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https://issues.apache.org/jira/browse/DERBY-6242?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Knut Anders Hatlen updated DERBY-6242:
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Attachment: derby-6242-01-a.diff
The attached patch makes XactFactory use a ConcurrentHashMap instead of a
Hashtable and removes the ConcurrentXactFactory class.
The patch also removes an abstraction layer that was used to hide the
differences between Hashtable and ConcurrentHashMap. That is, it removes the
classes TransactionMapFactory and ConcurrentTransactionMapFactory, and instead
creates and accesses the ConcurrentHashMap.
The TransactionTable class had a visitEntries() method that used to serve two
purposes:
1) It abstracted away the differences between Hashtable and ConcurrentHashMap
2) It allowed other classes to iterate over the elements in the transaction
table without exposing the internal representation of the table
It is still useful for (2), so the method is preserved and still used some
places. It is no longer needed for (1), so the patch replaces all usages of it
inside the TransactionTable class with loops that traversed the values in the
ConcurrentHashMap directly. Lots of anonymous inner EntryVisitor classes could
be removed this way, and it made it easier to read the code that iterated over
the transaction table entries, I believe.
All the regression tests ran cleanly on Java 6 and Java 8 with the patch.
> Merge ConcurrentXactFactory into XactFactory
> --------------------------------------------
>
> Key: DERBY-6242
> URL: https://issues.apache.org/jira/browse/DERBY-6242
> Project: Derby
> Issue Type: Improvement
> Components: Services
> Affects Versions: 10.11.0.0
> Reporter: Knut Anders Hatlen
> Assignee: Knut Anders Hatlen
> Priority: Minor
> Attachments: derby-6242-01-a.diff
>
>
> ConcurrentXactFactory extends XactFactory and replaces XactFactory's
> Hashtable with a ConcurrentHashMap for better scalability.
> Now that ConcurrentHashMap is available on all platforms supported on trunk,
> we could make XactFactory use a ConcurrentHashMap and remove
> ConcurrentXactFactory.
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