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https://issues.apache.org/jira/browse/LUCENE-5966?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Michael McCandless resolved LUCENE-5966.
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    Resolution: Won't Fix

We removed auto prefix terms ...

> How to migrate from numeric fields to auto-prefix terms
> -------------------------------------------------------
>
>                 Key: LUCENE-5966
>                 URL: https://issues.apache.org/jira/browse/LUCENE-5966
>             Project: Lucene - Core
>          Issue Type: Improvement
>            Reporter: Michael McCandless
>
> In LUCENE-5879 we are adding auto-prefix terms to the default terms dict, 
> which is generalized from numeric fields and offers faster performance while 
> using less indexing space and about the same indexing time.
> But there are many users out there with indices already created containing 
> numeric fields ... so ideally we have some simple way for such users to 
> switch over to auto-prefix  terms.
> Robert has a good plan (copied from LUCENE-5879):
> Here are some thoughts.
> # keep current trie "Encoding" for terms, it just uses precision step=Inf and 
> lets the term dictionary do it automatically.
> # create a filteratomicreader, that for a previous trie encoded field, 
> removes "fake" terms on merge.
> Users could continue to use NumericRangeQuery just with the infinite 
> precision step, and it will always work, just execute slower for old segments 
> as it doesnt take advantage of the trie terms that are not yet merged away.
> One issue to making it really nice, is that lucene doesnt know for sure that 
> a field is numeric, so it cannot be "full-auto". Apps would have to use their 
> schema or whatever to wrap with this reader in their merge policy.
> Maybe we could provide some sugar for this, such as a wrapping merge policy 
> that takes a list of field names that are numeric, or sugar to pass this to 
> IWC in IndexUpgrader to force it, and so on.



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