rusackas opened a new pull request, #42895: URL: https://github.com/apache/superset/pull/42895
### SUMMARY Draft-only, no code yet. This adds `docs/sip/median-stddev-variance-aggregates.md`, a proposal to add `MEDIAN`, `STDDEV_SAMP` (Sample Standard Deviation), and `VAR_SAMP` (Sample Variance) as real, system-wide metric aggregates, prompted by a report that Pivot Table lost several aggregation options somewhere along the way. Short version: most of what looked missing (Count Unique Values, Count/Average/Max/Min, "as fraction of" display) already has an equivalent today, see the doc for specifics. Median/StdDev/Variance are genuinely gone, system-wide, not just Pivot Table, since #41184 (SIP-216) deliberately removed the old pivot-only "Aggregation function" control as the mechanism behind our long-standing wrong-totals bug. This isn't purely hypothetical either: the MCP chart-creation service already advertises `STDDEV`/`VAR`/`MEDIAN` as valid aggregates in its own schemas, and they error at query time today since nothing actually wires them up. The doc lays out why adding these as proper system-wide aggregates is safe post-SIP-216 (they fall into the existing "non-additive" bucket automatically and get correct DB-rollup totals for free, same as `AVG`/`COUNT_DISTINCT` today, no Pivot-Table-specific code needed), plus the real per-engine landmines found so far via `sqlglot` cross-dialect testing (MySQL has no native `MEDIAN`; MySQL's `VARIANCE()` is population variance, not sample, so a naive dialect swap would silently compute the wrong number; SQLite's percentile support depends on a non-default compile flag). Opening as a draft PR rather than going straight to a SIP issue so a few of us can pressure-test the framing and the scope calls (particularly what's explicitly excluded: First/Last, List Unique Values) before it goes up for a vote. ### TESTING INSTRUCTIONS N/A, documentation only. ### ADDITIONAL INFORMATION - [ ] Has associated issue: - [ ] Required feature flags: - [ ] Changes UI - [ ] Includes DB Migration - [ ] Introduces new feature or API - [ ] Removes existing feature or API -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
