Add safe rootTaskRunId index and a README to @trigger.dev/database

Author: ericallam

packages/database/README.md

@@ -0,0 +1,38 @@
+## @trigger.dev/database
+
+This is the internal database package for the Trigger.dev project. It exports a generated prisma client that can be instantiated with a connection string.
+
+### How to add a new index on a large table
+
+1. Modify the Prisma.schema with a single index change (no other changes, just one index at a time)
+2. Create a Prisma migration using `cd packages/database && pnpm run db:migrate:dev --create-only`
+3. Modify the SQL file: add IF NOT EXISTS to it and CONCURRENTLY:
+
+```sql
+CREATE INDEX CONCURRENTLY IF NOT EXISTS "JobRun_eventId_idx" ON "JobRun" ("eventId");
+```
+
+4. Don’t apply the Prisma migration locally yet. This is a good opportunity to test the flow.
+5. Manually apply the index to your database, by running the index command.
+6. Then locally run `pnpm run db:migrate:deploy`
+
+#### Before deploying
+
+Run the index creation before deploying
+
+```sql
+CREATE INDEX CONCURRENTLY IF NOT EXISTS "JobRun_eventId_idx" ON "JobRun" ("eventId");
+```
+
+These commands are useful:
+
+```sql
+-- creates an index safely, this can take a long time (2 mins maybe)
+CREATE INDEX CONCURRENTLY IF NOT EXISTS "JobRun_eventId_idx" ON "JobRun" ("eventId");
+-- checks the status of an index
+SELECT * FROM pg_stat_progress_create_index WHERE relid = '"JobRun"'::regclass;
+-- checks if the index is there
+SELECT * FROM pg_indexes WHERE tablename = 'JobRun' AND indexname = 'JobRun_eventId_idx';
+```
+
+Now, when you deploy and prisma runs the migration, it will skip the index creation because it already exists. If you don't do this, there will be pain.

packages/database/prisma/migrations/20240924125845_add_root_task_run_id_index/migration.sql

@@ -0,0 +1,2 @@
+-- CreateIndex
+CREATE INDEX CONCURRENTLY IF NOT EXISTS "TaskRun_rootTaskRunId_idx" ON "TaskRun"("rootTaskRunId");

packages/database/prisma/schema.prisma

@@ -1751,6 +1751,8 @@ model TaskRun {
   @@unique([runtimeEnvironmentId, taskIdentifier, idempotencyKey])
   // Finding child runs
   @@index([parentTaskRunId])
+  // Finding ancestor runs
+  @@index([rootTaskRunId])
   // Task activity graph
   @@index([projectId, createdAt, taskIdentifier])
   //Runs list