Re: The enormous s->childXids problem - Mailing list pgsql-hackers

From Tom Lane
Subject Re: The enormous s->childXids problem
Date
Msg-id 14174.1158412119@sss.pgh.pa.us
Whole thread Raw
In response to The enormous s->childXids problem  (Theo Schlossnagle <jesus@omniti.com>)
Responses Re: The enormous s->childXids problem  (Gregory Stark <gsstark@mit.edu>)
List pgsql-hackers
Theo Schlossnagle <jesus@omniti.com> writes:
> The select function is dbi-link's remote_select.   
> remote_select will perform the query and then for each row  
> return_next which calls the SPI.xs stuff to do plperl_return_next  
> which is wrapped in a PG_TRY block.  I see the value of the try block  
> to kick back sensible errors to perl, but creating childXids for  
> every row of a setof seems wildly excessive.  What's the harm in  
> simply not TRY'ing around there?

Failing.

The real question is why does the subtransaction actually assign itself
an XID --- a simple RETURN NEXT operation ought not do that, AFAICS.
What is it you're doing in there that changes the database?
        regards, tom lane


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