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https://issues.jboss.org/browse/TEIID-942?page=com.atlassian.jira.plugin....
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Steven Hawkins resolved TEIID-942.
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Resolution: Done
Used table memory state cloning (persistent data is not cloned) to implement read
isolation for mat views and rollback support for local temporary tables. This was simpler
than implementing full MVCC, but allows for less concurrency and there is additional
overhead the larger the table. The simplified concurrency is fine given we assume mat
view updates are atomic - and performed outside of any running transaction and that the
dominate use case for local temporary tables will be from a single transaction at a time.
The code will prevent local temporary tables from being modified outside of a pending
transaction once they have been modified within the transaction - otherwise a rollback
would lead to inconsistency. Typically this scenario will not happen though as sharing
the same connection / temporary tables across concurrent transactions should be rare.
Another drawback (which simplified the implementation) is that in a cloned state
managedbatch removals are handled through garbage collection. This may delay the
reclaiming of buffer space and result in the unnecessary flushing of pages that may have
otherwise already been removed.
Make ad hoc temp tables transactional
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Key: TEIID-942
URL:
https://issues.jboss.org/browse/TEIID-942
Project: Teiid
Issue Type: Feature Request
Components: Query Engine
Affects Versions: 7.1
Reporter: Steven Hawkins
Assignee: Steven Hawkins
Fix For: 7.6
Ad hoc temp tables are scoped to the session and should be transactional.
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