Google App Engine error: NeedIndexError: no matching index found

Question

I\'m having trouble with Google\'s App engine indexes. When running my app via the GoogleAppEngineLauncher, the app is working fine. When deploying the app, I get the follow

Answer 1

This NeedIndexError can be triggered by different causes, as I arrived here while having a slightly different problem, so I'll try to explain all I was doing wrong in order to show things that can be done:

• I thought I have to had only one index per Kind of entity. That's not true, as long as I found you need to have as many indexes as different queries you will need to make.

• While on development web server indexes are autogenerated and placed below the #AUTOGENERATED line in index.yaml file.

• After modifying indexes I use first gcloud datastore indexes create index.yaml and I wait until indexes are Serving in https://console.cloud.google.com/datastore/indexes?project=your-project.

• I clean unused indexes by executing gcloud datastore indexes cleanup index.yaml be aware that you do not delete indexes that are being used on production. Reference here

• Be aware that if you don't specify direction on your index properties, it will be ASC by default. So if you are trying to make a - sort query it will again rise the error.

Things I think but I have not 100% evidence longer than my particular problem, but I think can help as a kind of brainstorming:

• Indexes are important while querying data, not when uploading.

• Creating manually the #AUTOGENERATED line not seem to be necessary if you are generating indexes manually. Reference here

• As the development server updates indexes below #AUTOGENERATED line while making queries, you can "accidentally" solve your problem by adding this lane. While the real problem is a lack of manually index update using gcloud datastore indexes create index.yaml command. Reference here and here