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https://issues.apache.org/jira/browse/OPENJPA-2139?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13213960#comment-13213960
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Rick Curtis commented on OPENJPA-2139:
--------------------------------------
Background details : The runtime isn't able to determine which type of DB we're
running against based off any of the connection properties so we need to make a
connection to figure it out.
The root problem is that when creating the first EM, in AbstractBrokerFactory
we have this[1] block of code that gets a MDR instance, and the configures it
as a class listener. As part of configuring the MDR, we get a reference to the
DBDictionary[2]. While instantiating the dictionary, we need to connect to the
DB to figure out which type to create. Instantiation of the dictionary results
in an exception, which blows out of the AbstractBrokerFactory.makeReadOnly()
method. Thus we never register the MDR as a register class listener, and thus
the MDR never gets populated with metadata..
To work around the problem, I modified the MDR so that we only will instantiate
a DBDictionary when we actually use it. Mark tested this patch in his
environment and it seemed to work fine.
[1]
MetaDataRepository repos = _conf.getMetaDataRepositoryInstance();
repos.setValidate(MetaDataRepository.VALIDATE_RUNTIME, true);
repos.setResolve(MetaDataModes.MODE_MAPPING_INIT, true);
PCRegistry.addRegisterClassListener(repos);
[2] MappingRepository.endConfiguration()
> OpenJPA fails to recover from a broken database on startup
> ----------------------------------------------------------
>
> Key: OPENJPA-2139
> URL: https://issues.apache.org/jira/browse/OPENJPA-2139
> Project: OpenJPA
> Issue Type: Bug
> Affects Versions: 2.2.0
> Reporter: Mark Struberg
> Assignee: Mark Struberg
> Priority: Critical
> Fix For: 2.3.0
>
> Attachments: OPENJPA-2139.mdr.patch, OPENJPA-2139.patch
>
>
> The following scenario:
> 1.) turn off the database
> 2.) perform a query against the database
> 3.) turn on the database
> 4.) try to re-run the query from 2.)
> In 4.) you will get the following Exception:
> openjpa-2.2.0-r422266:1244990 nonfatal user error>
> org.apache.openjpa.persistence.ArgumentException: An error occurred while
> parsing the query filter "SELECT k FROM DbEnumKey AS k where k.type=:typ
> ORDER BY k.ordinal". Error message: The name "DbEnumKey" is not a recognized
> entity or identifier. Known entity names: []
> Basically the whole app is stale afterwards!
> Solution: caching the entities might only be done if a connection can be
> established.
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