Fix: fatal error: concurrent map iteration and map write (Schema.Fields) (#1466)

This PR fixes the concurrent access bug. Query execution should use a
copy of the schema. The schema can be changed during that process.
Common table processing was OK.

Author: nablaone

platform/frontend_connectors/search_test.go

@@ -272,7 +272,7 @@ func TestSearchHandler(t *testing.T) {
 		"user.id":                         {PropertyName: "user.id", InternalPropertyName: "user_id", Type: schema.QuesmaTypeKeyword},
 		"tags":                            {PropertyName: "tags", InternalPropertyName: "tags", Type: schema.QuesmaTypeKeyword},
 		"age":                             {PropertyName: "age", InternalPropertyName: "age", Type: schema.QuesmaTypeInteger},
-		"host.name":                       {PropertyName: "host.name", InternalPropertyName: "host_name", Type: schema.QuesmaTypeObject},
+		"host.name":                       {PropertyName: "host.name", InternalPropertyName: "host_name", Type: schema.QuesmaTypeKeyword},
 		"status":                          {PropertyName: "status", InternalPropertyName: "status", Type: schema.QuesmaTypeKeyword},
 		"namespace":                       {PropertyName: "namespace", InternalPropertyName: "namespace", Type: schema.QuesmaTypeKeyword},
 		"namespaces":                      {PropertyName: "namespaces", InternalPropertyName: "namespaces", Type: schema.QuesmaTypeKeyword},

platform/frontend_connectors/search_util.go

@@ -110,7 +110,27 @@ func (q *QueryRunner) resolveIndexesNonCommonTable(ctx context.Context, clickhou
 		return
 	}
 
-	currentSchema = resolvedSchema
+	// Clone the resolved schema to currentSchema
+	//
+	// Schema can be modified during the query execution, we don't want to modify the original schema, and we don't need any concurrency issues here.
+	//
+	// resolveIndexesCommonTable also returns an ephemeral schema
+
+	currentSchema = schema.Schema{
+		Fields:             make(map[schema.FieldName]schema.Field),
+		Aliases:            make(map[schema.FieldName]schema.FieldName),
+		ExistsInDataSource: resolvedSchema.ExistsInDataSource,
+		DatabaseName:       resolvedSchema.DatabaseName,
+	}
+
+	for fieldName, field := range resolvedSchema.Fields {
+		currentSchema.Fields[fieldName] = field
+	}
+
+	for aliasName, targetFieldName := range resolvedSchema.Aliases {
+		currentSchema.Aliases[aliasName] = targetFieldName
+	}
+
 	return
 }