LCOV - code coverage report
Current view: top level - src/backend/replication - walreceiver.c (source / functions) Hit Total Coverage
Test: PostgreSQL 17devel Lines: 383 513 74.7 %
Date: 2024-03-19 03:11:18 Functions: 15 16 93.8 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * walreceiver.c
       4             :  *
       5             :  * The WAL receiver process (walreceiver) is new as of Postgres 9.0. It
       6             :  * is the process in the standby server that takes charge of receiving
       7             :  * XLOG records from a primary server during streaming replication.
       8             :  *
       9             :  * When the startup process determines that it's time to start streaming,
      10             :  * it instructs postmaster to start walreceiver. Walreceiver first connects
      11             :  * to the primary server (it will be served by a walsender process
      12             :  * in the primary server), and then keeps receiving XLOG records and
      13             :  * writing them to the disk as long as the connection is alive. As XLOG
      14             :  * records are received and flushed to disk, it updates the
      15             :  * WalRcv->flushedUpto variable in shared memory, to inform the startup
      16             :  * process of how far it can proceed with XLOG replay.
      17             :  *
      18             :  * A WAL receiver cannot directly load GUC parameters used when establishing
      19             :  * its connection to the primary. Instead it relies on parameter values
      20             :  * that are passed down by the startup process when streaming is requested.
      21             :  * This applies, for example, to the replication slot and the connection
      22             :  * string to be used for the connection with the primary.
      23             :  *
      24             :  * If the primary server ends streaming, but doesn't disconnect, walreceiver
      25             :  * goes into "waiting" mode, and waits for the startup process to give new
      26             :  * instructions. The startup process will treat that the same as
      27             :  * disconnection, and will rescan the archive/pg_wal directory. But when the
      28             :  * startup process wants to try streaming replication again, it will just
      29             :  * nudge the existing walreceiver process that's waiting, instead of launching
      30             :  * a new one.
      31             :  *
      32             :  * Normal termination is by SIGTERM, which instructs the walreceiver to
      33             :  * exit(0). Emergency termination is by SIGQUIT; like any postmaster child
      34             :  * process, the walreceiver will simply abort and exit on SIGQUIT. A close
      35             :  * of the connection and a FATAL error are treated not as a crash but as
      36             :  * normal operation.
      37             :  *
      38             :  * This file contains the server-facing parts of walreceiver. The libpq-
      39             :  * specific parts are in the libpqwalreceiver module. It's loaded
      40             :  * dynamically to avoid linking the server with libpq.
      41             :  *
      42             :  * Portions Copyright (c) 2010-2024, PostgreSQL Global Development Group
      43             :  *
      44             :  *
      45             :  * IDENTIFICATION
      46             :  *    src/backend/replication/walreceiver.c
      47             :  *
      48             :  *-------------------------------------------------------------------------
      49             :  */
      50             : #include "postgres.h"
      51             : 
      52             : #include <unistd.h>
      53             : 
      54             : #include "access/htup_details.h"
      55             : #include "access/timeline.h"
      56             : #include "access/transam.h"
      57             : #include "access/xlog_internal.h"
      58             : #include "access/xlogarchive.h"
      59             : #include "access/xlogrecovery.h"
      60             : #include "catalog/pg_authid.h"
      61             : #include "funcapi.h"
      62             : #include "libpq/pqformat.h"
      63             : #include "libpq/pqsignal.h"
      64             : #include "miscadmin.h"
      65             : #include "pgstat.h"
      66             : #include "postmaster/auxprocess.h"
      67             : #include "postmaster/interrupt.h"
      68             : #include "replication/walreceiver.h"
      69             : #include "replication/walsender.h"
      70             : #include "storage/ipc.h"
      71             : #include "storage/proc.h"
      72             : #include "storage/procarray.h"
      73             : #include "storage/procsignal.h"
      74             : #include "utils/acl.h"
      75             : #include "utils/builtins.h"
      76             : #include "utils/guc.h"
      77             : #include "utils/pg_lsn.h"
      78             : #include "utils/ps_status.h"
      79             : #include "utils/timestamp.h"
      80             : 
      81             : 
      82             : /*
      83             :  * GUC variables.  (Other variables that affect walreceiver are in xlog.c
      84             :  * because they're passed down from the startup process, for better
      85             :  * synchronization.)
      86             :  */
      87             : int         wal_receiver_status_interval;
      88             : int         wal_receiver_timeout;
      89             : bool        hot_standby_feedback;
      90             : 
      91             : /* libpqwalreceiver connection */
      92             : static WalReceiverConn *wrconn = NULL;
      93             : WalReceiverFunctionsType *WalReceiverFunctions = NULL;
      94             : 
      95             : /*
      96             :  * These variables are used similarly to openLogFile/SegNo,
      97             :  * but for walreceiver to write the XLOG. recvFileTLI is the TimeLineID
      98             :  * corresponding the filename of recvFile.
      99             :  */
     100             : static int  recvFile = -1;
     101             : static TimeLineID recvFileTLI = 0;
     102             : static XLogSegNo recvSegNo = 0;
     103             : 
     104             : /*
     105             :  * LogstreamResult indicates the byte positions that we have already
     106             :  * written/fsynced.
     107             :  */
     108             : static struct
     109             : {
     110             :     XLogRecPtr  Write;          /* last byte + 1 written out in the standby */
     111             :     XLogRecPtr  Flush;          /* last byte + 1 flushed in the standby */
     112             : }           LogstreamResult;
     113             : 
     114             : /*
     115             :  * Reasons to wake up and perform periodic tasks.
     116             :  */
     117             : typedef enum WalRcvWakeupReason
     118             : {
     119             :     WALRCV_WAKEUP_TERMINATE,
     120             :     WALRCV_WAKEUP_PING,
     121             :     WALRCV_WAKEUP_REPLY,
     122             :     WALRCV_WAKEUP_HSFEEDBACK,
     123             : #define NUM_WALRCV_WAKEUPS (WALRCV_WAKEUP_HSFEEDBACK + 1)
     124             : } WalRcvWakeupReason;
     125             : 
     126             : /*
     127             :  * Wake up times for periodic tasks.
     128             :  */
     129             : static TimestampTz wakeup[NUM_WALRCV_WAKEUPS];
     130             : 
     131             : static StringInfoData reply_message;
     132             : 
     133             : /* Prototypes for private functions */
     134             : static void WalRcvFetchTimeLineHistoryFiles(TimeLineID first, TimeLineID last);
     135             : static void WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI);
     136             : static void WalRcvDie(int code, Datum arg);
     137             : static void XLogWalRcvProcessMsg(unsigned char type, char *buf, Size len,
     138             :                                  TimeLineID tli);
     139             : static void XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr,
     140             :                             TimeLineID tli);
     141             : static void XLogWalRcvFlush(bool dying, TimeLineID tli);
     142             : static void XLogWalRcvClose(XLogRecPtr recptr, TimeLineID tli);
     143             : static void XLogWalRcvSendReply(bool force, bool requestReply);
     144             : static void XLogWalRcvSendHSFeedback(bool immed);
     145             : static void ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime);
     146             : static void WalRcvComputeNextWakeup(WalRcvWakeupReason reason, TimestampTz now);
     147             : 
     148             : /*
     149             :  * Process any interrupts the walreceiver process may have received.
     150             :  * This should be called any time the process's latch has become set.
     151             :  *
     152             :  * Currently, only SIGTERM is of interest.  We can't just exit(1) within the
     153             :  * SIGTERM signal handler, because the signal might arrive in the middle of
     154             :  * some critical operation, like while we're holding a spinlock.  Instead, the
     155             :  * signal handler sets a flag variable as well as setting the process's latch.
     156             :  * We must check the flag (by calling ProcessWalRcvInterrupts) anytime the
     157             :  * latch has become set.  Operations that could block for a long time, such as
     158             :  * reading from a remote server, must pay attention to the latch too; see
     159             :  * libpqrcv_PQgetResult for example.
     160             :  */
     161             : void
     162       93708 : ProcessWalRcvInterrupts(void)
     163             : {
     164             :     /*
     165             :      * Although walreceiver interrupt handling doesn't use the same scheme as
     166             :      * regular backends, call CHECK_FOR_INTERRUPTS() to make sure we receive
     167             :      * any incoming signals on Win32, and also to make sure we process any
     168             :      * barrier events.
     169             :      */
     170       93708 :     CHECK_FOR_INTERRUPTS();
     171             : 
     172       93706 :     if (ShutdownRequestPending)
     173             :     {
     174         130 :         ereport(FATAL,
     175             :                 (errcode(ERRCODE_ADMIN_SHUTDOWN),
     176             :                  errmsg("terminating walreceiver process due to administrator command")));
     177             :     }
     178       93576 : }
     179             : 
     180             : 
     181             : /* Main entry point for walreceiver process */
     182             : void
     183         358 : WalReceiverMain(char *startup_data, size_t startup_data_len)
     184             : {
     185             :     char        conninfo[MAXCONNINFO];
     186             :     char       *tmp_conninfo;
     187             :     char        slotname[NAMEDATALEN];
     188             :     bool        is_temp_slot;
     189             :     XLogRecPtr  startpoint;
     190             :     TimeLineID  startpointTLI;
     191             :     TimeLineID  primaryTLI;
     192             :     bool        first_stream;
     193             :     WalRcvData *walrcv;
     194             :     TimestampTz now;
     195             :     char       *err;
     196         358 :     char       *sender_host = NULL;
     197         358 :     int         sender_port = 0;
     198             : 
     199             :     Assert(startup_data_len == 0);
     200             : 
     201         358 :     MyBackendType = B_WAL_RECEIVER;
     202         358 :     AuxiliaryProcessMainCommon();
     203             : 
     204             :     /*
     205             :      * WalRcv should be set up already (if we are a backend, we inherit this
     206             :      * by fork() or EXEC_BACKEND mechanism from the postmaster).
