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Common errors and special scenarios for PostgreSQL Single Server to Flexible using the Single to Flex migration tool

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APPLIES TO: Azure Database for PostgreSQL - Single Server Azure Database for PostgreSQL - Flexible Server

Important

Azure Database for PostgreSQL - Single Server is on the retirement path. We strongly recommend for you to upgrade to Azure Database for PostgreSQL - Flexible Server. For more information about migrating to Azure Database for PostgreSQL - Flexible Server, see What's happening to Azure Database for PostgreSQL Single Server?

This articles explains common errors and special scenarios for PostgreSQL Single Server to Flexible using the Single to Flex migration tool.

Custom DNS

  • Error message Connecting to the Source DB server failed. ErrorMessage: Validation of one or more databases failed to run select 1; with exception 28000: The public network access on this server is disabled. Use the Private Endpoint inside your virtual network to connect to this server.

  • Root Cause

    The VNet is, by default, not enabled for outbound connections when we use CustomDNS. Migration makes outbound calls, which cause the failure.

  • Mitigation/Resolution

    While Microsoft is working on a fix as part of the product, customers can use one of the following mitigations to unblock: Temporarily enable the public network access on the server OR Reach out to Microsoft, and we enable the server for outbound connections for the selected DNS addresses.

Allowlist extensions

  • Symptom Error message appears as "Extensions plpgsql, pg_stat_statements, pg_buffercache aren't allowlisted on target server."

    Screenshot of scenario for allow listing extensions.

  • Root Cause

    The flexible server doesn't have extensions allow-listed by default and has to be manually allow-listed before migration/use.

  • Mitigation/Resolution

    Customers need to go to the server parameters of the flexible server and allowlist all the extensions they intend to use. At least the ones mentioned in the error message should be allowed to be listed. To add extensions to the allowlist, you can edit the list of the azure.extensions parameter in the Server parameters for your flexible server.

No pg_hba.conf entry for host

  • Error Message Connecting to the Source DB server failed. ErrorMessage: Validation of one or more databases failed. Failed to run select 1; with exception 28000: no pg_hba.conf entry for host "xx.xx.xx.xx", the user "username," database "postgres," SSL on Parameter name: SourceDBServerResourceId.

  • Root Cause

    The IP address isn't added to the firewall rules.

  • Mitigation/Resolution

    Add IP addresses in the Firewall rules in the Networking tab of the Flex Server.

    Screenshot of ip addresses.

Migration to Flex server with Burstable SKU isn't Supported

  • Error Message Migration to Flex server with Burstable SKU isn't Supported.

  • Root Cause

    By Design.

  • Mitigation/Resolution

    Change the flexible server from Burstable to General Purpose or Memory Optimized by going to compute + storage tab on the left menu.

Cross-region migration isn't supported

  • Error Message Cross-region migration isn't supported.

  • Root Cause

    By Design.

  • Mitigation/Resolution

    This feature is coming soon; in the meantime, only migrations within servers of the same region are supported.

Next steps