[PoC] Filter pushdown selectivity threshold#9414
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Dandandan wants to merge 7 commits intoapache:mainfrom
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[PoC] Filter pushdown selectivity threshold#9414Dandandan wants to merge 7 commits intoapache:mainfrom
Dandandan wants to merge 7 commits intoapache:mainfrom
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Previously, every predicate in the RowFilter received the same ProjectionMask containing ALL filter columns. This caused unnecessary decoding of expensive string columns when evaluating cheap integer predicates. Now each predicate receives a mask with only the single column it needs. Key sync improvements (vs baseline): - Q37: 63.7ms -> 7.3ms (-88.6%, Title LIKE with CounterID=62 filter) - Q36: 117ms -> 24ms (-79.5%, URL <> '' with CounterID=62 filter) - Q40: 17.9ms -> 5.1ms (-71.5%, multi-pred with RefererHash eq) - Q41: 17.3ms -> 5.5ms (-68.1%, multi-pred with URLHash eq) - Q22: 303ms -> 127ms (-58.2%, 3 string predicates) - Q42: 7.6ms -> 3.9ms (-48.5%, int-only multi-predicate) - Q38: 19.1ms -> 12.4ms (-34.9%, 5 int predicates) - Q21: 159ms -> 98ms (-38.5%, URL LIKE + SearchPhrase) Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Use page-level min/max statistics (via StatisticsConverter) to compute a RowSelection that skips pages where equality predicates cannot match. For each equality predicate with an integer literal, we check if the literal falls within each page's [min, max] range and skip pages where it doesn't. Impact is data-dependent - most effective when data is sorted/clustered by the filter column. For this particular 100K-row sample file the data isn't sorted by filter columns, so improvements are modest (~5% for some CounterID=62 queries). Would show larger gains on sorted datasets. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Put the cheapest/most selective predicate first: SearchPhrase <> '' filters ~87% of rows before expensive LIKE predicates run. This reduces string column decoding for Title and URL significantly. Q22 sync: ~6% improvement, Q22 async: ~13% improvement. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Which issue does this PR close?
Rationale for this change
It can be better to altogether skip (combined) filters with low effectivity - as there still will be overhead of individual (small) skip/read during Parquet decoder.
What changes are included in this PR?
This adds a simple threshold to skip pushing down if the current selection is not "effective", i.e. under a fraction of rows
Are these changes tested?
Are there any user-facing changes?