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Allow bidirectional copy messages in streaming replication mode.

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Fujii Masao.  Review by Alvaro Herrera, Tom Lane, and myself.
This commit is contained in:
Robert Haas
2010-12-11 09:27:37 -05:00
parent 20f3964291
commit d3d414696f
11 changed files with 172 additions and 21 deletions
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22
src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
View File

@@ -50,6 +50,7 @@ static char *recvBuf = NULL;
static bool libpqrcv_connect(char *conninfo, XLogRecPtr startpoint);
static bool libpqrcv_receive(int timeout, unsigned char *type,
char **buffer, int *len);
static void libpqrcv_send(const char *buffer, int nbytes);
static void libpqrcv_disconnect(void);
/* Prototypes for private functions */
@@ -64,10 +65,11 @@ _PG_init(void)
{
/* Tell walreceiver how to reach us */
if (walrcv_connect != NULL || walrcv_receive != NULL ||
walrcv_disconnect != NULL)
walrcv_send != NULL || walrcv_disconnect != NULL)
elog(ERROR, "libpqwalreceiver already loaded");
walrcv_connect = libpqrcv_connect;
walrcv_receive = libpqrcv_receive;
walrcv_send = libpqrcv_send;
walrcv_disconnect = libpqrcv_disconnect;
}
@@ -157,7 +159,7 @@ libpqrcv_connect(char *conninfo, XLogRecPtr startpoint)
snprintf(cmd, sizeof(cmd), "START_REPLICATION %X/%X",
startpoint.xlogid, startpoint.xrecoff);
res = libpqrcv_PQexec(cmd);
if (PQresultStatus(res) != PGRES_COPY_OUT)
if (PQresultStatus(res) != PGRES_COPY_BOTH)
{
PQclear(res);
ereport(ERROR,
@@ -303,6 +305,7 @@ libpqrcv_PQexec(const char *query)
if (PQresultStatus(lastResult) == PGRES_COPY_IN ||
PQresultStatus(lastResult) == PGRES_COPY_OUT ||
PQresultStatus(lastResult) == PGRES_COPY_BOTH ||
PQstatus(streamConn) == CONNECTION_BAD)
break;
}
@@ -398,3 +401,18 @@ libpqrcv_receive(int timeout, unsigned char *type, char **buffer, int *len)
return true;
}
/*
* Send a message to XLOG stream.
*
* ereports on error.
*/
static void
libpqrcv_send(const char *buffer, int nbytes)
{
if (PQputCopyData(streamConn, buffer, nbytes) <= 0 ||
PQflush(streamConn))
ereport(ERROR,
(errmsg("could not send data to WAL stream: %s",
PQerrorMessage(streamConn))));
}

3
src/backend/replication/walreceiver.c
View File

@@ -57,6 +57,7 @@ bool am_walreceiver;
/* libpqreceiver hooks to these when loaded */
walrcv_connect_type walrcv_connect = NULL;
walrcv_receive_type walrcv_receive = NULL;
walrcv_send_type walrcv_send = NULL;
walrcv_disconnect_type walrcv_disconnect = NULL;
#define NAPTIME_PER_CYCLE 100 /* max sleep time between cycles (100ms) */
@@ -247,7 +248,7 @@ WalReceiverMain(void)
/* Load the libpq-specific functions */
load_file("libpqwalreceiver", false);
if (walrcv_connect == NULL || walrcv_receive == NULL ||
walrcv_disconnect == NULL)
walrcv_send == NULL || walrcv_disconnect == NULL)
elog(ERROR, "libpqwalreceiver didn't initialize correctly");
/*

4
src/backend/replication/walsender.c
View File

@@ -287,8 +287,8 @@ WalSndHandshake(void)
(errcode(ERRCODE_CANNOT_CONNECT_NOW),
errmsg("standby connections not allowed because wal_level=minimal")));
/* Send a CopyOutResponse message, and start streaming */
pq_beginmessage(&buf, 'H');
/* Send a CopyBothResponse message, and start streaming */
pq_beginmessage(&buf, 'W');
pq_sendbyte(&buf, 0);
pq_sendint(&buf, 0, 2);
pq_endmessage(&buf);