Elasticsearch: count returning wrong value

Question

ES 1.7.3

We have around 20M documents. Each document has a unique ID. When we do a count-request (/index/type/_count) we get around 30K less documents than we indexed.

I checked the existence of each document by making requests on the ID field. Result: there is none missing.

Is there any reasons why _count returns not the exact count?

PS: I read about estimates when doing aggregations. Is this perhaps related?

Answer 1

Coutn API may result in inaccurate results. You can use search_type=count instead. It works in the same way as searching works but returns only count.

Use it like

GET /index/type/_search?search_type=count

Study more about search_type here.

You can also refer to this question