From b62b3108641cc5cd03dd439115dbc798cd7d6c60 Mon Sep 17 00:00:00 2001
From: Dayue Gao <gaodayue@meituan.com>
Date: Sat, 9 May 2020 11:01:48 +0800
Subject: [PATCH] [Bug] Fix BE crash when input to hll_merge is null (#3521)

---
 be/src/exprs/hll_function.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/be/src/exprs/hll_function.cpp b/be/src/exprs/hll_function.cpp
index e18f177429..849cf691e2 100644
--- a/be/src/exprs/hll_function.cpp
+++ b/be/src/exprs/hll_function.cpp
@@ -64,6 +64,9 @@ void HllFunctions::hll_update(FunctionContext *, const T &src, StringVal* dst) {
 }
 
 void HllFunctions::hll_merge(FunctionContext*, const StringVal& src, StringVal* dst) {
+    if (src.is_null) {
+        return;
+    }
     auto* dst_hll = reinterpret_cast<HyperLogLog*>(dst->ptr);
     // zero size means the src input is a agg object
     if (src.len == 0) {
@@ -81,6 +84,9 @@ BigIntVal HllFunctions::hll_finalize(FunctionContext*, const StringVal &src) {
 }
 
 BigIntVal HllFunctions::hll_get_value(FunctionContext*, const StringVal &src) {
+    if (src.is_null) {
+        return BigIntVal::null();
+    }
     auto* src_hll = reinterpret_cast<HyperLogLog*>(src.ptr);
     BigIntVal result(src_hll->estimate_cardinality());
     return result;