From 10f19a12068f00809165f34bda6bf47d5d40d4eb Mon Sep 17 00:00:00 2001
From: Gavin Halliday <gavin.halliday@lexisnexis.com>
Date: Fri, 8 Nov 2024 17:40:25 +0000
Subject: [PATCH] HPCC-32759 Fix deadlock in unordered concat activity with
 rows > 2MB

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
---
 thorlcr/activities/funnel/thfunnelslave.cpp | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/thorlcr/activities/funnel/thfunnelslave.cpp b/thorlcr/activities/funnel/thfunnelslave.cpp
index 32962951c52..87e1802f0d6 100644
--- a/thorlcr/activities/funnel/thfunnelslave.cpp
+++ b/thorlcr/activities/funnel/thfunnelslave.cpp
@@ -246,10 +246,22 @@ class CParallelFunnel : implements IRowStream, public CSimpleInterface
     }
     void informEos(unsigned input)
     {
-        CriticalBlock b(crit);
-        eoss++;
-        if (eoss == inputHandlers.ordinality())
-            rows.enqueue(NULL);
+        unsigned numToSignal = 0;
+        {
+            CriticalBlock b(crit);
+            eoss++;
+            if (eoss == inputHandlers.ordinality())
+                rows.enqueue(NULL);
+            // If the row sizes are very large then it is possible that other threads are waiting
+            // signal one of them that it can continue - because this thread will add no more records (HPCC-32759)
+            if (waiting && (totSize <= FUNNEL_MIN_BUFF_SIZE))
+            {
+                numToSignal = 1;
+                waiting--;
+            }
+        }
+        if (numToSignal)
+            fullSem.signal(numToSignal);
     }
     void abort()
     {