[postgis-users] Recursive query - ERROR: invalid memory alloc request size 1073741824

[Shaozhong SHI]

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 <pella.samu at gmail.com> 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 <shishaozhong at gmail.com> 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
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>> postgis-users at lists.osgeo.org
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