How to fix `user must specify LSN` when using AWS DMS for Postgres RDS

0
votes

I'm trying to migrate and synchronize a PostgreSQL database using AWS DMS and I'm getting the following error.

Last Error Task error notification received from subtask 0, thread 0 
[reptask/replicationtask.c:2673] [1020101] When working with Configured Slotname, user must 
specify LSN; Error executing source loop; Stream component failed at subtask 0, component 
st_0_D27UO7SI6SIKOSZ4V6RH4PPTZQ ; Stream component 'st_0_D27UO7SI6SIKOSZ4V6RH4PPTZQ' 
terminated [reptask/replicationtask.c:2680] [1020101] Stop Reason FATAL_ERROR Error Level FATAL

I already created a replication slot and configured its name in the source endpoint.

DMS Engine version: 3.1.4

Does anyone knows anything that could help me?

2
amazon-web-servicesrdsdms

2 Answers

1
votes

Luan -

I experienced the same issue - I was trying to replicate data from Postgres to an S3 bucket.I would check two things - your version of Postgres and the DMS version being used. I downgraded my RDS postgres version to 9.6 and my DMS version to 2.4.5 to get replication working.

enter image description here You can find more details here - https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Source.PostgreSQL.html

I wanted to try the newer versions of DMS (3.1.4 and 3.3.0[beta]) as it has parquet support but I have gotten the same errors you mentioned above.

Hope this helps.

0
votes

It appears AWS expects you to use the pglogical extension rather than test_decoding. You have to:

  1. add pglogical to shared_preload_libraries in parameter options
  2. reboot
  3. CREATE EXTENSION pglogical;

On dms 3.4.2 and postgres 12.3 without the slotName= setting DMS created the slot for itself. Also make sure you exclude the pglogical schema from the migration task as it has unsupported data types.

P.S. When DMS hits resource limits it silently fails. After resolving the LSN errors, I continued to get failures of the type Last Error Task 'psql2es' was suspended due to 6 successive unexpected failures Stop Reason FATAL_ERROR Error Level FATAL without any errors in the logs. I resolved this issue using the Advanced task settings > Full load tuning settings and tuning the parameters downward.