Tom Lane <t...@sss.pgh.pa.us> writes: > ilm...@ilmari.org (Dagfinn Ilmari =?utf-8?Q?Manns=C3=A5ker?=) writes: >> 1) Perl's integers are at least pointer-sized and either signed or >> unsigned, so can potentially hold up to 2⁶⁴-1. Floating point numbers >> can also be larger than double (up to 128bit), allowing for exact >> representation of integers beyond 2⁵³. Hence, adjust the setting of >> the "processed" hash item to use UV_MAX for the limit and (NV) or >> (UV) for the casts. > > I thought about using UV where feasible, but it was not clear to me > whether unsigned numbers behave semantically differently from signed ones > in Perl. If they do, the change you suggest would create a small semantic > change in the behavior of code using spi_exec_query. I'm not sure it's > worth taking any risk of that, considering we already discourage people > from using spi_exec_query for large results.
IVs and UVs are semantically equivalent, and Perl will automatically convert between them (and NVs) as necessary, i.e. when crossing IV_MAX/UV_MAX/IV_MIN. >> 2) Perl 5.20 and later use SSize_t for array indices, so can cope with >> up to SSize_t_max items in an array (if you have the memory). > > I don't much like having such hard-wired knowledge about Perl versions > in our code. Is there a way to identify this change other than > #if PERL_BCDVERSION >= 0x5019004 ? There isn't, unfortunately. I could add e.g. AVidx_t and _MAX defines, but that wouldn't be available until 5.26 (May 2017) at the earliest, since full code freeze for May's 5.24 is next week. >> 3) To be able to actually return such result sets from sp_exec_query(), >> I had to change the repalloc() in spi_printtup() to repalloc_huge(). > > Hmm, good point. I wonder if there are any hazards to doing that. One hazard would be that people not heeding the warning in spi_exec_query will get a visit from the OOM killer (or death by swap) instead of a friendly "invalid memory alloc request size". > regards, tom lane ilmari -- - Twitter seems more influential [than blogs] in the 'gets reported in the mainstream press' sense at least. - Matt McLeod - That'd be because the content of a tweet is easier to condense down to a mainstream media article. - Calle Dybedahl -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
