What's happen when the indexed configuration file is changed?

[Sea]

What's happen in Google App Engine when there are many entities are
stored and the indexed Configuration file is changed?
If there is a field of an entity is indexed in earlier version , and
become unindexed in this version?
If there is a field of an entity is unindexed in earlier version, and
become indexed in this version?
Will GAE perform re-indexing for all persisted entities? If it is, How
long does it needed?

Bests,

[Simon Knott]

Hi,

There are two types of indexes:

• Per-property indexes - each property of an entity has an ascending/descending index which is written at the time of entity persistence.  If you change whether a property is indexed, then you must manually read and re-write the entity for the index state to be modified in the datastore.  I usually write a little task which reads and re-writes all entities of a specific type, which I can call if I change an entity's configuration.
• Composite indexes - these are updated when the index configuration is modified, by uploading a new version of your application.  You do not need to re-write entities for these indexes to be updated.  It should be noted that a property must have a per-property index for it to be usable in a Composite index.

Hopefully that helps!

Cheers,

Simon

[Simon Knott]

Hi,

Just realised that I missed off the answer to "how long will it take" - this depends entirely on how many entities you have. :)

Cheers,

Simon