[Tile-serving] [openstreetmap/osm2pgsql] Huge performance loss when using --extra-atributes (#189)

[mmd]

`osmdata_t::{node,way,relation}_add` only processes an object, if it has at least one tag. In case of nodes, more than 97% of all nodes don't have any tags and would be discarded right away. However, when providing the "Extra parameters" option, every single object needs to be processed. 

Depending on the output, this much larger amount of total data to be processed could make a difference: for the Flex backend, turning on extra attributes for a completely empty style file reduces throughput by about 50%.

I wonder if this should be reflected in docs/flex.md. At this time, the page says: 
> osm2pgsql.process_node(object): Called for each node.

There's no mentioning of a tag filter, or the role of the extra-attributes parameter. It's role is described as turning on/off meta data. That's unrelated to the question of the object having tags or not.








-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/openstreetmap/osm2pgsql/issues/189#issuecomment-633212191
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/tile-serving/attachments/20200524/a4c28387/attachment.htm>