CODEWITHSUNDEEP
javaelasticsearch
user2022068
user2022068

Reputation:

Partial update on field that is not indexed

Let's consider the following situation - there are two fields in "article" document - content(string) and views(int). The views field is not indexed. The views field contains information how many times this article was read.

From official doc:

We also said that documents are immutable: they cannot be changed, only replaced. The update API must obey the same rules. Externally, it appears as though we are partially updating a document in place. Internally, however, the update API simply manages the same retrieve-change-reindex process that we have already described.

But what if we do particial update of not indexed field - will elasticsearch reindex the entire document? For example - I want to update views every time someone reads some article. If entire document is reindexed I can't do real time update (as it's too heavy operation). So I will have to work with delay, for example updates all articles the visitors have read every 3-5-10 minutes. Or I understand something wrong?

Upvotes: 2

Views: 3738

Answers (1)

Dan Tuffery
Dan Tuffery

Reputation: 5924

But what if we do particial update of not indexed field - will elasticsearch reindex the entire document?

Yes, whilst the views field is not indexed individually it is part of the _source field. The _source field contains the original JSON you sent to Elasticsearch when you indexed the document and is returned in the results if there is a match on the document during a search. The _source field is indexed with the document in Lucene. In your update script you are changing the _source field so the whole document will be re-indexed.

Could you then evaluate the following strategy. Every time someone reads the article I send update to elastic. However refresh_interval I set to 30 seconds. Will this strategy be normal if during 30 second interval about 1000 users have read one article?

You are still indexing the 1000 documents, 1 document will be indexed as the current document, 999 documents will be indexed marked as deleted and removed from the index during the next Lucene merge.

Upvotes: 6

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