---
id: change/bcapps/10009
type: change
title: "#10009 Disable low-usage Change Log Entry index"
summary: 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.
tier: official
language: en
tags:
  - performance
  - main
  - bc30
  - table change log entry
system: development
review:
  state: reviewed
  by: opus
  at: "2026-10-08T02:09:51.961Z"
  flags: []
generated:
  at: "2026-10-08T01:26:53.141Z"
  pipeline: 0.2.0
  prompts:
    extract-change: 1
  input_hash: 6f2e279e1b24ed3185024cf9c07b20b29a8c56e8
evidence:
  - kind: code
    url: https://github.com/microsoft/BCApps/pull/10009
    title: "microsoft/BCApps#10009: Disable low-usage Change Log Entry index"
    date: "2026-08-07"
    commit: 6f2e279e1b24ed3185024cf9c07b20b29a8c56e8
    t: null
    quote: null
links:
  learn: []
  objects:
    - object/table/405
  features: []
  topics: []
  localizations: []
  videos: []
  posts: []
  guidelines: []
  changes: []
number: 10009
repo: microsoft/BCApps
source_id: bcapps-prs
url: https://github.com/microsoft/BCApps/pull/10009
kind: pr
base_branch: main
major: "30"
merged_at: "2026-08-07T16:55:21Z"
author: PredragMaricic
author_type: User
community_contribution: false
labels:
  - "Team: Integrations"
change_class: code
change_kind: performance
behavior_change: false
breaking: false
files:
  count: 1
  additions: 10
  deletions: 0
  al: 1
apps:
  - Base Application
objects_touched:
  - key: table/405
    page: table/405
    type: table
    id: 405
    name: Change Log Entry
    app: Base Application
    status: modified
objects_unjoined: []
obsoletions:
  - object: Change Log Entry
    member: Key4
    replacement: null
backports: []
fixes_issues: []
work_items:
  - 644754
systems:
  - development
quote: null
joined_against:
  major: "30"
  commit: ecbc028c25dbe83b61313bc566e6c1d41184bb1c
---

# #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.

[Pull request](https://github.com/microsoft/BCApps/pull/10009) · 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

- [Table 405 "Change Log Entry"](../../objects/table/405.md), Base Application: modified

## 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).