[
https://issues.apache.org/jira/browse/LUCENE-9754?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17283116#comment-17283116
]
Robert Muir commented on LUCENE-9754:
-------------------------------------
We just use unicode properties for that stuff which is standard. Changing any
of that here won't address the root problem: the chunking is bad for long
documents and can cause other issues that look nothing like this, too. So let's
fix the chunking here to be more sane for long documents.
As far as allowing such tweaks, maybe there are improvements we can do, but i'd
prefer to look at that on separate issues. That's not related to chunking but
instead splitting on scripts.
> ICU Tokenizer: letter-space-number-letter tokenized inconsistently
> ------------------------------------------------------------------
>
> Key: LUCENE-9754
> URL: https://issues.apache.org/jira/browse/LUCENE-9754
> Project: Lucene - Core
> Issue Type: Bug
> Components: core/search
> Affects Versions: 7.5
> Environment: Tested most recently on Elasticsearch 6.5.4.
> Reporter: Trey Jones
> Priority: Major
>
> The tokenization of strings like _14th_ with the ICU tokenizer is affected by
> the character that comes before preceeding whitespace.
> For example, _x 14th_ is tokenized as x | 14th; _ァ 14th_ is tokenized as ァ |
> 14 | th.
> In general, in a letter-space-number-letter sequence, if the writing system
> before the space is the same as the writing system after the number, then you
> get two tokens. If the writing systems differ, you get three tokens.
> If the conditions are just right, the chunking that the ICU tokenizer does
> (trying to split on spaces to create <4k chunks) can create an artificial
> boundary between the tokens (e.g., between _ァ_ and _14th_) and prevent the
> unexpected split of the second token (_14th_). Because chunking changes can
> ripple through a long document, editing text or the effects of a character
> filter can cause changes in tokenization thousands of lines later in a
> document.
> My guess is that some "previous character set" flag is not reset at the
> space, and numbers are not in a character set, so _t_ is compared to _ァ_ and
> they are not the same—causing a token split at the character set change—but
> I'm not sure.
>
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org
For additional commands, e-mail: issues-h...@lucene.apache.org
