Switch for enablig/disabling typeName (entity) index in MongoDB

[croffler]

The mongoSchemaManager drops the following index on startup:
dropIndexIfExists(snapshots, GLOBAL_ID_ENTITY);

To speed up some of my queries I created an index on globalId.entity. Unfortunately every time I restart my app the index gets dropped.

Can this made configurable, to drop or not to drop ?

[bartoszwalacik]

Are you sure that javers still uses this index?

[bartoszwalacik]

I mean, this is only the name of a class, like Person. Index on this field wouldn't be selective in most cases and would be useful only when quering byClass. Do you have lot of different classes?

[croffler]

Yes I have about 150 different entities and growing.

For example:
List snapshots = getJavers().findSnapshots(QueryBuilder.byClass(klass).build());

JQL produces this:
{ $orderby: { commitMetadata.id: -1 }, $query: { $or: [ { globalId_key: /^rw.gov.ifmis.payment.domain.PaymentOrder/.*/, globalId.entity: { $exists: true } } ] } }
You can now imagine that this is very slow with 20million snapshots(and growing) and 150 different classes.

Here is my use case:
I want to find all snapshots for a PaymentOrder with paymentOderNumber="xxx"

[bartoszwalacik]

ok, so as a quick fix, lets remove this statement:

//schema migration script from JaVers 2.0 to 2.1
        dropIndexIfExists(snapshots, GLOBAL_ID_ENTITY);

and you will be able to add index on your own

would you create a Pull Request?

[croffler]

Hang on here ... there was a reason why thats implemented the way it is ...
Let me just create an index with a different name on that property in mongo .... and I should be ok.
In the meantime we have time to think about this a bit more .... perhaps this could be a configuration property that can be set with spring property injection ....(dropIndexes="${javers.dropIndexes}")

[bartoszwalacik]

ok, switch would be better. I would call it useTypeNameIndex, with default value false

[croffler]

sounds good