/*
* Regular reply from standby advising of WAL positions on standby server.
*/
static void
ProcessStandbyReplyMessage(void)
{
StandbyReplyMessage reply;
pq_copymsgbytes(&reply_message, (char *) &reply, sizeof(StandbyReplyMessage));
elog(DEBUG2, "write %X/%X flush %X/%X apply %X/%X",
reply.write.xlogid, reply.write.xrecoff,
reply.flush.xlogid, reply.flush.xrecoff,
reply.apply.xlogid, reply.apply.xrecoff);
/*
* Update shared state for this WalSender process based on reply data from
* standby.
*/
{
/* use volatile pointer to prevent code rearrangement */
volatile WalSnd *walsnd = MyWalSnd;
SpinLockAcquire(&walsnd->mutex);
walsnd->write = reply.write;
walsnd->flush = reply.flush;
walsnd->apply = reply.apply;
SpinLockRelease(&walsnd->mutex);
}
if (!am_cascading_walsender)
SyncRepReleaseWaiters();
}
/*
* Read tuple in remote format from stream.
*
* The returned tuple points into the input stringinfo.
*/
static void
logicalrep_read_tuple(StringInfo in, LogicalRepTupleData *tuple)
{
int i;
int natts;
/* Get number of attributes */
natts = pq_getmsgint(in, 2);
memset(tuple->changed, 0, sizeof(tuple->changed));
/* Read the data */
for (i = 0; i < natts; i++)
{
char kind;
kind = pq_getmsgbyte(in);
switch (kind)
{
case 'n': /* null */
tuple->values[i] = NULL;
tuple->changed[i] = true;
break;
case 'u': /* unchanged column */
/* we don't receive the value of an unchanged column */
tuple->values[i] = NULL;
break;
case 't': /* text formatted value */
{
int len;
tuple->changed[i] = true;
len = pq_getmsgint(in, 4); /* read length */
/* and data */
tuple->values[i] = palloc(len + 1);
pq_copymsgbytes(in, tuple->values[i], len);
tuple->values[i][len] = '\0';
}
break;
default:
elog(ERROR, "unrecognized data representation type '%c'", kind);
}
}
}
Datum UDT_receive(UDT udt, PG_FUNCTION_ARGS)
{
StringInfo buf;
char* tmp;
int32 dataLen = Type_getLength((Type)udt);
if(!UDT_isScalar(udt))
ereport(ERROR, (
errcode(ERRCODE_CANNOT_COERCE),
errmsg("UDT with Oid %d is not scalar", Type_getOid((Type)udt))));
if(dataLen == -1)
return bytearecv(fcinfo);
if(dataLen == -2)
return unknownrecv(fcinfo);
buf = (StringInfo)PG_GETARG_POINTER(0);
tmp = palloc(dataLen);
pq_copymsgbytes(buf, tmp, dataLen);
PG_RETURN_POINTER(tmp);
}
/*
* Hot Standby feedback
*/
static void
ProcessStandbyHSFeedbackMessage(void)
{
StandbyHSFeedbackMessage reply;
TransactionId newxmin = InvalidTransactionId;
pq_copymsgbytes(&reply_message, (char *) &reply, sizeof(StandbyHSFeedbackMessage));
elog(DEBUG2, "hot standby feedback xmin %u epoch %u",
reply.xmin,
reply.epoch);
/*
* Update the WalSender's proc xmin to allow it to be visible to
* snapshots. This will hold back the removal of dead rows and thereby
* prevent the generation of cleanup conflicts on the standby server.
*/
if (TransactionIdIsValid(reply.xmin))
{
TransactionId nextXid;
uint32 nextEpoch;
bool epochOK = false;
GetNextXidAndEpoch(&nextXid, &nextEpoch);
/*
* Epoch of oldestXmin should be same as standby or if the counter has
* wrapped, then one less than reply.
