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Refactor sending of RowDescription messages in replication protocol

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Some routines open-coded the construction of RowDescription messages.
Instead, we have support for doing this using tuple descriptors and
DestRemoteSimple, so use that instead.

Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/7e4fdbdc-699c-4cd0-115d-fb78a957fc22@enterprisedb.com
This commit is contained in:
Peter Eisentraut 2022-07-04 07:25:26 +02:00
parent f10a025cfe
commit 2ce648f750
3 changed files with 40 additions and 72 deletions
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9
src/backend/access/common/tupdesc.c
View File

@ -739,6 +739,15 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
att->attcollation = InvalidOid;
break;
case OIDOID:
att->attlen = 4;
att->attbyval = true;
att->attalign = TYPALIGN_INT;
att->attstorage = TYPSTORAGE_PLAIN;
att->attcompression = InvalidCompressionMethod;
att->attcollation = InvalidOid;
break;
default:
elog(ERROR, "unsupported type %u", oidtypeid);
}

74
src/backend/replication/basebackup_copy.c
View File

@ -25,11 +25,13 @@
*/
#include "postgres.h"
#include "access/tupdesc.h"
#include "catalog/pg_type_d.h"
#include "libpq/libpq.h"
#include "libpq/pqformat.h"
#include "replication/basebackup.h"
#include "replication/basebackup_sink.h"
#include "tcop/dest.h"
#include "utils/timestamp.h"
typedef struct bbsink_copystream
@ -336,35 +338,24 @@ SendCopyDone(void)
static void
SendXlogRecPtrResult(XLogRecPtr ptr, TimeLineID tli)
{
DestReceiver *dest;
TupleDesc tupdesc;
StringInfoData buf;
char str[MAXFNAMELEN];
Size len;
pq_beginmessage(&buf, 'T'); /* RowDescription */
pq_sendint16(&buf, 2); /* 2 fields */
/* Field headers */
pq_sendstring(&buf, "recptr");
pq_sendint32(&buf, 0); /* table oid */
pq_sendint16(&buf, 0); /* attnum */
pq_sendint32(&buf, TEXTOID); /* type oid */
pq_sendint16(&buf, -1);
pq_sendint32(&buf, 0);
pq_sendint16(&buf, 0);
pq_sendstring(&buf, "tli");
pq_sendint32(&buf, 0); /* table oid */
pq_sendint16(&buf, 0); /* attnum */
dest = CreateDestReceiver(DestRemoteSimple);
tupdesc = CreateTemplateTupleDesc(2);
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 1, "recptr", TEXTOID, -1, 0);
/*
* int8 may seem like a surprising data type for this, but in theory int4
* would not be wide enough for this, as TimeLineID is unsigned.
*/
pq_sendint32(&buf, INT8OID); /* type oid */
pq_sendint16(&buf, 8);
pq_sendint32(&buf, 0);
pq_sendint16(&buf, 0);
pq_endmessage(&buf);
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 2, "tli", INT8OID, -1, 0);
/* send RowDescription */
dest->rStartup(dest, CMD_SELECT, tupdesc);
/* Data row */
pq_beginmessage(&buf, 'D');
@ -391,41 +382,22 @@ SendXlogRecPtrResult(XLogRecPtr ptr, TimeLineID tli)
static void
SendTablespaceList(List *tablespaces)
{
DestReceiver *dest;
TupleDesc tupdesc;
StringInfoData buf;
ListCell *lc;
dest = CreateDestReceiver(DestRemoteSimple);
tupdesc = CreateTemplateTupleDesc(3);
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 1, "spcoid", OIDOID, -1, 0);
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 2, "spclocation", TEXTOID, -1, 0);
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 3, "size", INT8OID, -1, 0);
/* send RowDescription */
dest->rStartup(dest, CMD_SELECT, tupdesc);
/* Construct and send the directory information */
pq_beginmessage(&buf, 'T'); /* RowDescription */
pq_sendint16(&buf, 3); /* 3 fields */
/* First field - spcoid */
pq_sendstring(&buf, "spcoid");
pq_sendint32(&buf, 0); /* table oid */
pq_sendint16(&buf, 0); /* attnum */
pq_sendint32(&buf, OIDOID); /* type oid */
pq_sendint16(&buf, 4); /* typlen */
pq_sendint32(&buf, 0); /* typmod */
pq_sendint16(&buf, 0); /* format code */
/* Second field - spclocation */
pq_sendstring(&buf, "spclocation");
pq_sendint32(&buf, 0);
pq_sendint16(&buf, 0);
pq_sendint32(&buf, TEXTOID);
pq_sendint16(&buf, -1);
pq_sendint32(&buf, 0);
pq_sendint16(&buf, 0);
/* Third field - size */
pq_sendstring(&buf, "size");
pq_sendint32(&buf, 0);
pq_sendint16(&buf, 0);
pq_sendint32(&buf, INT8OID);
pq_sendint16(&buf, 8);
pq_sendint32(&buf, 0);
pq_sendint16(&buf, 0);
pq_endmessage(&buf);
foreach(lc, tablespaces)
{
tablespaceinfo *ti = lfirst(lc);

29
src/backend/replication/walsender.c
View File

@ -579,6 +579,8 @@ ReadReplicationSlot(ReadReplicationSlotCmd *cmd)
static void
SendTimeLineHistory(TimeLineHistoryCmd *cmd)
{
DestReceiver *dest;
TupleDesc tupdesc;
StringInfoData buf;
char histfname[MAXFNAMELEN];
char path[MAXPGPATH];
@ -587,36 +589,21 @@ SendTimeLineHistory(TimeLineHistoryCmd *cmd)
off_t bytesleft;
Size len;
dest = CreateDestReceiver(DestRemoteSimple);
/*
* Reply with a result set with one row, and two columns. The first col is
* the name of the history file, 2nd is the contents.
*/
tupdesc = CreateTemplateTupleDesc(2);
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 1, "filename", TEXTOID, -1, 0);
TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 2, "content", TEXTOID, -1, 0);
TLHistoryFileName(histfname, cmd->timeline);
TLHistoryFilePath(path, cmd->timeline);
/* Send a RowDescription message */
pq_beginmessage(&buf, 'T');
pq_sendint16(&buf, 2); /* 2 fields */
/* first field */
pq_sendstring(&buf, "filename"); /* col name */
pq_sendint32(&buf, 0); /* table oid */
pq_sendint16(&buf, 0); /* attnum */
pq_sendint32(&buf, TEXTOID); /* type oid */
pq_sendint16(&buf, -1); /* typlen */
pq_sendint32(&buf, 0); /* typmod */
pq_sendint16(&buf, 0); /* format code */
/* second field */
pq_sendstring(&buf, "content"); /* col name */
pq_sendint32(&buf, 0); /* table oid */
pq_sendint16(&buf, 0); /* attnum */
pq_sendint32(&buf, TEXTOID); /* type oid */
pq_sendint16(&buf, -1); /* typlen */
pq_sendint32(&buf, 0); /* typmod */
pq_sendint16(&buf, 0); /* format code */
pq_endmessage(&buf);
dest->rStartup(dest, CMD_SELECT, tupdesc);
/* Send a DataRow message */
pq_beginmessage(&buf, 'D');