Thanks Alexander,
'Scalar datatype' - given me a hint...
Looking further in btree_gist source, for inet datatype, which seems a bit complexier then uuid... (char, char, char[16]) structure for inet, compared to jut char[16] for uuid.
GiST pattern works with double datatype... and there is method convert_network_to_scalar(Datum, Oid), whick converts an inet value - to scalar value... and then all index compare functions are based on the doubles.... which leads me to conclusion (maybe is wrong) if I can convert UUID value to double it would make a "job" a lot easier... and pretty straight forward...
Any suggestion, how to convert UUID (char[16]) to scalar?
looking into convert inet to scalar, what confuses me, even there is char[16] for an ip address... code is:
takes just first 4, or 5 values from ipaddres even there is 16 - (decalred as char[16])
Many thanks,
Misa
2011/8/22 Alexander Korotkov
<aekorotkov@gmail.com>Hi!
On Mon, Aug 22, 2011 at 2:54 PM, Misa Simic
<misa.simic@gmail.com> wrote:
static int
m4_uuidkey_cmp(const void *a, const void *b)
{
uuidKEY *ia = (uuidKEY *) (((Usrt *) a)->t);
uuidKEY *ib = (uuidKEY *) (((Usrt *) b)->t);
int res;
res = DatumGetInt32(DirectFunctionCall2(uuid_cmp, UUIDPGetDatum(ia->upper), UUIDPGetDatum(ia->upper)));
if (res == 0)
return DatumGetInt32(DirectFunctionCall2(uuid_cmp, UUIDPGetDatum(ia->upper), UUIDPGetDatum(ib->upper)));
return res;
}
Getting error: aggregate error used where an integer was expected!
Seems that you need the address-of operator before ia->upper and ia->lower (likely one of operands should be "ia->lower"). UUIDPGetDatum except pointer as an argument, i.e. UUIDPGetDatum(&ia->upper).
It would be a lot appreciated if anyone could help me and suggest the best way to make Gist support for UUID datatype...
I think you're on the right way. btree_gist is an extension which provides GiST indexing of scalar datatype. UUID is one of them. So, the module you are writing should be quite similar.
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With best regards,
Alexander Korotkov.