*/
if (reply.xmin <= nextXid)
{
if (reply.epoch == nextEpoch)
epochOK = true;
}
else
{
if (nextEpoch > 0 && reply.epoch == nextEpoch - 1)
epochOK = true;
}
/*
* Feedback from standby must not go backwards, nor should it go
* forwards further than our most recent xid.
*/
if (epochOK && TransactionIdPrecedesOrEquals(reply.xmin, nextXid))
{
if (!TransactionIdIsValid(MyProc->xmin))
{
TransactionId oldestXmin = GetOldestXmin(true, true);
if (TransactionIdPrecedes(oldestXmin, reply.xmin))
newxmin = reply.xmin;
else
newxmin = oldestXmin;
}
else
{
if (TransactionIdPrecedes(MyProc->xmin, reply.xmin))
newxmin = reply.xmin;
else
newxmin = MyProc->xmin; /* stay the same */
}
}
}
/*
* Grab the ProcArrayLock to set xmin, or invalidate for bad reply
*/
if (MyProc->xmin != newxmin)
{
LWLockAcquire(ProcArrayLock, LW_SHARED);
MyProc->xmin = newxmin;
LWLockRelease(ProcArrayLock);
}
}
/*
* Deserialize a HeapTuple's data from a byte-array.
*
* This code is based on the binary input handling functions in copy.c.
*/
HeapTuple
DeserializeTuple(SerTupInfo * pSerInfo, StringInfo serialTup)
{
MemoryContext oldCtxt;
TupleDesc tupdesc;
HeapTuple htup;
int natts;
SerAttrInfo *attrInfo;
uint32 attr_size;
int i;
StringInfoData attr_data;
bool fHandled;
AssertArg(pSerInfo != NULL);
AssertArg(serialTup != NULL);
tupdesc = pSerInfo->tupdesc;
natts = tupdesc->natts;
/*
* Flip to our tuple-serialization memory-context, to speed up memory
* reclamation operations.
*/
AssertState(s_tupSerMemCtxt != NULL);
oldCtxt = MemoryContextSwitchTo(s_tupSerMemCtxt);
/* Receive nulls character-array. */
pq_copymsgbytes(serialTup, pSerInfo->nulls, natts);
skipPadding(serialTup);
/* Deserialize the non-NULL attributes of this tuple */
initStringInfo(&attr_data);
for (i = 0; i < natts; ++i)
{
attrInfo = pSerInfo->myinfo + i;
if (pSerInfo->nulls[i]) /* NULL field. */
{
pSerInfo->values[i] = (Datum) 0;
continue;
}
/*
* Assume that the data's output will be handled by the special IO
* code, and if not then we can handle it the slow way.
*/
fHandled = true;
switch (attrInfo->atttypid)
{
case INT4OID:
pSerInfo->values[i] = Int32GetDatum(stringInfoGetInt32(serialTup));
break;
case CHAROID:
pSerInfo->values[i] = CharGetDatum(pq_getmsgbyte(serialTup));
skipPadding(serialTup);
break;
case BPCHAROID:
case VARCHAROID:
case INT2VECTOROID: /* postgres serialization logic broken, use our own */
case OIDVECTOROID: /* postgres serialization logic broken, use our own */
case ANYARRAYOID:
{
text *pText;
int textSize;
textSize = stringInfoGetInt32(serialTup);
#ifdef TUPSER_SCRATCH_SPACE
if (textSize + VARHDRSZ <= attrInfo->varlen_scratch_size)
pText = (text *) attrInfo->pv_varlen_scratch;
else
pText = (text *) palloc(textSize + VARHDRSZ);
#else
pText = (text *) palloc(textSize + VARHDRSZ);
#endif
SET_VARSIZE(pText, textSize + VARHDRSZ);
pq_copymsgbytes(serialTup, VARDATA(pText), textSize);
skipPadding(serialTup);
pSerInfo->values[i] = PointerGetDatum(pText);
break;
}
case DATEOID:
{
/*
* TODO: I would LIKE to do something more efficient, but
* DateADT is not strictly limited to 4 bytes by its
* definition.
