Re: Endless loop calling PL/Python set returning functions - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Endless loop calling PL/Python set returning functions
Date
Msg-id 15022.1457630432@sss.pgh.pa.us
Whole thread Raw
In response to Re: Endless loop calling PL/Python set returning functions  (Alexey Grishchenko <agrishchenko@pivotal.io>)
Responses Re: Endless loop calling PL/Python set returning functions
List pgsql-hackers
Alexey Grishchenko <agrishchenko@pivotal.io> writes:
> No, my fix handles this well.
> In fact, with the first function call you allocate global variables
> representing Python function input parameters, call the function and
> receive iterator over the function results. Then in a series of Postgres
> calls to PL/Python handler you just fetch next value from the iterator, you
> are not calling the Python function anymore. When the iterator reaches the
> end, PL/Python call handler deallocates the global variable representing
> function input parameter.

> Regardless of the number of parallel invocations of the same function, each
> of them in my patch would set its own input parameters to the Python
> function, call the function and receive separate iterators. When the first
> function's result iterator would reach its end, it would deallocate the
> input global variable. But it won't affect other functions as they no
> longer need to invoke any Python code.

Well, if you think that works, why not undo the global-dictionary changes
at the end of the first call, rather than later?  Then there's certainly
no overlap in their lifespan.
        regards, tom lane



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