Hi Christian,

Currently we are explicitly creating the index (although the mapping comes from a template) before ingesting.  Would this problem be less likely to occur if we just let the bulk request create the indexes?

There are at most 3 indexes, 9 primary shards and 9 replica shards.

It seems this problem occurs less often if we restrict the batch size for the bulk insert to 1,000 (previously some requests would include up to around 5,000 documents).