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From "ASF subversion and git services (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (SOLR-7971) Reduce memory allocated by JavaBinCodec to encode large strings
Date Tue, 25 Aug 2015 16:37:45 GMT

    [ https://issues.apache.org/jira/browse/SOLR-7971?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14711591#comment-14711591
] 

ASF subversion and git services commented on SOLR-7971:
-------------------------------------------------------

Commit 1697727 from shalin@apache.org in branch 'dev/branches/branch_5x'
[ https://svn.apache.org/r1697727 ]

SOLR-7971: Reduce memory allocated by JavaBinCodec to encode large strings by an amount equal
to the string.length()

> Reduce memory allocated by JavaBinCodec to encode large strings
> ---------------------------------------------------------------
>
>                 Key: SOLR-7971
>                 URL: https://issues.apache.org/jira/browse/SOLR-7971
>             Project: Solr
>          Issue Type: Sub-task
>          Components: Response Writers, SolrCloud
>            Reporter: Shalin Shekhar Mangar
>            Assignee: Shalin Shekhar Mangar
>            Priority: Minor
>             Fix For: Trunk, 5.4
>
>         Attachments: SOLR-7971.patch
>
>
> As discussed in SOLR-7927, we can reduce the buffer memory allocated by JavaBinCodec
while writing large strings.
> https://issues.apache.org/jira/browse/SOLR-7927?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14700420#comment-14700420
> {quote}
> The maximum Unicode code point (as of Unicode 8 anyway) is U+10FFFF ([http://www.unicode.org/glossary/#code_point]).
 This is encoded in UTF-16 as surrogate pair {{\uDBFF\uDFFF}}, which takes up two Java chars,
and is represented in UTF-8 as the 4-byte sequence {{F4 8F BF BF}}.  This is likely where
the mistaken 4-bytes-per-Java-char formulation came from: the maximum number of UTF-8 bytes
required to represent a Unicode *code point* is 4.
> The maximum Java char is {{\uFFFF}}, which is represented in UTF-8 as the 3-byte sequence
{{EF BF BF}}.
> So I think it's safe to switch to using 3 bytes per Java char (the unit of measurement
returned by {{String.length()}}), like {{CompressingStoredFieldsWriter.writeField()}} does.
> {quote}



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