AWS DMS Failing to Migrate Tables with LOBs and JSONB Columns

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I’m using AWS DMS to migrate a Postgres database between two RDS instances (both Postgres 12.17). Most tables migrate successfully, but tables with LOBs and JSONB columns (public.contract and public.user) keep failing. The DMS task suspends with errors like:

  • Table 'public.contract' was errored/suspended
  • Failed to load data from csv file.
  • Handling End of table loading failed by subtask 1 thread 1.

Steps Taken:

  • Switched to Full LOB mode with no size limit.
  • Increased DMS instance to dms.r5.xlarge.
  • Checked JSONB column size (small, only 5 bytes).
  • Adjusted DMS timeouts and retries.

Key Questions:

  1. Is there an issue with non-optimized Full LOB mode causing these suspensions?
  2. Any DMS tuning tips to handle LOBs/JSONB better?
  3. Could the problem be related to target database resource limits?

Any insights or solutions are greatly appreciated. Thanks!

profile picture
Yusuf
asked 21 days ago43 views
2 Answers
1
Accepted Answer

Hi,

Re JSONB and LOB columns, are they nullable in target DB? As per doc, they must be so.

See https://docs.aws.amazon.com/dms/latest/userguide/CHAP_BestPractices.html#CHAP_BestPractices.LOBS for all details

Best,

Didier

profile pictureAWS
EXPERT
answered 21 days ago
profile picture
EXPERT
reviewed 20 days ago
  • Thank you so much. This helps.

  • Yusuf, you're very welcome! Thanks for accepting my answer

0

check the target postgres.log there would be more details about the error.

AWS
answered 20 days ago

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