1033 lines
26 KiB
C
1033 lines
26 KiB
C
/*-------------------------------------------------------------------------
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*
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* libpqwalreceiver.c
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*
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* This file contains the libpq-specific parts of walreceiver. It's
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* loaded as a dynamic module to avoid linking the main server binary with
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* libpq.
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*
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* Portions Copyright (c) 2010-2019, PostgreSQL Global Development Group
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*
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*
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* IDENTIFICATION
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* src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <unistd.h>
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#include <sys/time.h>
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#include "libpq-fe.h"
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#include "pqexpbuffer.h"
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#include "access/xlog.h"
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#include "catalog/pg_type.h"
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#include "funcapi.h"
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#include "mb/pg_wchar.h"
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#include "miscadmin.h"
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#include "pgstat.h"
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#include "replication/walreceiver.h"
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#include "utils/builtins.h"
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#include "utils/memutils.h"
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#include "utils/pg_lsn.h"
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#include "utils/tuplestore.h"
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PG_MODULE_MAGIC;
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void _PG_init(void);
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struct WalReceiverConn
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{
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/* Current connection to the primary, if any */
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PGconn *streamConn;
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/* Used to remember if the connection is logical or physical */
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bool logical;
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/* Buffer for currently read records */
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char *recvBuf;
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};
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/* Prototypes for interface functions */
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static WalReceiverConn *libpqrcv_connect(const char *conninfo,
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bool logical, const char *appname,
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char **err);
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static void libpqrcv_check_conninfo(const char *conninfo);
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static char *libpqrcv_get_conninfo(WalReceiverConn *conn);
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static void libpqrcv_get_senderinfo(WalReceiverConn *conn,
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char **sender_host, int *sender_port);
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static char *libpqrcv_identify_system(WalReceiverConn *conn,
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TimeLineID *primary_tli);
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static int libpqrcv_server_version(WalReceiverConn *conn);
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static void libpqrcv_readtimelinehistoryfile(WalReceiverConn *conn,
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TimeLineID tli, char **filename,
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char **content, int *len);
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static bool libpqrcv_startstreaming(WalReceiverConn *conn,
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const WalRcvStreamOptions *options);
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static void libpqrcv_endstreaming(WalReceiverConn *conn,
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TimeLineID *next_tli);
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static int libpqrcv_receive(WalReceiverConn *conn, char **buffer,
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pgsocket *wait_fd);
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static void libpqrcv_send(WalReceiverConn *conn, const char *buffer,
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int nbytes);
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static char *libpqrcv_create_slot(WalReceiverConn *conn,
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const char *slotname,
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bool temporary,
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CRSSnapshotAction snapshot_action,
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XLogRecPtr *lsn);
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static WalRcvExecResult *libpqrcv_exec(WalReceiverConn *conn,
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const char *query,
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const int nRetTypes,
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const Oid *retTypes);
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static void libpqrcv_disconnect(WalReceiverConn *conn);
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static WalReceiverFunctionsType PQWalReceiverFunctions = {
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libpqrcv_connect,
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libpqrcv_check_conninfo,
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libpqrcv_get_conninfo,
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libpqrcv_get_senderinfo,
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libpqrcv_identify_system,
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libpqrcv_server_version,
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libpqrcv_readtimelinehistoryfile,
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libpqrcv_startstreaming,
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libpqrcv_endstreaming,
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libpqrcv_receive,
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libpqrcv_send,
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libpqrcv_create_slot,
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libpqrcv_exec,
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libpqrcv_disconnect
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};
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/* Prototypes for private functions */
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static PGresult *libpqrcv_PQexec(PGconn *streamConn, const char *query);
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static PGresult *libpqrcv_PQgetResult(PGconn *streamConn);
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static char *stringlist_to_identifierstr(PGconn *conn, List *strings);
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/*
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* Module initialization function
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*/
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void
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_PG_init(void)
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{
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if (WalReceiverFunctions != NULL)
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elog(ERROR, "libpqwalreceiver already loaded");
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WalReceiverFunctions = &PQWalReceiverFunctions;
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}
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/*
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* Establish the connection to the primary server for XLOG streaming
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*
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* Returns NULL on error and fills the err with palloc'ed error message.
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*/
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static WalReceiverConn *
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libpqrcv_connect(const char *conninfo, bool logical, const char *appname,
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char **err)
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{
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WalReceiverConn *conn;
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PostgresPollingStatusType status;
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const char *keys[5];
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const char *vals[5];
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int i = 0;
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/*
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* We use the expand_dbname parameter to process the connection string (or
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* URI), and pass some extra options.
