launchpad-dev team mailing list archive

[Aaron Bentley <aaron@xxxxxxxxxxxxx>]

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On 11-01-25 10:33 PM, Robert Collins wrote:
> On Wed, Jan 26, 2011 at 4:18 PM, Aaron Bentley <aaron@xxxxxxxxxxxxx> wrote:
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>> On 11-01-25 09:46 PM, Robert Collins wrote:
>>> given the performance benefits history-db offers I imagine little
>>> trouble scheduling it.
>>
>> Also, history-db is the leading candidate for replacing the
>> BranchRevision table:
>>
>> https://dev.launchpad.net/Code/BranchRevisions
> 
> Thats a very interesting analysis; I don't see anything there about
> using a general purpose graph DB  - did you consider that? (e.g.
> flockdb).

No.  I'm not familiar with such things, and we weren't thinking outside
the box.  Everything we considered is listed there.

> History db seems like a very specific preprocessing answer to me; its
> nice (very nice!) but I'm wondering if we'll get more leverage in
> Launchpad by bringing in a slightly heavier tool which can answer all
> the things we need for bzr straight away

It is always hard to judge what will be most effective in these cases.
Such tech would be new and unfamiliar, and would probably be harder to
deploy initially.  history_db is just SQL, and we know how to handle
SQL.  But history_db is perfect either, and there are some changes I
would make if I were working on replacing the BranchRevision table with it.

>, replace our
> TeamParticipation construct (1.3M rows) , let us do the graph logic
> needed in derivative distributions, blueprint dependencies (a
> transitive data structure when the issue tracker arrives), and
> similarly bug dependencies and project relationships.

We also have a deadline with the BranchRevision table, as I believe we
are halfway to exceeding maximum index value.  Increasing the scope of
this project runs the risk of delaying it to the point that we run out
of BranchRevision index numbers.

Aaron
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