CODEWITHSUNDEEP
javahibernategrailsgrails-orm
nikmis
nikmis

Reputation: 1

Hibernate PersistentMap returning wrong values

I am working on an application running Grails 2.4.5 and Hibernate 3.6.10. There is a domain object that has a child PersistentMap. This map stores 4 key-value pairs where the value is always a String.

In our dev and test environments everything works fine and then occasionaly the persistent map starts returning "1" for either the key or the value. The other values in the parent domain object are fine. The problem has been resolved when it occurs by updating one of the records for the map directly in the database. This makes me think its a cacheing issue of some sort, but I haven't been able to recreate it in a local environment.

The database underneath is MySQL.

The following is not the actual code but is representative of the structure.

class MyDomain {

    static belongsTo = [owner: Owner]

    static hasMany = [relatedDomains: RelatedDomain]

    Set relatedDomains = []

    Map flags = [:]

    String simpleItem

    String anotherItem

    static constraints = {
        owner(nullable: true)
        relatedDomains(nullable: true)
        flags(nullable: true)
        simpleItem(nullable: true)
        anotherItem(nullable: true)
    }
}

This results in a couple of tables (ignoring RelatedDomain and Owner):

mydomain table
|  id   |  version  |owner_id|simple_item|another_item |
|-------|-----------|--------|-----------|-------------|
|   1   |    1      |    1   |  A value  |Another value|

mydomain_flags table

|flags| flags_ids |  flags_elt  |
|-----|-----------|-------------|
|  1  | KEY_ONE   | VALUE_ONE   |
|  1  | KEY_TWO   | VALUE_TWO   |
|  1  | KEY_THREE | VALUE_THREE |

When the MyDomain instance is retrieved the flags map will have:

[ "KEY_ONE": "VALUE_ONE", "KEY_TWO": "VALUE_TWO", "KEY_THREE" :"VALUE_THREE"]

Occasionally the map contains:

[ "KEY_ONE": "1", "KEY_TWO": "1", "KEY_THREE" :"1"]<br/>

OR

[ "1": "VALUE_ONE", "1": "VALUE_TWO", "1" :"VALUE_THREE"]

The rest of the data in the MyDomain instance is correct. It is just the flags map that seems to have an issue. The application only reads the information for the mydomain and flags, it never updates the data. It's basically configuration data for the application.

Has anyone else seen behavior like this? I don't know if its related to hibernate (version 3.6.10) or Grails/Gorm or both. I've been unable to reproduce it locally but it has happened in two separate environments.

Upvotes: 0

Views: 534

Answers (1)

nikmis
nikmis

Reputation: 1

I tracked it down to an issue with hibernate. The aliases generated for the persistent map resulted in the same alias for the key and the element. This is because the aliases are based on a static counter in the org.hibernate.mapping.Table class (in 3.6.10). The reason it was sporadic was because Grails loads all the domain classes into a HashSet and then iterates over the set binding each one. Since the Set is unordered sometimes the domain class with the persistent map would be the 3rd class mapped resulting in a key alias identical to the element alias.

This problem was fixed in Hibernate version 4.1.7 https://hibernate.atlassian.net/browse/HHH-7545

To get around the problem in Grails, I subclassed the GrailsAnnotationConfiguration class and in the constructor, created and discarded 10 Hibernate Table instances. This incremented the static counter to a safer seed value prior to loading the Grails domain classes.

Upvotes: 0

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