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Not yet released. This guide describes implemented changes awaiting rollout. Availability requires the corresponding backend and dashboard release.

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Goal

Take read load off the primary for reports, search or heavy dashboards.

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Prerequisites

  • A Dedicated database

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Workflow

1
Add a replica with stackshift database replica-add DATABASE (POST /api/v1/databases/{id}/replicas). Pass --data '{"instance_class":"s-2vcpu-4gb"}' to choose a size; each replica needs at least half the primary’s memory.
2
If the answer is 409 price_confirmation_required, resend the same request with confirm_charge_minor set to the quoted charge.
3
Wait until stackshift database ha DATABASE shows the replica healthy.
4
Point read-only queries at the read address db-<id>-ro.stackshift.internal. It answers with every replica that has caught up.
5
Remove a replica with stackshift database replica-remove DATABASE REPLICA, using the replica id from stackshift database ha DATABASE. Its unused time is credited to your wallet.

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Things to know

  • Replicas are a little behind the primary. Read your own writes from the primary when it matters.
  • A replica that falls too far behind leaves the read address until it catches up.
  • stackshift database ha DATABASE shows each member’s lag_seconds, and the database metrics chart one line per replica over 1, 6 or 24 hours. You get a warning event when a replica is more than 30 seconds behind, and it clears once every replica is under 5 seconds.
  • Each replica is billed like a database of its size; adding one asks you to confirm the price.

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Availability

Dedicated databases are rolling out. If Create doesn’t offer Dedicated, it isn’t switched on for your account yet, and the API answers 403.

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Expected result

Read queries run on the replicas, and writes keep going to the primary.

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Common failures

  • More than 5 replicas, or a replica size smaller than half the primary’s memory, is refused.
  • 409 price_confirmation_required: resend with confirm_charge_minor set to the quoted charge.

Standby and high availability

Add a standby on another server. If the primary fails, the standby takes over and your connection address stays the same.

Dedicated databases

Create a Dedicated PostgreSQL database, connect to it, resize it and manage its lifecycle.

Performance Insights and events

See what a Dedicated database spends its time on, find its slowest queries, and read a feed of failovers, backups and maintenance.