如何使用c#更快地从Oracle中插入400万条记录到Elasticsearch表中?

I have the following code written in C# but according to that, it would take me 4-5 days to migrate the data from Oracle database to Elasticsearch. I am inserting the records in batches of 100. Is there any other way that the migration of the 4 million records takes place faster (probably in less than a day, if possible)?I have the following code written in C# but acc