المدربA zone map is the minimum and maximum of a column within a unit of storage (a row group, a page). Predicate pushdown evaluates a query’s filter against zone maps before reading, and skips every unit whose range cannot satisfy it. Projection pushdown reads only the columns a query names, in its output or its filter.
| query | shuffled | time order | symbol, then time |
|---|---|---|---|
| one symbol, one hour | 86.0% | 3.30% | 3.30% |
| one symbol, one month | 34.1% | 28.2% | 1.07% |
| all symbols, one hour | 81.7% | 3.13% | 86.1% |
pl_colfmt.study.
pl_colfmt.study.