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*/
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keys[i] = "dbname";
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vals[i] = conninfo;
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keys[++i] = "replication";
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vals[i] = logical ? "database" : "true";
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if (!logical)
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{
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/*
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* The database name is ignored by the server in replication mode, but
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* specify "replication" for .pgpass lookup.
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*/
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keys[++i] = "dbname";
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vals[i] = "replication";
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}
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keys[++i] = "fallback_application_name";
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vals[i] = appname;
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if (logical)
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{
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keys[++i] = "client_encoding";
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vals[i] = GetDatabaseEncodingName();
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}
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keys[++i] = NULL;
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vals[i] = NULL;
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Assert(i < sizeof(keys));
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conn = palloc0(sizeof(WalReceiverConn));
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conn->streamConn = PQconnectStartParams(keys, vals,
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/* expand_dbname = */ true);
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if (PQstatus(conn->streamConn) == CONNECTION_BAD)
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{
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*err = pchomp(PQerrorMessage(conn->streamConn));
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return NULL;
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}
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/*
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* Poll connection until we have OK or FAILED status.
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*
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* Per spec for PQconnectPoll, first wait till socket is write-ready.
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*/
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status = PGRES_POLLING_WRITING;
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do
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{
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int io_flag;
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int rc;
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if (status == PGRES_POLLING_READING)
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io_flag = WL_SOCKET_READABLE;
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#ifdef WIN32
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/* Windows needs a different test while waiting for connection-made */
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else if (PQstatus(conn->streamConn) == CONNECTION_STARTED)
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io_flag = WL_SOCKET_CONNECTED;
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#endif
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else
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io_flag = WL_SOCKET_WRITEABLE;
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rc = WaitLatchOrSocket(MyLatch,
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WL_EXIT_ON_PM_DEATH | WL_LATCH_SET | io_flag,
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PQsocket(conn->streamConn),
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0,
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WAIT_EVENT_LIBPQWALRECEIVER_CONNECT);
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/* Interrupted? */
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if (rc & WL_LATCH_SET)
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{
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ResetLatch(MyLatch);
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ProcessWalRcvInterrupts();
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}
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/* If socket is ready, advance the libpq state machine */
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if (rc & io_flag)
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status = PQconnectPoll(conn->streamConn);
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} while (status != PGRES_POLLING_OK && status != PGRES_POLLING_FAILED);
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if (PQstatus(conn->streamConn) != CONNECTION_OK)
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{
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*err = pchomp(PQerrorMessage(conn->streamConn));
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return NULL;
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}
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conn->logical = logical;
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return conn;
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}
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/*
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* Validate connection info string (just try to parse it)
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*/
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static void
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libpqrcv_check_conninfo(const char *conninfo)
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{
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PQconninfoOption *opts = NULL;
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char *err = NULL;
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opts = PQconninfoParse(conninfo, &err);
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if (opts == NULL)
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ereport(ERROR,
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(errcode(ERRCODE_SYNTAX_ERROR),
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errmsg("invalid connection string syntax: %s", err)));
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PQconninfoFree(opts);
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}
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/*
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* Return a user-displayable conninfo string. Any security-sensitive fields
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* are obfuscated.
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*/
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static char *
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libpqrcv_get_conninfo(WalReceiverConn *conn)
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{
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PQconninfoOption *conn_opts;
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PQconninfoOption *conn_opt;
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PQExpBufferData buf;
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char *retval;
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Assert(conn->streamConn != NULL);
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initPQExpBuffer(&buf);
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conn_opts = PQconninfo(conn->streamConn);
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if (conn_opts == NULL)
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ereport(ERROR,
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(errmsg("could not parse connection string: %s",
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_("out of memory"))));
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/* build a clean connection string from pieces */
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for (conn_opt = conn_opts; conn_opt->keyword != NULL; conn_opt++)
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{
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bool obfuscate;
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/* Skip debug and empty options */
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if (strchr(conn_opt->dispchar, 'D') ||
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conn_opt->val == NULL ||
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conn_opt->val[0] == '\0')
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continue;
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/* Obfuscate security-sensitive options */
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obfuscate = strchr(conn_opt->dispchar, '*') != NULL;
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appendPQExpBuffer(&buf, "%s%s=%s",
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buf.len == 0 ? "" : " ",
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conn_opt->keyword,
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obfuscate ? "********" : conn_opt->val);
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}
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PQconninfoFree(conn_opts);
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retval = PQExpBufferDataBroken(buf) ? NULL : pstrdup(buf.data);
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termPQExpBuffer(&buf);
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return retval;
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}
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/*
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* Provides information of sender this WAL receiver is connected to.