*/
DateADT date;
pq_copymsgbytes(serialTup, (char *) &date, sizeof(DateADT));
skipPadding(serialTup);
pSerInfo->values[i] = DateADTGetDatum(date);
break;
}
case NUMERICOID:
{
/*
* Treat the numeric as a varlena variable, and just push
* the whole shebang to the output-buffer. We don't care
* about the guts of the numeric.
*/
Numeric num;
int numSize;
numSize = stringInfoGetInt32(serialTup);
#ifdef TUPSER_SCRATCH_SPACE
if (numSize + VARHDRSZ <= attrInfo->varlen_scratch_size)
num = (Numeric) attrInfo->pv_varlen_scratch;
else
num = (Numeric) palloc(numSize + VARHDRSZ);
#else
num = (Numeric) palloc(numSize + VARHDRSZ);
#endif
SET_VARSIZE(num, numSize + VARHDRSZ);
pq_copymsgbytes(serialTup, VARDATA(num), numSize);
skipPadding(serialTup);
pSerInfo->values[i] = NumericGetDatum(num);
break;
}
case ACLITEMOID:
{
int aclSize, k, cnt;
char *inputstring, *starsfree;
aclSize = stringInfoGetInt32(serialTup);
inputstring = (char*) palloc(aclSize + 1);
starsfree = (char*) palloc(aclSize + 1);
cnt = 0;
pq_copymsgbytes(serialTup, inputstring, aclSize);
skipPadding(serialTup);
inputstring[aclSize] = '\0';
for(k=0; k<aclSize; k++)
{
if( inputstring[k] != '*')
{
starsfree[cnt] = inputstring[k];
cnt++;
}
}
starsfree[cnt] = '\0';
pSerInfo->values[i] = DirectFunctionCall1(aclitemin, CStringGetDatum(starsfree));
pfree(inputstring);
break;
}
case 210:
{
int strsize;
char *smgrstr;
strsize = stringInfoGetInt32(serialTup);
smgrstr = (char*) palloc(strsize + 1);
pq_copymsgbytes(serialTup, smgrstr, strsize);
skipPadding(serialTup);
smgrstr[strsize] = '\0';
pSerInfo->values[i] = DirectFunctionCall1(smgrin, CStringGetDatum(smgrstr));
break;
}
default:
fHandled = false;
}
if (fHandled)
continue;
attr_size = stringInfoGetInt32(serialTup);
/* reset attr_data to empty, and load raw data into it */
attr_data.len = 0;
attr_data.data[0] = '\0';
attr_data.cursor = 0;
appendBinaryStringInfo(&attr_data,
pq_getmsgbytes(serialTup, attr_size), attr_size);
skipPadding(serialTup);
/* Call the attribute type's binary input converter. */
if (attrInfo->recv_finfo.fn_nargs == 1)
pSerInfo->values[i] = FunctionCall1(&attrInfo->recv_finfo,
PointerGetDatum(&attr_data));
else if (attrInfo->recv_finfo.fn_nargs == 2)
pSerInfo->values[i] = FunctionCall2(&attrInfo->recv_finfo,
PointerGetDatum(&attr_data),
ObjectIdGetDatum(attrInfo->recv_typio_param));
else if (attrInfo->recv_finfo.fn_nargs == 3)
pSerInfo->values[i] = FunctionCall3(&attrInfo->recv_finfo,
PointerGetDatum(&attr_data),
ObjectIdGetDatum(attrInfo->recv_typio_param),
Int32GetDatum(tupdesc->attrs[i]->atttypmod) );
else
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
errmsg("Conversion function takes %d args",attrInfo->recv_finfo.fn_nargs)));
}
/* Trouble if it didn't eat the whole buffer */
if (attr_data.cursor != attr_data.len)
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
errmsg("incorrect binary data format")));
}
}
/*
* Construct the tuple from the Datums and nulls values. NOTE: Switch
* out of our temporary context before we form the tuple!
