## TL;DR
Shrink the extract before tuning the views. Open the extract settings, hide every unused field, add extract filters for the date window the dashboard actually needs, and aggregate to the visible granularity where the design allows it. Refresh the smaller extract and time the dashboard again. Extract size drives both refresh time and the memory the server needs to open the views.

```text
Tableau dashboard load slow and timing out: extract too large performance error fix
```

## Use this when
- Dashboard open times grew steadily with source data volume and now stall or time out.
- The extract file size is large relative to what the views display.
- The performance recording shows time in data engine queries rather than in rendering.

## Not for this skill when
- The dashboard uses a live connection and is slow in the database. Tune the source queries instead.
- One view is slow while others on the same extract are fast. That points at view design, not extract size.

## Steps
1. Record a baseline by timing the dashboard open and running the Tableau performance recording on the slowest view. Verify: the recording attributes most time to data queries against the extract
2. Open the data source in Desktop, hide all fields no view uses, and confirm the used field list with the dashboard owner. Verify: hidden fields are excluded from the extract definition
3. Add extract filters that bound the extract to the window the dashboard serves, and set aggregation to the coarsest granularity the views need where appropriate. Verify: the extract settings show the filters and aggregation before refreshing
4. Refresh the extract and compare its new file size and refresh duration with the baseline. Verify: the extract is materially smaller and refreshes faster
5. Publish the reduced extract and time the dashboard open again as a viewer on the server. Verify: the dashboard opens inside the acceptable window with no timeout
6. Set an extract size or refresh duration alert so growth is caught before viewers hit timeouts again. Verify: the monitoring view or alert lists the extract with a threshold configured

## Why it happens
Extract performance problems are growth problems. The design that was fine at launch quietly degrades as history accumulates, and because every view shares the extract, the whole dashboard slows together. Bounding the extract to the questions the dashboard answers, and reviewing that bound as data grows, keeps the snapshot proportional to its job.

Tableau extracts are columnar snapshots, but size still matters. An extract that carries years of row level history, dozens of unused text fields, and no aggregation forces the server to scan and load far more than any view displays. As the source grows, the dashboard crosses from slow to timing out at open, and the performance recorder shows the time sitting in query and data engine stages rather than in layout rendering.

Field notes for Tableau specifically. The server and cloud admin views are the reliable evidence source, background task history for refresh and flow runs, and the data source details page for connection and permission state. Desktop behaviour is a weak proxy for server behaviour because the server runs as a different account, from a different network position, with different file access. Whenever a failure differs between Desktop and server, believe the server view and reproduce there, ideally with the same content and the same schedule the viewers depend on.

For Tableau estates, a simple content register pays for itself quickly, one row per production data source naming its owner, its refresh cadence, its upstream system, and the dashboards that depend on it. Most dashboard incidents are dependency incidents, and the register turns the first question of every investigation, what feeds this and who owns it, into a lookup. Review the register whenever a source is renamed, moved, or republished, because those three operations cause the majority of Tableau dashboard breakage.
## Variants and edge cases
### Tableau dashboard timeout extract too large shrink fix
The size-first phrasing matching the root cause.
### Tableau extract filters aggregation dashboard slow
The technique variant naming filters and aggregation.
### Tableau performance recording data engine slow extract
The diagnostic variant that starts from the performance recording.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_bPPew_u_Eb7u7-aZX5Hmog