I want to import into PostGIS the whole planet but I am interested for certain tags. Specifically I am not interested in nodes, ways and areas which are related with the land. Below is a small part from the openstreemap-carto.style
# OsmType Tag DataType Flags
node,way access text linear
node,way addr:housename text linear
node,way addr:housenumber text linear
node,way addr:interpolation text linear
node,way admin_level text linear
node,way aerialway text linear
node,way aeroway text polygon
node,way amenity text polygon
node,way area text # hard coded support for area=1/yes => polygon is in osm2pgsql
node,way barrier text linear
node,way bicycle text
node,way brand text linear
node,way bridge text linear
node,way boundary text linear
node,way building text polygon
After that there is some information regarding the flag delete
# Deleted tags
# These are tags that are generally regarded as useless for most rendering.
# Most of them are from imports or intended as internal information for mappers
# Some of them are automatically deleted by editors.
# If you want some of them, perhaps for a debugging layer, just delete the lines.
My question: If I use the flag delete for some nodes, does it mean that these nodes (or ways) will be completely discarded resulting in a smaller database? Do I also need less space during importing planet in PostGIS, if I use the delete flag?
If not (I mean if the space needed during the process of importing data into db is the same and only the resulting database is smaller) suggest me a tool for dropping some nodes or ways with certain tags from the planet.osm in order to produce a smaller planet file for use with osm2pgsql.