*/
MemoryContextSwitchTo(oldCtxt);
htup = heap_form_tuple(tupdesc, pSerInfo->values, pSerInfo->nulls);
MemoryContextReset(s_tupSerMemCtxt);
/* All done. Return the result. */
return htup;
}
/*
* Hot Standby feedback
*/
static void
ProcessStandbyHSFeedbackMessage(void)
{
StandbyHSFeedbackMessage reply;
TransactionId nextXid;
uint32 nextEpoch;
/* Decipher the reply message */
pq_copymsgbytes(&reply_message, (char *) &reply,
sizeof(StandbyHSFeedbackMessage));
elog(DEBUG2, "hot standby feedback xmin %u epoch %u",
reply.xmin,
reply.epoch);
/* Ignore invalid xmin (can't actually happen with current walreceiver) */
if (!TransactionIdIsNormal(reply.xmin))
return;
/*
* Check that the provided xmin/epoch are sane, that is, not in the future
* and not so far back as to be already wrapped around. Ignore if not.
*
* Epoch of nextXid should be same as standby, or if the counter has
* wrapped, then one greater than standby.
*/
GetNextXidAndEpoch(&nextXid, &nextEpoch);
if (reply.xmin <= nextXid)
{
if (reply.epoch != nextEpoch)
return;
}
else
{
if (reply.epoch + 1 != nextEpoch)
return;
}
if (!TransactionIdPrecedesOrEquals(reply.xmin, nextXid))
return; /* epoch OK, but it's wrapped around */
/*
* Set the WalSender's xmin equal to the standby's requested xmin, so that
* the xmin will be taken into account by GetOldestXmin. This will hold
* back the removal of dead rows and thereby prevent the generation of
* cleanup conflicts on the standby server.
*
* There is a small window for a race condition here: although we just
* checked that reply.xmin precedes nextXid, the nextXid could have gotten
* advanced between our fetching it and applying the xmin below, perhaps
* far enough to make reply.xmin wrap around. In that case the xmin we
* set here would be "in the future" and have no effect. No point in
* worrying about this since it's too late to save the desired data
* anyway. Assuming that the standby sends us an increasing sequence of
* xmins, this could only happen during the first reply cycle, else our
* own xmin would prevent nextXid from advancing so far.
*
* We don't bother taking the ProcArrayLock here. Setting the xmin field
* is assumed atomic, and there's no real need to prevent a concurrent
* GetOldestXmin. (If we're moving our xmin forward, this is obviously
* safe, and if we're moving it backwards, well, the data is at risk
* already since a VACUUM could have just finished calling GetOldestXmin.)
*/
MyPgXact->xmin = reply.xmin;
}
/*
* Deserialize a HeapTuple's data from a byte-array.
*
* This code is based on the binary input handling functions in copy.c.
*/
HeapTuple
DeserializeTuple(SerTupInfo * pSerInfo, StringInfo serialTup)
{
MemoryContext oldCtxt;
TupleDesc tupdesc;
HeapTuple htup;
int natts;
SerAttrInfo *attrInfo;
int i;
AssertArg(pSerInfo != NULL);
AssertArg(serialTup != NULL);
tupdesc = pSerInfo->tupdesc;
natts = tupdesc->natts;
/*
* Flip to our tuple-serialization memory-context, to speed up memory
* reclamation operations.
