Elastic Search GET没有提供最新文档

Question

I am using Elastic 5.1.2 version. I am using Elastic java Restclient for posting and query the documents from Elastic search.

I am not getting the accurate count of documents when i use GET operation immediately after the POST operation. If i sleep for > 1 sec between POST and GET, then the GET operation is able to give the accurate count.

My flow of operations are: 1) post a new transaction(document) using POST operation. 2) retrieve the count of total documents using GET operation. this is immediately after the POST.

I am thinking that, Elastic is taking time to update the index. Is this a problem with Elasticsearch or with any of my settings. Please help

Answer 1

That's normal behavior! When you index new data it isn't immediately available, but will be after the next refresh which happens once every second by default.

If that bothers you, you have a few options:

1. you can call the /_refresh endpoint after POSTing your documents and that will immediately refresh your index and the next GET call will work
2. you can add the ?refresh=true parameter in your POST call when you index documents and that will basically do the same as 1
3. you can add the ?refresh=wait_for parameter in your POST call when you index documents and the call will only return when the refresh operation has occurred, so that the next GET call will return the documents
4. you can decrease the index.refresh_interval in your settings (defaults to 1 second) so that the refresh operations happen more often.

Just know that from a performance standpoint, the least aggressive way of achieving what you want is 3, ie that's a new parameter introduced in ES 5 that will not force a refresh on your index but will only return once the newly indexed documents are available for search. Forcing a refresh too often (1, 2 and 3) can kill your performance.