Parent-child relationship performance and global ordinals

Elastic Stack Elasticsearch
1

I was reading Practical Considerations which states that:

  • Parent-child queries can be 5 to 10 times slower than the equivalent nested query.

    Is it a worst case scenario or general case? It seems except that nested documents can be stored together, the algorithm for parent-child and nested query should be similar. Is it due to lack of optimization for the parent-child case or some fundamental limitation?

  • Global ordinals needs to be rebuild after every refresh, which could take up to several seconds.

    Is the rebuild an incremental rebuild or a full rebuild? As I understand it, when a new segment is added the global ordinal map only need to assign an ordinal number to any new terms. Why does it take so long to rebuild it? If I add parent documents frequently, will this become a bottleneck?

Thanks!

2

Bumping.

3

This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.