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From Trejkaz <>
Subject Re: Using Lucene 2.3 indices with Lucene 4.0
Date Wed, 21 Nov 2012 01:53:11 GMT
On Wed, Nov 21, 2012 at 12:33 AM, Ramprakash Ramamoorthy
<> wrote:
> On Tue, Nov 20, 2012 at 5:42 PM, Danil Ε’ORIN <> wrote:
>> Ironically most of the changes are in unicode handling and standard
>> analyzer ;)
> Ouch! It hurts then ;)

What we did going from 2 -> 3 (and in some cases where passing the
right Version into a constructor didn't actually give the same
behaviour as the old version... I'm looking at you, StandardTokenizer)
was to archive copies of the classes from older versions of Lucene and
layer our own backwards-compatible API on top of them. You just have
to come up with a way to identify how something was indexed and
support that forever (e.g. give all the Tokenizer and TokenFilter
implementations unique names and never change the names.)

The only time this really hurts is when Lucene change the API on
something like TokenFilter and you have 20 or so implementations of it
which you now have to update.

It's a good example of how backwards compatibility slows down
development time. The amount of work you have to do each time upstream
changes something is more or less directly proportional to how long
your application has been supported for. If I were making the
decisions, I wouldn't support anything across major versions and you
would just get an export/import tool for each version so you could
bring the data across if you really wanted it.


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