So you have a lot of nested docs here which is causing lot of internal "joins" at search time.
Few things I can think about:
- First once the segments are loaded in memory (if you have enough memory left for the OS FS Cache), hopefully this will be much faster.
- May be having more shards in that case with fewer documents per shard would help to reduce that time
- Depending on your use case, don't use nested when not absolutely necessary.
But may be @jpountz has other ideas?