Is there any performance gain from making an elasticsearch index read-only
elasticsearch
Solution
I assume you mean 'search performance' (search time) since you try to make your index read-only.
Without any changes to index (add/delete), the search performance (search time) should be the same whether it's set to read-only or not.
In both cases, a shard may be optimized to have only one segment. There is no overhead to maintain/search increasing number of segments inside a shard. Also, there is no need to merge segments and refresh/flush as well.
Please refer to ElasticSearch official document: Dynamically updatable indices to understand how an index update is done by ElasticSearch.
Also, according to this discussion in Github, Aaron Mildenstein mentioned:
It has no improvement on performance whatever.
Technically speaking, once an index has been optimized to 1 segment per shard, and had bloom filters disabled, there's not really anything else at the software level that will improve performance in any way.
Problem
Though a trivial easy task, am curious as to whether or not this has a positive performance benefit. ``` curl -XPUT 'localhost:9200/my_index/_settings' -d ' { "index" : { "blocks" { "read_only" : "true" } } } ' ```