Batch apex - partial success issue?

Question

I'm working on creating a batch which inserts a child record to accounts. The child record creation kicks off a separate process that relies on a lot of specific information being in place and is prone to failures, which we're trying to log on the accounts if the child record fails when its inserted. The partial success from AllOrNone being false doesn't seem to be working as expected, and when running more than a single record, if any fail at all the entire batch is updated to reflect the error. Example of the batch below (updated to be a bit more generic). Am is using the saveresult incorrectly or is there some other issue here? It works correctly when running 1 at a time.

global class Batch_CreateDunningInstance implements Database.Batchable<sObject>, Database.AllowsCallouts, Schedulable {

public Iterable<sObject> start(Database.BatchableContext bc) {
    system.debug('start of Batch_CreateDunningInstance');
    
    List<Account> scope = [SELECT Id, MS_Dunning_Profile__c
                           FROM Account
                           WHERE Create_Dunning_Cycle__c = true and Dunning_Criteria__c = true];
    return scope;
}

global void execute(Database.BatchableContext BC, List<Account> scope) {
    system.debug('entered execute of Batch_CreateDunningInstance');
    List<Dunning_Instance__c> dunningInstancesToInsert = new List<Dunning_Instance__c>();
    Map<Id, Account> accountsToUpdate = new Map<Id, Account>();
    List<Account> accountsToUpdateList = new List<Account>();
    
    for (Account acct : scope) {
        Dunning_Instance__c di = new Dunning_Instance__C(
            Account__c = acct.Id,
            Dunning_Profile__c = acct.MS_Dunning_Profile__c
        );
        dunningInstancesToInsert.add(di);
        accountsToUpdate.put(acct.Id, acct);
    }
    
    Database.SaveResult[] insertResults = Database.insert(dunningInstancesToInsert, false);
    
    for (Integer i = 0; i < insertResults.size(); i++) {
        Account acctToUpdate = accountsToUpdate.get(dunningInstancesToInsert[i].Account__c);
        
        if (insertResults.get(i).isSuccess()) {
            acctToUpdate.Create_Dunning_Cycle__c = false;
        } else {
            acctToUpdate.Dunning_Errors__c = insertResults[i].getErrors()[0].getMessage().trim();
        }
        accountsToUpdateList.add(acctToUpdate);
    }
    
    if(!accountsToUpdateList.isEmpty()) {
        update accountsToUpdateList;
    }
    
}

global void finish(Database.BatchableContext BC) {
}

global void execute(SchedulableContext sc) {
    Database.executeBatch(new Batch_CreateDunningInstance(), 20);
}

}

Answer 1

I had an incorrect assumption that AllOrNone would allow some records to process and others to fail while retaining successes throughout the transaction. If any fail the entire transaction fails/rolls back and the save result will display that regardless of the index.