[jira] [Commented] (LUCENE-9673) The level of IntBlockPool slice is always 1

["Michael McCandless (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/LUCENE-9673?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17267389#comment-17267389 ] 

Michael McCandless commented on LUCENE-9673:
--------------------------------------------

Whoa, this is horrible and probably ancient bug!

The slices are supposed to increase in size as ints are appended to the logical single (chunked) stream, to make the overhead lower the larger the number of ints stored.

Does {{ByteBlockPool}} have the same issue?

> 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
>
> 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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