> encountered more than 2 answers/outputs. > It may get confused and cannot finish.
You can find a very good SQL "graph" tutorial/basics - with examples. https://docs.yugabyte.com/preview/api/ysql/the-sql-language/with-clause/traversing-general-graphs/ So you have to decide - what type of graph you have - Undirected cyclic graph - Directed cyclic graph - Directed acyclic graph - Rooted tree ( a specialization of the directed acyclic graph. ) If you know the "type of your graph network" ( and the name of your problem ) Then it will be easier to find an algorithm. You can ask your DB team - or You can search the internet. But without minimal example data - not so easy to help you. IMHO: Your link ["Network Walking in PostGIS"(2010)] is a very simple "Rooted tree" example. Regards, Imre Shaozhong SHI <[email protected]> ezt írta (időpont: 2022. máj. 8., V, 22:10): > Hi, Imre, > > There is a possibility that the Walk the Network (Network Walking in > PostGIS · Paul Ramsey (cleverelephant.ca) > <http://blog.cleverelephant.ca/2010/07/network-walking-in-postgis.html?m=1&msclkid=5cf8409ecf0a11ecbbe2896397a25c2b>) > encountered more than 2 answers/outputs. > > It may get confused and cannot finish. > > Can we build something in the script to report these and should there be > an exception, allow it to complete the task? > > Regards, > > David > > On Sun, 8 May 2022 at 00:59, Imre Samu <[email protected]> wrote: > >> Hi David, >> > There is a loop of recursive query. It runs at a point where it stops. >> >Can anyone provide pointers how to solve this problem or work around? >> >> Please share "this" recursive query; >> >> My guess: Probably you have a "forever/endless loop" in your data; *so >> you have to LIMIT the recursive part ;* >> >> related links : >> 1.) with limiting "depth" ( where depth < 1000 ) >> "Prevent infinite loop in recursive query in Postgresql" >> >> https://stackoverflow.com/questions/51025607/prevent-infinite-loop-in-recursive-query-in-postgresql >> 2.) with LIMITING clause >> https://www.cybertec-postgresql.com/en/recursive-queries-postgresql/ >> *"This example also demonstrates how an endless loop can be avoided with >> a LIMIT clause on the parent query."* >> >> Regards, >> Imre >> >> Shaozhong SHI <[email protected]> ezt írta (időpont: 2022. máj. 7., >> Szo, 15:23): >> >>> There is a loop of recursive query. It runs at a point where it stops. >>> >>> This error turned up.- ERROR: invalid memory alloc request size >>> 1073741824 >>> >>> Can anyone provide pointers how to solve this problem or work around? >>> >>> Regards, >>> >>> David >>> _______________________________________________ >>> postgis-users mailing list >>> [email protected] >>> https://lists.osgeo.org/mailman/listinfo/postgis-users >>> >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> https://lists.osgeo.org/mailman/listinfo/postgis-users >> > _______________________________________________ > postgis-users mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/postgis-users >
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