---
title: "dbt table models dominating build time | Metacenta"
description: "When one dbt table model takes a quarter of the build and recomputes in full every run, the whole team waits on it. How we find it from run timings."
url: "https://metacenta.com/rules/run-slow-full-rebuild"
updated: "2026-10-14"
tokens: 592
---

Execution health · rule run-slow-full-rebuild

# dbt table models dominating build time

A Metacenta review checks this under the rule **No full-rebuild model dominates the build**. Everything below applies whether or not you ever commission one.

## What this rule checks

From the timings in your last run, this rule flags models built as a `table` that took at least 10% of the measured build time. At 25% or more, the finding is high severity. It needs at least ten timed models, because below that every share is large by arithmetic.

## Why it matters

Build time is the floor on how quickly a change can be made, tested and shipped. One model sets most of it, and the team waits for it on every run, whether or not its inputs moved.

## How to fix it

**Stop rebuilding the largest tables from scratch on every run.** Confirm the timing over a few runs, then switch the model to an `incremental` materialisation with a `unique_key`, so a build recomputes only what changed.

Before:

```sql
{{ config(materialized='table') }}
select * from {{ ref('stg_shop__events') }}
```

After:

```sql
{{ config(materialized='incremental', unique_key='event_id') }}
select * from {{ ref('stg_shop__events') }}
{% if is_incremental() %}
where loaded_at > (select max(loaded_at) from {{ this }})
{% endif %}
```

## When it is fine to leave

A small or fast-changing table, where most rows change every run, gains little from being incremental and adds complexity. So does a table rebuilt in full on purpose to correct late-arriving data.

## What we need to check it

`run_results.json` alongside `manifest.json`. One run is one sample, so we report this at medium confidence. The rule declines when the run covered only part of the project.

[Ask about a review](https://metacenta.com/enquire?src=rule-run-slow-full-rebuild&via=md)

## Related pages

- [dbt tests that are failing](https://metacenta.com/rules/test-failing)
- [dbt models that failed to build](https://metacenta.com/rules/node-build-error)
- [dbt models skipped behind a failure](https://metacenta.com/rules/run-blocked-cascade)
- [dbt tests slower than the model they test](https://metacenta.com/rules/run-slow-test)
- [A sample review, as a client reads it](https://metacenta.com/sample)
- [All published rules](https://metacenta.com/rules)
- [How a review is assessed](https://metacenta.com/standard)