fix: handle table_schema = '' without failing

Signed-off-by: Andres Taylor <andres@planetscale.com>
vitessio · May 9, 2024 · 9dce594 · 9dce594
1 parent cf8039e
commit 9dce594
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Showing 3 changed files with 11 additions and 8 deletions.
diff --git a/go/test/endtoend/vtgate/queries/informationschema/informationschema_test.go b/go/test/endtoend/vtgate/queries/informationschema/informationschema_test.go
@@ -201,6 +201,10 @@ func TestMultipleSchemaPredicates(t *testing.T) {
 	_, err := mcmp.VtConn.ExecuteFetch(query, 1000, true)
 	require.Error(t, err)
 	require.Contains(t, err.Error(), "specifying two different database in the query is not supported")
+
+	if utils.BinaryIsAtLeastAtVersion(20, "vtgate") {
+		_, _ = mcmp.ExecNoCompare("select * from information_schema.columns where table_schema = '' limit 1")
+	}
 }
 
 func TestInfrSchemaAndUnionAll(t *testing.T) {

diff --git a/go/vt/vtgate/engine/routing.go b/go/vt/vtgate/engine/routing.go
@@ -192,22 +192,21 @@ func (rp *RoutingParameters) routeInfoSchemaQuery(ctx context.Context, vcursor V
 
 	env := evalengine.NewExpressionEnv(ctx, bindVars, vcursor)
 	var specifiedKS string
-	for _, tableSchema := range rp.SysTableTableSchema {
+	for idx, tableSchema := range rp.SysTableTableSchema {
 		result, err := env.Evaluate(tableSchema)
 		if err != nil {
 			return nil, err
 		}
 		ks := result.Value(vcursor.ConnCollation()).ToString()
-		if specifiedKS == "" {
+		switch {
+		case idx == 0:
 			specifiedKS = ks
-		}
-		if specifiedKS != ks {
+		case specifiedKS != ks:
 			return nil, vterrors.Errorf(vtrpcpb.Code_UNIMPLEMENTED, "specifying two different database in the query is not supported")
 		}
 	}
-	if specifiedKS != "" {
-		bindVars[sqltypes.BvSchemaName] = sqltypes.StringBindVariable(specifiedKS)
-	}
+
+	bindVars[sqltypes.BvSchemaName] = sqltypes.StringBindVariable(specifiedKS)
 
 	tableNames := map[string]string{}
 	for tblBvName, sysTableName := range rp.SysTableTableName {

diff --git a/go/vt/vtgate/planbuilder/testdata/onecase.json b/go/vt/vtgate/planbuilder/testdata/onecase.json
@@ -1,7 +1,7 @@
 [
   {
     "comment": "Add your test case here for debugging and run go test -run=One.",
-    "query": "",
+    "query": "select table_schema, table_name, ordinal_position from information_schema.columns where table_schema = '' limit 1",
     "plan": {
 
     }