static void
printtup_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
{
DR_printtup *myState = (DR_printtup *) self;
Portal portal = myState->portal;
/* create buffer to be used for all messages */
initStringInfo(&myState->buf);
/*
* Create a temporary memory context that we can reset once per row to
* recover palloc'd memory. This avoids any problems with leaks inside
* datatype output routines, and should be faster than retail pfree's
* anyway.
*/
myState->tmpcontext = AllocSetContextCreate(CurrentMemoryContext,
"printtup",
ALLOCSET_DEFAULT_SIZES);
if (PG_PROTOCOL_MAJOR(FrontendProtocol) < 3)
{
/*
* Send portal name to frontend (obsolete cruft, gone in proto 3.0)
*
* If portal name not specified, use "blank" portal.
*/
const char *portalName = portal->name;
if (portalName == NULL || portalName[0] == '\0')
portalName = "blank";
pq_puttextmessage('P', portalName);
}
/*
* If we are supposed to emit row descriptions, then send the tuple
* descriptor of the tuples.
*/
if (myState->sendDescrip)
SendRowDescriptionMessage(&myState->buf,
typeinfo,
FetchPortalTargetList(portal),
portal->formats);
/* ----------------
* We could set up the derived attr info at this time, but we postpone it
* until the first call of printtup, for 2 reasons:
* 1. We don't waste time (compared to the old way) if there are no
* tuples at all to output.
* 2. Checking in printtup allows us to handle the case that the tuples
* change type midway through (although this probably can't happen in
* the current executor).
* ----------------
*/
}
static void
printtup_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
{
DR_printtup *myState = (DR_printtup *) self;
Portal portal = myState->portal;
if (PG_PROTOCOL_MAJOR(FrontendProtocol) < 3)
{
/*
* Send portal name to frontend (obsolete cruft, gone in proto 3.0)
*
* If portal name not specified, use "blank" portal.
*/
const char *portalName = portal->name;
if (portalName == NULL || portalName[0] == '\0')
portalName = "blank";
pq_puttextmessage('P', portalName);
}
/*
* If we are supposed to emit row descriptions, then send the tuple
* descriptor of the tuples.
*/
if (myState->sendDescrip)
SendRowDescriptionMessage(typeinfo,
FetchPortalTargetList(portal),
portal->formats);
/* ----------------
* We could set up the derived attr info at this time, but we postpone it
* until the first call of printtup, for 2 reasons:
* 1. We don't waste time (compared to the old way) if there are no
* tuples at all to output.
* 2. Checking in printtup allows us to handle the case that the tuples
* change type midway through (although this probably can't happen in
* the current executor).
* ----------------
*/
}
