Re: Speedup usages of pg_*toa() functions

On Thu, 11 Jun 2020 at 18:52, Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk> wrote:
>
> >>>>> "David" == David Rowley <dgrowleyml(at)gmail(dot)com> writes:
>
> David> Pending any objections, I'd like to push both of these patches
> David> in the next few days to master.
>
> For the second patch, can we take the opportunity to remove the
> extraneous blank line at the top of pg_ltoa, and add the two missing
> "extern"s in builtins.h for pg_ultoa_n and pg_ulltoa_n ?
>
> David> Anyone object to changing the signature of these functions in
> David> 0002, or have concerns about allocating the maximum memory that
> David> we might require in int8out()?
>
> Changing the function signatures seems safe enough. The memory thing
> only seems likely to be an issue if you allocate a lot of text strings
> for bigint values without a context reset, and I'm not sure where that
> would happen (maybe passing large bigint arrays to pl/perl or pl/python
> would do it?)

I ended up chickening out of doing the larger allocation
unconditionally. Instead, I pushed the original idea of doing the
palloc/memcpy of the length returned by pg_lltoa. That gets us most
of the gains without the change in memory usage behaviour.

Thanks for your reviews on this.

David