From 9f13008aae92f0163bd1193253800236cc489d4e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lisen=20=E6=9D=A8?= <li.yang@timeplus.io>
Date: Mon, 13 May 2024 14:53:06 +0800
Subject: [PATCH] tweak default sharding rule for one shard stream with primary
 keys

---
 src/Interpreters/Streaming/DDLHelper.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Interpreters/Streaming/DDLHelper.cpp b/src/Interpreters/Streaming/DDLHelper.cpp
index 51a2caadee9..bb2a9706f99 100644
--- a/src/Interpreters/Streaming/DDLHelper.cpp
+++ b/src/Interpreters/Streaming/DDLHelper.cpp
@@ -175,9 +175,9 @@ void prepareEngine(ASTCreateQuery & create, ContextPtr ctx)
     if (expr.empty())
     {
         /// Default sharding expr:
-        /// 1) If has primary keys, default is `weak_hash32(<primary_keys>)`
+        /// 1) If has multiple shards and has primary keys, default is `weak_hash32(<primary_keys>)`
         /// 2) Otherwise, default is `rand()`
-        if (create.storage->primary_key)
+        if (shards > 1 && create.storage->primary_key)
             sharding_expr = makeASTFunction("weak_hash32", create.storage->primary_key->clone());
         else
             sharding_expr = makeASTFunction("rand");