     207             :      */
     208         358 :     walrcv = WalRcv;
     209             :     Assert(walrcv != NULL);
     210             : 
     211             :     /*
     212             :      * Mark walreceiver as running in shared memory.
     213             :      *
     214             :      * Do this as early as possible, so that if we fail later on, we'll set
     215             :      * state to STOPPED. If we die before this, the startup process will keep
     216             :      * waiting for us to start up, until it times out.
     217             :      */
     218         358 :     SpinLockAcquire(&walrcv->mutex);
     219             :     Assert(walrcv->pid == 0);
     220         358 :     switch (walrcv->walRcvState)
     221             :     {
     222           0 :         case WALRCV_STOPPING:
     223             :             /* If we've already been requested to stop, don't start up. */
     224           0 :             walrcv->walRcvState = WALRCV_STOPPED;
     225             :             /* fall through */
     226             : 
     227          10 :         case WALRCV_STOPPED:
     228          10 :             SpinLockRelease(&walrcv->mutex);
     229          10 :             ConditionVariableBroadcast(&walrcv->walRcvStoppedCV);
     230          10 :             proc_exit(1);
     231             :             break;
     232             : 
     233         348 :         case WALRCV_STARTING:
     234             :             /* The usual case */
     235         348 :             break;
     236             : 
     237           0 :         case WALRCV_WAITING:
     238             :         case WALRCV_STREAMING:
     239             :         case WALRCV_RESTARTING:
     240             :         default:
     241             :             /* Shouldn't happen */
     242           0 :             SpinLockRelease(&walrcv->mutex);
     243           0 :             elog(PANIC, "walreceiver still running according to shared memory state");
     244             :     }
     245             :     /* Advertise our PID so that the startup process can kill us */
     246         348 :     walrcv->pid = MyProcPid;
     247         348 :     walrcv->walRcvState = WALRCV_STREAMING;
     248             : 
     249             :     /* Fetch information required to start streaming */
     250         348 :     walrcv->ready_to_display = false;
     251         348 :     strlcpy(conninfo, (char *) walrcv->conninfo, MAXCONNINFO);
     252         348 :     strlcpy(slotname, (char *) walrcv->slotname, NAMEDATALEN);
     253         348 :     is_temp_slot = walrcv->is_temp_slot;
     254         348 :     startpoint = walrcv->receiveStart;
     255         348 :     startpointTLI = walrcv->receiveStartTLI;
     256             : 
     257             :     /*
     258             :      * At most one of is_temp_slot and slotname can be set; otherwise,
     259             :      * RequestXLogStreaming messed up.
     260             :      */
     261             :     Assert(!is_temp_slot || (slotname[0] == '\0'));
     262             : 
     263             :     /* Initialise to a sanish value */
     264         348 :     now = GetCurrentTimestamp();
     265         348 :     walrcv->lastMsgSendTime =
     266         348 :         walrcv->lastMsgReceiptTime = walrcv->latestWalEndTime = now;
     267             : 
     268             :     /* Report the latch to use to awaken this process */
     269         348 :     walrcv->latch = &MyProc->procLatch;
     270             : 
     271         348 :     SpinLockRelease(&walrcv->mutex);
     272             : 
     273         348 :     pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
     274             : 
     275             :     /* Arrange to clean up at walreceiver exit */
     276         348 :     on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
     277             : 
     278             :     /* Properly accept or ignore signals the postmaster might send us */
     279         348 :     pqsignal(SIGHUP, SignalHandlerForConfigReload); /* set flag to read config
     280             :                                                      * file */
     281         348 :     pqsignal(SIGINT, SIG_IGN);
     282         348 :     pqsignal(SIGTERM, SignalHandlerForShutdownRequest); /* request shutdown */
     283             :     /* SIGQUIT handler was already set up by InitPostmasterChild */
     284         348 :     pqsignal(SIGALRM, SIG_IGN);
     285         348 :     pqsignal(SIGPIPE, SIG_IGN);
     286         348 :     pqsignal(SIGUSR1, procsignal_sigusr1_handler);
     287         348 :     pqsignal(SIGUSR2, SIG_IGN);
     288             : 
     289             :     /* Reset some signals that are accepted by postmaster but not here */
     290         348 :     pqsignal(SIGCHLD, SIG_DFL);
     291             : 
     292             :     /* Load the libpq-specific functions */
     293         348 :     load_file("libpqwalreceiver", false);
     294         348 :     if (WalReceiverFunctions == NULL)
     295           0 :         elog(ERROR, "libpqwalreceiver didn't initialize correctly");
     296             : 
     297             :     /* Unblock signals (they were blocked when the postmaster forked us) */
     298         348 :     sigprocmask(SIG_SETMASK, &UnBlockSig, NULL);
     299             : 
     300             :     /* Establish the connection to the primary for XLOG streaming */
     301         348 :     wrconn = walrcv_connect(conninfo, true, false, false,
     302             :                             cluster_name[0] ? cluster_name : "walreceiver",
     303             :                             &err);
     304         340 :     if (!wrconn)
     305         114 :         ereport(ERROR,
     306             :                 (errcode(ERRCODE_CONNECTION_FAILURE),
     307             :                  errmsg("could not connect to the primary server: %s", err)));
     308             : 
     309             :     /*
     310             :      * Save user-visible connection string.  This clobbers the original
     311             :      * conninfo, for security. Also save host and port of the sender server
     312             :      * this walreceiver is connected to.
     313             :      */
     314         226 :     tmp_conninfo = walrcv_get_conninfo(wrconn);
     315         226 :     walrcv_get_senderinfo(wrconn, &sender_host, &sender_port);
     316         226 :     SpinLockAcquire(&walrcv->mutex);
     317         226 :     memset(walrcv->conninfo, 0, MAXCONNINFO);
     318         226 :     if (tmp_conninfo)
     319         226 :         strlcpy((char *) walrcv->conninfo, tmp_conninfo, MAXCONNINFO);
     320             : 
     321         226 :     memset(walrcv->sender_host, 0, NI_MAXHOST);
     322         226 :     if (sender_host)
     323         226 :         strlcpy((char *) walrcv->sender_host, sender_host, NI_MAXHOST);
     324             : 
     325         226 :     walrcv->sender_port = sender_port;
     326         226 :     walrcv->ready_to_display = true;
     327         226 :     SpinLockRelease(&walrcv->mutex);
     328             : 
     329         226 :     if (tmp_conninfo)
     330         226 :         pfree(tmp_conninfo);
     331             : 
     332         226 :     if (sender_host)
     333         226 :         pfree(sender_host);
     334             : 
     335         226 :     first_stream = true;
     336             :     for (;;)
     337           0 :     {
     338             :         char       *primary_sysid;
     339             :         char        standby_sysid[32];
     340             :         WalRcvStreamOptions options;
     341             : 
     342             :         /*
     343             :          * Check that we're connected to a valid server using the
     344             :          * IDENTIFY_SYSTEM replication command.
     345             :          */
     346         226 :         primary_sysid = walrcv_identify_system(wrconn, &primaryTLI);
     347             : 
     348         226 :         snprintf(standby_sysid, sizeof(standby_sysid), UINT64_FORMAT,
     349             :                  GetSystemIdentifier());
     350         226 :         if (strcmp(primary_sysid, standby_sysid) != 0)
     351             :         {
     352           0 :             ereport(ERROR,
     353             :                     (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
     354             :                      errmsg("database system identifier differs between the primary and standby"),
     355             :                      errdetail("The primary's identifier is %s, the standby's identifier is %s.",
     356             :                                primary_sysid, standby_sysid)));
     357             :         }
     358             : 
     359             :         /*
     360             :          * Confirm that the current timeline of the primary is the same or
     361             :          * ahead of ours.
     362             :          */
     363         226 :         if (primaryTLI < startpointTLI)
     364           0 :             ereport(ERROR,
     365             :                     (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
     366             :                      errmsg("highest timeline %u of the primary is behind recovery timeline %u",
     367             :                             primaryTLI, startpointTLI)));
     368             : 
     369             :         /*
     370             :          * Get any missing history files. We do this always, even when we're
     371             :          * not interested in that timeline, so that if we're promoted to
     372             :          * become the primary later on, we don't select the same timeline that
     373             :          * was already used in the current primary. This isn't bullet-proof -
     374             :          * you'll need some external software to manage your cluster if you
     375             :          * need to ensure that a unique timeline id is chosen in every case,
     376             :          * but let's avoid the confusion of timeline id collisions where we
     377             :          * can.
