pingcap · ti-chi-bot · Nov 20, 2024 · Nov 28, 2024
diff --git a/DEPS.bzl b/DEPS.bzl
@@ -4179,8 +4179,8 @@ def go_deps():
         name = "com_github_tikv_client_go_v2",
         build_file_proto_mode = "disable_global",
         importpath = "github.com/tikv/client-go/v2",
-        sum = "h1:DeZMstuDPx80CNsJdmN47biH+8PL5qK4TmTyNcDRDdI=",
-        version = "v2.0.8-0.20241111142004-e10335846244",
+        sum = "h1:R7aDTnYD3+MNiSUsOzcmCfPuDevCZHrcl52MdBcwx3k=",
+        version = "v2.0.8-0.20241125064438-6e8281b62eae",
     )
     go_repository(
         name = "com_github_tikv_pd",

diff --git a/executor/adapter.go b/executor/adapter.go
@@ -590,7 +590,7 @@ func (a *ExecStmt) handleStmtForeignKeyTrigger(ctx context.Context, e Executor)
 	if stmtCtx.ForeignKeyTriggerCtx.HasFKCascades {
 		// If the ExecStmt has foreign key cascade to be executed, we need call `StmtCommit` to commit the ExecStmt itself
 		// change first.
-		// Since `UnionScanExec` use `SnapshotIter` and `SnapshotGetter` to read txn mem-buffer, if we don't  do `StmtCommit`,
+		// Since `UnionScanExec` use `SnapshotIter` and `SnapshotGetter` to read txn mem-buffer, if we don't do `StmtCommit`,
 		// then the fk cascade executor can't read the mem-buffer changed by the ExecStmt.
 		a.Ctx.StmtCommit(ctx)
 	}

diff --git a/executor/union_scan_test.go b/executor/union_scan_test.go
@@ -595,6 +595,21 @@ func TestIssue36903(t *testing.T) {
 	tk.MustQuery("select pkey from t_vwvgdc where 0 <> 0 union select pkey from t_vwvgdc;").Sort().Check(testkit.Rows("15000", "228000"))
 }
 
+func TestSnapshotWithConcurrentWrite(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("create table t1 (id int auto_increment key, b int, index(b));")
+
+	tk.MustExec("begin")
+	tk.MustExec("insert into t1 (b) values (1),(2),(3),(4),(5),(6),(7),(8);")
+	for j := 0; j < 16; j++ {
+		tk.MustExec("insert into t1 (b) select /*+ use_index(t1, b) */ id from t1;")
+	}
+	tk.MustQuery("select count(1) from t1").Check(testkit.Rows("524288")) // 8 * 2^16 rows
+	tk.MustExec("rollback")
+}
+
 func BenchmarkUnionScanRead(b *testing.B) {
 	store := testkit.CreateMockStore(b)
 

diff --git a/go.mod b/go.mod
@@ -94,7 +94,7 @@ require (
 	github.com/stretchr/testify v1.8.2
 	github.com/tdakkota/asciicheck v0.2.0
 	github.com/tiancaiamao/appdash v0.0.0-20181126055449-889f96f722a2
-	github.com/tikv/client-go/v2 v2.0.8-0.20241111142004-e10335846244
+	github.com/tikv/client-go/v2 v2.0.8-0.20241125064438-6e8281b62eae
 	github.com/tikv/pd/client v0.0.0-20240725070735-fb162bf0aa3f
 	github.com/timakin/bodyclose v0.0.0-20221125081123-e39cf3fc478e
 	github.com/twmb/murmur3 v1.1.6

diff --git a/go.sum b/go.sum
@@ -968,8 +968,8 @@ github.com/tiancaiamao/appdash v0.0.0-20181126055449-889f96f722a2 h1:mbAskLJ0oJf
 github.com/tiancaiamao/appdash v0.0.0-20181126055449-889f96f722a2/go.mod h1:2PfKggNGDuadAa0LElHrByyrz4JPZ9fFx6Gs7nx7ZZU=
 github.com/tiancaiamao/gp v0.0.0-20221230034425-4025bc8a4d4a h1:J/YdBZ46WKpXsxsW93SG+q0F8KI+yFrcIDT4c/RNoc4=
 github.com/tiancaiamao/gp v0.0.0-20221230034425-4025bc8a4d4a/go.mod h1:h4xBhSNtOeEosLJ4P7JyKXX7Cabg7AVkWCK5gV2vOrM=
-github.com/tikv/client-go/v2 v2.0.8-0.20241111142004-e10335846244 h1:DeZMstuDPx80CNsJdmN47biH+8PL5qK4TmTyNcDRDdI=
-github.com/tikv/client-go/v2 v2.0.8-0.20241111142004-e10335846244/go.mod h1:45NuHB8x+VAoztMIjF6hEgXvPQXhXWPfMxDg0N8CoRY=
+github.com/tikv/client-go/v2 v2.0.8-0.20241125064438-6e8281b62eae h1:R7aDTnYD3+MNiSUsOzcmCfPuDevCZHrcl52MdBcwx3k=
+github.com/tikv/client-go/v2 v2.0.8-0.20241125064438-6e8281b62eae/go.mod h1:45NuHB8x+VAoztMIjF6hEgXvPQXhXWPfMxDg0N8CoRY=
 github.com/tikv/pd/client v0.0.0-20240725070735-fb162bf0aa3f h1:Szw9YxqGGEneSniBd4ep09jgB77cKUy+AuhKOmdGPdE=
 github.com/tikv/pd/client v0.0.0-20240725070735-fb162bf0aa3f/go.mod h1:QCBn54O5lhfkYfxj8Tyiqaxue/mthHEMyi7AqJP/+n4=
 github.com/timakin/bodyclose v0.0.0-20221125081123-e39cf3fc478e h1:MV6KaVu/hzByHP0UvJ4HcMGE/8a6A4Rggc/0wx2AvJo=

