I'm wondering if I can change the default behavior for '_id' field generation.
I'd like ES to generate ids, but, instead of Flake-based string UUIDs I would like to get long (incremental, sequential) numbers (represented as strings).
No, that is not configurable. Trying to assign sequential long identifiers in a highly concurrent and distributed system would also be very tricky and potentially quite slow. If you need them, generate then externally and send with the indexing requests.
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