diff --git a/docker/oasst-postgres/backup_pg_to_s3.sh b/docker/oasst-postgres/backup_pg_to_s3.sh
index ff509947..34b13eb7 100755
--- a/docker/oasst-postgres/backup_pg_to_s3.sh
+++ b/docker/oasst-postgres/backup_pg_to_s3.sh
@@ -4,10 +4,10 @@ set -e
 set -x
 
 # filename with timestamp
-filename="postgres-$(date +%Y-%m-%d_%H-%M-%S).sql"
+filename="postgres-$(date +%Y-%m-%d_%H-%M-%S).sql.gz"
 
 # perform pg_dump
-pg_dump -U postgres postgres > /tmp/$filename
+pg_dump -U postgres postgres | gzip -c > /tmp/$filename
 
 # upload to s3
 aws s3 cp /tmp/$filename s3://$S3_BUCKET_NAME/$filename