hi Francois,
Let me first apologize for the late reply. more inline
Francois Orsini wrote:
Hi Kiran,
We're currently working on this and I hope we can provide you guys son
enough with an implemented API for some early test drive.
I have not posted in the directory dev mailing list as the API is not
available yet.
There is a thread in the Apache Derby dev forum as as far as the
motivation for this and see how we can deliver it:
http://www.nabble.com/simpler-api-to-the-Derby-store-to18137499.html#a18137499
I'd be interested in knowing more about that new API you have on top
of JDBM. Do you have any description and Javadoc for it? That would be
great for us to see how it'd would work against the Derby B-Tree store
one.
There are three top level interfaces namely Table, Index and Cursor.
A Table basically contains two columns <key, value> where keys are
sorted and both keys and values if
duplicate keys are allowed.
Index is a bidirectional lookup table ( internally maintains two
_Table_s)
A Cursor abstracts the JDBM specific browsing mechanism while also
adding support for traversal over
duplicate keys if they have been enabled in the Table.
FYI There is an excellent doc written by Alex explaining these
interfaces in detail which is present at
http://cwiki.apache.org/confluence/display/DIRxSRVx11/JDBM+Partition+Design
The SVN urls for
Table
http://svn.apache.org/viewvc/directory/apacheds/branches/bigbang/btree-base/src/main/java/org/apache/directory/server/xdbm/Table.java?revision=662411&view=markup
Index
http://svn.apache.org/viewvc/directory/apacheds/branches/bigbang/btree-base/src/main/java/org/apache/directory/server/xdbm/Index.java?revision=656489&view=markup
Cursor
http://svn.apache.org/viewvc/directory/apacheds/branches/bigbang/core-cursor/src/main/java/org/apache/directory/server/core/cursor/Cursor.java?revision=655158&view=markup
The corresponding implementation classes are
JdbmTable
http://svn.apache.org/viewvc/directory/apacheds/branches/bigbang/jdbm-store/src/main/java/org/apache/directory/server/core/partition/impl/btree/jdbm/JdbmTable.java?revision=662411&view=markup
JdbmIndex
http://svn.apache.org/viewvc/directory/apacheds/branches/bigbang/jdbm-store/src/main/java/org/apache/directory/server/core/partition/impl/btree/jdbm/JdbmIndex.java?revision=659719&view=markup
There are numerous implementations for the Cursor interface. The two
main cursor implementations are
NoDupsCursor
http://svn.apache.org/viewvc/directory/apacheds/branches/bigbang/jdbm-store/src/main/java/org/apache/directory/server/core/partition/impl/btree/jdbm/NoDupsCursor.java?revision=676922&view=markup
DupsCursor ( when duplicates are allowed in the Table )
http://svn.apache.org/viewvc/directory/apacheds/branches/bigbang/jdbm-store/src/main/java/org/apache/directory/server/core/partition/impl/btree/jdbm/DupsCursor.java?revision=656019&view=markup
Also may I ask what were/are the issues you are encountering with
JDBM? I would assume that concurrency is likely one of them and also
not being able to get new updates, etc.
one issue ( that I know of ) with JDBM is its browser's getPrevious()
and getNext() when called in succession will
return the same key ( I was told that this not a bug but JDBM actually
works in this way )
e.x in a sequence of keys 1,2,3
assuming that browser is positioned at the beginning if we call
browser.getNext() (returns 1)
browser.getNext() (returns 2)
and finally browser.getPrevious() (returns *2* but logically speaking
should be 1)
ADS dev, please add any JDBM issues that you encountered or know about
Thanks
--francois
Kiran Ayyagari wrote:
hi Francois,
I have searched directory dev mail archive but haven't found any
discussion threads in which you participated
( infact there were some mails about BTree impl used in JDBM )
Could you let me know about the derby revision in which this new
API is present ( will be glad if you can
provide some filenames related to BTree impl instead :) )
Thanks for your time
Kiran Ayyagari
Emmanuel Lecharny wrote:
Hi Kiran,
last spring we had an interesting convo with François Orsini about
Derby BTree implementation. As we have a new API on top of JDBM, and
as they have started to redisign their API to get it easier to use,
it would be interesting to look at what they are doing and see how
we can leverage this API. They are also interested to know what we
think about the new API, so any feedback would be good.
The best would for you two guys to get in touch, and see how you can
collaborate.
wdyt ?
--
Kiran Ayyagari
