For complete support, it requires two GDAL fixes:
- One to avoid feature count to be invalid when using ROLLBACK TO SAVEPOINT
f73ec8cd1d
- Another one to avoid nasty issues, at least on Linux, with the POSIX
advisory locks used by libsqlite that could be invalidated due to how GDAL
could open files behind the back of libsqlite. The consequence of this
could be the deletion of -wal and -shm files, which caused issues in QGIS
(non working iterators when the edit is finished, and later edits in the
same session not working). Those issues could appear for example if doing
ogrinfo on the .gpkg opened by QGIS, or if opening two QGIS session on the
.gpkg
Both fixes are queued for GDAL 2.3.1
Convert OGC Filter's literals accordings to field type.
This can have a huge impact on performance in some cases.
For example for a filter like "num_char" = '+2' converted to "num_char" = 2,
this result with PostgreSQL provider in a fallback to client side evaluation for the whole filter,
including the bbox if present.
Checks whether a function declaration has parameters that are
top level const.
const values in declarations do not affect the signature of a
function, so they should not be put there.
their underlying algorithm's provider
E.g. for model outputs generated by a saga algorithm, only
sdat and shp files are valid outputs. So only give users choices
of these instead of all formats.
Also fixes temporary file names generated as part of model
execution may use formats which are not compatible with the
algorithm's provider.
Fixes#18908
This method allows to determine if a feature source has content or not
(or maybe).
This method works for "generator" sources as well as for "collection"
sources.
Collection sources like QgsVectorDataProvider which allow to easily and
in a cheap way determine if features are available can return
FeaturesAvailable or NoFeaturesAvailable, generators will return
FeaturesMaybeAvailable.
QgsVectorDataProvider also implements an empty() method.
