LUCENE-9539: Use more compact datastructures for sorting doc-values #1908
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jimczi
approved these changes
Sep 22, 2020
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Sparse sorting, nice! The change looks great to me.
I was wondering if we could also compact the offsets array but that would require an extra sort per field. Although, that's probably not needed since we can also remove the caching of the doc values in order to ensure that we load only one field at a time during a merge.
dweiss
reviewed
Sep 22, 2020
| } | ||
| if (startOffset != ordOffset) { // do we have any values? | ||
| offsets[newDocID] = startOffset; | ||
| builder.add(0); // 0 ord marks next value |
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Technically you could also have a sign switch as boundary (~value marks first value) but I don't think it'd result in any savings and would only complicate the value stream.
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agreed, I didn't do it since it would have impacted readability too much IMO
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Nice. +1. |
s1monw
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Sep 22, 2020
…1908) This change cuts over from object based data-structures to primitive / compressed data-structures.
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This change cuts over from object based datastructures to primitive / compressed datastructures.