Elasticsearch reindexing approach

Question

I do data research based on 200Mil records using elasticsearch. From time to time the index needs to be updated with new synonyms and stop words so records should be reindexed. Now I'm trying to find approaches to do the reindexing process as fast as possible. I got to the idea of building the elasticsearch plugin which should:

1. Watch filestystem for synonym/stopwords file change
2. Make diff of previous synonym/stopwords file
3. Find records which could be affected because of synonym/stopwords file change
4. Reindex only records found on 3

Maby you have better approach please share it.

Answer 1

What about following approach:

1. create alias for the index and use it in searching
2. when key/stopwords changing create a new index
3. when new index is full of data move previously created alias from the old index to the new one
4. delete the old index

Thank to that you will always have your index available (except during moving the alias but it takes seconds) and thanks to that the reindexing time won't matter.

Here you have more details and better explanation of using aliases when updating indexes: Is there a smarter way to reindex elasticsearch?