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*/
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static void
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libpqrcv_get_senderinfo(WalReceiverConn *conn, char **sender_host,
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int *sender_port)
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{
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char *ret = NULL;
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*sender_host = NULL;
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*sender_port = 0;
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Assert(conn->streamConn != NULL);
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ret = PQhost(conn->streamConn);
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if (ret && strlen(ret) != 0)
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*sender_host = pstrdup(ret);
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ret = PQport(conn->streamConn);
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if (ret && strlen(ret) != 0)
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*sender_port = atoi(ret);
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}
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/*
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* Check that primary's system identifier matches ours, and fetch the current
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* timeline ID of the primary.
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*/
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static char *
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libpqrcv_identify_system(WalReceiverConn *conn, TimeLineID *primary_tli)
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{
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PGresult *res;
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char *primary_sysid;
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/*
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* Get the system identifier and timeline ID as a DataRow message from the
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* primary server.
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*/
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res = libpqrcv_PQexec(conn->streamConn, "IDENTIFY_SYSTEM");
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if (PQresultStatus(res) != PGRES_TUPLES_OK)
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{
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PQclear(res);
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ereport(ERROR,
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(errmsg("could not receive database system identifier and timeline ID from "
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"the primary server: %s",
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pchomp(PQerrorMessage(conn->streamConn)))));
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}
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if (PQnfields(res) < 3 || PQntuples(res) != 1)
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{
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int ntuples = PQntuples(res);
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int nfields = PQnfields(res);
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PQclear(res);
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ereport(ERROR,
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(errmsg("invalid response from primary server"),
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errdetail("Could not identify system: got %d rows and %d fields, expected %d rows and %d or more fields.",
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ntuples, nfields, 3, 1)));
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}
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primary_sysid = pstrdup(PQgetvalue(res, 0, 0));
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*primary_tli = pg_strtoint32(PQgetvalue(res, 0, 1));
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PQclear(res);
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return primary_sysid;
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}
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/*
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* Thin wrapper around libpq to obtain server version.
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*/
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static int
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libpqrcv_server_version(WalReceiverConn *conn)
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{
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return PQserverVersion(conn->streamConn);
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}
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/*
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* Start streaming WAL data from given streaming options.
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*
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* Returns true if we switched successfully to copy-both mode. False
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* means the server received the command and executed it successfully, but
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* didn't switch to copy-mode. That means that there was no WAL on the
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* requested timeline and starting point, because the server switched to
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* another timeline at or before the requested starting point. On failure,
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* throws an ERROR.
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*/
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static bool
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libpqrcv_startstreaming(WalReceiverConn *conn,
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const WalRcvStreamOptions *options)
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{
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StringInfoData cmd;
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PGresult *res;
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Assert(options->logical == conn->logical);
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Assert(options->slotname || !options->logical);
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initStringInfo(&cmd);
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/* Build the command. */
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appendStringInfoString(&cmd, "START_REPLICATION");
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if (options->slotname != NULL)
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appendStringInfo(&cmd, " SLOT \"%s\"",
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options->slotname);
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if (options->logical)
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appendStringInfoString(&cmd, " LOGICAL");
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appendStringInfo(&cmd, " %X/%X",
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(uint32) (options->startpoint >> 32),
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(uint32) options->startpoint);
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/*
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* Additional options are different depending on if we are doing logical
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* or physical replication.
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*/
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if (options->logical)
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{
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char *pubnames_str;
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List *pubnames;
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char *pubnames_literal;
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appendStringInfoString(&cmd, " (");
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appendStringInfo(&cmd, "proto_version '%u'",
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options->proto.logical.proto_version);
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pubnames = options->proto.logical.publication_names;
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pubnames_str = stringlist_to_identifierstr(conn->streamConn, pubnames);
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if (!pubnames_str)
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ereport(ERROR,
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(errmsg("could not start WAL streaming: %s",
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pchomp(PQerrorMessage(conn->streamConn)))));
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pubnames_literal = PQescapeLiteral(conn->streamConn, pubnames_str,
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strlen(pubnames_str));
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if (!pubnames_literal)
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ereport(ERROR,
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(errmsg("could not start WAL streaming: %s",
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pchomp(PQerrorMessage(conn->streamConn)))));
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appendStringInfo(&cmd, ", publication_names %s", pubnames_literal);
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PQfreemem(pubnames_literal);
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pfree(pubnames_str);
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appendStringInfoChar(&cmd, ')');
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}
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else
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appendStringInfo(&cmd, " TIMELINE %u",
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options->proto.physical.startpointTLI);
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/* Start streaming. */
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res = libpqrcv_PQexec(conn->streamConn, cmd.data);
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pfree(cmd.data);
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if (PQresultStatus(res) == PGRES_COMMAND_OK)
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{
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PQclear(res);
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return false;
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}
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else if (PQresultStatus(res) != PGRES_COPY_BOTH)
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{
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PQclear(res);
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ereport(ERROR,
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(errmsg("could not start WAL streaming: %s",
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pchomp(PQerrorMessage(conn->streamConn)))));
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}
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PQclear(res);
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return true;
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}
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|
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/*
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* Stop streaming WAL data. Returns the next timeline's ID in *next_tli, as
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* reported by the server, or 0 if it did not report it.
