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Posted to dev@lucene.apache.org by "Adrien Grand (JIRA)" <ji...@apache.org> on 2012/06/01 20:25:23 UTC
[jira] [Commented] (LUCENE-4098) Efficient bulk operations for
packed integer arrays
[ https://issues.apache.org/jira/browse/LUCENE-4098?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13287581#comment-13287581 ]
Adrien Grand commented on LUCENE-4098:
--------------------------------------
The bulk get and set are not guaranteed to return/set exactly len longs (so that they can stay at a block boundary to make the subsequent reads/writes faster). So I think
{{code}}
int got = packed1.get(start, buffer, offset, len);
assertTrue(got <= len);
int sot = packed2.set(start, buffer, offset, len);
assertTrue(sot <= len);
{{code}}
should be replaced with
{{code}}
int got = packed1.get(start, buffer, offset, len);
assertTrue(got <= len);
int sot = packed2.set(start, buffer, offset, got);
assertTrue(sot <= len);
{{code}}
> Efficient bulk operations for packed integer arrays
> ---------------------------------------------------
>
> Key: LUCENE-4098
> URL: https://issues.apache.org/jira/browse/LUCENE-4098
> Project: Lucene - Java
> Issue Type: Improvement
> Components: core/other
> Reporter: Adrien Grand
> Assignee: Michael McCandless
> Priority: Minor
> Fix For: 4.1
>
> Attachments: LUCENE-4098.patch, LUCENE-4098.patch
>
>
> There are some places in Lucene code that {iterate over,set} ranges of values of a packed integer array. Because bit-packing implementations (Packed*) tend be slower than direct implementations, this can take a lot of time.
> For example, under some scenarii, GrowableWriter can take most of its (averaged) {{set}} time in resizing operations.
> However, some bit-packing schemes, such as the one that is used by {{Packed64SingleBlock*}}, allow to implement efficient bulk operations such as get/set/fill. Implementing these bulk operations in {{PackedInts.{Reader,Mutable}}} and using them across other components instead of their single-value counterpart could help improve performance.
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