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robertmhaasrobertmhaas
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Refactor other replication commands to use DestRemoteSimple.
Commit a84069d added a new type of DestReceiver to avoid duplicating the existing code for the SHOW command, but it turns out we can leverage that new DestReceiver type in a few more places, saving some code. Michael Paquier, reviewed by Andres Freund and by me. Discussion: http://postgr.es/m/CAB7nPqSdFOQC0evc0r1nJeQyGBqjBrR41MC4rcMqUUpoJaZbtQ%40mail.gmail.com Discussion: http://postgr.es/m/CAB7nPqT2K4XFT1JgqufFBjsOc-NUKXg5qBDucHPMbk6Xi1kYaA@mail.gmail.com
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3 files changed

+114
-162
lines changed

3 files changed

+114
-162
lines changed

‎src/backend/access/common/printsimple.c‎

Lines changed: 21 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -22,6 +22,7 @@
2222
#include "catalog/pg_type.h"
2323
#include "fmgr.h"
2424
#include "libpq/pqformat.h"
25+
#include "utils/builtins.h"
2526

2627
/*
2728
* At startup time, send a RowDescription message.
@@ -99,6 +100,26 @@ printsimple(TupleTableSlot *slot, DestReceiver *self)
99100
}
100101
break;
101102

103+
case INT4OID:
104+
{
105+
int32 num = DatumGetInt32(value);
106+
char str[12]; /* sign, 10 digits and '\0' */
107+
108+
pg_ltoa(num, str);
109+
pq_sendcountedtext(&buf, str, strlen(str), false);
110+
}
111+
break;
112+
113+
case INT8OID:
114+
{
115+
int64 num = DatumGetInt64(value);
116+
char str[23]; /* sign, 21 digits and '\0' */
117+
118+
pg_lltoa(num, str);
119+
pq_sendcountedtext(&buf, str, strlen(str), false);
120+
}
121+
break;
122+
102123
default:
103124
elog(ERROR, "unsupported type OID: %u", attr->atttypid);
104125
}

‎src/backend/access/common/tupdesc.c‎

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -629,6 +629,14 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
629629
att->attstorage = 'p';
630630
att->attcollation = InvalidOid;
631631
break;
632+
633+
case INT8OID:
634+
att->attlen = 8;
635+
att->attbyval = FLOAT8PASSBYVAL;
636+
att->attalign = 'd';
637+
att->attstorage = 'p';
638+
att->attcollation = InvalidOid;
639+
break;
632640
}
633641
}
634642

‎src/backend/replication/walsender.c‎

Lines changed: 85 additions & 162 deletions
Original file line numberDiff line numberDiff line change
@@ -302,13 +302,15 @@ WalSndShutdown(void)
302302
static void
303303
IdentifySystem(void)
304304
{
305-
StringInfoData buf;
306305
char sysid[32];
307-
char tli[11];
308306
char xpos[MAXFNAMELEN];
309307
XLogRecPtr logptr;
310308
char *dbname = NULL;
311-
Size len;
309+
DestReceiver *dest;
310+
TupOutputState *tstate;
311+
TupleDesc tupdesc;
312+
Datum values[4];
313+
bool nulls[4];
312314

313315
/*
314316
* Reply with a result set with one row, four columns. First col is system
@@ -328,8 +330,6 @@ IdentifySystem(void)
328330
else
329331
logptr = GetFlushRecPtr();
330332

331-
snprintf(tli, sizeof(tli), "%u", ThisTimeLineID);
332-
333333
snprintf(xpos, sizeof(xpos), "%X/%X", (uint32) (logptr >> 32), (uint32) logptr);
334334

335335
if (MyDatabaseId != InvalidOid)
@@ -346,79 +346,42 @@ IdentifySystem(void)
346346
MemoryContextSwitchTo(cur);
347347
}
348348