     378             :          */
     379         226 :         WalRcvFetchTimeLineHistoryFiles(startpointTLI, primaryTLI);
     380             : 
     381             :         /*
     382             :          * Create temporary replication slot if requested, and update slot
     383             :          * name in shared memory.  (Note the slot name cannot already be set
     384             :          * in this case.)
     385             :          */
     386         226 :         if (is_temp_slot)
     387             :         {
     388           0 :             snprintf(slotname, sizeof(slotname),
     389             :                      "pg_walreceiver_%lld",
     390           0 :                      (long long int) walrcv_get_backend_pid(wrconn));
     391             : 
     392           0 :             walrcv_create_slot(wrconn, slotname, true, false, false, 0, NULL);
     393             : 
     394           0 :             SpinLockAcquire(&walrcv->mutex);
     395           0 :             strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
     396           0 :             SpinLockRelease(&walrcv->mutex);
     397             :         }
     398             : 
     399             :         /*
     400             :          * Start streaming.
     401             :          *
     402             :          * We'll try to start at the requested starting point and timeline,
     403             :          * even if it's different from the server's latest timeline. In case
     404             :          * we've already reached the end of the old timeline, the server will
     405             :          * finish the streaming immediately, and we will go back to await
     406             :          * orders from the startup process. If recovery_target_timeline is
     407             :          * 'latest', the startup process will scan pg_wal and find the new
     408             :          * history file, bump recovery target timeline, and ask us to restart
     409             :          * on the new timeline.
     410             :          */
     411         226 :         options.logical = false;
     412         226 :         options.startpoint = startpoint;
     413         226 :         options.slotname = slotname[0] != '\0' ? slotname : NULL;
     414         226 :         options.proto.physical.startpointTLI = startpointTLI;
     415         226 :         if (walrcv_startstreaming(wrconn, &options))
     416             :         {
     417         226 :             if (first_stream)
     418         226 :                 ereport(LOG,
     419             :                         (errmsg("started streaming WAL from primary at %X/%X on timeline %u",
     420             :                                 LSN_FORMAT_ARGS(startpoint), startpointTLI)));
     421             :             else
     422           0 :                 ereport(LOG,
     423             :                         (errmsg("restarted WAL streaming at %X/%X on timeline %u",
     424             :                                 LSN_FORMAT_ARGS(startpoint), startpointTLI)));
     425         226 :             first_stream = false;
     426             : 
     427             :             /* Initialize LogstreamResult and buffers for processing messages */
     428         226 :             LogstreamResult.Write = LogstreamResult.Flush = GetXLogReplayRecPtr(NULL);
     429         226 :             initStringInfo(&reply_message);
     430             : 
     431             :             /* Initialize nap wakeup times. */
     432         226 :             now = GetCurrentTimestamp();
     433        1130 :             for (int i = 0; i < NUM_WALRCV_WAKEUPS; ++i)
     434         904 :                 WalRcvComputeNextWakeup(i, now);
     435             : 
     436             :             /* Send initial reply/feedback messages. */
     437         226 :             XLogWalRcvSendReply(true, false);
     438         226 :             XLogWalRcvSendHSFeedback(true);
     439             : 
     440             :             /* Loop until end-of-streaming or error */
     441             :             for (;;)
     442       63874 :             {
     443             :                 char       *buf;
     444             :                 int         len;
     445       64100 :                 bool        endofwal = false;
     446       64100 :                 pgsocket    wait_fd = PGINVALID_SOCKET;
     447             :                 int         rc;
     448             :                 TimestampTz nextWakeup;
     449             :                 long        nap;
     450             : 
     451             :                 /*
     452             :                  * Exit walreceiver if we're not in recovery. This should not
     453             :                  * happen, but cross-check the status here.
     454             :                  */
     455       64100 :                 if (!RecoveryInProgress())
     456           0 :                     ereport(FATAL,
     457             :                             (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
     458             :                              errmsg("cannot continue WAL streaming, recovery has already ended")));
     459             : 
     460             :                 /* Process any requests or signals received recently */
     461       64100 :                 ProcessWalRcvInterrupts();
     462             : 
     463       64100 :                 if (ConfigReloadPending)
     464             :                 {
     465          44 :                     ConfigReloadPending = false;
     466          44 :                     ProcessConfigFile(PGC_SIGHUP);
     467             :                     /* recompute wakeup times */
     468          44 :                     now = GetCurrentTimestamp();
     469         220 :                     for (int i = 0; i < NUM_WALRCV_WAKEUPS; ++i)
     470         176 :                         WalRcvComputeNextWakeup(i, now);
     471          44 :                     XLogWalRcvSendHSFeedback(true);
     472             :                 }
     473             : 
     474             :                 /* See if we can read data immediately */
     475       64100 :                 len = walrcv_receive(wrconn, &buf, &wait_fd);
     476       64040 :                 if (len != 0)
     477             :                 {
     478             :                     /*
     479             :                      * Process the received data, and any subsequent data we
     480             :                      * can read without blocking.
     481             :                      */
     482             :                     for (;;)
     483             :                     {
     484       81872 :                         if (len > 0)
     485             :                         {
     486             :                             /*
     487             :                              * Something was received from primary, so adjust
     488             :                              * the ping and terminate wakeup times.
     489             :                              */
     490       44130 :                             now = GetCurrentTimestamp();
     491       44130 :                             WalRcvComputeNextWakeup(WALRCV_WAKEUP_TERMINATE,
     492             :                                                     now);
     493       44130 :                             WalRcvComputeNextWakeup(WALRCV_WAKEUP_PING, now);
     494       44130 :                             XLogWalRcvProcessMsg(buf[0], &buf[1], len - 1,
     495             :                                                  startpointTLI);
     496             :                         }
     497       37742 :                         else if (len == 0)
     498       37676 :                             break;
     499          66 :                         else if (len < 0)
     500             :                         {
     501          66 :                             ereport(LOG,
     502             :                                     (errmsg("replication terminated by primary server"),
     503             :                                      errdetail("End of WAL reached on timeline %u at %X/%X.",
     504             :                                                startpointTLI,
     505             :                                                LSN_FORMAT_ARGS(LogstreamResult.Write))));
     506          66 :                             endofwal = true;
     507          66 :                             break;
     508             :                         }
     509       44130 :                         len = walrcv_receive(wrconn, &buf, &wait_fd);
     510             :                     }
     511             : 
     512             :                     /* Let the primary know that we received some data. */
     513       37742 :                     XLogWalRcvSendReply(false, false);
     514             : 
     515             :                     /*
     516             :                      * If we've written some records, flush them to disk and
     517             :                      * let the startup process and primary server know about
     518             :                      * them.
     519             :                      */
     520       37742 :                     XLogWalRcvFlush(false, startpointTLI);
     521             :                 }
     522             : 
     523             :                 /* Check if we need to exit the streaming loop. */
     524       64038 :                 if (endofwal)
     525          66 :                     break;
     526             : 
     527             :                 /* Find the soonest wakeup time, to limit our nap. */
     528       63972 :                 nextWakeup = TIMESTAMP_INFINITY;
     529      319860 :                 for (int i = 0; i < NUM_WALRCV_WAKEUPS; ++i)
     530      255888 :                     nextWakeup = Min(wakeup[i], nextWakeup);
     531             : 
     532             :                 /* Calculate the nap time, clamping as necessary. */
     533       63972 :                 now = GetCurrentTimestamp();
     534       63972 :                 nap = TimestampDifferenceMilliseconds(now, nextWakeup);
     535             : 
     536             :                 /*
     537             :                  * Ideally we would reuse a WaitEventSet object repeatedly
     538             :                  * here to avoid the overheads of WaitLatchOrSocket on epoll
     539             :                  * systems, but we can't be sure that libpq (or any other
     540             :                  * walreceiver implementation) has the same socket (even if
     541             :                  * the fd is the same number, it may have been closed and
     542             :                  * reopened since the last time).  In future, if there is a
     543             :                  * function for removing sockets from WaitEventSet, then we
     544             :                  * could add and remove just the socket each time, potentially
     545             :                  * avoiding some system calls.
     546             :                  */
     547             :                 Assert(wait_fd != PGINVALID_SOCKET);
     548       63972 :                 rc = WaitLatchOrSocket(MyLatch,
     549             :                                        WL_EXIT_ON_PM_DEATH | WL_SOCKET_READABLE |
     550             :                                        WL_TIMEOUT | WL_LATCH_SET,
     551             :                                        wait_fd,
     552             :                                        nap,
     553             :                                        WAIT_EVENT_WAL_RECEIVER_MAIN);
     554       63972 :                 if (rc & WL_LATCH_SET)
     555             :                 {
     556       26222 :                     ResetLatch(MyLatch);
     557       26222 :                     ProcessWalRcvInterrupts();
     558             : 
     559       26124 :                     if (walrcv->force_reply)
     560             :                     {
     561             :                         /*
     562             :                          * The recovery process has asked us to send apply
     563             :                          * feedback now.  Make sure the flag is really set to
     564             :                          * false in shared memory before sending the reply, so
     565             :                          * we don't miss a new request for a reply.
