Initialize the migration of notes.id and dependant columns to bigint

The column notes.id is a 4-byte integer at risk of saturation, having grown from roughly 25% saturation a year ago to over 50% saturation now.

Timeline

This process needs to be started ASAP - exhausting this column would cause serious harm to the running application.

Process

Following the process outlined here, in %15.9 we must initialize the migration to bigint for notes.id and all dependent columns:

• notes.id
  • Create column and triggers !110597 (merged)
  • Backfill
• todos.note_id
  • Create column and triggers !110704 (merged)
  • Backfill
• system_note_metadata.note_id
  • Create column and triggers !110705 (merged)
  • Backfill
• epic_user_mentions.note_id
  • Create column and triggers !110851 (merged)
  • Backfill
• suggestions.note_id
  • Create column and triggers !110861 (merged)
  • Backfill
• issue_user_mentions.note_id
  • Create column and triggers !110864 (merged)
  • Backfill
• note_diff_files.diff_note_id
  • Create column and triggers !111251 (merged)
  • Backfill
• snippet_user_mentions.note_id
  • Create column and triggers !111253 (merged)
  • Backfill
• design_user_mentions.note_id
  • Create column and triggers !111256 (merged)
  • Backfill
• vulnerability_user_mentions.note_id
  • Create column and triggers !111259 (merged)
  • Backfill
• commit_user_mentions.note_id
  • Create column and triggers !111261 (merged)
  • Backfill
• merge_request_user_mentions.note_id
  • Create column and triggers !111267 (merged)
  • Backfill
• timelogs.note_id
  • Create column and triggers !111268 (merged)
  • Backfill
• award_emoji.awardable_id
  • Create column and triggers !115928 (merged)
  • Backfill
• events.target_id
  • Create column and triggers !115932 (merged)
  • Backfill