fix(data-drains): cadence buffer + clear stale error on success

- Dispatcher: subtract a 5-minute buffer from the cadence cutoff. Without
  this, a drain that finishes a few minutes after the hourly tick
  (lastRunAt = 10:05) won't satisfy lastRunAt < now - 1h at the next tick,
  causing "hourly" drains to run every ~2 hours.
- Service: clear `error` to null on the success update so a row previously
  reaped as orphaned doesn't render as success-with-error.

Author: waleedlatif1

apps/sim/lib/data-drains/dispatcher.ts

@@ -12,6 +12,16 @@ const logger = createLogger('DataDrainsDispatcher')
 const HOUR_MS = 60 * 60 * 1000
 const DAY_MS = 24 * HOUR_MS
 
+/**
+ * Cron fires hourly. Without a buffer, a drain that finishes a few minutes
+ * after the tick (lastRunAt = 10:05) won't satisfy `lastRunAt < now - cadence`
+ * at the next tick (10:05 < 10:00 is false), so an "hourly" drain effectively
+ * runs every two hours. Subtracting a small buffer from the cadence absorbs
+ * normal run duration plus cron jitter without allowing back-to-back runs
+ * within the same tick.
+ */
+const CADENCE_BUFFER_MS = 5 * 60 * 1000
+
 /**
  * Maximum wall-clock duration any single drain run is allowed before its
  * `data_drain_runs` row is considered orphaned. Runs that exceed this are
@@ -59,8 +69,8 @@ export async function dispatchDueDrains(now: Date = new Date()): Promise<{
 }> {
   const { reaped } = await reapOrphanedRuns(now)
 
-  const hourlyCutoff = new Date(now.getTime() - HOUR_MS)
-  const dailyCutoff = new Date(now.getTime() - DAY_MS)
+  const hourlyCutoff = new Date(now.getTime() - HOUR_MS + CADENCE_BUFFER_MS)
+  const dailyCutoff = new Date(now.getTime() - DAY_MS + CADENCE_BUFFER_MS)
 
   const duePredicate = and(
     eq(dataDrains.enabled, true),

apps/sim/lib/data-drains/service.ts

@@ -144,6 +144,7 @@ export async function runDrain(
           bytesWritten,
           cursorAfter: cursor,
           locators,
+          error: null,
         })
         .where(eq(dataDrainRuns.id, runId))
     })