     566             :                          */
     567       26044 :                         walrcv->force_reply = false;
     568       26044 :                         pg_memory_barrier();
     569       26044 :                         XLogWalRcvSendReply(true, false);
     570             :                     }
     571             :                 }
     572       63874 :                 if (rc & WL_TIMEOUT)
     573             :                 {
     574             :                     /*
     575             :                      * We didn't receive anything new. If we haven't heard
     576             :                      * anything from the server for more than
     577             :                      * wal_receiver_timeout / 2, ping the server. Also, if
     578             :                      * it's been longer than wal_receiver_status_interval
     579             :                      * since the last update we sent, send a status update to
     580             :                      * the primary anyway, to report any progress in applying
     581             :                      * WAL.
     582             :                      */
     583           8 :                     bool        requestReply = false;
     584             : 
     585             :                     /*
     586             :                      * Check if time since last receive from primary has
     587             :                      * reached the configured limit.
     588             :                      */
     589           8 :                     now = GetCurrentTimestamp();
     590           8 :                     if (now >= wakeup[WALRCV_WAKEUP_TERMINATE])
     591           0 :                         ereport(ERROR,
     592             :                                 (errcode(ERRCODE_CONNECTION_FAILURE),
     593             :                                  errmsg("terminating walreceiver due to timeout")));
     594             : 
     595             :                     /*
     596             :                      * If we didn't receive anything new for half of receiver
     597             :                      * replication timeout, then ping the server.
     598             :                      */
     599           8 :                     if (now >= wakeup[WALRCV_WAKEUP_PING])
     600             :                     {
     601           0 :                         requestReply = true;
     602           0 :                         wakeup[WALRCV_WAKEUP_PING] = TIMESTAMP_INFINITY;
     603             :                     }
     604             : 
     605           8 :                     XLogWalRcvSendReply(requestReply, requestReply);
     606           8 :                     XLogWalRcvSendHSFeedback(false);
     607             :                 }
     608             :             }
     609             : 
     610             :             /*
     611             :              * The backend finished streaming. Exit streaming COPY-mode from
     612             :              * our side, too.
     613             :              */
     614          66 :             walrcv_endstreaming(wrconn, &primaryTLI);
     615             : 
     616             :             /*
     617             :              * If the server had switched to a new timeline that we didn't
     618             :              * know about when we began streaming, fetch its timeline history
     619             :              * file now.
     620             :              */
     621          24 :             WalRcvFetchTimeLineHistoryFiles(startpointTLI, primaryTLI);
     622             :         }
     623             :         else
     624           0 :             ereport(LOG,
     625             :                     (errmsg("primary server contains no more WAL on requested timeline %u",
     626             :                             startpointTLI)));
     627             : 
     628             :         /*
     629             :          * End of WAL reached on the requested timeline. Close the last
     630             :          * segment, and await for new orders from the startup process.
     631             :          */
     632          24 :         if (recvFile >= 0)
     633             :         {
     634             :             char        xlogfname[MAXFNAMELEN];
     635             : 
     636          22 :             XLogWalRcvFlush(false, startpointTLI);
     637          22 :             XLogFileName(xlogfname, recvFileTLI, recvSegNo, wal_segment_size);
     638          22 :             if (close(recvFile) != 0)
     639           0 :                 ereport(PANIC,
     640             :                         (errcode_for_file_access(),
     641             :                          errmsg("could not close WAL segment %s: %m",
     642             :                                 xlogfname)));
     643             : 
     644             :             /*
     645             :              * Create .done file forcibly to prevent the streamed segment from
     646             :              * being archived later.
     647             :              */
     648          22 :             if (XLogArchiveMode != ARCHIVE_MODE_ALWAYS)
     649          22 :                 XLogArchiveForceDone(xlogfname);
     650             :             else
     651           0 :                 XLogArchiveNotify(xlogfname);
     652             :         }
     653          24 :         recvFile = -1;
     654             : 
     655          24 :         elog(DEBUG1, "walreceiver ended streaming and awaits new instructions");
     656          24 :         WalRcvWaitForStartPosition(&startpoint, &startpointTLI);
     657             :     }
     658             :     /* not reached */
     659             : }
     660             : 
     661             : /*
     662             :  * Wait for startup process to set receiveStart and receiveStartTLI.
     663             :  */
     664             : static void
     665          24 : WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
     666             : {
     667          24 :     WalRcvData *walrcv = WalRcv;
     668             :     int         state;
     669             : 
     670          24 :     SpinLockAcquire(&walrcv->mutex);
     671          24 :     state = walrcv->walRcvState;
     672          24 :     if (state != WALRCV_STREAMING)
     673             :     {
     674           0 :         SpinLockRelease(&walrcv->mutex);
     675           0 :         if (state == WALRCV_STOPPING)
     676           0 :             proc_exit(0);
     677             :         else
     678           0 :             elog(FATAL, "unexpected walreceiver state");
     679             :     }
     680          24 :     walrcv->walRcvState = WALRCV_WAITING;
     681          24 :     walrcv->receiveStart = InvalidXLogRecPtr;
     682          24 :     walrcv->receiveStartTLI = 0;
     683          24 :     SpinLockRelease(&walrcv->mutex);
     684             : 
     685          24 :     set_ps_display("idle");
     686             : 
     687             :     /*
     688             :      * nudge startup process to notice that we've stopped streaming and are
     689             :      * now waiting for instructions.
     690             :      */
     691          24 :     WakeupRecovery();
     692             :     for (;;)
     693             :     {
     694          46 :         ResetLatch(MyLatch);
     695             : 
     696          46 :         ProcessWalRcvInterrupts();
     697             : 
     698          22 :         SpinLockAcquire(&walrcv->mutex);
     699             :         Assert(walrcv->walRcvState == WALRCV_RESTARTING ||
     700             :                walrcv->walRcvState == WALRCV_WAITING ||
     701             :                walrcv->walRcvState == WALRCV_STOPPING);
     702          22 :         if (walrcv->walRcvState == WALRCV_RESTARTING)
     703             :         {
     704             :             /*
     705             :              * No need to handle changes in primary_conninfo or
     706             :              * primary_slot_name here. Startup process will signal us to
     707             :              * terminate in case those change.
     708             :              */
     709           0 :             *startpoint = walrcv->receiveStart;
     710           0 :             *startpointTLI = walrcv->receiveStartTLI;
     711           0 :             walrcv->walRcvState = WALRCV_STREAMING;
     712           0 :             SpinLockRelease(&walrcv->mutex);
     713           0 :             break;
     714             :         }
     715          22 :         if (walrcv->walRcvState == WALRCV_STOPPING)
     716             :         {
     717             :             /*
     718             :              * We should've received SIGTERM if the startup process wants us
     719             :              * to die, but might as well check it here too.
     720             :              */
     721           0 :             SpinLockRelease(&walrcv->mutex);
     722           0 :             exit(1);
     723             :         }
     724          22 :         SpinLockRelease(&walrcv->mutex);
     725             : 
     726          22 :         (void) WaitLatch(MyLatch, WL_LATCH_SET | WL_EXIT_ON_PM_DEATH, 0,
     727             :                          WAIT_EVENT_WAL_RECEIVER_WAIT_START);
     728             :     }
     729             : 
     730           0 :     if (update_process_title)
     731             :     {
     732             :         char        activitymsg[50];
     733             : 
     734           0 :         snprintf(activitymsg, sizeof(activitymsg), "restarting at %X/%X",
     735           0 :                  LSN_FORMAT_ARGS(*startpoint));
     736           0 :         set_ps_display(activitymsg);
     737             :     }
     738           0 : }
     739             : 
     740             : /*
     741             :  * Fetch any missing timeline history files between 'first' and 'last'
     742             :  * (inclusive) from the server.
     743             :  */
     744             : static void
     745         250 : WalRcvFetchTimeLineHistoryFiles(TimeLineID first, TimeLineID last)
     746             : {
     747             :     TimeLineID  tli;
     748             : 
     749         546 :     for (tli = first; tli <= last; tli++)
     750             :     {
     751             :         /* there's no history file for timeline 1 */
     752         296 :         if (tli != 1 && !existsTimeLineHistory(tli))
     753             :         {
     754             :             char       *fname;
     755             :             char       *content;
     756             :             int         len;
     757             :             char        expectedfname[MAXFNAMELEN];
     758             : 
     759          22 :             ereport(LOG,
     760             :                     (errmsg("fetching timeline history file for timeline %u from primary server",
     761             :                             tli)));
     762             : 
     763          22 :             walrcv_readtimelinehistoryfile(wrconn, tli, &fname, &content, &len);
     764             : 
     765             :             /*
     766             :              * Check that the filename on the primary matches what we
     767             :              * calculated ourselves. This is just a sanity check, it should
     768             :              * always match.
     769             :              */
     770          22 :             TLHistoryFileName(expectedfname, tli);
     771          22 :             if (strcmp(fname, expectedfname) != 0)
     772           0 :                 ereport(ERROR,
     773             :                         (errcode(ERRCODE_PROTOCOL_VIOLATION),
     774             :                          errmsg_internal("primary reported unexpected file name for timeline history file of timeline %u",
     775             :                                          tli)));
     776             : 
     777             :             /*
     778             :              * Write the file to pg_wal.
