We have 200k records. When running search query for the first time with size: 500 I am getting results in doc-1, doc-2, doc-3. But when I run the same search query for the second time I am getting the order changed to doc-2, doc-1, etc ... why the search result order varies each time when we run the same query ?
Without knowing the mapping, query and content of your index it's rather hard to guess at what's going on there.
Did you try using the explain API:
To figure out why your documents are sorted the way they are sorted?
Other than that, maybe you can come up with a minimal curl reproduction of your problem that doesn't involve first indexing 200k documents so others can have a look...
Hope this helps,
Response order is not guaranteed in searches as far as I understand. It returns results in terms of scoring.