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*/
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static void
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libpqrcv_endstreaming(WalReceiverConn *conn, TimeLineID *next_tli)
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{
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PGresult *res;
|
|
|
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/*
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* Send copy-end message. As in libpqrcv_PQexec, this could theoretically
|
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* block, but the risk seems small.
|
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*/
|
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if (PQputCopyEnd(conn->streamConn, NULL) <= 0 ||
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PQflush(conn->streamConn))
|
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ereport(ERROR,
|
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(errmsg("could not send end-of-streaming message to primary: %s",
|
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pchomp(PQerrorMessage(conn->streamConn)))));
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|
|
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*next_tli = 0;
|
|
|
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/*
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* After COPY is finished, we should receive a result set indicating the
|
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* next timeline's ID, or just CommandComplete if the server was shut
|
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* down.
|
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*
|
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* If we had not yet received CopyDone from the backend, PGRES_COPY_OUT is
|
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* also possible in case we aborted the copy in mid-stream.
|
|
*/
|
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res = libpqrcv_PQgetResult(conn->streamConn);
|
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if (PQresultStatus(res) == PGRES_TUPLES_OK)
|
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{
|
|
/*
|
|
* Read the next timeline's ID. The server also sends the timeline's
|
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* starting point, but it is ignored.
|
|
*/
|
|
if (PQnfields(res) < 2 || PQntuples(res) != 1)
|
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ereport(ERROR,
|
|
(errmsg("unexpected result set after end-of-streaming")));
|
|
*next_tli = pg_strtoint32(PQgetvalue(res, 0, 0));
|
|
PQclear(res);
|
|
|
|
/* the result set should be followed by CommandComplete */
|
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res = libpqrcv_PQgetResult(conn->streamConn);
|
|
}
|
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else if (PQresultStatus(res) == PGRES_COPY_OUT)
|
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{
|
|
PQclear(res);
|
|
|
|
/* End the copy */
|
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if (PQendcopy(conn->streamConn))
|
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ereport(ERROR,
|
|
(errmsg("error while shutting down streaming COPY: %s",
|
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pchomp(PQerrorMessage(conn->streamConn)))));
|
|
|
|
/* CommandComplete should follow */
|
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res = libpqrcv_PQgetResult(conn->streamConn);
|
|
}
|
|
|
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if (PQresultStatus(res) != PGRES_COMMAND_OK)
|
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ereport(ERROR,
|
|
(errmsg("error reading result of streaming command: %s",
|
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pchomp(PQerrorMessage(conn->streamConn)))));
|
|
PQclear(res);
|
|
|
|
/* Verify that there are no more results */
|
|
res = libpqrcv_PQgetResult(conn->streamConn);
|
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if (res != NULL)
|
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ereport(ERROR,
|
|
(errmsg("unexpected result after CommandComplete: %s",
|
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pchomp(PQerrorMessage(conn->streamConn)))));
|
|
}
|
|
|
|
/*
|
|
* Fetch the timeline history file for 'tli' from primary.
|
|
*/
|
|
static void
|
|
libpqrcv_readtimelinehistoryfile(WalReceiverConn *conn,
|
|
TimeLineID tli, char **filename,
|
|
char **content, int *len)
|
|
{
|
|
PGresult *res;
|
|
char cmd[64];
|
|
|
|
Assert(!conn->logical);
|
|
|
|
/*
|
|
* Request the primary to send over the history file for given timeline.
