PROBLEM WITH STORAGE OF MY POSTGRES RDS INSTANCE

Hi,

There could be several reasons for your database to run out of storage. The DB storage is used for the following

• Temporary tables or files that are created by PostgreSQL transactions
  

• Data files
  

• Write ahead logs (WAL logs)
  

• Replication slots
  

• DB logs (error files) that are retained for too long
  

• Other DB or Linux files that support the consistent state of the RDS DB instance
  

If your DB instance is still consuming more storage than expected, check for the following:

• Size of the DB log files

• Presence of temporary files
  

• Constant increase in transaction logs disk usage
  

• Replication slot:
  

• Physical replication slots are created by cross-Region read replicas or same-Region read replicas only if they are running on PostgreSQL 14.1 and higher versions
  

• Logical replication slots are created for a replica or subscriber
  

• Bloat or improper removal of dead rows
  

• Presence of orphaned files
  

You can utilize Amazon CloudWatch to monitor your DB storage space using the FreeStorageSpace metric. When you set a CloudWatch alarm for free storage space, you receive a notification when the space starts to decrease. If you receive an alarm, review the causes of storage issues mentioned previously.

More details can be found in the below AWS blog: https://repost.aws/knowledge-center/diskfull-error-rds-postgresql

Hope this helps.