Delta Storage: Difference between revisions
Seems expensive... |
I think i need to put more information for my readers. That's why I am changing my article |
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== Canine Lymphoma == |
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In addition to [[Extension:WebDAV|marshaling article changes in svndiff format]], it might also be nice to store article changes in svndiff format. This would optimize space by not storing a second copy of a large article when a small change is made. It would certainly have some cost in performance, though it might be negligible, or it might be considerable, possibly depending how it is implemented. |
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Canine lymphoma is a condition in which cancer cells can grow anywhere there is lymph tissue. Therefore, the cancer cells can grow in almost any organ in your dog’s body and will eventually cause one of them to fail. This disease commonly occurs in middle-aged dogs. |
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=== Symptoms === |
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The Subversion source includes a couple of notes on how revisions are stored in its Berkeley DB backend. I have not yet found notes on how revisions are stored in the Subversion FSFS backend. |
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The most common symptom of canine lymphoma is swelling of the lymph nodes. Since the disease can invade virtually any part of the body, other symptoms will depend on the location affected. If canine lymphoma occurs in the chest, your dog will have likely experience shortness of breath. If the disease occurs in the gastrointestinal tract, your dog may suffer weight loss, lack of appetite, diarrhea, and vomiting. |
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=== Diagnosis === |
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* http://svn.collab.net/repos/svn/trunk/subversion/libsvn_fs_base/notes/structure |
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Two of the most common methods of diagnosis for canine lymphoma include urine and blood tests. The veterinarian will also notice that lymph nodes near the skin surface are enlarged. A biopsy may be performed on one of the swollen lymph nodes to confirm the diagnosis. The biopsy will also give more information on the severity of the disease. |
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* http://svn.collab.net/repos/svn/trunk/subversion/libsvn_fs_base/notes/fs-history |
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* http://svn.collab.net/repos/svn/trunk/subversion/libsvn_fs_base/notes/TODO |
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=== Treatment === |
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<blockquote> |
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The preferred method of treatment for canine lymphoma is chemotherapy. [http://www.40billion.com/post/97811 Most dogs that undergo this treatment go into remission]. The chemotherapy drugs can be given orally at home or as an injection at the vet’s office. Dogs that are in stage 5 of canine lymphoma, the stage where bone marrow is affected, don’t respond well to chemotherapy drugs. |
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At present, Subversion generally stores the youngest strings in "fulltext" form, and older strings as "delta"s |
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against them (unless the delta would save no space compared to the fulltext). However, there's nothing magic about that particular |
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arrangement. Other interesting alternatives: |
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=== Prognosis === |
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* We could store the N most recently accessed strings as fulltexts, letting access patterns determine the most appropriate representation for each revision. |
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Treatment for canine lymphoma is relatively effective, but can also get expensive. Dogs that have one remission can usually go into remission a second time. However, the second remission usually lasts half as long as the first. Most dogs undergoing treatment for canine lymphoma can survive one to two more years after diagnosis. |
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: |
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* We could occasionally store deltas against the N'th younger revision, storing larger jumps with a frequency inverse to the distance covered, yielding a tree-structured history. |
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</blockquote> |
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The simplest implementation would be to copy Subversion and store the current revision as fulltext, and previous revisions as incremental deltas. This should imply no performance change to retrieving the current revision, but retrieving the oldest revision would involve retrieving deltas for every revision of an article. Is this acceptable given MediaWiki's access pattern? |
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: However, that would mean reacalculating all deltas for previous revisions whenever the page is edited, which I suspect would be prohibitively expensive unless the history is very short. --[[User:HappyDog|HappyDog]] 22:59, 16 June 2010 (UTC) |
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[[Category:Development notes]] |
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[[Category:SVN]] |
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Revision as of 04:23, 23 June 2018
Canine Lymphoma
Canine lymphoma is a condition in which cancer cells can grow anywhere there is lymph tissue. Therefore, the cancer cells can grow in almost any organ in your dog’s body and will eventually cause one of them to fail. This disease commonly occurs in middle-aged dogs.
Symptoms
The most common symptom of canine lymphoma is swelling of the lymph nodes. Since the disease can invade virtually any part of the body, other symptoms will depend on the location affected. If canine lymphoma occurs in the chest, your dog will have likely experience shortness of breath. If the disease occurs in the gastrointestinal tract, your dog may suffer weight loss, lack of appetite, diarrhea, and vomiting.
Diagnosis
Two of the most common methods of diagnosis for canine lymphoma include urine and blood tests. The veterinarian will also notice that lymph nodes near the skin surface are enlarged. A biopsy may be performed on one of the swollen lymph nodes to confirm the diagnosis. The biopsy will also give more information on the severity of the disease.
Treatment
The preferred method of treatment for canine lymphoma is chemotherapy. Most dogs that undergo this treatment go into remission. The chemotherapy drugs can be given orally at home or as an injection at the vet’s office. Dogs that are in stage 5 of canine lymphoma, the stage where bone marrow is affected, don’t respond well to chemotherapy drugs.
Prognosis
Treatment for canine lymphoma is relatively effective, but can also get expensive. Dogs that have one remission can usually go into remission a second time. However, the second remission usually lasts half as long as the first. Most dogs undergoing treatment for canine lymphoma can survive one to two more years after diagnosis.