Lucene Index: DataStore vs BlobStore

[Alexandr Savochkin]

Hello!
As far as I understand, LAE uses AppEngine's DataStore as storage for Lucene index.But it looks like blobstore is another option which might work. Is there any consideration why choose datastore or blobstore for lucene index?

Thank you.

[Alexandr Savochkin]

I see that blobstore is cheaper (if you're out of free quota) but it will not allow to add documents to index online. It is more suitable for creating index locally and uploading it to GAE. Datastore allows to modify index in running application. Is there something else with this topic to take into account?

[Alexandr Savochkin]

I am probably wrong about "read only" restriction for lucene blobstore. Lucene Directory class does not require possibility to modify already created file, so it seems to be possible to add documents to blobstore-based index.

[Fabio Grucci]

Writing files to the Blobstore is deprecated, maybe you mean Google Cloud Storage API. However I started the developing of LAE with 1.7.0 and Google Cloud Storage API could not be tested in development server until SDK 1.8.1. That's the first reason why I've chosen the DataStore, the second one is that I was driven by the usage of memcache that is easily integrated within Objectify project.

I'm sure that in a future release I'll develop a Google Cloud Storage API enabled LAE version because it can be an interesting asset.

Thank you for your interest and sorry for my late response