elasticsearch/elasticsearch — pull request #7729 by kimchy (2014-09-15 16:27:57+00:00)
Title: Bulk operation can create duplicates on primary relocation

When executing a bulk request, with create index operation and auto generate id, if while the primary is relocating the bulk is executed, and the relocation is done while N items from the bulk have executed, the full shard bulk request will be retried on the new primary. This can create duplicates because the request is not makred as potentially holding conflicts.

This change carries over the response for each item on the request level, and if a conflict is detected on the primary shard, and the response is there (indicating that the request was executed once already), use the mentioned response as the actual response for that bulk shard item.

On top of that, when a primary fails and is retried, the change now marks the request as potentially causing duplicates, so the actual impl will do the extra lookup needed.

This change also fixes a bug in our exception handling on the replica, where if a specific item failed, and its not an exception we can ignore, we should actually cause the shard to fail.