feat(nimble): Add per-chunk null count (#992) - #992
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Summary: Pull Request resolved: #992 The first real per-chunk statistic. Chunk stats are still purely positional; this records how many nulls each chunk holds, so a later reader can skip chunks on null-related predicates and we can eventually retire the read-time byte-peeking row estimates in ChunkedDecoder. - The writer counts nulls per chunk during encode, only when chunk stats are enabled. The fleet default is off, so no writer pays for this yet. - Stored as a new field appended to the existing chunk-stats flatbuffer. Files written before this simply lack it, and the reader reports "unknown" rather than a wrong value. - Reader accessor StreamIndex::chunkNullCount returns the count, or nullopt for pre-stats files. Differential Revision: D111913795
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Summary: Pull Request resolved: #992 The first real per-chunk statistic. Chunk stats are still purely positional; this records how many nulls each chunk holds, so a later reader can skip chunks on null-related predicates and we can eventually retire the read-time byte-peeking row estimates in ChunkedDecoder. - The writer counts nulls per chunk during encode, only when chunk stats are enabled. The fleet default is off, so no writer pays for this yet. - Stored as a new field appended to the existing chunk-stats flatbuffer. Files written before this simply lack it, and the reader reports "unknown" rather than a wrong value. - Reader accessor StreamIndex::chunkNullCount returns the count, or nullopt for pre-stats files. Differential Revision: D111913795
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Summary: Pull Request resolved: #992 The first real per-chunk statistic. Chunk stats are still purely positional; this records how many nulls each chunk holds, so a later reader can skip chunks on null-related predicates and we can eventually retire the read-time byte-peeking row estimates in ChunkedDecoder. - The writer counts nulls per chunk during encode, only when chunk stats are enabled. The fleet default is off, so no writer pays for this yet. - Stored as a new field appended to the existing chunk-stats flatbuffer. Files written before this simply lack it, and the reader reports "unknown" rather than a wrong value. - Reader accessor StreamIndex::chunkNullCount returns the count, or nullopt for pre-stats files. Rationale: https://docs.google.com/document/d/1cTCXje3RkPdhwFGK-FTY5muy4Cky2qnfnP-e_VFkjQA/edit?tab=t.0#heading=h.rpljwjiiglku Differential Revision: D111913795
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Summary: Pull Request resolved: #992 The first real per-chunk statistic. Chunk stats are still purely positional; this records how many nulls each chunk holds, so a later reader can skip chunks on null-related predicates and we can eventually retire the read-time byte-peeking row estimates in ChunkedDecoder. - The writer counts nulls per chunk during encode, only when chunk stats are enabled. The fleet default is off, so no writer pays for this yet. - Stored as a new field appended to the existing chunk-stats flatbuffer. Files written before this simply lack it, and the reader reports "unknown" rather than a wrong value. - Reader accessor StreamIndex::chunkNullCount returns the count, or nullopt for pre-stats files. Rationale: https://docs.google.com/document/d/1cTCXje3RkPdhwFGK-FTY5muy4Cky2qnfnP-e_VFkjQA/edit?tab=t.0#heading=h.rpljwjiiglku Reviewed By: xiaoxmeng Differential Revision: D111913795
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Summary: Pull Request resolved: #992 The first real per-chunk statistic. Chunk stats are still purely positional; this records how many nulls each chunk holds, so a later reader can skip chunks on null-related predicates and we can eventually retire the read-time byte-peeking row estimates in ChunkedDecoder. - The writer counts nulls per chunk during encode, only when chunk stats are enabled. The fleet default is off, so no writer pays for this yet. - Stored as a new field appended to the existing chunk-stats flatbuffer. Files written before this simply lack it, and the reader reports "unknown" rather than a wrong value. - Reader accessor StreamIndex::chunkNullCount returns the count, or nullopt for pre-stats files. Rationale: https://docs.google.com/document/d/1cTCXje3RkPdhwFGK-FTY5muy4Cky2qnfnP-e_VFkjQA/edit?tab=t.0#heading=h.rpljwjiiglku Reviewed By: xiaoxmeng Differential Revision: D111913795
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Summary: The first real per-chunk statistic. Chunk stats are still purely positional; this records how many nulls each chunk holds, so a later reader can skip chunks on null-related predicates and we can eventually retire the read-time byte-peeking row estimates in ChunkedDecoder. - The writer counts nulls per chunk during encode, only when chunk stats are enabled. The fleet default is off, so no writer pays for this yet. - Stored as a new field appended to the existing chunk-stats flatbuffer. Files written before this simply lack it, and the reader reports "unknown" rather than a wrong value. - Reader accessor StreamIndex::chunkNullCount returns the count, or nullopt for pre-stats files. Rationale: https://docs.google.com/document/d/1cTCXje3RkPdhwFGK-FTY5muy4Cky2qnfnP-e_VFkjQA/edit?tab=t.0#heading=h.rpljwjiiglku Reviewed By: xiaoxmeng Differential Revision: D111913795
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Summary: The first real per-chunk statistic. Chunk stats are still purely positional; this records how many nulls each chunk holds, so a later reader can skip chunks on null-related predicates and we can eventually retire the read-time byte-peeking row estimates in ChunkedDecoder. - The writer counts nulls per chunk during encode, only when chunk stats are enabled. The fleet default is off, so no writer pays for this yet. - Stored as a new field appended to the existing chunk-stats flatbuffer. Files written before this simply lack it, and the reader reports "unknown" rather than a wrong value. - Reader accessor StreamIndex::chunkNullCount returns the count, or nullopt for pre-stats files. Rationale: https://docs.google.com/document/d/1cTCXje3RkPdhwFGK-FTY5muy4Cky2qnfnP-e_VFkjQA/edit?tab=t.0#heading=h.rpljwjiiglku Reviewed By: xiaoxmeng Differential Revision: D111913795
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Summary:
The first real per-chunk statistic. Chunk stats are still purely positional;
this records how many nulls each chunk holds, so a later reader can skip chunks
on null-related predicates and we can eventually retire the read-time
byte-peeking row estimates in ChunkedDecoder.
enabled. The fleet default is off, so no writer pays for this yet.
written before this simply lack it, and the reader reports "unknown" rather
than a wrong value.
pre-stats files.
Rationale: https://docs.google.com/document/d/1cTCXje3RkPdhwFGK-FTY5muy4Cky2qnfnP-e_VFkjQA/edit?tab=t.0#heading=h.rpljwjiiglku
Reviewed By: xiaoxmeng
Differential Revision: D111913795