After cdc connection using postgresql connector, OldestReplicationSlotLag continues to increase as shown below.

I think it's a wal disk space consumption issue.Please check if there is something wrong with my settings

here is my cdc config 

publication.autocreate.mode=disabled
publication.name=cdc_publication
plugin.name=pgoutput
heartbeat.interval.ms=1000
heartbeat.action.query=update public.cdc_heart_beat set id = 1, last_heart_beat = current_timestamp where id = 1;

i'm using 

confluent platform 5.5.1 on aws ecs cluster 

debezium 1.7.1