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A server-side predicate over a stored NaN or infinite float answers in PostgreSQL's order; only loading throws #232
Description
Problem
docs/why.md says loading a row with a NaN or infinite float "throws instead of returning a value that would sort differently in memory", and docs/efcore.md says "Only finite values load". Both suggest the model is protected from PostgreSQL's NaN order, but a server-side predicate over such a row answers silently in PostgreSQL's order. Found by the pre-tag analysis (#179), part B, with rows written directly in SQL:
| Stored | Query | Answer |
|---|---|---|
Score = '[0,NaN)' |
Where(r => r.Score.Contains(1e308)) |
the row is returned |
Ratio = 'NaN' |
r.Score.Contains(r.Ratio) on [0,) |
1 row |
Weights = '{1,NaN}' |
Select(r => r.Weights.Count) |
2 |
Only materializing the entity throws. The operand guards are complete: a NaN constant, a NaN parameter, and server-side constructors all throw before the query runs.
Change
Document it where the finite-only rule is stated, in docs/efcore.md (custom types / "stricter than the database") and docs/why.md. A query over rows the application did not write can answer in PostgreSQL's NaN order. To keep NaN and infinity out of a column, add a CHECK constraint (for example lower(x) <> 'NaN' AND upper(x) <> 'NaN', NOT ('NaN' = ANY(x)) for arrays, and the infinity equivalents), measured on a live server. Add a claim for the sentence.
Done when
The docs state the boundary. A live test shows the recommended constraints refuse NaN and ±Infinity in each column kind (range, multirange, array).
Activity
CaffeinatedCoder commentedon Oct 18, 2026
Measured on PostgreSQL 16.15 and 18.1 while fixing this (#241): the bounds check suggested above (
lower(x) <> 'NaN' AND upper(x) <> 'NaN'and the infinity equivalents) is complete for a range but not for a multirange. A multirange'slower/upperare its outer bounds and are NULL beside an unbounded side, which a CHECK lets pass, so{(,-Infinity],[1,2)},{(,-Infinity),[1,2)},{[1,2),[Infinity,)},{[1,2),(Infinity,)}and{(,0),[1,Infinity),[NaN,)}are all stored. The documented multirange constraint checks the text instead (m::text !~* '(nan|inf)'); arrays useNOT (a && '{NaN,Infinity,-Infinity}').