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List:       lucene-user
Subject:    Re: Strategy for optimal read-only index
From:       Sriram Sankar <sankar () gmail ! com>
Date:       2013-06-25 17:21:39
Message-ID: CACdbTQiUAahV0bYKjEs=qpHbyO+RTa6eqwY9SGmHjz+qYU6-kw () mail ! gmail ! com
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Thanks!

Sriram.


On Tue, Jun 25, 2013 at 10:01 AM, Michael McCandless <
lucene@mikemccandless.com> wrote:

> On Tue, Jun 25, 2013 at 12:49 PM, Sriram Sankar <sankar@gmail.com> wrote:
> > I have a use case where I build my index only occasionally and am willing
> > to pay the cost to build a read-only index that occupies as small a
> memory
> > footprint as possible and also remains efficient for  posting list
> > traversal.  I.e., I will not be making any changes at all once it is
> built.
> >
> > 1. What is the best strategy to build this index - is there the
> equivalent
> > of an "optimize()" method (it seems to be gone now, is there a specific
> > codec I can use, etc.
>
> optimize() was renamed to forceMerge(1)
>
> > 2. Do we get any better read (posting list traversal essentially)
> > performance by doing this (as opposed to using a mutable index)?
>
> You save seeks when the index has only one segment (optimized) but if
> the index fits entirely in RAM this may not matter much.
>
> You also have fewer open files, in case that matters...
>
> Test both and report back!
>
> Mike McCandless
>
> http://blog.mikemccandless.com
>
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