Performance regression when saving features

Advanced Use & Customization
1

Hi @nirvn,

I’m experiencing a significant performance regression when saving features in QField 4.1.1 compared to versions prior to 4.1 (last confirmed working version: 4.0.5). Saving a feature in the Observacion layer takes approximately 10 seconds in 4.1.6, while the same operation completes in about 1 second in 4.0.5.

Setup:

  • QGIS 3.40.11 (desktop)
  • QField >=4.1.x (field device, Android)
  • PostGIS/PostgreSQL backend, offline editing via QFieldCloud (layers packaged as GeoPackage on device)

Behaviour:

  • The delay occurs specifically when pressing the Save button, not while interacting with widgets
  • The regression is specific to one layer (Observacion). Other layers in the same project save instantly
  • The delay is consistent (~10 seconds) from the very first save after opening the project, regardless of how many features have been saved in that session

Layer characteristics:
The Observacion layer has 76 fields with the following widget distribution: 26 Range, 22 ValueRelation, 10 ValueMap, 10 CheckBox, 7 TextEdit, 1 DateTime.

Extensive troubleshooting already performed — none resolved the issue:

  1. Rewrote overlay_nearest() default value expressions to short-circuit eagerly in the majority of cases — no improvement
  2. Removed ALL default value expressions from the layer — no improvement
  3. Removed ALL constraint expressions from the layer — no improvement
  4. Removed the layer’s SQL filter (which included a subquery with now()) — no improvement
  5. Tested a minimal layer with 75 plain text fields, no expressions, no filters, published via QFieldCloud — save was instant
  6. Tested the same minimal layer with 20 fields configured as ValueRelation widgets pointing to a small lookup table — save was still instant

None of the individual characteristics of the Observacion layer reproduce the issue in isolation. The delay appears to be caused by a combination of factors specific to this layer’s full structure that only manifests in 4.1+.

I was unable to obtain a useful runtime profile from the Message Log, as the ‘Log runtime profile’ button only captures project load state, not the state immediately after a save operation.

I’m attaching the application log captured immediately after a save. Unfortunately I’m unable to share the project file due to confidentiality constraints, but I’m happy to answer any questions about its configuration.

Is there any additional diagnostic information I can provide to help identify the regression introduced between 4.0.5 and 4.1.0?

Thanks for your work on QField.

2

@Mathieu_Pellerin possibly interesting for you

3

@Angel_Martinez , would you be able to share your project for us to look at? You can do so privately by emailing me at mathieu@opengis.ch.

4

Ok @Mathieu_Pellerin
I’ll send you to the email.

Thank you very much for your support.

5

@Mathieu_Pellerin Solved!!!

Thank you very much!

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6

Good Morning @Angel_Martinez , if you do get a minute it would be interesting to see what the issue was and how it solved, Kind Regards

David.

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7

@DavyKay , the issue was a regression in QField, ironically tied to a really good optimization tied to tracking sessions.

The fix is here: Only update feature attributes/geometry that have actually changed by nirvn · Pull Request #7347 · opengisch/QField · GitHub , it’ll make its way into QField’s next patch release soon enough :slight_smile:

1 Like