If I reduce the number in "ignore_above" will I use less disk space?

[ElasticLiver (Dense Man)]

Hi, I have an APM span index, and I realize that in the mapping the "ignore_above" is set to 1024, I was wandering if I change some of this setting I can use less disk space.
for example in agent.name, the longest value in this field has 10 characters

What do you think?

[mayya (Mayya Sharipova)]

ignore_above of 1024 for agent.name means that if a document contains a field agent.name with a value that is bigger than 1024 characters, this field will ignored and will not be indexed, as though this document doesn't have a field agent.name (the source will still be saved in the original format).

If all values of your agent.name have less than 10 characters, changing ignore_above for anything less than 10 characters will have no effect. If you change it to 9 characters, fields that have values bigger than 9 will be ignored, not indexed and you will save space there at the expense that you will not be able search by agent.name for these documents.