     779             :              */
     780          22 :             writeTimeLineHistoryFile(tli, content, len);
     781             : 
     782             :             /*
     783             :              * Mark the streamed history file as ready for archiving if
     784             :              * archive_mode is always.
     785             :              */
     786          22 :             if (XLogArchiveMode != ARCHIVE_MODE_ALWAYS)
     787          22 :                 XLogArchiveForceDone(fname);
     788             :             else
     789           0 :                 XLogArchiveNotify(fname);
     790             : 
     791          22 :             pfree(fname);
     792          22 :             pfree(content);
     793             :         }
     794             :     }
     795         250 : }
     796             : 
     797             : /*
     798             :  * Mark us as STOPPED in shared memory at exit.
     799             :  */
     800             : static void
     801         348 : WalRcvDie(int code, Datum arg)
     802             : {
     803         348 :     WalRcvData *walrcv = WalRcv;
     804         348 :     TimeLineID *startpointTLI_p = (TimeLineID *) DatumGetPointer(arg);
     805             : 
     806             :     Assert(*startpointTLI_p != 0);
     807             : 
     808             :     /* Ensure that all WAL records received are flushed to disk */
     809         348 :     XLogWalRcvFlush(true, *startpointTLI_p);
     810             : 
     811             :     /* Mark ourselves inactive in shared memory */
     812         348 :     SpinLockAcquire(&walrcv->mutex);
     813             :     Assert(walrcv->walRcvState == WALRCV_STREAMING ||
     814             :            walrcv->walRcvState == WALRCV_RESTARTING ||
     815             :            walrcv->walRcvState == WALRCV_STARTING ||
     816             :            walrcv->walRcvState == WALRCV_WAITING ||
     817             :            walrcv->walRcvState == WALRCV_STOPPING);
     818             :     Assert(walrcv->pid == MyProcPid);
     819         348 :     walrcv->walRcvState = WALRCV_STOPPED;
     820         348 :     walrcv->pid = 0;
     821         348 :     walrcv->ready_to_display = false;
     822         348 :     walrcv->latch = NULL;
     823         348 :     SpinLockRelease(&walrcv->mutex);
     824             : 
     825         348 :     ConditionVariableBroadcast(&walrcv->walRcvStoppedCV);
     826             : 
     827             :     /* Terminate the connection gracefully. */
     828         348 :     if (wrconn != NULL)
     829         226 :         walrcv_disconnect(wrconn);
     830             : 
     831             :     /* Wake up the startup process to notice promptly that we're gone */
     832         348 :     WakeupRecovery();
     833         348 : }
     834             : 
     835             : /*
     836             :  * Accept the message from XLOG stream, and process it.
     837             :  */
     838             : static void
     839       44130 : XLogWalRcvProcessMsg(unsigned char type, char *buf, Size len, TimeLineID tli)
     840             : {
     841             :     int         hdrlen;
     842             :     XLogRecPtr  dataStart;
     843             :     XLogRecPtr  walEnd;
     844             :     TimestampTz sendTime;
     845             :     bool        replyRequested;
     846             : 
     847       44130 :     switch (type)
     848             :     {
     849       44130 :         case 'w':               /* WAL records */
     850             :             {
     851             :                 StringInfoData incoming_message;
     852             : 
     853       44130 :                 hdrlen = sizeof(int64) + sizeof(int64) + sizeof(int64);
     854       44130 :                 if (len < hdrlen)
     855           0 :                     ereport(ERROR,
     856             :                             (errcode(ERRCODE_PROTOCOL_VIOLATION),
     857             :                              errmsg_internal("invalid WAL message received from primary")));
     858             : 
     859             :                 /* initialize a StringInfo with the given buffer */
     860       44130 :                 initReadOnlyStringInfo(&incoming_message, buf, hdrlen);
     861             : 
     862             :                 /* read the fields */
     863       44130 :                 dataStart = pq_getmsgint64(&incoming_message);
     864       44130 :                 walEnd = pq_getmsgint64(&incoming_message);
     865       44130 :                 sendTime = pq_getmsgint64(&incoming_message);
     866       44130 :                 ProcessWalSndrMessage(walEnd, sendTime);
     867             : 
     868       44130 :                 buf += hdrlen;
     869       44130 :                 len -= hdrlen;
     870       44130 :                 XLogWalRcvWrite(buf, len, dataStart, tli);
     871       44130 :                 break;
     872             :             }
     873           0 :         case 'k':               /* Keepalive */
     874             :             {
     875             :                 StringInfoData incoming_message;
     876             : 
     877           0 :                 hdrlen = sizeof(int64) + sizeof(int64) + sizeof(char);
     878           0 :                 if (len != hdrlen)
     879           0 :                     ereport(ERROR,
     880             :                             (errcode(ERRCODE_PROTOCOL_VIOLATION),
     881             :                              errmsg_internal("invalid keepalive message received from primary")));
     882             : 
     883             :                 /* initialize a StringInfo with the given buffer */
     884           0 :                 initReadOnlyStringInfo(&incoming_message, buf, hdrlen);
     885             : 
     886             :                 /* read the fields */
     887           0 :                 walEnd = pq_getmsgint64(&incoming_message);
     888           0 :                 sendTime = pq_getmsgint64(&incoming_message);
     889           0 :                 replyRequested = pq_getmsgbyte(&incoming_message);
     890             : 
     891           0 :                 ProcessWalSndrMessage(walEnd, sendTime);
     892             : 
     893             :                 /* If the primary requested a reply, send one immediately */
     894           0 :                 if (replyRequested)
     895           0 :                     XLogWalRcvSendReply(true, false);
     896           0 :                 break;
     897             :             }
     898           0 :         default:
     899           0 :             ereport(ERROR,
     900             :                     (errcode(ERRCODE_PROTOCOL_VIOLATION),
     901             :                      errmsg_internal("invalid replication message type %d",
     902             :                                      type)));
     903             :     }
     904       44130 : }
     905             : 
     906             : /*
     907             :  * Write XLOG data to disk.
     908             :  */
     909             : static void
     910       44130 : XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr, TimeLineID tli)
     911             : {
     912             :     int         startoff;
     913             :     int         byteswritten;
     914             : 
     915             :     Assert(tli != 0);
     916             : 
     917       88292 :     while (nbytes > 0)
     918             :     {
     919             :         int         segbytes;
     920             : 
     921             :         /* Close the current segment if it's completed */
     922       44162 :         if (recvFile >= 0 && !XLByteInSeg(recptr, recvSegNo, wal_segment_size))
     923          32 :             XLogWalRcvClose(recptr, tli);
     924             : 
     925       44162 :         if (recvFile < 0)
     926             :         {
     927             :             /* Create/use new log file */
     928         296 :             XLByteToSeg(recptr, recvSegNo, wal_segment_size);
     929         296 :             recvFile = XLogFileInit(recvSegNo, tli);
     930         296 :             recvFileTLI = tli;
     931             :         }
     932             : 
     933             :         /* Calculate the start offset of the received logs */
     934       44162 :         startoff = XLogSegmentOffset(recptr, wal_segment_size);
     935             : 
     936       44162 :         if (startoff + nbytes > wal_segment_size)
     937          32 :             segbytes = wal_segment_size - startoff;
     938             :         else
     939       44130 :             segbytes = nbytes;
     940             : 
     941             :         /* OK to write the logs */
     942       44162 :         errno = 0;
     943             : 
     944       44162 :         byteswritten = pg_pwrite(recvFile, buf, segbytes, (off_t) startoff);
     945       44162 :         if (byteswritten <= 0)
     946             :         {
     947             :             char        xlogfname[MAXFNAMELEN];
     948             :             int         save_errno;
     949             : 
     950             :             /* if write didn't set errno, assume no disk space */
     951           0 :             if (errno == 0)
     952           0 :                 errno = ENOSPC;
     953             : 
     954           0 :             save_errno = errno;
     955           0 :             XLogFileName(xlogfname, recvFileTLI, recvSegNo, wal_segment_size);
     956           0 :             errno = save_errno;
     957           0 :             ereport(PANIC,
     958             :                     (errcode_for_file_access(),
     959             :                      errmsg("could not write to WAL segment %s "
     960             :                             "at offset %d, length %lu: %m",
     961             :                             xlogfname, startoff, (unsigned long) segbytes)));
     962             :         }
     963             : 
     964             :         /* Update state for write */
     965       44162 :         recptr += byteswritten;
     966             : 
     967       44162 :         nbytes -= byteswritten;
     968       44162 :         buf += byteswritten;
     969             : 
     970       44162 :         LogstreamResult.Write = recptr;
     971             :     }
     972             : 
     973             :     /* Update shared-memory status */
     974       44130 :     pg_atomic_write_u64(&WalRcv->writtenUpto, LogstreamResult.Write);
     975             : 
     976             :     /*
     977             :      * Close the current segment if it's fully written up in the last cycle of
     978             :      * the loop, to create its archive notification file soon. Otherwise WAL
     979             :      * archiving of the segment will be delayed until any data in the next
     980             :      * segment is received and written.
