I have a question related to this one. It's about a more specific scenario then what has been discussed in the linked topic.
Let's suppose following is true:
- EXTERNAL_GT versioning is used on an index
- Indexing application guarantees updates for a single document are sent to ElasticSearch serially with strictly increasing version numbers. In other words, no concurrent HTTP requests can happen with an update for a single document.
In this scenario, is it ever possible to get a 409 Conflict response from the ElasticSearch? I would have guessed this is not possible, because version numbers are strictly increasing and requests are serial.
More generally, I would have guessed that once accepted with 200 Ok, two or more successive serial versioned update requests must not be reordered inside ElasticSearch due to any reason, not even due to the threading model issues, as described in the linked topic.
Insights would be greatly appreciated!