349-
/* Send a RowDescription message */
350-
pq_beginmessage(&buf, 'T');
351-
pq_sendint(&buf, 4, 2); /* 4 fields */
352-
353-
/* first field */
354-
pq_sendstring(&buf, "systemid"); /* col name */
355-
pq_sendint(&buf, 0, 4); /* table oid */
356-
pq_sendint(&buf, 0, 2); /* attnum */
357-
pq_sendint(&buf, TEXTOID, 4); /* type oid */
358-
pq_sendint(&buf, -1, 2); /* typlen */
359-
pq_sendint(&buf, 0, 4); /* typmod */
360-
pq_sendint(&buf, 0, 2); /* format code */
361-
362-
/* second field */
363-
pq_sendstring(&buf, "timeline"); /* col name */
364-
pq_sendint(&buf, 0, 4); /* table oid */
365-
pq_sendint(&buf, 0, 2); /* attnum */
366-
pq_sendint(&buf, INT4OID, 4); /* type oid */
367-
pq_sendint(&buf, 4, 2); /* typlen */
368-
pq_sendint(&buf, 0, 4); /* typmod */
369-
pq_sendint(&buf, 0, 2); /* format code */
370-
371-
/* third field */
372-
pq_sendstring(&buf, "xlogpos"); /* col name */
373-
pq_sendint(&buf, 0, 4); /* table oid */
374-
pq_sendint(&buf, 0, 2); /* attnum */
375-
pq_sendint(&buf, TEXTOID, 4); /* type oid */
376-
pq_sendint(&buf, -1, 2); /* typlen */
377-
pq_sendint(&buf, 0, 4); /* typmod */
378-
pq_sendint(&buf, 0, 2); /* format code */
349+
dest = CreateDestReceiver(DestRemoteSimple);
350+
MemSet(nulls, false, sizeof(nulls));
379351

380-
/* fourth field */
381-
pq_sendstring(&buf, "dbname"); /* col name */
382-
pq_sendint(&buf, 0, 4); /* table oid */
383-
pq_sendint(&buf, 0, 2); /* attnum */
384-
pq_sendint(&buf, TEXTOID, 4); /* type oid */
385-
pq_sendint(&buf, -1, 2); /* typlen */
386-
pq_sendint(&buf, 0, 4); /* typmod */
387-
pq_sendint(&buf, 0, 2); /* format code */
388-
pq_endmessage(&buf);
352+
/* need a tuple descriptor representing four columns */
353+
tupdesc = CreateTemplateTupleDesc(4, false);
354+
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 1, "systemid",
355+
TEXTOID, -1, 0);
356+
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 2, "timeline",
357+
INT4OID, -1, 0);
358+
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 3, "xlogpos",
359+
TEXTOID, -1, 0);
360+
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 4, "dbname",
361+
TEXTOID, -1, 0);
389362

390-
/* Send a DataRow message */
391-
pq_beginmessage(&buf, 'D');
392-
pq_sendint(&buf, 4, 2); /* # of columns */
363+
/* prepare for projection of tuples */
364+
tstate = begin_tup_output_tupdesc(dest, tupdesc);
393365

394366
/* column 1: system identifier */
395-
len = strlen(sysid);
396-
pq_sendint(&buf, len, 4);
397-
pq_sendbytes(&buf, (char *) &sysid, len);
367+
values[0] = CStringGetTextDatum(sysid);
398368

399369
/* column 2: timeline */
400-
len = strlen(tli);
401-
pq_sendint(&buf, len, 4);
402-
pq_sendbytes(&buf, (char *) tli, len);
370+
values[1] = Int32GetDatum(ThisTimeLineID);
403371

404372
/* column 3: xlog position */
405-
len = strlen(xpos);
406-
pq_sendint(&buf, len, 4);
407-
pq_sendbytes(&buf, (char *) xpos, len);
373+
values[2] = CStringGetTextDatum(xpos);
408374

409375
/* column 4: database name, or NULL if none */
410376
if (dbname)
411-
{
412-
len = strlen(dbname);
413-
pq_sendint(&buf, len, 4);
414-
pq_sendbytes(&buf, (char *) dbname, len);
415-
}
377+
values[3] = CStringGetTextDatum(dbname);
416378
else
417-
{
418-
pq_sendint(&buf, -1, 4);
419-
}
379+
nulls[3] = true;
420380

421-
pq_endmessage(&buf);
381+
/* send it to dest */
382+
do_tup_output(tstate, values, nulls);
383+
384+
end_tup_output(tstate);
422385
}
423386

424387

@@ -695,54 +658,41 @@ StartReplication(StartReplicationCmd *cmd)
695658
*/
696659
if (sendTimeLineIsHistoric)
697660
{
698-
char tli_str[11];
699661
char startpos_str[8 + 1 + 8 + 1];
700-
Size len;
662+
DestReceiver *dest;
663+
TupOutputState *tstate;
664+
TupleDesc tupdesc;
665+
Datum values[2];
666+
bool nulls[2];
701667

