The PostgreSQL exporter delete-task option does not seem to be working

We were hoping to use the delete-task option to keep our dev databases a bit smaller. Our conduit.yml file looks like this:

exporter:
  name: postgresql
  config:
    connection-string: <redacted>
      sslmode=disable
    delete-task:
      rounds: 1000
      interval: 20

However, when running against either a fully-synced PostgreSQL instance or an instance that is starting from 0, it does not appear that the txn table is being culled. Using the above configs, I can see the following in the DB:

betanet=> select round from txn;
 round 
-------
   357
 12166
 12178
 12188
 13011
 13018
 13020
 14810
 14817
 14823
 14864
 15655
 15661
 15668
 18075
 36998
(16 rows)

I'd have expected the early rows to have been thrown out as conduit moves through later blocks.

Your environment

• Conduit 1.2.0 (37a13fe)
• PostgreSQL 13.10
• Algod 3.16.3.stable [rel/stable] (commit #cbccc6de)
• Ledger: Betanet

Steps to reproduce

1. Bootstrap an empty PosgreSQL DB
2. Start Conduit using the PostgreSQL exporter from block 0 using the configs above.

Expected behaviour

Only transactions within the last 1000 blocks would be present

Actual behaviour

All transactions appear to be present. Table continues to get longer as conduit works its way through the ledger.