     981             :      */
     982       44130 :     if (recvFile >= 0 && !XLByteInSeg(recptr, recvSegNo, wal_segment_size))
     983          70 :         XLogWalRcvClose(recptr, tli);
     984       44130 : }
     985             : 
     986             : /*
     987             :  * Flush the log to disk.
     988             :  *
     989             :  * If we're in the midst of dying, it's unwise to do anything that might throw
     990             :  * an error, so we skip sending a reply in that case.
     991             :  */
     992             : static void
     993       38214 : XLogWalRcvFlush(bool dying, TimeLineID tli)
     994             : {
     995             :     Assert(tli != 0);
     996             : 
     997       38214 :     if (LogstreamResult.Flush < LogstreamResult.Write)
     998             :     {
     999       37696 :         WalRcvData *walrcv = WalRcv;
    1000             : 
    1001       37696 :         issue_xlog_fsync(recvFile, recvSegNo, tli);
    1002             : 
    1003       37696 :         LogstreamResult.Flush = LogstreamResult.Write;
    1004             : 
    1005             :         /* Update shared-memory status */
    1006       37696 :         SpinLockAcquire(&walrcv->mutex);
    1007       37696 :         if (walrcv->flushedUpto < LogstreamResult.Flush)
    1008             :         {
    1009       37696 :             walrcv->latestChunkStart = walrcv->flushedUpto;
    1010       37696 :             walrcv->flushedUpto = LogstreamResult.Flush;
    1011       37696 :             walrcv->receivedTLI = tli;
    1012             :         }
    1013       37696 :         SpinLockRelease(&walrcv->mutex);
    1014             : 
    1015             :         /* Signal the startup process and walsender that new WAL has arrived */
    1016       37696 :         WakeupRecovery();
    1017       37696 :         if (AllowCascadeReplication())
    1018       37696 :             WalSndWakeup(true, false);
    1019             : 
    1020             :         /* Report XLOG streaming progress in PS display */
    1021       37696 :         if (update_process_title)
    1022             :         {
    1023             :             char        activitymsg[50];
    1024             : 
    1025       37696 :             snprintf(activitymsg, sizeof(activitymsg), "streaming %X/%X",
    1026       37696 :                      LSN_FORMAT_ARGS(LogstreamResult.Write));
    1027       37696 :             set_ps_display(activitymsg);
    1028             :         }
    1029             : 
    1030             :         /* Also let the primary know that we made some progress */
    1031       37696 :         if (!dying)
    1032             :         {
    1033       37694 :             XLogWalRcvSendReply(false, false);
    1034       37694 :             XLogWalRcvSendHSFeedback(false);
    1035             :         }
    1036             :     }
    1037       38214 : }
    1038             : 
    1039             : /*
    1040             :  * Close the current segment.
    1041             :  *
    1042             :  * Flush the segment to disk before closing it. Otherwise we have to
    1043             :  * reopen and fsync it later.
    1044             :  *
    1045             :  * Create an archive notification file since the segment is known completed.
    1046             :  */
    1047             : static void
    1048         102 : XLogWalRcvClose(XLogRecPtr recptr, TimeLineID tli)
    1049             : {
    1050             :     char        xlogfname[MAXFNAMELEN];
    1051             : 
    1052             :     Assert(recvFile >= 0 && !XLByteInSeg(recptr, recvSegNo, wal_segment_size));
    1053             :     Assert(tli != 0);
    1054             : 
    1055             :     /*
    1056             :      * fsync() and close current file before we switch to next one. We would
    1057             :      * otherwise have to reopen this file to fsync it later
    1058             :      */
    1059         102 :     XLogWalRcvFlush(false, tli);
    1060             : 
    1061         102 :     XLogFileName(xlogfname, recvFileTLI, recvSegNo, wal_segment_size);
    1062             : 
    1063             :     /*
    1064             :      * XLOG segment files will be re-read by recovery in startup process soon,
    1065             :      * so we don't advise the OS to release cache pages associated with the
    1066             :      * file like XLogFileClose() does.
    1067             :      */
    1068         102 :     if (close(recvFile) != 0)
    1069           0 :         ereport(PANIC,
    1070             :                 (errcode_for_file_access(),
    1071             :                  errmsg("could not close WAL segment %s: %m",
    1072             :                         xlogfname)));
    1073             : 
    1074             :     /*
    1075             :      * Create .done file forcibly to prevent the streamed segment from being
    1076             :      * archived later.
    1077             :      */
    1078         102 :     if (XLogArchiveMode != ARCHIVE_MODE_ALWAYS)
    1079         102 :         XLogArchiveForceDone(xlogfname);
    1080             :     else
    1081           0 :         XLogArchiveNotify(xlogfname);
    1082             : 
    1083         102 :     recvFile = -1;
    1084         102 : }
    1085             : 
    1086             : /*
    1087             :  * Send reply message to primary, indicating our current WAL locations, oldest
    1088             :  * xmin and the current time.
    1089             :  *
    1090             :  * If 'force' is not set, the message is only sent if enough time has
    1091             :  * passed since last status update to reach wal_receiver_status_interval.
    1092             :  * If wal_receiver_status_interval is disabled altogether and 'force' is
    1093             :  * false, this is a no-op.
    1094             :  *
    1095             :  * If 'requestReply' is true, requests the server to reply immediately upon
    1096             :  * receiving this message. This is used for heartbeats, when approaching
    1097             :  * wal_receiver_timeout.
    1098             :  */
    1099             : static void
    1100      101714 : XLogWalRcvSendReply(bool force, bool requestReply)
    1101             : {
    1102             :     static XLogRecPtr writePtr = 0;
    1103             :     static XLogRecPtr flushPtr = 0;
    1104             :     XLogRecPtr  applyPtr;
    1105             :     TimestampTz now;
    1106             : 
    1107             :     /*
    1108             :      * If the user doesn't want status to be reported to the primary, be sure
    1109             :      * to exit before doing anything at all.
    1110             :      */
    1111      101714 :     if (!force && wal_receiver_status_interval <= 0)
    1112           0 :         return;
    1113             : 
    1114             :     /* Get current timestamp. */
    1115      101714 :     now = GetCurrentTimestamp();
    1116             : 
    1117             :     /*
    1118             :      * We can compare the write and flush positions to the last message we
    1119             :      * sent without taking any lock, but the apply position requires a spin
    1120             :      * lock, so we don't check that unless something else has changed or 10
    1121             :      * seconds have passed.  This means that the apply WAL location will
    1122             :      * appear, from the primary's point of view, to lag slightly, but since
    1123             :      * this is only for reporting purposes and only on idle systems, that's
    1124             :      * probably OK.
    1125             :      */
    1126      101714 :     if (!force
    1127       75444 :         && writePtr == LogstreamResult.Write
    1128       37716 :         && flushPtr == LogstreamResult.Flush
    1129         124 :         && now < wakeup[WALRCV_WAKEUP_REPLY])
    1130         124 :         return;
    1131             : 
    1132             :     /* Make sure we wake up when it's time to send another reply. */
    1133      101590 :     WalRcvComputeNextWakeup(WALRCV_WAKEUP_REPLY, now);
    1134             : 
    1135             :     /* Construct a new message */
    1136      101590 :     writePtr = LogstreamResult.Write;
    1137      101590 :     flushPtr = LogstreamResult.Flush;
    1138      101590 :     applyPtr = GetXLogReplayRecPtr(NULL);
    1139             : 
    1140      101590 :     resetStringInfo(&reply_message);
    1141      101590 :     pq_sendbyte(&reply_message, 'r');
    1142      101590 :     pq_sendint64(&reply_message, writePtr);
    1143      101590 :     pq_sendint64(&reply_message, flushPtr);
    1144      101590 :     pq_sendint64(&reply_message, applyPtr);
    1145      101590 :     pq_sendint64(&reply_message, GetCurrentTimestamp());
    1146      101590 :     pq_sendbyte(&reply_message, requestReply ? 1 : 0);
    1147             : 
    1148             :     /* Send it */
    1149      101590 :     elog(DEBUG2, "sending write %X/%X flush %X/%X apply %X/%X%s",
    1150             :          LSN_FORMAT_ARGS(writePtr),
    1151             :          LSN_FORMAT_ARGS(flushPtr),
    1152             :          LSN_FORMAT_ARGS(applyPtr),
    1153             :          requestReply ? " (reply requested)" : "");
    1154             : 
    1155      101590 :     walrcv_send(wrconn, reply_message.data, reply_message.len);
    1156             : }
    1157             : 
    1158             : /*
    1159             :  * Send hot standby feedback message to primary, plus the current time,
    1160             :  * in case they don't have a watch.
    1161             :  *
    1162             :  * If the user disables feedback, send one final message to tell sender
    1163             :  * to forget about the xmin on this standby. We also send this message
    1164             :  * on first connect because a previous connection might have set xmin
    1165             :  * on a replication slot. (If we're not using a slot it's harmless to
    1166             :  * send a feedback message explicitly setting InvalidTransactionId).
