Mutations to update entity store by several versions - confused

Question

I am slightly confused about how mutations work. We have been working in our development environments making changes to a particular entity as follows:
Version 1 - deleted a field. It was not marked as a database key. Added a deleter like this:
new Deleter(XXXXXXX.class.getName(), 0, "xxxxx")
Version 2 - added a field. It is not marked as a database key, hence incremented version number, but no mutation code.
Version 3 - deleted a filed. It is not marked as a database key. Added a deleter like this:
new Deleter(XXXXXXX.class.getName(), 2, "yyyyy")
This worked fine for multiple deployments in local development environments, but when we tried to deploy to a test environment, we got this error message when trying to initialise the database:
Caused by: com.sleepycat.persist.evolve.IncompatibleClassException: (JE 4.0.103) Mutation is missing to evolve class: com.chello.booking.model.XXXXXXX version: 0 to class: com.chello.booking.model.XXXXXXX version: 3 Error: Field is not present or not persistent: yyyyy
Mutation is missing to evolve class: com.chello.booking.model.XXXXXXX version: 1 to class: com.chello.booking.model.XXXXXXX version: 3 Error: Field is not present or not persistent: yyyyy
(Note that when upgrading an application in a replicated environment, this exception may indicate that the Master was mistakenly upgraded before this Replica could be upgraded, and the solution is to upgrade this Replica.)
     at com.sleepycat.persist.impl.PersistCatalog.init(PersistCatalog.java:440)
     at com.sleepycat.persist.impl.PersistCatalog.<init>(PersistCatalog.java:221)
     at com.sleepycat.persist.impl.Store.<init>(Store.java:186)
This is not a replicated environment. I had a read through the documentation and don't see anything that prevents us from working like this. Can anyone explain what is going on please?
Incidentally, in case it matters, this is how the mutations are handled during entity store initialisation:
storeConfig.setMutations(mutations);
storeConfig.setAllowCreate(true);
storeConfig.setTransactional(true);
EntityModel model = new AnnotationModel();
model.registerClass(XXXXXXX.class);
storeConfig.setModel(model);
entityStore = new EntityStore(......
Kind regards
James

Answer 1

Hi James,
Mutations must be configured to transform all old versions to the current version. So you also need:
new Deleter(XXXXXXX.class.getName(), 0, "yyyyy")
new Deleter(XXXXXXX.class.getName(), 1, "yyyyy")
I figured this out from the version numbers in the error messages. Note that there are two error messages listed in the exception. The doc explains this in a little more detail, although in very abstract way:
http://www.oracle.com/technology/documentation/berkeley-db/je/java/com/sleepycat/persist/evolve/package-summary.html
Mutations are therefore responsible for converting each existing incompatible class version to the current version as defined by a current class definition. For example, consider that class-version A-1 is initially changed to A-2 and a mutation is added for converting A-1 to A-2. If later changes in version A-3 occur before converting all A-1 instances to version A-2, the converter for A-1 will have to be changed. Instead of converting from A-1 to A-2 it will need to convert from A-1 to A-3. In addition, a mutation converting A-2 to A-3 will be needed.When you say this:
This worked fine for multiple deployments in local development environments, but when we tried to deploy to a test environment, we got this error message when trying to initialise the database:I worry that you're evolving your environment separately on different machines. This won't work. I'm not sure exactly what happened, but if you add mutations and create multiple new versions in a development environment, that sequence of steps won't work for the deployed environment that hasn't gone through the same sequence of steps. Perhaps something like this is what happened.
--mark