Query determining latest channel revision needs help

[bjester]

Observed behavior

The following query has significant query times in production, ranging from minimum of 0.5 seconds to 86 seconds over the last 7 days. We may want to evaluate similar queries in the sync endpoint.

SELECT
  "contentcuration_change"."server_rev"
FROM
  "contentcuration_change"
WHERE
  ("contentcuration_change"."applied"
    AND "contentcuration_change"."channel_id" = '<channel_id>')
ORDER BY
  "contentcuration_change"."server_rev" DESC
LIMIT
  1;

Expected behavior

The query is executed when loading the channel edit page, here.

User-facing consequences

Users may run into 502 timeout errors when attempting to open a channel.

Errors and logs

Additional information

https://learningequality.slack.com/archives/C0LK8QS9J/p1731706062874869

[rtibbles]

Fixed in #4826