From 6955f49ea652f24a36c8e5a2e928072d79057ac6 Mon Sep 17 00:00:00 2001
From: zer0stars <74260741+zer0stars@users.noreply.github.com>
Date: Thu, 11 Jun 2026 14:53:54 -0400
Subject: [PATCH] feat(migrations): drop per-part latest projections
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Superseded by signal_latest (00010) and the summary tables (00011).
Projections are stored per part, so latest-state reads through them
fan out across all ~140 parts of the signal table — measured p50 ~3s
in prod vs ~110ms for raw primary-key reads. Dropping also removes
the projection rebuild cost from every merge.
---
 .../00012_drop_latest_projections.sql         | 73 +++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 pkg/migrations/00012_drop_latest_projections.sql

diff --git a/pkg/migrations/00012_drop_latest_projections.sql b/pkg/migrations/00012_drop_latest_projections.sql
new file mode 100644
index 0000000..3d8bab4
--- /dev/null
+++ b/pkg/migrations/00012_drop_latest_projections.sql
@@ -0,0 +1,73 @@
+-- +goose Up
+
+-- The per-part latest projections inherited the signal table's part fan-out
+-- (projections are stored per part) with fatter aggregate-state granules, and
+-- measured slower than raw primary-key reads in prod (signalsLatest p50 ~3s
+-- via projection vs ~110ms raw, 2026-06-11). signal_latest (00010) and the
+-- summary tables (00011) replace them. Apply only after telemetry-api reads
+-- the new tables (this migration ships in a later model-garage release to
+-- enforce that ordering).
+
+-- +goose StatementBegin
+ALTER TABLE signal DROP PROJECTION IF EXISTS signal_latest_by_subject_source_name;
+-- +goose StatementEnd
+
+-- +goose StatementBegin
+ALTER TABLE event DROP PROJECTION IF EXISTS event_latest_by_subject_source_name;
+-- +goose StatementEnd
+
+-- +goose StatementBegin
+ALTER TABLE signal RESET SETTING deduplicate_merge_projection_mode;
+-- +goose StatementEnd
+
+-- +goose StatementBegin
+ALTER TABLE event RESET SETTING deduplicate_merge_projection_mode;
+-- +goose StatementEnd
+
+-- +goose Down
+
+-- Recreate the projections as defined in migration 00009. Re-materializing is
+-- an operator decision (heavy mutation); without it the projections only
+-- cover parts written after this rollback.
+
+-- +goose StatementBegin
+ALTER TABLE signal MODIFY SETTING deduplicate_merge_projection_mode = 'rebuild';
+-- +goose StatementEnd
+
+-- +goose StatementBegin
+ALTER TABLE event MODIFY SETTING deduplicate_merge_projection_mode = 'rebuild';
+-- +goose StatementEnd
+
+-- +goose StatementBegin
+ALTER TABLE signal ADD PROJECTION IF NOT EXISTS signal_latest_by_subject_source_name (
+    SELECT
+        subject,
+        source,
+        name,
+        max(timestamp),
+        min(timestamp),
+        argMax(value_number, timestamp),
+        argMax(value_string, timestamp),
+        argMaxIf(value_location, timestamp, (tupleElement(value_location, 'latitude') != 0) OR (tupleElement(value_location, 'longitude') != 0)),
+        maxIf(timestamp, (tupleElement(value_location, 'latitude') != 0) OR (tupleElement(value_location, 'longitude') != 0)),
+        argMax(producer, timestamp),
+        argMax(cloud_event_id, timestamp),
+        count()
+    GROUP BY subject, source, name
+);
+-- +goose StatementEnd
+
+-- +goose StatementBegin
+ALTER TABLE event ADD PROJECTION IF NOT EXISTS event_latest_by_subject_source_name (
+    SELECT
+        subject,
+        source,
+        name,
+        max(timestamp),
+        min(timestamp),
+        argMax(producer, timestamp),
+        argMax(cloud_event_id, timestamp),
+        count()
+    GROUP BY subject, source, name
+);
+-- +goose StatementEnd