|
|
*/
|
|
snprintf(cmd, sizeof(cmd), "TIMELINE_HISTORY %u", tli);
|
|
res = libpqrcv_PQexec(conn->streamConn, cmd);
|
|
if (PQresultStatus(res) != PGRES_TUPLES_OK)
|
|
{
|
|
PQclear(res);
|
|
ereport(ERROR,
|
|
(errmsg("could not receive timeline history file from "
|
|
"the primary server: %s",
|
|
pchomp(PQerrorMessage(conn->streamConn)))));
|
|
}
|
|
if (PQnfields(res) != 2 || PQntuples(res) != 1)
|
|
{
|
|
int ntuples = PQntuples(res);
|
|
int nfields = PQnfields(res);
|
|
|
|
PQclear(res);
|
|
ereport(ERROR,
|
|
(errmsg("invalid response from primary server"),
|
|
errdetail("Expected 1 tuple with 2 fields, got %d tuples with %d fields.",
|
|
ntuples, nfields)));
|
|
}
|
|
*filename = pstrdup(PQgetvalue(res, 0, 0));
|
|
|
|
*len = PQgetlength(res, 0, 1);
|
|
*content = palloc(*len);
|
|
memcpy(*content, PQgetvalue(res, 0, 1), *len);
|
|
PQclear(res);
|
|
}
|
|
|
|
/*
|
|
* Send a query and wait for the results by using the asynchronous libpq
|
|
* functions and socket readiness events.
|
|
*
|
|
* We must not use the regular blocking libpq functions like PQexec()
|
|
* since they are uninterruptible by signals on some platforms, such as
|
|
* Windows.
|
|
*
|
|
* The function is modeled on PQexec() in libpq, but only implements
|
|
* those parts that are in use in the walreceiver api.
|
|
*
|
|
* May return NULL, rather than an error result, on failure.
|
|
*/
|
|
static PGresult *
|
|
libpqrcv_PQexec(PGconn *streamConn, const char *query)
|
|
{
|
|
PGresult *lastResult = NULL;
|
|
|
|
/*
|
|
* PQexec() silently discards any prior query results on the connection.
|
|
* This is not required for this function as it's expected that the caller
|
|
* (which is this library in all cases) will behave correctly and we don't
|
|
* have to be backwards compatible with old libpq.
|
|
*/
|
|
|
|
/*
|
|
* Submit the query. Since we don't use non-blocking mode, this could
|
|
* theoretically block. In practice, since we don't send very long query
|
|
* strings, the risk seems negligible.
|
|
*/
|
|
if (!PQsendQuery(streamConn, query))
|
|
return NULL;
|
|
|
|
for (;;)
|
|
{
|
|
/* Wait for, and collect, the next PGresult. */
|
|
PGresult *result;
|
|
|
|
result = libpqrcv_PQgetResult(streamConn);
|
|
if (result == NULL)
|
|
break; /* query is complete, or failure */
|
|
|
|
/*
|
|
* Emulate PQexec()'s behavior of returning the last result when there
|
|
* are many. We are fine with returning just last error message.
|
|
*/
|
|
PQclear(lastResult);
|
|
lastResult = result;
|
|
|
|
if (PQresultStatus(lastResult) == PGRES_COPY_IN ||
|
|
PQresultStatus(lastResult) == PGRES_COPY_OUT ||
|
|
PQresultStatus(lastResult) == PGRES_COPY_BOTH ||
|
|
PQstatus(streamConn) == CONNECTION_BAD)
|
|
break;
|
|
}
|
|
|
|
return lastResult;
|
|
}
|
|
|
|
/*
|
|
* Perform the equivalent of PQgetResult(), but watch for interrupts.
|
|
*/
|
|
static PGresult *
|
|
libpqrcv_PQgetResult(PGconn *streamConn)
|
|
{
|
|
/*
|
|
* Collect data until PQgetResult is ready to get the result without
|
|
* blocking.
|
|
*/
|
|
while (PQisBusy(streamConn))
|
|
{
|
|
int rc;
|
|
|
|
/*
|
|
* We don't need to break down the sleep into smaller increments,
|
|
* since we'll get interrupted by signals and can handle any
|
|
* interrupts here.
|
|
*/
|
|
rc = WaitLatchOrSocket(MyLatch,
|
|
WL_EXIT_ON_PM_DEATH | WL_SOCKET_READABLE |
|
|
WL_LATCH_SET,
|
|
PQsocket(streamConn),
|
|
0,
|
|
WAIT_EVENT_LIBPQWALRECEIVER_RECEIVE);
|
|
|
|
/* Interrupted? */
|
|
if (rc & WL_LATCH_SET)
|
|
{
|
|
ResetLatch(MyLatch);
|
|
ProcessWalRcvInterrupts();
|
|
}
|
|
|
|
/* Consume whatever data is available from the socket */
|
|
if (PQconsumeInput(streamConn) == 0)
|
|
{
|
|
/* trouble; return NULL */
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
/* Now we can collect and return the next PGresult */
|
|
return PQgetResult(streamConn);
|
|
}
|
|
|
|
/*
|
|
* Disconnect connection to primary, if any.
