# Database Index Fragmentation

**Purpose:** Which indexes and tables have degraded and need maintenance. A tab group separating index-level from table-level fragmentation, each with a top-thirty chart and a detail grid.

![Database Index Fragmentation showing an index and table fragmentation tab group and a top thirty fragmentation percentage chart, with object names redacted](https://visualoneintelligence.com/wp-content/uploads/2026/08/voi-docs-db-index-fragmentation.png)

## When to use it

- Build a rebuild or reorganize worklist for a maintenance window
- Check whether an existing maintenance job is actually keeping up
- Investigate a query that has slowed without its plan changing
- Scope how much of the estate needs index maintenance at all

## Key areas and metrics

- **Tab group.** `Index Fragmentation` and `Table Fragmentation`, switching the whole panel between the two scopes.
- **Chart.** Top thirty by fragmentation percentage, one bar per object, with hover showing the object name and its exact percentage.
- **Grid.** The full result set beneath, sortable and groupable, typically running to hundreds or thousands of rows.

## Fragmentation percentage alone is not a priority

A top-thirty chart on this screen will usually be a wall of bars at or near one hundred percent, because in any estate of size there are more fully-fragmented objects than thirty. That makes the chart poor at prioritizing: every candidate looks equally bad.

Two things separate the ones worth acting on. **Size**, because fragmentation on a small object has negligible effect and rebuilding it wastes a maintenance window, while a large fragmented index is a real performance cost. And **whether anything reads it**, since a heavily fragmented index no query uses is a candidate for removal rather than maintenance.

So the useful order is large and heavily fragmented and actively read. The chart gives you the third of those criteria only.

## Index against table fragmentation

- **Index fragmentation** is logical disorder within an index structure, addressed by rebuilding or reorganizing that index.
- **Table fragmentation** concerns the underlying data pages, and is usually addressed differently depending on platform and table structure.

Check both tabs. An object appearing high in both is a stronger maintenance candidate than one appearing in a single view.

## Common actions

- **Work from the grid, not the chart.** Sort by size where available, filtered to high fragmentation.
- **Group by Database Name** to find databases with no effective maintenance job, which usually show as whole clusters of fragmented objects.
- **Cross-check against Unused Indexes.** Do not spend a maintenance window rebuilding something nothing reads.
- **Re-run after the window** to confirm the maintenance job did what was intended.

## Tips

> Small objects routinely report high fragmentation and it is normal rather than actionable. Below a few hundred pages the measure is not meaningful, so filtering by size before reading percentage avoids a maintenance window spent on objects too small to matter.

## Related screens

[Unused Indexes](https://visualoneintelligence.com/docs/databases-unused-indexes/) identifies fragmented indexes not worth maintaining. [Queries Performance](https://visualoneintelligence.com/docs/databases-queries-performance/) shows whether fragmentation is affecting anything measurable. [Missing Indexes](https://visualoneintelligence.com/docs/databases-missing-indexes/) covers the other direction of index work.

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Source: https://visualoneintelligence.com/docs/databases-index-fragmentation/