    1167             :  */
    1168             : static void
    1169       37972 : XLogWalRcvSendHSFeedback(bool immed)
    1170             : {
    1171             :     TimestampTz now;
    1172             :     FullTransactionId nextFullXid;
    1173             :     TransactionId nextXid;
    1174             :     uint32      xmin_epoch,
    1175             :                 catalog_xmin_epoch;
    1176             :     TransactionId xmin,
    1177             :                 catalog_xmin;
    1178             : 
    1179             :     /* initially true so we always send at least one feedback message */
    1180             :     static bool primary_has_standby_xmin = true;
    1181             : 
    1182             :     /*
    1183             :      * If the user doesn't want status to be reported to the primary, be sure
    1184             :      * to exit before doing anything at all.
    1185             :      */
    1186       37972 :     if ((wal_receiver_status_interval <= 0 || !hot_standby_feedback) &&
    1187       37576 :         !primary_has_standby_xmin)
    1188       37704 :         return;
    1189             : 
    1190             :     /* Get current timestamp. */
    1191         606 :     now = GetCurrentTimestamp();
    1192             : 
    1193             :     /* Send feedback at most once per wal_receiver_status_interval. */
    1194         606 :     if (!immed && now < wakeup[WALRCV_WAKEUP_HSFEEDBACK])
    1195         336 :         return;
    1196             : 
    1197             :     /* Make sure we wake up when it's time to send feedback again. */
    1198         270 :     WalRcvComputeNextWakeup(WALRCV_WAKEUP_HSFEEDBACK, now);
    1199             : 
    1200             :     /*
    1201             :      * If Hot Standby is not yet accepting connections there is nothing to
    1202             :      * send. Check this after the interval has expired to reduce number of
    1203             :      * calls.
    1204             :      *
    1205             :      * Bailing out here also ensures that we don't send feedback until we've
    1206             :      * read our own replication slot state, so we don't tell the primary to
    1207             :      * discard needed xmin or catalog_xmin from any slots that may exist on
    1208             :      * this replica.
    1209             :      */
    1210         270 :     if (!HotStandbyActive())
    1211           2 :         return;
    1212             : 
    1213             :     /*
    1214             :      * Make the expensive call to get the oldest xmin once we are certain
    1215             :      * everything else has been checked.
    1216             :      */
    1217         268 :     if (hot_standby_feedback)
    1218             :     {
    1219          62 :         GetReplicationHorizons(&xmin, &catalog_xmin);
    1220             :     }
    1221             :     else
    1222             :     {
    1223         206 :         xmin = InvalidTransactionId;
    1224         206 :         catalog_xmin = InvalidTransactionId;
    1225             :     }
    1226             : 
    1227             :     /*
    1228             :      * Get epoch and adjust if nextXid and oldestXmin are different sides of
    1229             :      * the epoch boundary.
    1230             :      */
    1231         268 :     nextFullXid = ReadNextFullTransactionId();
    1232         268 :     nextXid = XidFromFullTransactionId(nextFullXid);
    1233         268 :     xmin_epoch = EpochFromFullTransactionId(nextFullXid);
    1234         268 :     catalog_xmin_epoch = xmin_epoch;
    1235         268 :     if (nextXid < xmin)
    1236           0 :         xmin_epoch--;
    1237         268 :     if (nextXid < catalog_xmin)
    1238           0 :         catalog_xmin_epoch--;
    1239             : 
    1240         268 :     elog(DEBUG2, "sending hot standby feedback xmin %u epoch %u catalog_xmin %u catalog_xmin_epoch %u",
    1241             :          xmin, xmin_epoch, catalog_xmin, catalog_xmin_epoch);
    1242             : 
    1243             :     /* Construct the message and send it. */
    1244         268 :     resetStringInfo(&reply_message);
    1245         268 :     pq_sendbyte(&reply_message, 'h');
    1246         268 :     pq_sendint64(&reply_message, GetCurrentTimestamp());
    1247         268 :     pq_sendint32(&reply_message, xmin);
    1248         268 :     pq_sendint32(&reply_message, xmin_epoch);
    1249         268 :     pq_sendint32(&reply_message, catalog_xmin);
    1250         268 :     pq_sendint32(&reply_message, catalog_xmin_epoch);
    1251         268 :     walrcv_send(wrconn, reply_message.data, reply_message.len);
    1252         268 :     if (TransactionIdIsValid(xmin) || TransactionIdIsValid(catalog_xmin))
    1253          62 :         primary_has_standby_xmin = true;
    1254             :     else
    1255         206 :         primary_has_standby_xmin = false;
    1256             : }
    1257             : 
    1258             : /*
    1259             :  * Update shared memory status upon receiving a message from primary.
    1260             :  *
    1261             :  * 'walEnd' and 'sendTime' are the end-of-WAL and timestamp of the latest
    1262             :  * message, reported by primary.
    1263             :  */
    1264             : static void
    1265       44130 : ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime)
    1266             : {
    1267       44130 :     WalRcvData *walrcv = WalRcv;
    1268       44130 :     TimestampTz lastMsgReceiptTime = GetCurrentTimestamp();
    1269             : 
    1270             :     /* Update shared-memory status */
    1271       44130 :     SpinLockAcquire(&walrcv->mutex);
    1272       44130 :     if (walrcv->latestWalEnd < walEnd)
    1273       37760 :         walrcv->latestWalEndTime = sendTime;
    1274       44130 :     walrcv->latestWalEnd = walEnd;
    1275       44130 :     walrcv->lastMsgSendTime = sendTime;
    1276       44130 :     walrcv->lastMsgReceiptTime = lastMsgReceiptTime;
    1277       44130 :     SpinLockRelease(&walrcv->mutex);
    1278             : 
    1279       44130 :     if (message_level_is_interesting(DEBUG2))
    1280             :     {
    1281             :         char       *sendtime;
    1282             :         char       *receipttime;
    1283             :         int         applyDelay;
    1284             : 
    1285             :         /* Copy because timestamptz_to_str returns a static buffer */
    1286         780 :         sendtime = pstrdup(timestamptz_to_str(sendTime));
    1287         780 :         receipttime = pstrdup(timestamptz_to_str(lastMsgReceiptTime));
    1288         780 :         applyDelay = GetReplicationApplyDelay();
    1289             : 
    1290             :         /* apply delay is not available */
    1291         780 :         if (applyDelay == -1)
    1292           2 :             elog(DEBUG2, "sendtime %s receipttime %s replication apply delay (N/A) transfer latency %d ms",
    1293             :                  sendtime,
    1294             :                  receipttime,
    1295             :                  GetReplicationTransferLatency());
    1296             :         else
    1297         778 :             elog(DEBUG2, "sendtime %s receipttime %s replication apply delay %d ms transfer latency %d ms",
    1298             :                  sendtime,
    1299             :                  receipttime,
    1300             :                  applyDelay,
    1301             :                  GetReplicationTransferLatency());
    1302             : 
    1303         780 :         pfree(sendtime);
    1304         780 :         pfree(receipttime);
    1305             :     }
    1306       44130 : }
    1307             : 
    1308             : /*
    1309             :  * Compute the next wakeup time for a given wakeup reason.  Can be called to
    1310             :  * initialize a wakeup time, to adjust it for the next wakeup, or to
    1311             :  * reinitialize it when GUCs have changed.  We ask the caller to pass in the
    1312             :  * value of "now" because this frequently avoids multiple calls of
    1313             :  * GetCurrentTimestamp().  It had better be a reasonably up-to-date value
    1314             :  * though.
    1315             :  */
    1316             : static void
    1317      191200 : WalRcvComputeNextWakeup(WalRcvWakeupReason reason, TimestampTz now)
    1318             : {
    1319      191200 :     switch (reason)
    1320             :     {
    1321       44400 :         case WALRCV_WAKEUP_TERMINATE:
    1322       44400 :             if (wal_receiver_timeout <= 0)
    1323           0 :                 wakeup[reason] = TIMESTAMP_INFINITY;
    1324             :             else
    1325       44400 :                 wakeup[reason] = TimestampTzPlusMilliseconds(now, wal_receiver_timeout);
    1326       44400 :             break;
    1327       44400 :         case WALRCV_WAKEUP_PING:
    1328       44400 :             if (wal_receiver_timeout <= 0)
    1329           0 :                 wakeup[reason] = TIMESTAMP_INFINITY;
    1330             :             else
    1331       44400 :                 wakeup[reason] = TimestampTzPlusMilliseconds(now, wal_receiver_timeout / 2);
    1332       44400 :             break;
    1333         540 :         case WALRCV_WAKEUP_HSFEEDBACK:
    1334         540 :             if (!hot_standby_feedback || wal_receiver_status_interval <= 0)
    1335         424 :                 wakeup[reason] = TIMESTAMP_INFINITY;
    1336             :             else
    1337         116 :                 wakeup[reason] = TimestampTzPlusSeconds(now, wal_receiver_status_interval);
    1338         540 :             break;
    1339      101860 :         case WALRCV_WAKEUP_REPLY:
    1340      101860 :             if (wal_receiver_status_interval <= 0)
    1341           0 :                 wakeup[reason] = TIMESTAMP_INFINITY;
    1342             :             else
    1343      101860 :                 wakeup[reason] = TimestampTzPlusSeconds(now, wal_receiver_status_interval);
    1344      101860 :             break;
    1345             :             /* there's intentionally no default: here */
    1346             :     }
    1347      191200 : }
    1348             : 
    1349             : /*
    1350             :  * Wake up the walreceiver main loop.