|
|
*/
|
|
static void
|
|
libpqrcv_disconnect(WalReceiverConn *conn)
|
|
{
|
|
PQfinish(conn->streamConn);
|
|
if (conn->recvBuf != NULL)
|
|
PQfreemem(conn->recvBuf);
|
|
pfree(conn);
|
|
}
|
|
|
|
/*
|
|
* Receive a message available from XLOG stream.
|
|
*
|
|
* Returns:
|
|
*
|
|
* If data was received, returns the length of the data. *buffer is set to
|
|
* point to a buffer holding the received message. The buffer is only valid
|
|
* until the next libpqrcv_* call.
|
|
*
|
|
* If no data was available immediately, returns 0, and *wait_fd is set to a
|
|
* socket descriptor which can be waited on before trying again.
|
|
*
|
|
* -1 if the server ended the COPY.
|
|
*
|
|
* ereports on error.
|
|
*/
|
|
static int
|
|
libpqrcv_receive(WalReceiverConn *conn, char **buffer,
|
|
pgsocket *wait_fd)
|
|
{
|
|
int rawlen;
|
|
|
|
if (conn->recvBuf != NULL)
|
|
PQfreemem(conn->recvBuf);
|
|
conn->recvBuf = NULL;
|
|
|
|
/* Try to receive a CopyData message */
|
|
rawlen = PQgetCopyData(conn->streamConn, &conn->recvBuf, 1);
|
|
if (rawlen == 0)
|
|
{
|
|
/* Try consuming some data. */
|
|
if (PQconsumeInput(conn->streamConn) == 0)
|
|
ereport(ERROR,
|
|
(errmsg("could not receive data from WAL stream: %s",
|
|
pchomp(PQerrorMessage(conn->streamConn)))));
|
|
|
|
/* Now that we've consumed some input, try again */
|
|
rawlen = PQgetCopyData(conn->streamConn, &conn->recvBuf, 1);
|
|
if (rawlen == 0)
|
|
{
|
|
/* Tell caller to try again when our socket is ready. */
|
|
*wait_fd = PQsocket(conn->streamConn);
|
|
return 0;
|
|
}
|
|
}
|
|
if (rawlen == -1) /* end-of-streaming or error */
|
|
{
|
|
PGresult *res;
|
|
|
|
res = libpqrcv_PQgetResult(conn->streamConn);
|
|
if (PQresultStatus(res) == PGRES_COMMAND_OK)
|
|
{
|
|
PQclear(res);
|
|
|
|
/* Verify that there are no more results. */
|
|
res = libpqrcv_PQgetResult(conn->streamConn);
|
|
if (res != NULL)
|
|
{
|
|
PQclear(res);
|
|
|
|
/*
|
|
* If the other side closed the connection orderly (otherwise
|
|
* we'd seen an error, or PGRES_COPY_IN) don't report an error
|
|
* here, but let callers deal with it.
|
|
*/
|
|
if (PQstatus(conn->streamConn) == CONNECTION_BAD)
|
|
return -1;
|
|
|
|
ereport(ERROR,
|
|
(errmsg("unexpected result after CommandComplete: %s",
|
|
PQerrorMessage(conn->streamConn))));
|
|
}
|
|
|
|
return -1;
|
|
}
|
|
else if (PQresultStatus(res) == PGRES_COPY_IN)
|
|
{
|
|
PQclear(res);
|
|
return -1;
|
|
}
|
|
else
|
|
{
|
|
PQclear(res);
|
|
ereport(ERROR,
|
|
(errmsg("could not receive data from WAL stream: %s",
|
|
pchomp(PQerrorMessage(conn->streamConn)))));
|
|
}
|
|
}
|
|
if (rawlen < -1)
|
|
ereport(ERROR,
|
|
(errmsg("could not receive data from WAL stream: %s",
|
|
pchomp(PQerrorMessage(conn->streamConn)))));
|
|
|
|
/* Return received messages to caller */
|
|
*buffer = conn->recvBuf;
|
|
return rawlen;
|
|
}
|
|
|
|
/*
|
|
* Send a message to XLOG stream.
|
|
*
|
|
* ereports on error.
|
|
*/
|
|
static void
|
|
libpqrcv_send(WalReceiverConn *conn, const char *buffer, int nbytes)
|
|
{
|
|
if (PQputCopyData(conn->streamConn, buffer, nbytes) <= 0 ||
|
|
PQflush(conn->streamConn))
|
|
ereport(ERROR,
|
|
(errmsg("could not send data to WAL stream: %s",
|
|
pchomp(PQerrorMessage(conn->streamConn)))));
|
|
}
|
|
|
|
/*
|
|
* Create new replication slot.
