Hello, recently I've been trying to write a plperlu function like this:
CREATE FUNCTION foo RETURNS bytea AS ' use Storable qw(freeze thaw); my @a = (1,2,3,4,5); return freeze (\@a);
' LANGUAGE plperlu;
In other words, serialize some data (maybe some rows, would be a great
aggregate function :)) and store it in some table.
And I also wrote similar function which thaws the data from bytea argument.
PostgreSQL however seems to be doing two things:
1) when returning any data from function (including bytea return
type), it copies it up to first '\0' character. Looking at the
plperl.c sources, solution would be changing lines like this: result = FunctionCall3(&prodesc->result_in_func,
PointerGetDatum(SvPV(*svp, PL_na)), ObjectIdGetDatum(prodesc->result_typioparam),
Int32GetDatum(-1));
into something like this: size_t ret_length; /* size_t? */ (...) result = FunctionCall3(&prodesc->result_in_func,
PointerGetDatum(SvPV(*svp, ret_length)),
ObjectIdGetDatum(prodesc->result_typioparam), Int32GetDatum(-1));
In other words, use the fact that SvPV's second argument is used to
pass string length ... but I don't know where to pass the returned
length. I don't suppose (-1) is the right place...
2) When function receives bytea as an argument it converts it into
\NNN-escaped string. I think it would be more natural to pass
unescaped string to a perl function.
Ah, and while we are at it -- I think it could be nice to embed
Storable module (functions freeze, nfreeze and thaw) into plperl --
ability to pass "raw serialized" perl data between functions, and
store it in tables could be quite useful.
Regards, Dawid
