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# Find the slow task in a Mammoth pipeline and get help

> Find which Mammoth pipeline task is slow with Preview Data at this Task, watch running and stuck work in Monitor, check limits, and what to send support.
>
> Applies to: Where: Monitor › Running

To find what slows a pipeline, check the row count at each task, then watch running work in **Monitor** in the left sidebar. If it's still slow after the fixes in [Speed up Mammoth pipelines](https://mammoth.io/docs/learn/help/performance/), contact support with the details below.

## Find the slow task in a pipeline

Use **Preview Data at this Task** on each task to see the row count at that point. Look for:

- tasks where the row count is higher than you expect (a filter that should cut rows but doesn't)
- tasks that work across the whole dataset, such as joins and Group & Pivot on large datasets
- Math Function columns with complex calculations across millions of rows

Then apply the matching fix:

| What you find | Fix |
| --- | --- |
| Row counts stay high | Move **Conditional Filter** tasks as early as possible, ideally right after the source |
| A slow Join | Check whether **Lookup** is enough, and whether the join key has duplicates |
| Many unused columns | Add a **Remove Column** task right after the source |
| Heavy rebuilds while you edit | Turn on Draft mode |

## Watch running work in Monitor

Open **Monitor** in the left sidebar. You don't need to stay on the page, because Mammoth runs processing on its servers.

| Tab | What it shows |
| --- | --- |
| **Needs Attention** | Errors, pending data, and governance items (pipeline checkpoints, failed data checks) waiting on you |
| **Running** | Pipelines, tasks and automations running or queued. A task that runs unusually long is flagged **Stuck** |
| **Paused** | Pipeline tasks, exports and connections with Auto-sync off |
| **Activity Log** | A history of events, if your role has activity log access |

See [Monitor running, failing and paused pipelines](https://mammoth.io/docs/learn/automate/monitor/) and [Activity log](https://mammoth.io/docs/learn/automate/activity-log/).

## Limits that affect performance

Storage is set by your plan: see **Workspace Settings → Plan & Storage** for your allowance and per-dataset usage. Uploads from your computer are limited to 50 MB per request, and BI workbook imports (Tableau `.twbx`, Power BI `.pbix`) to 1 GB. A BigQuery query times out after 5 minutes, and a long-running job after 1 hour; contact Mammoth support if a connector's timeout interrupts your work. Contact your account team for the limits that apply to your workspace and plan, and see [Limits and quotas](https://mammoth.io/docs/learn/help/limits/).

## Still slow? Contact support

1. Check **Monitor**: **Running** shows whether a task is **Stuck**, and **Needs Attention** lists failed runs and errors.
2. Find the slowest task. Joins are the most common culprit: check them for duplicate keys, because fan-out multiplies rows.
3. Move any Conditional Filter tasks earlier.
4. Email [support@mammoth.io](mailto:support@mammoth.io). Support can inspect server-side run logs. Include:
   - your workspace name and dataset name
   - the View's name and the slow task (or the pipeline ID)
   - the approximate row count and column count
   - the operation that's slow (dashboard load, pipeline run, export, automation)
   - how long it takes, and how long you'd expect

## Related

- [Speed up Mammoth pipelines](https://mammoth.io/docs/learn/help/performance/): filter early, order tasks and use Draft mode.
- [Speed up refreshes and exports](https://mammoth.io/docs/learn/help/slow-refreshes/): when a refresh, not the pipeline, is slow.
- [Fix connection and refresh failures](https://mammoth.io/docs/learn/help/connection-failures/): when a refresh fails instead of running slowly.

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Source: https://mammoth.io/docs/learn/help/find-slow-tasks.md · Updated: 2026-11-08