|
|
* Returns the name of the exported snapshot for logical slot or NULL for
|
|
* physical slot.
|
|
*/
|
|
static char *
|
|
libpqrcv_create_slot(WalReceiverConn *conn, const char *slotname,
|
|
bool temporary, CRSSnapshotAction snapshot_action,
|
|
XLogRecPtr *lsn)
|
|
{
|
|
PGresult *res;
|
|
StringInfoData cmd;
|
|
char *snapshot;
|
|
|
|
initStringInfo(&cmd);
|
|
|
|
appendStringInfo(&cmd, "CREATE_REPLICATION_SLOT \"%s\"", slotname);
|
|
|
|
if (temporary)
|
|
appendStringInfoString(&cmd, " TEMPORARY");
|
|
|
|
if (conn->logical)
|
|
{
|
|
appendStringInfoString(&cmd, " LOGICAL pgoutput");
|
|
switch (snapshot_action)
|
|
{
|
|
case CRS_EXPORT_SNAPSHOT:
|
|
appendStringInfoString(&cmd, " EXPORT_SNAPSHOT");
|
|
break;
|
|
case CRS_NOEXPORT_SNAPSHOT:
|
|
appendStringInfoString(&cmd, " NOEXPORT_SNAPSHOT");
|
|
break;
|
|
case CRS_USE_SNAPSHOT:
|
|
appendStringInfoString(&cmd, " USE_SNAPSHOT");
|
|
break;
|
|
}
|
|
}
|
|
|
|
res = libpqrcv_PQexec(conn->streamConn, cmd.data);
|
|
pfree(cmd.data);
|
|
|
|
if (PQresultStatus(res) != PGRES_TUPLES_OK)
|
|
{
|
|
PQclear(res);
|
|
ereport(ERROR,
|
|
(errmsg("could not create replication slot \"%s\": %s",
|
|
slotname, pchomp(PQerrorMessage(conn->streamConn)))));
|
|
}
|
|
|
|
*lsn = DatumGetLSN(DirectFunctionCall1Coll(pg_lsn_in, InvalidOid,
|
|
CStringGetDatum(PQgetvalue(res, 0, 1))));
|
|
if (!PQgetisnull(res, 0, 2))
|
|
snapshot = pstrdup(PQgetvalue(res, 0, 2));
|
|
else
|
|
snapshot = NULL;
|
|
|
|
PQclear(res);
|
|
|
|
return snapshot;
|
|
}
|
|
|
|
/*
|
|
* Convert tuple query result to tuplestore.
|
|
*/
|
|
static void
|
|
libpqrcv_processTuples(PGresult *pgres, WalRcvExecResult *walres,
|
|
const int nRetTypes, const Oid *retTypes)
|
|
{
|
|
int tupn;
|
|
int coln;
|
|
int nfields = PQnfields(pgres);
|
|
HeapTuple tuple;
|
|
AttInMetadata *attinmeta;
|
|
MemoryContext rowcontext;
|
|
MemoryContext oldcontext;
|
|
|
|
/* Make sure we got expected number of fields. */
|
|
if (nfields != nRetTypes)
|
|
ereport(ERROR,
|
|
(errmsg("invalid query response"),
|
|
errdetail("Expected %d fields, got %d fields.",
|
|
nRetTypes, nfields)));
|
|
|
|
walres->tuplestore = tuplestore_begin_heap(true, false, work_mem);
|
|
|
|
/* Create tuple descriptor corresponding to expected result. */
|
|
walres->tupledesc = CreateTemplateTupleDesc(nRetTypes);
|
|
for (coln = 0; coln < nRetTypes; coln++)
|
|
TupleDescInitEntry(walres->tupledesc, (AttrNumber) coln + 1,
|
|
PQfname(pgres, coln), retTypes[coln], -1, 0);
|
|
attinmeta = TupleDescGetAttInMetadata(walres->tupledesc);
|
|
|
|
/* No point in doing more here if there were no tuples returned. */
|
|
if (PQntuples(pgres) == 0)
|
|
return;
|
|
|
|
/* Create temporary context for local allocations. */
|
|
rowcontext = AllocSetContextCreate(CurrentMemoryContext,
|
|
"libpqrcv query result context",
|
|
ALLOCSET_DEFAULT_SIZES);
|
|
|
|
/* Process returned rows. */
|
|
for (tupn = 0; tupn < PQntuples(pgres); tupn++)
|
|
{
|
|
char *cstrs[MaxTupleAttributeNumber];
|
|
|
|
ProcessWalRcvInterrupts();
|
|
|
|
/* Do the allocations in temporary context. */
|
|
oldcontext = MemoryContextSwitchTo(rowcontext);
|
|
|
|
/*
|
|
* Fill cstrs with null-terminated strings of column values.
