Tom, Thanks a lot.
The part I cant understand is I cant see where SendFunctionResult construct the return value into the buf. I expect it should copy something in retval to buf, but I cant find any of this in the code, the main logic of SendFunctionResult is: 00159 getTypeOutputInfo <http://doxygen.postgresql.org/lsyscache_8c.html#48d637426d06bfdf607eb29da3be558a>(rettype <http://doxygen.postgresql.org/structfp__info.html#2b1f02caad79fae010cdc5836a2fcb83>, &typoutput, &typisvarlena);00160 outputstr = OidOutputFunctionCall <http://doxygen.postgresql.org/fmgr_8c.html#9b747dd35f098ab369b44e94f4708210>(typoutput, retval);00161 pq_sendcountedtext <http://doxygen.postgresql.org/pqformat_8c.html#e6acc43bbc9bee686de201de82a26db5>(&buf, outputstr, strlen(outputstr), false);00162 pfree <http://doxygen.postgresql.org/mcxt_8c.html#4de9741ca04b2f01a82d3de16a1d6bf2>(outputstr); I think it should copy the real result in OidOutputFunctionCall, but unfortunately I can only find it call FunctionCall1() again. Do I miss something? If I copy the tuples returnned from pl module here, is it possible to send a vector result from fastpath function call? 2011/5/9 Tom Lane <t...@sss.pgh.pa.us> > lee Richard <clipper.ken...@gmail.com> writes: > > I still can not see how it return a single return value to the client, > and > > why it call FunctionCall1() again when it want to send the result. > > pq_endmessage is where the bytes actually get pushed out to the client, > if that's what you're looking for. The rest of the activity in > SendFunctionResult is just concerned with constructing the message to be > sent within "buf". > > regards, tom lane >
