From f211b3278f5f964a7ec0fbc54b92d6cb44aec784 Mon Sep 17 00:00:00 2001
From: Nils Dijk <nils@citusdata.com>
Date: Fri, 18 Jun 2021 13:51:49 +0200
Subject: [PATCH] allow ctid system column

---
 src/backend/columnar/columnar_customscan.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/backend/columnar/columnar_customscan.c b/src/backend/columnar/columnar_customscan.c
index 763625053..d571a33e2 100644
--- a/src/backend/columnar/columnar_customscan.c
+++ b/src/backend/columnar/columnar_customscan.c
@@ -385,9 +385,20 @@ ColumnarAttrNeeded(ScanState *ss)
 
 		if (var->varattno < 0)
 		{
-			ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-							errmsg(
-								"UPDATE and CTID scans not supported for ColumnarScan")));
+			switch (var->varattno)
+			{
+				case SelfItemPointerAttributeNumber:
+				{
+					ereport(DEBUG5, (errmsg("querying ctid")));
+					continue;
+				}
+
+				default:
+				{
+					ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+									errmsg("unsupported system column")));
+				}
+			}
 		}
 
 		if (var->varattno == 0)