Speed up emap-star waveform table writes by ~50%

[jeremyestein]

Hibernate needs to be able to tell if the in-memory object has changed vs what it thinks is in the database. It uses the equals method of the Entity object to do so. If it looks like it has changed, it will issue an UPDATE to the database.

Our equals method always returned false, thus causing an unecessary UPDATE shortly after we do the initial INSERT.

Objects.equals(a1, a2) delegates to a1.equals(a2) in the case of Java arrays, which only tests for referential equality! The fix is to use Arrays.equals(a1, a2), which tests for equality of the values inside.

(Note that this is not part of the Waveform export pipeline that we've been actively working on the last few months. This is the waveform table inside the Postgres DB.)

[github-actions]

PR checklist

Default guide for a PR (if multiple PRs for the work, only keep one version of it and link to it on the other PRs)

• From the UCLH data science desktop, a validation run has been set off
• Check that content that reveals Epic IP (eg. Clarity/Caboodle queries) has not been checked into a public repo.
• load times
  in UCL teams has been populated with the run information
• During the run, glowroot has been checked for any queries which are taking a substantial proportion of the
  total processing time. This can be useful to identify indexes that are required.
• After the run, look for any unexpected errors in the etl_per_message_logging table, the error_search.sql file
  on the shared drive can be used for this \\sharefs6\UCLH6\EMAP\Shared\EmapSqlScripts\devops\error_search.sql.
  Create an issue if you find an unexpected exception and is not related to the changes you've made, otherwise
  fix them!
• After the run, populate the end time in
  load times
• Let Aasiyah know about the completed validation and give her information on the changes and where to start
  with the validation
• Check validation report and give any feedback to Aasiyah if there are any changes needed on her side,
  iterate on getting the validation to match at least 99% (validation and emap code).

[skeating]

This is really good fix