append(ret);
         return ret;
@@ -1281,6 +1284,10 @@ class CThreadPool: public CThreadPoolBase, implements IThreadPool, public CInter
     {
         traceStartDelayPeriod = secs;
     }
+    void setNiceValue(int value)
+    {
+        niceValue = value;
+    }
     bool waitAvailable(unsigned timeout)
     {
         if (!defaultmax)
diff --git a/system/jlib/jthread.hpp b/system/jlib/jthread.hpp
index 5d312aa9d2f..b48dff635a1 100644
--- a/system/jlib/jthread.hpp
+++ b/system/jlib/jthread.hpp
@@ -289,6 +289,7 @@ interface IThreadPool : extends IInterface
         virtual unsigned runningCount()=0;                  // number of currently running threads
         virtual PooledThreadHandle startNoBlock(void *param)=0; // starts a new thread if it can do so without blocking, else throws exception
         virtual void setStartDelayTracing(unsigned secs) = 0;        // set start delay tracing period
+        virtual void setNiceValue(int value) = 0;                    // set priority for thread
         virtual bool waitAvailable(unsigned timeout) = 0;            // wait until a pool member is available
 };