From 8a0b68f25ed333758c95319828831dff329718c2 Mon Sep 17 00:00:00 2001
From: Alexey Antipovsky <alexey.vladimirovich@mariadb.com>
Date: Wed, 23 Jun 2021 12:56:38 +0300
Subject: [PATCH] [MCOL-4709] Fix UB in disk aggregation

---
 utils/rowgroup/rowstorage.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/utils/rowgroup/rowstorage.cpp b/utils/rowgroup/rowstorage.cpp
index b7a64e3f8..7c9522f78 100644
--- a/utils/rowgroup/rowstorage.cpp
+++ b/utils/rowgroup/rowstorage.cpp
@@ -660,6 +660,19 @@ public:
     fLRU->clear();
     fMM->release();
     fRGDatas.clear();
+
+    // we need at least one RGData so create it right now
+    auto* curRG = new RGData(*fRowGroupOut, fMaxRows);
+    fRowGroupOut->setData(curRG);
+    fRowGroupOut->resetRowGroup(0);
+    fRGDatas.emplace_back(curRG);
+    auto memSz = fRowGroupOut->getSizeWithStrings(fMaxRows);
+    if (!fMM->acquire(memSz))
+    {
+      throw logging::IDBExcept(logging::IDBErrorInfo::instance()->errorMsg(
+          logging::ERR_AGGREGATION_TOO_BIG),
+                               logging::ERR_AGGREGATION_TOO_BIG);
+    }
     ++fGeneration;
   }