Max length of String stored with App Engine?

Question

When storing String fields with App Engine:

• What is the maximum length() of the String that App Engine datastore can handle?
• Also if using Objectify, is this max length the same or Objectify does some processing that affect this max length?

Answer 1

Based on updates to Google Datastore documentation from October, 2016, here are the limits

Maximum size of an indexed string property's UTF-8 encoding: 1,500 bytes

Maximum size for an unindexed property: 1,048,487 bytes (1 MiB - 89 bytes)

So you can store strings close to 1MB in size in an unindexed String property.

Answer 2

Objectify will automatically convert Strings of more than 500 characters to native Text storage. Be careful if you are indexing strings; Text objects are not indexed so the String > 500 chars will be unindexed.