[jira] [Commented] (JENA-352) Vast numbers of bNodes can overwhelm the parser

["Andy Seaborne (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/JENA-352?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13618126#comment-13618126 ] 

Andy Seaborne commented on JENA-352:
------------------------------------

A new blank node allocator for RIOT has been added.

It uses a large seed (a random UUID - 122 bits of random information) and the label given.  These are combined into an MD5 value (128 bits) which then forms the bNode id, currently as a hex string, in lower case.
                
> Vast numbers of bNodes can overwhelm the parser
> -----------------------------------------------
>
>                 Key: JENA-352
>                 URL: https://issues.apache.org/jira/browse/JENA-352
>             Project: Apache Jena
>          Issue Type: Bug
>          Components: RIOT, TDB
>            Reporter: Andy Seaborne
>            Priority: Minor
>
> The parsers need to keep a bNode label to bNode map which (unusual data) can grow too large.  As it takes unusual data, rated as "minor".
> outline of solution: 
> 1/ switch to a bNode allocation scheme which has a seed (a large random number per parser run), and concat or XOR with the claimed bNode label to generate a unique label without state build up.
> 2/ (Turtle) don't remember [] bnodes past their usage scope.
> 3/ Partial - keep a sliding window of bNodes label mappings 
> 4/ Direct allocation for _:label and tracked allocation for []
> e.g.
> http://mail-archives.apache.org/mod_mbox/jena-users/201112.mbox/%3C4EDFE45F.6090202@apache.org%3E

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