From 9c85e0ecdc22cdf7599b15df4917c0269e4dc321 Mon Sep 17 00:00:00 2001
From: Eric Allam <eric@trigger.dev>
Date: Fri, 24 Jul 2026 11:52:34 +0100
Subject: [PATCH] perf(database): index BatchTaskRun on (runtimeEnvironmentId,
 createdAt, id) for the batches list (#4361)

## Summary

The batches list page orders by `createdAt DESC, id DESC` filtered by
environment and a created-at window, but the only supporting index on
`BatchTaskRun` was `(runtimeEnvironmentId, id)`. That index can't
satisfy the `createdAt` ordering, so on environments with a large number
of batches the query fell back to a full table scan and in-memory sort,
which could run long enough to hit the statement timeout.

## Fix

Adds `(runtimeEnvironmentId, createdAt DESC, id DESC)` on
`BatchTaskRun`. The query now reads straight from the index in order
with no sort step, returning a page with only a handful of heap fetches
instead of scanning the whole environment slice.

The migration uses `CREATE INDEX CONCURRENTLY IF NOT EXISTS`, so it
takes no table lock and is a no-op if the index already exists.
---
 .server-changes/batch-list-created-at-index.md              | 6 ++++++
 .../migration.sql                                           | 2 ++
 internal-packages/database/prisma/schema.prisma             | 1 +
 3 files changed, 9 insertions(+)
 create mode 100644 .server-changes/batch-list-created-at-index.md
 create mode 100644 internal-packages/database/prisma/migrations/20260724120000_add_batch_task_run_created_at_dashboard_index/migration.sql

diff --git a/.server-changes/batch-list-created-at-index.md b/.server-changes/batch-list-created-at-index.md
new file mode 100644
index 000000000..b5a243866
--- /dev/null
+++ b/.server-changes/batch-list-created-at-index.md
@@ -0,0 +1,6 @@
+---
+area: webapp
+type: fix
+---
+
+Speed up the Batches list page for environments with a large number of batches, which could previously time out while loading.
diff --git a/internal-packages/database/prisma/migrations/20260724120000_add_batch_task_run_created_at_dashboard_index/migration.sql b/internal-packages/database/prisma/migrations/20260724120000_add_batch_task_run_created_at_dashboard_index/migration.sql
new file mode 100644
index 000000000..4ff6ed34b
--- /dev/null
+++ b/internal-packages/database/prisma/migrations/20260724120000_add_batch_task_run_created_at_dashboard_index/migration.sql
@@ -0,0 +1,2 @@
+-- CreateIndex
+CREATE INDEX CONCURRENTLY IF NOT EXISTS "BatchTaskRun_runtimeEnvironmentId_createdAt_id_idx" ON "public"."BatchTaskRun"("runtimeEnvironmentId", "createdAt" DESC, "id" DESC);
diff --git a/internal-packages/database/prisma/schema.prisma b/internal-packages/database/prisma/schema.prisma
index 2800dd5dd..7d6f4ac54 100644
--- a/internal-packages/database/prisma/schema.prisma
+++ b/internal-packages/database/prisma/schema.prisma
@@ -1935,6 +1935,7 @@ model BatchTaskRun {
   @@index([dependentTaskAttemptId])
   // This is for the batch list dashboard page
   @@index([runtimeEnvironmentId, id(sort: Desc)])
+  @@index([runtimeEnvironmentId, createdAt(sort: Desc), id(sort: Desc)])
 }
 
 enum BatchTaskRunStatus {