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cs.DB2026
Partial Partial Aggregates
Claude Brisson
We introduce partial partial aggregates (PPA), a query optimization technique for distributed engines that pushes only the local compute phase of an aggregate operation through joi…
cs.DB2026
Zero-Cost NDV Estimation from Columnar File Metadata
Claude Brisson
We present a method for estimating the number of distinct values (NDV) of a column in columnar file formats, using only existing file metadata--no extra storage, no data access. Tw…