# The chat reconnected. Did you count the ad twice?

Walk one sponsored impression through a lost acknowledgement, a retry and a page reload.

Published: 2026-11-05T03:01:04Z

![The chat reconnected. Did you count the ad twice?](https://jolts.xyz/rails/active_storage/blobs/redirect/eyJfcmFpbHMiOnsiZGF0YSI6NCwicHVyIjoiYmxvYl9pZCJ9fQ==--94c017ffaa8e06fd5ea624015a91eedb53ba18ad/one-impression-after-reconnect.webp)

The server commits an impression. The phone goes through a tunnel before the acknowledgement arrives. When the connection comes back, the phone still has an unsent event in its queue. The advertiser’s invoice now depends on one small implementation detail: when did the client assign the event ID?

Assign it when the display first qualifies. Store it alongside the queued event. If the phone generates a fresh ID inside the retry loop, the server has no way to distinguish a second delivery attempt from a second display.

## Try the lost acknowledgement in PostgreSQL

This example uses a temporary table. Run the statements in one database session. The two inserts are the two deliveries of the same display.

```sql
CREATE TEMP TABLE counted_displays (
  publisher text,
  display_id text,
  PRIMARY KEY (publisher, display_id)
);

INSERT INTO counted_displays VALUES ('demo', 'turn-42-card-1')
ON CONFLICT DO NOTHING RETURNING display_id;

INSERT INTO counted_displays VALUES ('demo', 'turn-42-card-1')
ON CONFLICT DO NOTHING RETURNING display_id;
```

The first insert returns one row. The retry returns zero. Both requests can receive a successful acknowledgement. If the reporting pipeline increments a counter on every received request, the invoice will still be wrong. Count the committed rows, or queue the accounting event in the same transaction as the successful insert. [PostgreSQL documents the conflict and RETURNING semantics here](https://www.postgresql.org/docs/current/sql-insert.html).

One question remains for the publisher. If someone scrolls back to yesterday’s chat and sees the same card again, does that qualify as a new impression? Agree on that before implementing replay. A component that generates a new display ID every time it mounts has already made the decision for you.


## Related terms
- [Impression](https://jolts.xyz/resources/glossary/impression)

## Next step

[Explore advertising](https://jolts.xyz/advertisers) or [monetize your AI app](https://jolts.xyz/publishers).