Decided to remove UAT. In order to do this we deactivated users from UAT to see what noise was created (none). Then we adjusted the TIS UAT→NDW UAT ETL to be a TIS Stage→NDW UAT ETL - this way any impact of changes we're pushing through on NDW are more likely* to get surfaced in advance of them appearing on NDW Prod. Then we switched off Stage. Finally we set up a scheduled data sync from TIS Prod→TIS Stage (every weekend - our of working hours, enabling multi-day data tests to be carried out during a working week (but not spanning multiple working weeks).
*not always: in the case of code going up to Stage, approved on Stage and released to Prod within one day, and; in the case of rogue code passing existing tests but erroring because of a missing test
Background
UAT was set up as a temporary pre-Prod environment before we went live, as a training ground for new TIS users.
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There is a possibility it is also a step in a process for HiCom and/or NDW team.
Action items
Check with NDW / HiCom whether they are still using UAT - If so do whatever is necessary to ween them off it, immediately!
Take away all user access to UAT
Copy data from Prod to Stage
Schedule update of Stage data with Prod data daily