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From "Marshall Schor (JIRA)" <...@uima.apache.org>
Subject [jira] [Resolved] (UIMA-4279) tune space-time tradeoffs for internal array structures in core uima
Date Mon, 09 Mar 2015 21:48:39 GMT

     [ https://issues.apache.org/jira/browse/UIMA-4279?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Marshall Schor resolved UIMA-4279.
----------------------------------
    Resolution: Fixed

> tune space-time tradeoffs for internal array structures in core uima
> --------------------------------------------------------------------
>
>                 Key: UIMA-4279
>                 URL: https://issues.apache.org/jira/browse/UIMA-4279
>             Project: UIMA
>          Issue Type: Improvement
>          Components: Core Java Framework
>    Affects Versions: 2.7.0SDK
>            Reporter: Marshall Schor
>            Assignee: Marshall Schor
>            Priority: Trivial
>             Fix For: 2.7.1SDK
>
>
> Several internal array structures in UIMA expand like array lists by doubling, up to
some size, usually 2 million entries, and then expand by adding that size (e.g., 2 million)
instead of doubling.  
> The switch-over point for most of these is 2 million entries.   Increasing this makes
(for large allocations > 2 million) for more wasted space, since, on average, about 1/2
of the last reallocation may be unused  On the other hand, having a large allocation size
increment means that fewer reallocations are needed (each one requires copying the entries
from the old into the new, usually with System.arraycopy).
> Given the drop in memory cost, increase the reallocation switch-over limit for the 2
million entries to 16 million, to rebalance a bit more in favor of speed vs memory.  Note
this has no effect except when the size of these internal tables grows beyond 2 million entries.



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