From 689eb8f620aa72ca48d560d816308046c43288cd Mon Sep 17 00:00:00 2001
From: Jiaming Yuan <jm.yuan@outlook.com>
Date: Thu, 8 Jul 2021 02:12:57 +0800
Subject: [PATCH] Check external memory support for exact tree method. (#7088)

---
 src/tree/updater_colmaker.cc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/tree/updater_colmaker.cc b/src/tree/updater_colmaker.cc
index 93bd0189e26b..fd612b04b850 100644
--- a/src/tree/updater_colmaker.cc
+++ b/src/tree/updater_colmaker.cc
@@ -98,6 +98,10 @@ class ColMaker: public TreeUpdater {
       LOG(FATAL) << "Updater `grow_colmaker` or `exact` tree method doesn't "
                     "support distributed training.";
     }
+    if (!dmat->SingleColBlock()) {
+      LOG(FATAL) << "Updater `grow_colmaker` or `exact` tree method doesn't "
+                    "support external memory training.";
+    }
     this->LazyGetColumnDensity(dmat);
     // rescale learning rate according to size of trees
     float lr = param_.learning_rate;