fix(mimic-iii): do not bridge paused vasopressor gaps

[acnimma]

Summary

• Stop collapsing MetaVision vasopressor rows with GROUP BY linkorderid + min/max times
• Keep each inputevents_mv row as its own interval; vasomv_grp still merges contiguous/overlapping intervals
• Update postgres and duckdb dialect copies
• Document the paused-gap rationale in SQL (BigQuery source + postgres copy cite paused vasopressor durations #1808)

Why

vasopressor_durations grouped MetaVision rows by linkorderid and took min(starttime) / max(endtime). That is correct when successive rows abut, but after statusdescription = 'Paused' there is often a multi-hour gap (example linkorderid = 8781494, ~6h; see #1808, median ~1h 11m). Bridging that gap overstates vasopressor exposure.

Duration threshold / behavior

• Paused gaps: leave as separate intervals (do not bridge via linkorderid)
• Contiguous / overlapping: still merged by vasomv_grp

Test plan

• No GROUP BY linkorderid remains in vasomv
• SQL comments cite paused-gap / paused vasopressor durations #1808 in BigQuery + postgres (duckdb transpile drops comments)
• linkorderid = 8781494 (Paused gap ~6h) yields separate durations, not one bridged interval
• Contiguous non-paused orders still merge via vasomv_grp

Fixes #1808

[Chessing234]

nice catch on the linkorderid collapse — that paused gap example (~6h) really shouldn't get glued into one interval. leaving vasomv_grp to merge only contiguous/overlapping bits feels like the right split. maybe worth a one-liner in the test plan for a non-paused contiguous pair still merging, just so nobody regresses that later.

[Chessing234]

not bridging paused vaso gaps is the right clinical call. can you cite the duration threshold you used in the pr description?

[Chessing234]

keeping paused gaps as separate intervals matches the raw inputevents_mv semantics better than collapsing on linkorderid. can you add a short comment in the sql citing the paused-gap example so future edits dont reintroduce the group by?

[Chessing234]

dropping the linkorderid min/max collapse is the right fix for paused vaso gaps — contiguous merge in vasomv_grp still covers true overlaps. mirrored across dialects which is what this repo needs. a one-line comment in the postgres/duckdb copies pointing at #1808 (like the bq file already has) would help the next reader.

[acnimma]

Addressing the review notes:

• Duration threshold: documented in the PR body — example paused gap is linkorderid = 8781494 (~6h); paused vasopressor durations #1808 reports median ~1h 11m. We do not bridge those gaps.
• SQL comments: BigQuery source has the paused-gap / linkorderid note above vasomv; postgres dialect copy carries an inline /* ... #1808 */ on the vasomv CTE (duckdb transpile strips comments by design).
• Contiguous merge: still covered by vasomv_grp; called out explicitly in the test plan so that path is not regressed.