On Fri, Feb 3, 2017 at 8:29 PM, Robert Haas <robertmh...@gmail.com> wrote: > On Fri, Feb 3, 2017 at 7:41 AM, Ashutosh Sharma <ashu.coe...@gmail.com> wrote: >> I think UInt32GetDatum(metad->hashm_procid) looks fine, the reason >> being 'hashm_procid' is defined as 32-bit unsigned integer but then we >> may have to define procid as int8 in SQL function. > > No, you're wrong. The GetDatum you choose macro has to match the SQL > type, not the type of the variable that you're passing to it. For > example, if you've got an "int" in the code and the SQL type is > "int8", you have to use Int64GetDatum, not Int32GetDatum. Otherwise, > stuff breaks, because on some systems 64-bit integers are passed by > reference, not by value, so the representation that Int32GetDatum > produces isn't valid when interpreted by DatumGetInt64 later on. The > latter is expecting a pointer, but the former didn't produce one. >
Thank you very much for detailed information and explanation. It is really very helpful and understandable. But, As per your explanation, GetDatum we choose need to match the SQL type, not the type of the variable used in code and I do not see any unsigned integer SQL type in PostgreSQL then I am just wondering on why do we have UInt32GetDatum or UInt64GetDatum macros. >> Note: I am extremely sorry for wrongly choosing some of the SQL types >> in the patch for pageinspect. I think there were few platform specific >> things that too should have been addressed by me. Moreover, I feel >> being the owner of this project I should have participated in this >> discussion a bit earlier but as I was not subscribed to >> pgsql-committers list I could not be on time. > > It might be a good idea to subscribe to pgsql-committers; that way you > can follow what's getting committed, whether it is your patch or > otherwise. But we also should perhaps have migrated this discussion > to pgsql-hackers. Adjusting recipient list. > > -- > Robert Haas > EnterpriseDB: http://www.enterprisedb.com > The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