|
|
*/
|
|
for (coln = 0; coln < nfields; coln++)
|
|
{
|
|
if (PQgetisnull(pgres, tupn, coln))
|
|
cstrs[coln] = NULL;
|
|
else
|
|
cstrs[coln] = PQgetvalue(pgres, tupn, coln);
|
|
}
|
|
|
|
/* Convert row to a tuple, and add it to the tuplestore */
|
|
tuple = BuildTupleFromCStrings(attinmeta, cstrs);
|
|
tuplestore_puttuple(walres->tuplestore, tuple);
|
|
|
|
/* Clean up */
|
|
MemoryContextSwitchTo(oldcontext);
|
|
MemoryContextReset(rowcontext);
|
|
}
|
|
|
|
MemoryContextDelete(rowcontext);
|
|
}
|
|
|
|
/*
|
|
* Public interface for sending generic queries (and commands).
|
|
*
|
|
* This can only be called from process connected to database.
|
|
*/
|
|
static WalRcvExecResult *
|
|
libpqrcv_exec(WalReceiverConn *conn, const char *query,
|
|
const int nRetTypes, const Oid *retTypes)
|
|
{
|
|
PGresult *pgres = NULL;
|
|
WalRcvExecResult *walres = palloc0(sizeof(WalRcvExecResult));
|
|
|
|
if (MyDatabaseId == InvalidOid)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
|
|
errmsg("the query interface requires a database connection")));
|
|
|
|
pgres = libpqrcv_PQexec(conn->streamConn, query);
|
|
|
|
switch (PQresultStatus(pgres))
|
|
{
|
|
case PGRES_SINGLE_TUPLE:
|
|
case PGRES_TUPLES_OK:
|
|
walres->status = WALRCV_OK_TUPLES;
|
|
libpqrcv_processTuples(pgres, walres, nRetTypes, retTypes);
|
|
break;
|
|
|
|
case PGRES_COPY_IN:
|
|
walres->status = WALRCV_OK_COPY_IN;
|
|
break;
|
|
|
|
case PGRES_COPY_OUT:
|
|
walres->status = WALRCV_OK_COPY_OUT;
|
|
break;
|
|
|
|
case PGRES_COPY_BOTH:
|
|
walres->status = WALRCV_OK_COPY_BOTH;
|
|
break;
|
|
|
|
case PGRES_COMMAND_OK:
|
|
walres->status = WALRCV_OK_COMMAND;
|
|
break;
|
|
|
|
/* Empty query is considered error. */
|
|
case PGRES_EMPTY_QUERY:
|
|
walres->status = WALRCV_ERROR;
|
|
walres->err = _("empty query");
|
|
break;
|
|
|
|
case PGRES_NONFATAL_ERROR:
|
|
case PGRES_FATAL_ERROR:
|
|
case PGRES_BAD_RESPONSE:
|
|
walres->status = WALRCV_ERROR;
|
|
walres->err = pchomp(PQerrorMessage(conn->streamConn));
|
|
break;
|
|
}
|
|
|
|
PQclear(pgres);
|
|
|
|
return walres;
|
|
}
|
|
|
|
/*
|
|
* Given a List of strings, return it as single comma separated
|
|
* string, quoting identifiers as needed.
|
|
*
|
|
* This is essentially the reverse of SplitIdentifierString.
|
|
*
|
|
* The caller should free the result.
|
|
*/
|
|
static char *
|
|
stringlist_to_identifierstr(PGconn *conn, List *strings)
|
|
{
|
|
ListCell *lc;
|
|
StringInfoData res;
|
|
bool first = true;
|
|
|
|
initStringInfo(&res);
|
|
|
|
foreach(lc, strings)
|
|
{
|
|
char *val = strVal(lfirst(lc));
|
|
char *val_escaped;
|
|
|
|
if (first)
|
|
first = false;
|
|
else
|
|
appendStringInfoChar(&res, ',');
|
|
|
|
val_escaped = PQescapeIdentifier(conn, val, strlen(val));
|
|
if (!val_escaped)
|
|
{
|
|
free(res.data);
|
|
return NULL;
|
|
}
|
|
appendStringInfoString(&res, val_escaped);
|
|
PQfreemem(val_escaped);
|
|
}
|
|
|
|
return res.data;
|
|
}
|