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

[Shaozhong SHI]

It is simply this recursive query.

Network Walking in PostGIS · Paul Ramsey (cleverelephant.ca)
<http://blog.cleverelephant.ca/2010/07/network-walking-in-postgis.html>

It is not the issue of forever/endless loop.

It runs at a point where it stops.

This error turned up.- ERROR:  invalid memory alloc request size 1073741824

Now, I have put the following statement in the loop


If (select count(*) <2500 from primary_watercourse) then


The idea is to skip over too big tables that are generated.

It keeps running at the moment.

This memory allocation issue was encountered before.

I think that it does not like large data sets.

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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