I ran into a problem with the Google Apps
local dev server where my DataStore
became corrupted. This happened around the time that I was modifying some of my code to be more efficient by offloading some processing to the DataStore
. Unfortunately I didn't fully read the limitations of the DataStore GQL
and wrote a statement that was not supported, which caused a DataStore
This is the kind of error I was getting from the dev server:
I tracked this down to a GQL
statement like this:
The problem was with the !=
operator. It's not supported!
From the GQL reference
Python GQL supports operators != and OR. Those operators are not yet supported by Datastore GQL.
Doh! Oh well. That explained some of the problem, but what went wrong, but how to fix it? Well the reason why the DataStore
became corrupted was this (source
The development web server (dev_appserver.py) automatically adds items to this file when the application tries to execute a query that needs an index that does not have an appropriate entry in the configuration file.
Apparently the dev server doesn't really check what it's indexing, it just blindly tries to create an index. So the index.yaml
file in my case got the following entry:
The entry "name: !"
is not valid, so the DataStore
dies. Fixing it is easy, just remove the invalid name entry, and restart the dev server. Easy!