diff --git a/pkg/ddl/partition.go b/pkg/ddl/partition.go
index 4b0a43d451b90..1f35c7960cd25 100644
--- a/pkg/ddl/partition.go
+++ b/pkg/ddl/partition.go
@@ -33,6 +33,7 @@ import (
 	"github.com/pingcap/tidb/pkg/ddl/placement"
 	"github.com/pingcap/tidb/pkg/domain/infosync"
 	"github.com/pingcap/tidb/pkg/expression"
+	"github.com/pingcap/tidb/pkg/expression/contextstatic"
 	"github.com/pingcap/tidb/pkg/infoschema"
 	"github.com/pingcap/tidb/pkg/kv"
 	"github.com/pingcap/tidb/pkg/meta"
@@ -59,7 +60,6 @@ import (
 	"github.com/pingcap/tidb/pkg/util/dbterror"
 	"github.com/pingcap/tidb/pkg/util/hack"
 	"github.com/pingcap/tidb/pkg/util/mathutil"
-	"github.com/pingcap/tidb/pkg/util/mock"
 	decoder "github.com/pingcap/tidb/pkg/util/rowDecoder"
 	"github.com/pingcap/tidb/pkg/util/slice"
 	"github.com/pingcap/tidb/pkg/util/stringutil"
@@ -4258,9 +4258,9 @@ func (cns columnNameSlice) At(i int) string {
 }
 
 func isPartExprUnsigned(ectx expression.EvalContext, tbInfo *model.TableInfo) bool {
-	// We should not rely on any configuration, system or session variables, so use a mock ctx!
+	// We should not rely on any configuration, system or session variables, so use a default context.
 	// Same as in tables.newPartitionExpr
-	ctx := mock.NewContext()
+	ctx := contextstatic.NewStaticExprContext()
 	expr, err := expression.ParseSimpleExpr(ctx, tbInfo.Partition.Expr, expression.WithTableInfo("", tbInfo))
 	if err != nil {
 		logutil.DDLLogger().Error("isPartExpr failed parsing expression!", zap.Error(err))
diff --git a/pkg/table/tables/BUILD.bazel b/pkg/table/tables/BUILD.bazel
index 84cbc629f1ef2..4392c47fcd9bd 100644
--- a/pkg/table/tables/BUILD.bazel
+++ b/pkg/table/tables/BUILD.bazel
@@ -18,6 +18,7 @@ go_library(
         "//pkg/errno",
         "//pkg/expression",
         "//pkg/expression/context",
+        "//pkg/expression/contextstatic",
         "//pkg/kv",
         "//pkg/meta",
         "//pkg/meta/autoid",
@@ -43,7 +44,6 @@ go_library(
         "//pkg/util/generatedexpr",
         "//pkg/util/hack",
         "//pkg/util/logutil",
-        "//pkg/util/mock",
         "//pkg/util/ranger",
         "//pkg/util/rowcodec",
         "//pkg/util/sqlexec",
diff --git a/pkg/table/tables/partition.go b/pkg/table/tables/partition.go
index 0525258813866..1c6bf4b4af3ca 100644
--- a/pkg/table/tables/partition.go
+++ b/pkg/table/tables/partition.go
@@ -29,6 +29,7 @@ import (
 	"github.com/pingcap/errors"
 	"github.com/pingcap/tidb/pkg/errctx"
 	"github.com/pingcap/tidb/pkg/expression"
+	"github.com/pingcap/tidb/pkg/expression/contextstatic"
 	"github.com/pingcap/tidb/pkg/kv"
 	"github.com/pingcap/tidb/pkg/parser"
 	"github.com/pingcap/tidb/pkg/parser/ast"
@@ -44,7 +45,6 @@ import (
 	"github.com/pingcap/tidb/pkg/util/dbterror"
 	"github.com/pingcap/tidb/pkg/util/hack"
 	"github.com/pingcap/tidb/pkg/util/logutil"
-	"github.com/pingcap/tidb/pkg/util/mock"
 	"github.com/pingcap/tidb/pkg/util/ranger"
 	"github.com/pingcap/tidb/pkg/util/stringutil"
 	"go.uber.org/zap"
@@ -240,8 +240,8 @@ func initPartition(t *partitionedTable, def model.PartitionDefinition) (*partiti
 
 func newPartitionExpr(tblInfo *model.TableInfo, tp model.PartitionType, expr string, partCols []model.CIStr, defs []model.PartitionDefinition) (*PartitionExpr, error) {
 	// a partitioned table cannot rely on session context/sql modes, so use a default one!
-	ctx := mock.NewContext()
-	dbName := model.NewCIStr(ctx.GetSessionVars().CurrentDB)
+	ctx := contextstatic.NewStaticExprContext()
+	dbName := model.NewCIStr(ctx.GetEvalCtx().CurrentDB())
 	columns, names, err := expression.ColumnInfos2ColumnsAndNames(ctx, dbName, tblInfo.Name, tblInfo.Cols(), tblInfo)
 	if err != nil {
 		return nil, err