:PROPERTIES:
:ID:       091bce6d-e15b-434f-a7be-bc6627a71925
:END:
#+title: 2022-04-06
* Fixing normalized tag search
https://jira.aweber.io/browse/ASE-8617

- *What was broken?* :: Searches and segments with a "tag is not" constraint
  failed to match subscribers with no tags.
- *When was it broken?* :: April 5th at 16:00, following the release of
  CCPANEL-12034.
- *What did you do to fix the problem?* :: The change was rolled back by
  updating search terms in the analytics search database to their previous
  values at 19:12 on April 5th.
- *How many customers did it likely impact?* :: Likely all customers using the
  "tag not in" filter in their searches and segments.
- *Is the issue automatically fixed for all customers now?* :: Yes.
- *Does the customer or CS need to manually do something to fix their account?* :: No.
- *Should a new monitoring check, metric, or test be created to prevent this from happening again?* :: Additional
  tests will be added to ensure future releases of this feature do not break
  search and segment behavior.
** What happened?
=ARRAY_AGG= returns =NULL= when given an empty set. This breaks the tag
comparison, as =NOT(NULL @> ARRAY['tag'])= is equal to =NULL=, not =TRUE=.
Updating the logic to =COALESCE= null values with an empty array allows the
comparison to function as intended. =normalize_tags= must also omit invalid tags
(tags that normalize to the empty string) from its results.