Why does an error occur when a method is called frequently?

Question

Dart

foo() async {
  await db.KVToTableInsert(tableToInsert, jsonMap);
  }

Inside `KVToTableInsert` a set of SQL Insert statements is generated.
I pull the foo method in the microservice in this way:

app.post('/foo', (req, res) async {
    dbEnums insertResult = await matchQuery.foo("tablename", req.body);

I have a feeling that when many requests come in at the same time, KVToTableInsert, without having time to process one, starts processing another request and this leads to errors. because I get errors that it is trying to insert the result into a table from another query (KVToTableInsert stores the table name in itself).

Question. Am I right. How to fix. And how to organize such code correctly.