diff --git a/pkg/sessionctx/BUILD.bazel b/pkg/sessionctx/BUILD.bazel
diff --git a/session/sessiontest/session_test.go b/session/sessiontest/session_test.go
@@ -3685,3 +3685,74 @@ func TestPrepareExecuteWithSQLHints(t *testing.T) {
 		}
 	}
 }
+
+func TestMemBufferSnapshotRead(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+
+	tk.MustExec("drop table if exists t;")
+	tk.MustExec("create table t(a int primary key, b int, index i(b));")
+
+	tk.MustExec("set session tidb_distsql_scan_concurrency = 1;")
+	tk.MustExec("set session tidb_index_lookup_join_concurrency = 1;")
+	tk.MustExec("set session tidb_projection_concurrency=1;")
+	tk.MustExec("set session tidb_init_chunk_size=1;")
+	tk.MustExec("set session tidb_max_chunk_size=40;")
+	tk.MustExec("set session tidb_index_join_batch_size = 10")
+
+	tk.MustExec("begin;")
+	// write (0, 0), (1, 1), ... ,(100, 100) into membuffer
+	var sb strings.Builder
+	sb.WriteString("insert into t values ")
+	for i := 0; i <= 100; i++ {
+		if i > 0 {
+			sb.WriteString(", ")
+		}
+		sb.WriteString(fmt.Sprintf("(%d, %d)", i, i))
+	}
+	tk.MustExec(sb.String())
+
+	// insert on duplicate key statement should update the table to (0, 100), (1, 99), ... (100, 0)
+	// This statement will create UnionScan dynamically during execution, and some UnionScan will see staging data(should be bypassed),
+	// so it relies on correct snapshot read to get the expected result.
+	tk.MustExec("insert into t (select /*+ INL_JOIN(t1) */ 100 - t1.a as a, t1.b from t t1, (select a, b from t) t2 where t1.b = t2.b) on duplicate key update b = values(b)")
+
+	require.Empty(t, tk.MustQuery("select a, b from t where a + b != 100;").Rows())
+	tk.MustExec("commit;")
+	require.Empty(t, tk.MustQuery("select a, b from t where a + b != 100;").Rows())
+
+	tk.MustExec("set session tidb_distsql_scan_concurrency = default;")
+	tk.MustExec("set session tidb_index_lookup_join_concurrency = default;")
+	tk.MustExec("set session tidb_projection_concurrency=default;")
+	tk.MustExec("set session tidb_init_chunk_size=default;")
+	tk.MustExec("set session tidb_max_chunk_size=default;")
+	tk.MustExec("set session tidb_index_join_batch_size = default")
+}
+
+func TestMemBufferCleanupMemoryLeak(t *testing.T) {
+	// Test if cleanup memory will cause a memory leak.
+	// When an in-txn statement fails, TiDB cleans up the mutations from this statement.
+	// If there's a memory leak, the memory usage could increase uncontrollably with retries.
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("create table t(a varchar(255) primary key)")
+	key1 := strings.Repeat("a", 255)
+	key2 := strings.Repeat("b", 255)
+	tk.MustExec(`set global tidb_mem_oom_action='cancel'`)
+	tk.MustExec("set session tidb_mem_quota_query=10240")
+	tk.MustExec("begin")
+	tk.MustExec("insert into t values(?)", key2)
+	for i := 0; i < 100; i++ {
+		// The insert statement will fail because of the duplicate key error.
+		err := tk.ExecToErr("insert into t values(?), (?)", key1, key2)
+		require.Error(t, err)
+		if strings.Contains(err.Error(), "Duplicate") {
+			continue
+		}
+		require.NoError(t, err)
+	}
+	tk.MustExec("commit")
+}