702-
snprintf(tli_str, sizeof(tli_str), "%u", sendTimeLineNextTLI);
703668
snprintf(startpos_str, sizeof(startpos_str), "%X/%X",
704669
(uint32) (sendTimeLineValidUpto >> 32),
705670
(uint32) sendTimeLineValidUpto);
706671

707-
pq_beginmessage(&buf, 'T'); /* RowDescription */
708-
pq_sendint(&buf, 2, 2); /* 2 fields */
709-
710-
/* Field header */
711-
pq_sendstring(&buf, "next_tli");
712-
pq_sendint(&buf, 0, 4); /* table oid */
713-
pq_sendint(&buf, 0, 2); /* attnum */
672+
dest = CreateDestReceiver(DestRemoteSimple);
673+
MemSet(nulls, false, sizeof(nulls));
714674

715675
/*
676+
* Need a tuple descriptor representing two columns.
716677
* int8 may seem like a surprising data type for this, but in theory
717678
* int4 would not be wide enough for this, as TimeLineID is unsigned.
718679
*/
719-
pq_sendint(&buf, INT8OID, 4); /* type oid */
720-
pq_sendint(&buf, -1, 2);
721-
pq_sendint(&buf, 0, 4);
722-
pq_sendint(&buf, 0, 2);
723-
724-
pq_sendstring(&buf, "next_tli_startpos");
725-
pq_sendint(&buf, 0, 4); /* table oid */
726-
pq_sendint(&buf, 0, 2); /* attnum */
727-
pq_sendint(&buf, TEXTOID, 4); /* type oid */
728-
pq_sendint(&buf, -1, 2);
729-
pq_sendint(&buf, 0, 4);
730-
pq_sendint(&buf, 0, 2);
731-
pq_endmessage(&buf);
680+
tupdesc = CreateTemplateTupleDesc(2, false);
681+
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 1, "next_tli",
682+
INT8OID, -1, 0);
683+
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 2, "next_tli_startpos",
684+
TEXTOID, -1, 0);
732685

733-
/* Data row */
734-
pq_beginmessage(&buf, 'D');
735-
pq_sendint(&buf, 2, 2); /* number of columns */
686+
/* prepare for projection of tuple */
687+
tstate = begin_tup_output_tupdesc(dest, tupdesc);
736688

737-
len = strlen(tli_str);
738-
pq_sendint(&buf, len, 4); /* length */
739-
pq_sendbytes(&buf, tli_str, len);
689+
values[0] = Int64GetDatum((int64) sendTimeLineNextTLI);
690+
values[1] = CStringGetTextDatum(startpos_str);
740691

741-
len = strlen(startpos_str);
742-
pq_sendint(&buf, len, 4); /* length */
743-
pq_sendbytes(&buf, startpos_str, len);
692+
/* send it to dest */
693+
do_tup_output(tstate, values, nulls);
744694

745-
pq_endmessage(&buf);
695+
end_tup_output(tstate);
746696
}
747697

748698
/* Send CommandComplete message */
@@ -790,8 +740,12 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd)
790740
{
791741
const char *snapshot_name = NULL;
792742
char xpos[MAXFNAMELEN];
793-
StringInfoData buf;
794-
Size len;
743+
char *slot_name;
744+
DestReceiver *dest;
745+
TupOutputState *tstate;
746+
TupleDesc tupdesc;
747+
Datum values[4];
748+
bool nulls[4];
795749

796750
Assert(!MyReplicationSlot);
797751

@@ -868,82 +822,51 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd)
868822
(uint32) (MyReplicationSlot->data.confirmed_flush >> 32),
869823
(uint32) MyReplicationSlot->data.confirmed_flush);
870824

