You are comparing apples and pears.
From a quick scan at the links you posted, the LineCombiner does a
fundamentally different thing than the "network-walking" example, it
simply "combines" any line connected to any other line at its end
vertex, which is not the same as "network-walking". This is more like a
PostGIS "ST_Collect()" operation, that also doesn't care about network
connectivity.
By the way, I never see PostgreSQL take full CPU (2x14 core
workstation), even with PostgreSQL configured to allow as many CPU cores
for parallel operations as there are physically. I wish it did, it would
speed up some operations that really need it. The only way I can get
full CPU usage is through a custom build Python multi-threading
framework putting PostgreSQL and PostGIS to work.
Maybe your server is underpowered for the type of work you wish to do.
Marco
Op 22-4-2022 om 01:19 schreef Shaozhong SHI:
Whenever geospatial functions such as St_intersects or recursive query
used, the PostGIS appears to spawn away to many child queries and just
obliterate the CPU. Nothing finishes.
That forced me to try out to do the some tasks on the FME server.
I tried to use this
http://blog.cleverelephant.ca/2010/07/network-walking-in-postgis.html
<http://blog.cleverelephant.ca/2010/07/network-walking-in-postgis.html> in
the PostGIS.
I tried to linecombiner in FME. LineCombiner | FME (safe.com)
<https://www.safe.com/transformers/line-combiner/>.
With a large data set, the running of processors were monitored. It
was estimated the PostGIS one would take 16 days to complete.
But, it only took a few minute to do the same thing in FME.
This suggests that something is not right with the PostGIS Server.
Have anyone got experience with configuration and improving perfomance
of PostGIS Server?
Regards,
David
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