Azure Search - Is the count approximate or real?

Question

I am with an Azure Search with around 615k docs. I am getting different counts when using $count when comparing with the previous search based on sql server. O the official doc I could not find any information about it, but here on StackOverflow I’ve found the following:

https://stackoverflow.com/a/47089349

So is the $count approximate or real? Is there any information in the official doc about it that I’ve missed?

Are you checking $count in the response of a search request, or are you calling the docs/$count API? — Bruce Johnston, Jul 03 '18 at 03:45

score 3 · Accepted Answer · answered Jul 03 '18 at 02:59

The count is approximate. From the REST API documentation page:

$count=true | false

Optional, defaults to false. When calling via POST, this parameter is named count instead of $count. Specifies whether to fetch the total count of results. This is the count of all documents that match the search and $filter parameters, ignoring $top and $skip. Setting this value to true may have a performance impact. Note that the count returned is an approximation. If you’d like to get only the count without any documents, you can use $top=0

It seems that microsoft has adjusted the relevant sentence in the REST API documentation to: **Count is accurate if the index is stable, but will under or over-report any documents that are actively added, updated, or deleted.** — lgraf, Aug 22 '22 at 07:11

score 0 · Answer 2 · answered Jul 03 '18 at 17:16

0

The returned count is an approximation. Besides "REST API document", it's documented in ".NET API document" too.

answered Jul 03 '18 at 17:16

rudin

151
3

yeap, but no info in here: https://learn.microsoft.com/en-us/azure/search/search-pagination-page-layout – Thiago Custodio Jul 03 '18 at 20:03

Azure Search - Is the count approximate or real?

2 Answers2