[xwiki-devs] Question about hibernate transaction handling in XWiki
Hi Devs, While working on a client project I came across an issue where an exception is thrown with a message that reads something like: "Caused by: org.hibernate.HibernateException: Failed to commit or rollback transaction. Root cause []" Upon further digging I found the following code in XWikiHibernateBaseStore: <code> /** * Ends a transaction * * @param context * @param commit should we commit or not */ public void endTransaction(XWikiContext context, boolean commit) { endTransaction(context, commit, false); } /** * Ends a transaction * * @param context * @param commit should we commit or not * @param withTransaction * @throws HibernateException */ public void endTransaction(XWikiContext context, boolean commit, boolean withTransaction) throws HibernateException { Session session = null; try { session = getSession(context); Transaction transaction = getTransaction(context); setSession(null, context); setTransaction(null, context); if (transaction != null) { // We need to clean up our connection map first because the connection will // be aggressively closed by hibernate 3.1 and more preCloseSession(session); if (log.isDebugEnabled()) { log.debug("Releasing hibernate transaction " + transaction); } if (commit) { transaction.commit(); } else { transaction.rollback(); } } } catch (HibernateException e) { // Ensure the original cause will get printed. throw new HibernateException("Failed to commit or rollback transaction. Root cause [" + getExceptionMessage(e) + "]", e); } finally { closeSession(session); } } </code> The problem i see in this code is that if preCloseSession(session) or transaction.commit() throws an exception, there is no attempt made to rollback the transaction. Normally a transaction rollback attempt should be made within the catch block. If I understand the basics of transaction handling, this code is wrong. I want to discuss this with you (other developers) because I'm not an expert in this subject :) Thanks. - Asiri
Hi Again, } catch (HibernateException e) {
// Ensure the original cause will get printed. throw new HibernateException("Failed to commit or rollback transaction. Root cause [" + getExceptionMessage(e) + "]", e);
This also sounds bit wrong, why do we generate HibernateExceptions? - Asiri
On 04/15/2010 01:07 PM, Asiri Rathnayake wrote:
Hi Devs,
While working on a client project I came across an issue where an exception is thrown with a message that reads something like:
"Caused by: org.hibernate.HibernateException: Failed to commit or rollback transaction. Root cause []"
Upon further digging I found the following code in XWikiHibernateBaseStore:
<code> /** * Ends a transaction * * @param context * @param commit should we commit or not */ public void endTransaction(XWikiContext context, boolean commit) { endTransaction(context, commit, false); }
/** * Ends a transaction * * @param context * @param commit should we commit or not * @param withTransaction * @throws HibernateException */ public void endTransaction(XWikiContext context, boolean commit, boolean withTransaction) throws HibernateException { Session session = null; try { session = getSession(context); Transaction transaction = getTransaction(context); setSession(null, context); setTransaction(null, context);
if (transaction != null) { // We need to clean up our connection map first because the connection will // be aggressively closed by hibernate 3.1 and more preCloseSession(session);
if (log.isDebugEnabled()) { log.debug("Releasing hibernate transaction " + transaction); } if (commit) { transaction.commit(); } else { transaction.rollback(); } } } catch (HibernateException e) { // Ensure the original cause will get printed. throw new HibernateException("Failed to commit or rollback transaction. Root cause [" + getExceptionMessage(e) + "]", e); } finally { closeSession(session); } } </code>
The problem i see in this code is that if preCloseSession(session) or transaction.commit() throws an exception, there is no attempt made to rollback the transaction. Normally a transaction rollback attempt should be made within the catch block.
If I understand the basics of transaction handling, this code is wrong. I want to discuss this with you (other developers) because I'm not an expert in this subject :)
Yes, not calling rollback when an exception occurs, is a critical mistake. Does anybody know why we're not doing this? This is really old code, from the first days of XWiki, so this is an important change, we need to properly understand why is done like this. Ludovic, any thoughts? -- Sergiu Dumitriu http://purl.org/net/sergiu/
participants (2)
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Asiri Rathnayake -
Sergiu Dumitriu