Gateway raw reads return a stored NULL as value 0 (SQL backends return null) #690

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2026-10-12T16:03:37-04:00

dohertj2 commented

2026-10-12 16:03:37 -04:00

Found by the #685–#688 live AVEVA gate (2026-10-12), pre-existing.

A stored NULL sample inside the window comes back from Gateway HistoryRead-Raw as value 0 with a Bad status (histsdk puts a value on every row; a NULL row is value 0 + Bad OPC quality). The SqlServer and QuestDB backends return a null value with the Bad status. Clients that read the value without checking the status see a fabricated 0.

Suggested fix: in SampleMapper.ToSnapshots, null the value when the OPC quality is Bad (as the aggregate mapper already does for no-data rows), and pin it with a wire-shaped fake.

Found by the #685–#688 live AVEVA gate (2026-10-12), pre-existing. A stored NULL sample inside the window comes back from Gateway HistoryRead-Raw as value `0` with a Bad status (histsdk puts a value on every row; a NULL row is value 0 + Bad OPC quality). The SqlServer and QuestDB backends return a null value with the Bad status. Clients that read the value without checking the status see a fabricated 0. Suggested fix: in `SampleMapper.ToSnapshots`, null the value when the OPC quality is Bad (as the aggregate mapper already does for no-data rows), and pin it with a wire-shaped fake.

dohertj2 referenced this issue

2026-10-12 16:03:53 -04:00

Gateway historian: raw HistoryRead returns AVEVA synthetic boundary row as a stored sample #687

dohertj2 referenced this issue from a commit

2026-10-13 00:10:38 -04:00

fix(historian): #690 Gateway raw/AtTime Bad rows carry no value (a stored NULL was value 0)

dohertj2 referenced this issue from a commit

2026-10-13 00:10:38 -04:00

Merge fix/690-691-gateway-mapping: Bad Gateway rows carry no value, learned gateway ceiling, native TimeAverage/Total grid both directions (#690 #691.2 #691.3)

dohertj2 commented

2026-10-13 00:11:26 -04:00

Fixed on master 15ccd9b7 (merge f0d064a6): SampleMapper.ToSnapshot nulls the value whenever the mapped status is Bad (AVEVA stores a Bad sample as NULL; Uncertain keeps its value). Applies to raw and AtTime; per-sample aggregates were already correct.

Live AVEVA gate PASS: a stored NULL returns null + Bad in raw, reverse, bounded and AtTime reads. (AtTime has separate interpolation issues — #693.)

Fixed on master `15ccd9b7` (merge `f0d064a6`): `SampleMapper.ToSnapshot` nulls the value whenever the mapped status is Bad (AVEVA stores a Bad sample as NULL; Uncertain keeps its value). Applies to raw and AtTime; per-sample aggregates were already correct. **Live AVEVA gate PASS:** a stored NULL returns null + Bad in raw, reverse, bounded and AtTime reads. (AtTime has separate interpolation issues — #693.)

dohertj2 closed this issue

2026-10-13 00:11:26 -04:00

dohertj2 referenced this issue from a commit

2026-10-13 02:11:17 -04:00

fix(historian): #693 Gateway AtTime evaluated from raw reads with the shared AtTimeEvaluator

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Reference: dohertj2/lmxopcua#690