    1351             :  *
    1352             :  * This is called by the startup process whenever interesting xlog records
    1353             :  * are applied, so that walreceiver can check if it needs to send an apply
    1354             :  * notification back to the primary which may be waiting in a COMMIT with
    1355             :  * synchronous_commit = remote_apply.
    1356             :  */
    1357             : void
    1358       25560 : WalRcvForceReply(void)
    1359             : {
    1360             :     Latch      *latch;
    1361             : 
    1362       25560 :     WalRcv->force_reply = true;
    1363             :     /* fetching the latch pointer might not be atomic, so use spinlock */
    1364       25560 :     SpinLockAcquire(&WalRcv->mutex);
    1365       25560 :     latch = WalRcv->latch;
    1366       25560 :     SpinLockRelease(&WalRcv->mutex);
    1367       25560 :     if (latch)
    1368       25326 :         SetLatch(latch);
    1369       25560 : }
    1370             : 
    1371             : /*
    1372             :  * Return a string constant representing the state. This is used
    1373             :  * in system functions and views, and should *not* be translated.
    1374             :  */
    1375             : static const char *
    1376           0 : WalRcvGetStateString(WalRcvState state)
    1377             : {
    1378           0 :     switch (state)
    1379             :     {
    1380           0 :         case WALRCV_STOPPED:
    1381           0 :             return "stopped";
    1382           0 :         case WALRCV_STARTING:
    1383           0 :             return "starting";
    1384           0 :         case WALRCV_STREAMING:
    1385           0 :             return "streaming";
    1386           0 :         case WALRCV_WAITING:
    1387           0 :             return "waiting";
    1388           0 :         case WALRCV_RESTARTING:
    1389           0 :             return "restarting";
    1390           0 :         case WALRCV_STOPPING:
    1391           0 :             return "stopping";
    1392             :     }
    1393           0 :     return "UNKNOWN";
    1394             : }
    1395             : 
    1396             : /*
    1397             :  * Returns activity of WAL receiver, including pid, state and xlog locations
    1398             :  * received from the WAL sender of another server.
    1399             :  */
    1400             : Datum
    1401           6 : pg_stat_get_wal_receiver(PG_FUNCTION_ARGS)
    1402             : {
    1403             :     TupleDesc   tupdesc;
    1404             :     Datum      *values;
    1405             :     bool       *nulls;
    1406             :     int         pid;
    1407             :     bool        ready_to_display;
    1408             :     WalRcvState state;
    1409             :     XLogRecPtr  receive_start_lsn;
    1410             :     TimeLineID  receive_start_tli;
    1411             :     XLogRecPtr  written_lsn;
    1412             :     XLogRecPtr  flushed_lsn;
    1413             :     TimeLineID  received_tli;
    1414             :     TimestampTz last_send_time;
    1415             :     TimestampTz last_receipt_time;
    1416             :     XLogRecPtr  latest_end_lsn;
    1417             :     TimestampTz latest_end_time;
    1418             :     char        sender_host[NI_MAXHOST];
    1419           6 :     int         sender_port = 0;
    1420             :     char        slotname[NAMEDATALEN];
    1421             :     char        conninfo[MAXCONNINFO];
    1422             : 
    1423             :     /* Take a lock to ensure value consistency */
    1424           6 :     SpinLockAcquire(&WalRcv->mutex);
    1425           6 :     pid = (int) WalRcv->pid;
    1426           6 :     ready_to_display = WalRcv->ready_to_display;
    1427           6 :     state = WalRcv->walRcvState;
    1428           6 :     receive_start_lsn = WalRcv->receiveStart;
    1429           6 :     receive_start_tli = WalRcv->receiveStartTLI;
    1430           6 :     flushed_lsn = WalRcv->flushedUpto;
    1431           6 :     received_tli = WalRcv->receivedTLI;
    1432           6 :     last_send_time = WalRcv->lastMsgSendTime;
    1433           6 :     last_receipt_time = WalRcv->lastMsgReceiptTime;
    1434           6 :     latest_end_lsn = WalRcv->latestWalEnd;
    1435           6 :     latest_end_time = WalRcv->latestWalEndTime;
    1436           6 :     strlcpy(slotname, (char *) WalRcv->slotname, sizeof(slotname));
    1437           6 :     strlcpy(sender_host, (char *) WalRcv->sender_host, sizeof(sender_host));
    1438           6 :     sender_port = WalRcv->sender_port;
    1439           6 :     strlcpy(conninfo, (char *) WalRcv->conninfo, sizeof(conninfo));
    1440           6 :     SpinLockRelease(&WalRcv->mutex);
    1441             : 
    1442             :     /*
    1443             :      * No WAL receiver (or not ready yet), just return a tuple with NULL
    1444             :      * values
    1445             :      */
    1446           6 :     if (pid == 0 || !ready_to_display)
    1447           6 :         PG_RETURN_NULL();
    1448             : 
    1449             :     /*
    1450             :      * Read "writtenUpto" without holding a spinlock.  Note that it may not be
    1451             :      * consistent with the other shared variables of the WAL receiver
    1452             :      * protected by a spinlock, but this should not be used for data integrity
    1453             :      * checks.
    1454             :      */
    1455           0 :     written_lsn = pg_atomic_read_u64(&WalRcv->writtenUpto);
    1456             : 
    1457             :     /* determine result type */
    1458           0 :     if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
    1459           0 :         elog(ERROR, "return type must be a row type");
    1460             : 
    1461           0 :     values = palloc0(sizeof(Datum) * tupdesc->natts);
    1462           0 :     nulls = palloc0(sizeof(bool) * tupdesc->natts);
    1463             : 
    1464             :     /* Fetch values */
    1465           0 :     values[0] = Int32GetDatum(pid);
    1466             : 
    1467           0 :     if (!has_privs_of_role(GetUserId(), ROLE_PG_READ_ALL_STATS))
    1468             :     {
    1469             :         /*
    1470             :          * Only superusers and roles with privileges of pg_read_all_stats can
    1471             :          * see details. Other users only get the pid value to know whether it
    1472             :          * is a WAL receiver, but no details.
    1473             :          */
    1474           0 :         memset(&nulls[1], true, sizeof(bool) * (tupdesc->natts - 1));
    1475             :     }
    1476             :     else
    1477             :     {
    1478           0 :         values[1] = CStringGetTextDatum(WalRcvGetStateString(state));
    1479             : 
    1480           0 :         if (XLogRecPtrIsInvalid(receive_start_lsn))
    1481           0 :             nulls[2] = true;
    1482             :         else
    1483           0 :             values[2] = LSNGetDatum(receive_start_lsn);
    1484           0 :         values[3] = Int32GetDatum(receive_start_tli);
    1485           0 :         if (XLogRecPtrIsInvalid(written_lsn))
    1486           0 :             nulls[4] = true;
    1487             :         else
    1488           0 :             values[4] = LSNGetDatum(written_lsn);
    1489           0 :         if (XLogRecPtrIsInvalid(flushed_lsn))
    1490           0 :             nulls[5] = true;
    1491             :         else
    1492           0 :             values[5] = LSNGetDatum(flushed_lsn);
    1493           0 :         values[6] = Int32GetDatum(received_tli);
    1494           0 :         if (last_send_time == 0)
    1495           0 :             nulls[7] = true;
    1496             :         else
    1497           0 :             values[7] = TimestampTzGetDatum(last_send_time);
    1498           0 :         if (last_receipt_time == 0)
    1499           0 :             nulls[8] = true;
    1500             :         else
    1501           0 :             values[8] = TimestampTzGetDatum(last_receipt_time);
    1502           0 :         if (XLogRecPtrIsInvalid(latest_end_lsn))
    1503           0 :             nulls[9] = true;
    1504             :         else
    1505           0 :             values[9] = LSNGetDatum(latest_end_lsn);
    1506           0 :         if (latest_end_time == 0)
    1507           0 :             nulls[10] = true;
    1508             :         else
    1509           0 :             values[10] = TimestampTzGetDatum(latest_end_time);
    1510           0 :         if (*slotname == '\0')
    1511           0 :             nulls[11] = true;
    1512             :         else
    1513           0 :             values[11] = CStringGetTextDatum(slotname);
    1514           0 :         if (*sender_host == '\0')
    1515           0 :             nulls[12] = true;
    1516             :         else
    1517           0 :             values[12] = CStringGetTextDatum(sender_host);
    1518           0 :         if (sender_port == 0)
    1519           0 :             nulls[13] = true;
    1520             :         else
    1521           0 :             values[13] = Int32GetDatum(sender_port);
    1522           0 :         if (*conninfo == '\0')
    1523           0 :             nulls[14] = true;
    1524             :         else
    1525           0 :             values[14] = CStringGetTextDatum(conninfo);
    1526             :     }
    1527             : 
    1528             :     /* Returns the record as Datum */
    1529           0 :     PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
    1530             : }

Generated by: LCOV version 1.14