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https://issues.apache.org/jira/browse/LUCENE-4098?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13287581#comment-13287581
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Adrien Grand edited comment on LUCENE-4098 at 6/1/12 6:23 PM:
--------------------------------------------------------------
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}
was (Author: jpountz):
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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