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masato
masato

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How I burned through Supabase's free egress limit (5GB 10.26GB) with polling and select=*

#supabase #postgres #nextjs #webdev

TL;DR

  • Supabase free plan: 5GB egress/month
  • My project: 10.26GB (205% over limit)
  • Root cause: 5-second polling × select('*') on a table with a 200,000-char text column
  • Fix: generated column flag + select column restriction + visibilitychange polling stop

What happened

My KOBO project (issue-finder) had a collection-queue-form component polling if_jobs every 5 seconds via select('*'). The table includes raw_input_text (up to 200K chars). Through Vercel Functions, every poll was shipping that full column downstream.

5s interval × 200,000 chars × hours of operation = GB gone
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Noticed when I checked the Supabase dashboard on 2026-05-31.

Fix 1: Generated column as boolean flag

If I only need to know whether raw input exists, I don't need to ship the text:

ALTER TABLE if_jobs
ADD COLUMN has_raw_input boolean
  GENERATED ALWAYS AS (raw_input_text IS NOT NULL) STORED;
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Fix 2: Narrow the select 

// Before
const { data } = await supabase.from('if_jobs').select('*')

// After — list view only needs lightweight columns
const { data } = await supabase
  .from('if_jobs')
  .select('id, status, has_raw_input, created_at, updated_at')
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Fix 3: Slow down polling + stop on hidden tab 

useEffect(() => {
  let interval: ReturnType<typeof setInterval> | null = null
  const start = () => { interval = setInterval(fetch, 30_000) } // 5s → 30s
  const stop = () => { if (interval) clearInterval(interval) }
  document.addEventListener('visibilitychange', () =>
    document.hidden ? stop() : start()
  )
  start()
  return stop
}, [])
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When does this happen to you?

  • select('*') on a table with large text/JSON columns
  • Polling interval ≤ 10s
  • Serverless function proxy (Vercel, etc.) — egress counted on every hop

Full writeup (Japanese): https://masatoman.net/articles/supabase-egress-overage-free-plan-2026

Top comments (1)

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vollos profile image
Pon •

Nice catch chasing the egress bill down to the actual column, that's the kind of bug that only shows up once you're already over the limit. Since if_jobs holds raw_input_text per job, is that table scoped to the owning user through RLS, or does the fetch happen server-side where that doesn't come into play?