BC Observatoryunofficial, made by waldo
code change · performanceAL Developmentofficial - Microsoftreviewed - checked by Opus

#10009 Disable low-usage Change Log Entry index

The Change Log Entry table's Key4 index on Notification Message Id is disabled to improve write performance. The index showed negligible read usage (967 reads) compared to extremely high write maintenance costs (1.3 billion writes), making it a significant performance drain.

Open in Claude10009.mdPull request #10009

Pull request · merged into main (BC30) on 2026-08-07 by PredragMaricic · 1 file (+10 -0), 1 AL · performance · tier official · reviewed (checked by Opus)

What changed

  • Key4 (Notification Message Id) index disabled in Change Log Entry table due to 1.36 million writes per read ratio
  • Index remains in schema as disabled following obsoletion lifecycle: Pending in 29.0, Removed in 32.0
  • Telemetry analysis across 40k databases shows minimal functional impact with strong performance benefit
  • Extensions using SetCurrentKey or sorting by Notification Message Id can add their own table-extension key
  • Schema synchronization during upgrade will remove the physical index, potentially creating transient deployment load on large tables

AL objects touched

Obsoletions

  • Change Log Entry: Key4

Context

  • Work items: AB#644754
  • Labels: Team: Integrations
  • Systems: development

Source: metadata of a merged pull request in microsoft/BCApps (bcapps): title, labels, changed paths and counts, with a summary in our words. No source text and no description beyond one short quote (D10, D61).