[hibernate-issues] [Hibernate-JIRA] Updated: (HHH-1889) LockMode.UPGRADE does not work for get(), load() and refresh() on SQL Server
[ http://opensource.atlassian.com/projects/hibernate/browse/HHH-1889?page=all ]
Steve Finch updated HHH-1889:
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Attachment: SQLServerDialect.applyLocks.patch
I'm attaching a second patch that fixes the use of inline lock hints for HQL and
Criteria queries. I thought it would be harder than it was, but I've tested it and it
works as expected.
My methodology:
1) Locate all the places where ForUpdateFragment is appended to the existing SQL
(QueryTranslatorImpl, QueryLoader, and CriteriaLoader);
2) Refactor the code to move this behavior to the Dialect class;
3) Override the new method in the SQLServerDialect class;
4) Create a new class InlineUpdateLockModification which replaces the aliases in the FROM
clause with the appropriate update lock hint, if necessary.
I'm not exactly happy with the solution, as it causes the query to be reprocessed each
time lock hints occur. However, it seemed a lesser risk than playing with the
HQLQueryPlanKey class and adding some metadata about what locks would be needed. My fix
could be sped up if there were bookmarks telling where each alias existed in the existing
query; with that information a search would not be necessary and the resulting code would
be safer.
LockMode.UPGRADE does not work for get(), load() and refresh() on SQL
Server
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Key: HHH-1889
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-1889
Project: Hibernate3
Type: Bug
Components: core
Versions: 3.2.0.cr2, 3.2.0.cr3
Environment: Windows XP, Hibernate 3.2.cr3
Reporter: Matthias Germann
Priority: Critical
Attachments: AbstractEntityJoinWalker.java.patch, SQLServerDialect.applyLocks.patch
Passing a LockMode parameter to the get(), load() or refresh() method of the Session
class has no effect on MS SQL Server.
The statement
session.load(ProcessInstance.class, 33l, LockMode.UPGRADE)
produces this SQL Statement with the SQLServerDialect:
select
processins0_.ID_ as ID1_20_0_,
processins0_.VERSION_ as VERSION2_20_0_,
processins0_.START_ as START3_20_0_,
processins0_.END_ as END4_20_0_,
processins0_.ISSUSPENDED_ as ISSUSPEN5_20_0_,
processins0_.PROCESSDEFINITION_ as PROCESSD6_20_0_,
processins0_.ROOTTOKEN_ as ROOTTOKEN7_20_0_,
processins0_.SUPERPROCESSTOKEN_ as SUPERPRO8_20_0_
from
JBPM_PROCESSINSTANCE processins0_
where
processins0_.ID_=?
This Statement does not contain the requested locking hint. The FROM claus should look
like this:
from JBPM_PROCESSINSTANCE processins0_ with (updlock, rowlock)
The OracleDialect produces a correct statement with a FOR UPDATE clause
select
processins0_.ID_ as ID1_20_0_,
processins0_.VERSION_ as VERSION2_20_0_,
processins0_.START_ as START3_20_0_,
processins0_.END_ as END4_20_0_,
processins0_.ISSUSPENDED_ as ISSUSPEN5_20_0_,
processins0_.PROCESSDEFINITION_ as PROCESSD6_20_0_,
processins0_.ROOTTOKEN_ as ROOTTOKEN7_20_0_,
processins0_.SUPERPROCESSTOKEN_ as SUPERPRO8_20_0_
from
JBPM_PROCESSINSTANCE processins0_
where
processins0_.ID_=? for update
The lock() method works correctly.
IMHO, the problem is that only the SimpleSelect class uses the appendLockHint() method of
the Dialect class. The Select class does not seam to use the appendLockHint() method.
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