871-
pq_beginmessage(&buf, 'T');
872-
pq_sendint(&buf, 4, 2); /* 4 fields */
873-
874-
/* first field: slot name */
875-
pq_sendstring(&buf, "slot_name"); /* col name */
876-
pq_sendint(&buf, 0, 4); /* table oid */
877-
pq_sendint(&buf, 0, 2); /* attnum */
878-
pq_sendint(&buf, TEXTOID, 4); /* type oid */
879-
pq_sendint(&buf, -1, 2); /* typlen */
880-
pq_sendint(&buf, 0, 4); /* typmod */
881-
pq_sendint(&buf, 0, 2); /* format code */
882-
883-
/* second field: LSN at which we became consistent */
884-
pq_sendstring(&buf, "consistent_point"); /* col name */
885-
pq_sendint(&buf, 0, 4); /* table oid */
886-
pq_sendint(&buf, 0, 2); /* attnum */
887-
pq_sendint(&buf, TEXTOID, 4); /* type oid */
888-
pq_sendint(&buf, -1, 2); /* typlen */
889-
pq_sendint(&buf, 0, 4); /* typmod */
890-
pq_sendint(&buf, 0, 2); /* format code */
891-
892-
/* third field: exported snapshot's name */
893-
pq_sendstring(&buf, "snapshot_name"); /* col name */
894-
pq_sendint(&buf, 0, 4); /* table oid */
895-
pq_sendint(&buf, 0, 2); /* attnum */
896-
pq_sendint(&buf, TEXTOID, 4); /* type oid */
897-
pq_sendint(&buf, -1, 2); /* typlen */
898-
pq_sendint(&buf, 0, 4); /* typmod */
899-
pq_sendint(&buf, 0, 2); /* format code */
900-
901-
/* fourth field: output plugin */
902-
pq_sendstring(&buf, "output_plugin"); /* col name */
903-
pq_sendint(&buf, 0, 4); /* table oid */
904-
pq_sendint(&buf, 0, 2); /* attnum */
905-
pq_sendint(&buf, TEXTOID, 4); /* type oid */
906-
pq_sendint(&buf, -1, 2); /* typlen */
907-
pq_sendint(&buf, 0, 4); /* typmod */
908-
pq_sendint(&buf, 0, 2); /* format code */
825+
dest = CreateDestReceiver(DestRemoteSimple);
826+
MemSet(nulls, false, sizeof(nulls));
909827

910-
pq_endmessage(&buf);
911-
912-
/* Send a DataRow message */
913-
pq_beginmessage(&buf, 'D');
914-
pq_sendint(&buf, 4, 2); /* # of columns */
828+
/*
829+
* Need a tuple descriptor representing four columns:
830+
* - first field: the slot name
831+
* - second field: LSN at which we became consistent
832+
* - third field: exported snapshot's name
833+
* - fourth field: output plugin
834+
*/
835+
tupdesc = CreateTemplateTupleDesc(4, false);
836+
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 1, "slot_name",
837+
TEXTOID, -1, 0);
838+
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 2, "consistent_point",
839+
TEXTOID, -1, 0);
840+
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 3, "snapshot_name",
841+
TEXTOID, -1, 0);
842+
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 4, "output_plugin",
843+
TEXTOID, -1, 0);
844+
845+
/* prepare for projection of tuples */
846+
tstate = begin_tup_output_tupdesc(dest, tupdesc);
915847

916848
/* slot_name */
917-
len = strlen(NameStr(MyReplicationSlot->data.name));
918-
pq_sendint(&buf, len, 4); /* col1 len */
919-
pq_sendbytes(&buf, NameStr(MyReplicationSlot->data.name), len);
849+
slot_name = NameStr(MyReplicationSlot->data.name);
850+
values[0] = CStringGetTextDatum(slot_name);
920851

921852
/* consistent wal location */
922-
len = strlen(xpos);
923-
pq_sendint(&buf, len, 4);
924-
pq_sendbytes(&buf, xpos, len);
853+
values[1] = CStringGetTextDatum(xpos);
925854

926855
/* snapshot name, or NULL if none */
927856
if (snapshot_name != NULL)
928-
{
929-
len = strlen(snapshot_name);
930-
pq_sendint(&buf, len, 4);
931-
pq_sendbytes(&buf, snapshot_name, len);
932-
}
857+
values[2] = CStringGetTextDatum(snapshot_name);
933858
else
934-
pq_sendint(&buf, -1, 4);
859+
nulls[2] = true;
935860

936861
/* plugin, or NULL if none */
937862
if (cmd->plugin != NULL)
938-
{
939-
len = strlen(cmd->plugin);
940-
pq_sendint(&buf, len, 4);
941-
pq_sendbytes(&buf, cmd->plugin, len);
942-
}
863+
values[3] = CStringGetTextDatum(cmd->plugin);
943864
else
944-
pq_sendint(&buf, -1, 4);
865+
nulls[3] = true;
945866

946-
pq_endmessage(&buf);
867+
/* send it to dest */
868+
do_tup_output(tstate, values, nulls);
869+
end_tup_output(tstate);
947870

948871
ReplicationSlotRelease();
949872
}

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