[gdal-dev] ogrinfo UPDATE performance request

[Andreas Oxenstierna]

Hi

AFAIK, UPDATE only works with ogrinfo and the sqlite dialect. We have not tested the native PG SQL dialect extensively though, it took some time to find the correct syntax.
And to answer one other mail, the table name needs to be written as \”<schema>.<table>\”, at least on macOS

The performance issue is mainly that ogrinfo updates one feature at a time. Even if it should pack all data, copy it into a temp SQLite, do the update and transact back, it would be vastly faster if it is done in one transaction instead of one transaction for each feature as it is done now.

However, I realised that a workaround may be to add needed attribute info to any file format (GeoPackage or shape) - need to verify the performance though.
It should be nice to be able to execute this in a pure GDAL/OGR environment - the use case is to aggregate on different values, resolutions and interpolation methods for an AI platform so we may need to test thousands of variants.

Best Regards

Andreas Oxenstierna
T-Kartor Geospatial AB
Olof Mohlins väg 12 Kristianstad
mobile: +46 733 206831
mailto: andreas.oxenstierna at t-kartor.com<mailto:andreas.oxenstierna at t-kartor.com>
www.t-kartor.com<http://www.t-kartor.com>
On 9 Jun 2022, 09:46 +0200, Rahkonen Jukka <jukka.rahkonen at maanmittauslaitos.fi>, wrote:
Hi,

Do not use “-dialect sqlite” if you play with PostgreSQL but let GDAL to use the native PG SQL dialect.

-Jukka Rahkonen-

Lähettäjä: gdal-dev <gdal-dev-bounces at lists.osgeo.org> Puolesta Andreas Oxenstierna
Lähetetty: torstai 9. kesäkuuta 2022 9.50
Vastaanottaja: gdal-dev at lists.osgeo.org
Aihe: [gdal-dev] ogrinfo UPDATE performance request

Dear developers

Ogr SQL update capabilities are really impressing but there is one major performance issue with update of many features, exemplified by:
ogrinfo -dialect sqlite -sql "UPDATE <table> SET x = 1" PG:”<connection>"

This is painfully slow because ogr updates features one by one and furthermore updates all existing attributes incl. geometries.
Eg. updating 10000 features in pgAdmin/psql with UPDATE <table> SET x = 1 executes in milliseconds but takes several minutes with ogr.

The current ogr functionality is also not correct from a database transactional point of view.

I found an old RFC, https://gdal.org/development/rfc/rfc13_createfeatures.html, requesting this but it was withdrawn for reasons not anymore digitally available.

Best Regards

Andreas Oxenstierna
T-Kartor Geospatial AB
Olof Mohlins väg 12 Kristianstad
mobile: +46 733 206831
mailto: andreas.oxenstierna at t-kartor.com<mailto:andreas.oxenstierna at t-kartor.com>
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