Warning "Unknown GDAL driver" on Aurora PostgreSQL with PostGIS

Question

When trying to import raster data into Aurora PostgreSQL, we get the error `WARNING:  Unknown GDAL driver: `.

Sample import that produces the error:

```sh
$ raster2pgsql -d -f raster_data -Y 1000 -s 54009 -I -C -M -t auto /data/ghsl/GHS_SMOD_E2030_GLOBE_R2023A_54009_1000_V2_0.tif imports.ghs_smod | psql service=udc
Processing 1/1: /data/ghsl/GHS_SMOD_E2030_GLOBE_R2023A_54009_1000_V2_0.tif
INFO: Using computed tile size: 256x256
BEGIN
NOTICE:  table "ghs_smod_test_to_delete" does not exist, skipping
DROP TABLE
CREATE TABLE
WARNING:  Unknown GDAL driver: 
COPY 1000
[...]
```

The driver that the `raster2pgsql` command is using the `GTiff/GeoTIFF` driver:
```sh
$ gdalinfo /data/ghsl/GHS_SMOD_E2030_GLOBE_R2023A_54009_1000_V2_0.tif | grep "Driver:"
Driver: GTiff/GeoTIFF
```

The PostGIS extension installed as per the [documentation](https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/Appendix.PostgreSQL.CommonDBATasks.PostGIS.html) and `postgis.gdal_enabled_drivers` is set to `ENABLE_ALL` via an AWS parameter group – as confirmed below – including the `GTiff/GeoTIFF` driver.

```
udc=> SHOW postgis.gdal_enabled_drivers;
 postgis.gdal_enabled_drivers 
------------------------------
 ENABLE_ALL
(1 row)

udc=> SELECT PostGIS_GDAL_Version();
      postgis_gdal_version       
---------------------------------
 GDAL 3.5.3, released 2022/10/21
(1 row)

The warning is produced by the PostGIS extension (see [PostGIS source code](https://github.com/postgis/postgis/blob/935e23f3c42b24ed9074e77e5473ae18ab8eedbe/raster/rt_pg/rtpostgis.c#L619)), which lets me anticipate that this could be something that needs fixing by AWS. Alternatively, it could be that `raster2pgsql` is not handing over the driver requirement properly. Usually, the warning message would state the specific driver that is unknown. In this case, it seems like `enabled_drivers_array[i]` that is defined in the [PostGIS source code](https://github.com/postgis/postgis/blob/935e23f3c42b24ed9074e77e5473ae18ab8eedbe/raster/rt_pg/rtpostgis.c#L619) is empty.

Many thanks for any comments in advance!

re:Post Agent · Answer

The issue you're experiencing with the "Unknown GDAL driver" warning on Aurora PostgreSQL with PostGIS is unusual, especially given that you've properly installed the PostGIS extension and configured the GDAL drivers.

There are a few potential reasons for this warning:

1. Version mismatch: Ensure that the version of PostGIS installed on your Aurora PostgreSQL instance is compatible with the GDAL version being used. You're using PostGIS 3.4.0 with GDAL 3.5.3, which should be compatible, but it's worth double-checking for any known issues with this specific combination.

2. Configuration issue: Although you've set postgis.gdal_enabled_drivers to ENABLE_ALL, there might be an issue with how this setting is being applied or recognized by the PostGIS extension.

3. Raster functionality: Starting with PostGIS 3.0, the raster functionality is separated into its own extension called postgis_raster. Make sure this extension is properly installed and configured.

4. AWS-specific limitation: There might be an AWS-specific limitation or configuration issue that's preventing the proper recognition of GDAL drivers.

To troubleshoot this issue:

1. Verify that the postgis_raster extension is properly installed and up to date.

2. Try explicitly enabling the GTiff driver by setting postgis.gdal_enabled_drivers to 'GTiff' instead of 'ENABLE_ALL'.

3. Check if the issue persists with different raster file formats.

4. Review the Aurora PostgreSQL and PostGIS logs for any additional error messages or warnings that might provide more context.

5. Consider reaching out to AWS support, as this could be related to how PostGIS and GDAL are implemented in the Aurora PostgreSQL environment.

Despite the warning, if your data is being imported correctly, it might not affect your workflow. However, if you're experiencing data import issues or unexpected results, it's crucial to resolve this warning to ensure proper functionality of PostGIS raster capabilities in your Aurora PostgreSQL environment.  
**Sources**  
[Managing spatial data with the PostGIS extension - Amazon Aurora](https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/Appendix.PostgreSQL.CommonDBATasks.PostGIS.html)  
[Unsupported PostgreSQL features in Aurora DSQL - Amazon Aurora DSQL](https://docs.aws.amazon.com/aurora-dsql/latest/userguide/working-with-postgresql-compatibility-unsupported-features.html)

Warning "Unknown GDAL driver" on Aurora PostgreSQL with PostGIS

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