*/
AssertState(s_tupSerMemCtxt != NULL);
oldCtxt = MemoryContextSwitchTo(s_tupSerMemCtxt);
/* Receive nulls character-array. */
pq_copymsgbytes(serialTup, pSerInfo->nulls, natts);
skipPadding(serialTup);
/* Deserialize the non-NULL attributes of this tuple */
for (i = 0; i < natts; ++i)
{
attrInfo = pSerInfo->myinfo + i;
if (pSerInfo->nulls[i]) /* NULL field. */
{
pSerInfo->values[i] = (Datum) 0;
continue;
}
if (attrInfo->typlen == -1)
{
int32 sz;
struct varlena *p;
/* Read length first */
pq_copymsgbytes(serialTup, (char *) &sz, sizeof(int32));
if (sz < 0)
elog(ERROR, "invalid length received for a varlen Datum");
p = palloc(sz + VARHDRSZ);
pq_copymsgbytes(serialTup, VARDATA(p), sz);
SET_VARSIZE(p, sz + VARHDRSZ);
pSerInfo->values[i] = PointerGetDatum(p);
}
else if (attrInfo->typlen == -2)
{
int32 sz;
char *p;
/* CString, with terminating '\0' included */
/* Read length first */
pq_copymsgbytes(serialTup, (char *) &sz, sizeof(int32));
if (sz < 0)
elog(ERROR, "invalid length received for a CString");
p = palloc(sz + VARHDRSZ);
/* Then data */
pq_copymsgbytes(serialTup, p, sz);
pSerInfo->values[i] = CStringGetDatum(p);
}
else if (attrInfo->typbyval)
{
/* Read a whole Datum */
pq_copymsgbytes(serialTup, (char *) &(pSerInfo->values[i]), sizeof(Datum));
}
else
{
/* fixed width, pass-by-ref */
char *p = palloc(attrInfo->typlen);
pq_copymsgbytes(serialTup, p, attrInfo->typlen);
pSerInfo->values[i] = PointerGetDatum(p);
}
}
/*
* Construct the tuple from the Datums and nulls values. NOTE: Switch
* out of our temporary context before we form the tuple!
*/
MemoryContextSwitchTo(oldCtxt);
htup = heap_form_tuple(tupdesc, pSerInfo->values, pSerInfo->nulls);
MemoryContextReset(s_tupSerMemCtxt);
/* Trouble if it didn't eat the whole buffer */
if (serialTup->cursor != serialTup->len)
ereport(ERROR,
(errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
errmsg("incorrect binary data format")));
/* All done. Return the result. */
return htup;
}
static size_t
RemoteSourceRead(RemoteSource *self, void *buffer, size_t len)
{
size_t bytesread;
size_t minread = len;
bytesread = 0;
while (len > 0 && bytesread < minread && !self->eof)
{
int avail;
while (self->buffer->cursor >= self->buffer->len)
{
/* Try to receive another message */
int mtype;
readmessage:
mtype = Wrappered_pq_getbyte();
if (mtype == EOF)
ereport(ERROR,
(errcode(ERRCODE_CONNECTION_FAILURE),
errmsg("unexpected EOF on client connection")));
if (pq_getmessage(self->buffer, 0))
ereport(ERROR,
(errcode(ERRCODE_CONNECTION_FAILURE),
errmsg("unexpected EOF on client connection")));
switch (mtype)
{
case 'd': /* CopyData */
break;
case 'c': /* CopyDone */
/* COPY IN correctly terminated by frontend */
self->eof = true;
return bytesread;
case 'f': /* CopyFail */
ereport(ERROR,
(errcode(ERRCODE_QUERY_CANCELED),
errmsg("COPY from stdin failed: %s",
pq_getmsgstring(self->buffer))));
break;
case 'H': /* Flush */
case 'S': /* Sync */
/*
* Ignore Flush/Sync for the convenience of client
* libraries (such as libpq) that may send those
* without noticing that the command they just
* sent was COPY.
*/
goto readmessage;
default:
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("unexpected message type 0x%02X during COPY from stdin",
mtype)));
break;
}
}
avail = self->buffer->len - self->buffer->cursor;
if (avail > len)
avail = len;
pq_copymsgbytes(self->buffer, (char *) buffer, avail);
buffer = (void *) ((char *) buffer + avail);
len -= avail;
bytesread += avail;
}
return bytesread;
}