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https://issues.apache.org/jira/browse/LUCENE-9673?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17281862#comment-17281862
]
Michael McCandless commented on LUCENE-9673:
--------------------------------------------
I was curious if this impacted indexing throughput and ran `luceneutil` three
times with this change (confusingly, named `trunkN.txt` below) and three times
without this change (`baseN.log`):
```
[mike@beast3 trunk]$ grep "indexing done" /l/logs/trunk?.txt
/l/logs/trunk1.txt:Indexer: indexing done (89114 msec); total 27624170 docs
/l/logs/trunk2.txt:Indexer: indexing done (89974 msec); total 27624192 docs
/l/logs/trunk3.txt:Indexer: indexing done (90614 msec); total 27624409 docs
[mike@beast3 trunk]$ grep "indexing done" /l/logs/base?.log
/l/logs/base1.log:Indexer: indexing done (89271 msec); total 27623915 docs
/l/logs/base2.log:Indexer: indexing done (91676 msec); total 27624107 docs
/l/logs/base3.log:Indexer: indexing done (93120 msec); total 27624268 docs
```
Possibly a small speedup, but within the noise/variance of the test. Plus, the
precise doc count indexed changes each time, which is not right! I opened
[https://github.com/mikemccand/luceneutil/issues/106] to get to the bottom of
that ...
> The level of IntBlockPool slice is always 1
> --------------------------------------------
>
> Key: LUCENE-9673
> URL: https://issues.apache.org/jira/browse/LUCENE-9673
> Project: Lucene - Core
> Issue Type: Bug
> Components: core/other
> Reporter: mashudong
> Priority: Minor
> Attachments: LUCENE-9673.patch
>
>
> First slice is allocated by IntBlockPoo.newSlice(), and its level is 1,
>
> {code:java}
> private int newSlice(final int size) {
> if (intUpto > INT_BLOCK_SIZE-size) {
> nextBuffer();
> assert assertSliceBuffer(buffer);
> }
>
> final int upto = intUpto;
> intUpto += size;
> buffer[intUpto-1] = 1;
> return upto;
> }{code}
>
>
> If one slice is not enough, IntBlockPoo.allocSlice() is called to allocate
> more slices,
> as the following code shows, level is 1, newLevel is NEXT_LEVEL_ARRAY[0]
> which is also 1.
>
> The result is the level of IntBlockPool slice is always 1, the first slice is
> 2 bytes long, and all subsequent slices are 4 bytes long.
>
> {code:java}
> private static final int[] NEXT_LEVEL_ARRAY = {1, 2, 3, 4, 5, 6, 7, 8, 9, 9};
> private int allocSlice(final int[] slice, final int sliceOffset) {
> final int level = slice[sliceOffset];
> final int newLevel = NEXT_LEVEL_ARRAY[level - 1];
> final int newSize = LEVEL_SIZE_ARRAY[newLevel];
> // Maybe allocate another block
> if (intUpto > INT_BLOCK_SIZE - newSize) {
> nextBuffer();
> assert assertSliceBuffer(buffer);
> }
> final int newUpto = intUpto;
> final int offset = newUpto + intOffset;
> intUpto += newSize;
> // Write forwarding address at end of last slice:
> slice[sliceOffset] = offset;
> // Write new level:
> buffer[intUpto - 1] = newLevel;
> return newUpto;
> }
> {code}
>
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