Support page for failed payments takes seconds

Reported by: Gwen Alvarado (Merchant Support, Cinder Pay) · Priority: High · Component: Support tools

When a merchant calls about declined payments we open "recent failed attempts" for them. Since about the middle of last month that page takes three to five seconds, sometimes more when two of us are on calls. Last time I looked the payments team said their own dashboards are fine, so it must be something in the support page. Slow-query log lines from Thursday 22 October are attached. One thing the platform team keeps repeating: the payment API writes to that table all day long and we can't pause it or take it offline for a fix, so whatever we change has to go in while payments keep coming in.

Support note (Kwame): It is not every merchant: small ones with a handful of failures are slow too, so it is not about how many rows come back. The page only shows the 50 most recent failures.

Expected

The page opens in well under 200 ms for any merchant on the production table, with the same rows as today.

Actual

3-5 seconds per page view; the slow-query log shows the same statement each time.