# Very long waiting times for S2S retrieval requests on ECDS

**URL:** <https://forum.ecmwf.int/t/very-long-waiting-times-for-s2s-retrieval-requests-on-ecds/15011>\
**Category:** Datasets and Usage\
**Tags:** ecds\
**Created:** [26 May 2026 08:16 UTC](https://forum.ecmwf.int/t/very-long-waiting-times-for-s2s-retrieval-requests-on-ecds/15011 "2026-05-26T08:16:53Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![liu\_chennshuai](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/l/58956e/32.png) [@liu\_chennshuai](https://forum.ecmwf.int/u/liu_chennshuai)\
**Post date:** [26 May 2026 08:16 UTC](https://forum.ecmwf.int/t/very-long-waiting-times-for-s2s-retrieval-requests-on-ecds/15011/1 "2026-05-26T08:16:53Z")

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Hello everyone,

I have recently experienced extremely long waiting times when downloading S2S forecast data from ECDS using the CDS API.

For example:

- A request submitted on May 22 took approximately 21 hours before it finally completed successfully.

- The same request submitted again on May 25 has still not completed after waiting for many hours.

Below is the Python code I am using:

```python
import cdsapi

STEP_6H = [str(6*i) for i in range(1, 185)]

dataset = "s2s-forecasts"

request = {
    "origin": "ecmwf",
    "year": "2026",
    "month": "05",
    "day": "19",
    "time": "00:00",
    "level_type": "single_level",
    "variable": [
        "10_m_u_component_of_wind",
        "10_m_v_component_of_wind",
        "maximum_2_m_temperature_in_the_last_6_hours",
        "mean_sea_level_pressure",
        "minimum_2_m_temperature_in_the_last_6_hours",
        "surface_pressure",
        "total_precipitation"
    ],
    "forecast_type": "control_forecast",
    "leadtime_hour": STEP_6H,
    "data_format": "grib",
    "area": [25.7, 109.4, 20, 118],
}

target = "test.grib"

client = cdsapi.Client(key=key, url=url)
client.retrieve(dataset, request, target)

```

I would also like to know whether this issue is caused by my request configuration or by the ECDS server side.

The requested data volume is actually not very large — the final GRIB file is only a few tens of MB.

So I am wondering whether:

- there is something inefficient in my request setup,

- or whether the long waiting time is mainly due to current server load and queue congestion.

Any advice would be appreciated.

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**Author:** ![Steve\_McGee](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/s/6a8cbe/32.png) [@Steve\_McGee](https://forum.ecmwf.int/u/Steve_McGee)\
**Post date:** [1 June 2026 12:57 UTC](https://forum.ecmwf.int/t/very-long-waiting-times-for-s2s-retrieval-requests-on-ecds/15011/2 "2026-06-01T12:57:12Z")

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Hello.

I too have noticed very long processing time compared to past queries ( though for reanalyses, not forecast data ).

Have you learned the reasons for this?

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**Author:** ![ang\_gao](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/a/977dab/32.png) [@ang\_gao](https://forum.ecmwf.int/u/ang_gao)\
**Post date:** [2 June 2026 07:14 UTC](https://forum.ecmwf.int/t/very-long-waiting-times-for-s2s-retrieval-requests-on-ecds/15011/3 "2026-06-02T07:14:21Z")

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I encountered the same problem as you. The download speed is very slow, and I have to queue for a long time. Has anyone solved this problem?

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**Author:** ![Jayne\_Doshi](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/j/278dde/32.png) [@Jayne\_Doshi](https://forum.ecmwf.int/u/Jayne_Doshi)\
**Post date:** [4 June 2026 14:49 UTC](https://forum.ecmwf.int/t/very-long-waiting-times-for-s2s-retrieval-requests-on-ecds/15011/4 "2026-06-04T14:49:09Z")

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> [@Steve\_McGee](#):
>
> Hello.
> 
> I too have noticed very long processing time compared to past queries ( though for reanalyses, not forecast data ).
> 
> Have you learned the reasons for this?

No even for reanalysis it is the same problem it is just running for hours and hours even for a simple monthly data.