Limit pg_basebackup progress output to 1/second

This prevents pg_basebackup from generating excessive output when
dumping large clusters. The status is now updated once / second,
still making it possible to see that there is progress happening,
but limiting the total bandwidth.

Mika Eloranta, reviewed by Sawada Masahiko and Oskari Saarenmaa

src/bin/pg_basebackup/pg_basebackup.c

@@ -15,6 +15,7 @@
 #include "libpq-fe.h"
 #include "pqexpbuffer.h"
 #include "pgtar.h"
+#include "pgtime.h"
 
 #include <unistd.h>
 #include <dirent.h>
@@ -46,6 +47,7 @@ static bool	streamwal = false;
 static bool	fastcheckpoint = false;
 static bool	writerecoveryconf = false;
 static int	standby_message_timeout = 10 * 1000;		/* 10 sec = default */
+static pg_time_t last_progress_report = 0;
 
 /* Progress counters */
 static uint64 totalsize;
@@ -75,7 +77,7 @@ static PQExpBuffer recoveryconfcontents = NULL;
 /* Function headers */
 static void usage(void);
 static void verify_dir_is_empty_or_create(char *dirname);
-static void progress_report(int tablespacenum, const char *filename);
+static void progress_report(int tablespacenum, const char *filename, bool force);
 
 static void ReceiveTarFile(PGconn *conn, PGresult *res, int rownum);
 static void ReceiveAndUnpackTarFile(PGconn *conn, PGresult *res, int rownum);
@@ -399,13 +401,27 @@ verify_dir_is_empty_or_create(char *dirname)
 /*
  * Print a progress report based on the global variables. If verbose output
  * is enabled, also print the current file name.
+ *
+ * Progress report is written at maximum once per second, unless the
+ * force parameter is set to true.
  */
 static void
-progress_report(int tablespacenum, const char *filename)
+progress_report(int tablespacenum, const char *filename, bool force)
 {
-	int			percent = (int) ((totaldone / 1024) * 100 / totalsize);
+	int			percent;
 	char		totaldone_str[32];
 	char		totalsize_str[32];
+	pg_time_t	now;
+
+	if (!showprogress)
+		return;
+
+	now = time(NULL);
+	if (now == last_progress_report && !force)
+		return; /* Max once per second */
+
+	last_progress_report = now;
+	percent = totalsize ? (int) ((totaldone / 1024) * 100 / totalsize) : 0;
 
 	/*
 	 * Avoid overflowing past 100% or the full size. This may make the total
@@ -853,9 +869,9 @@ ReceiveTarFile(PGconn *conn, PGresult *res, int rownum)
 			}
 		}
 		totaldone += r;
-		if (showprogress)
-			progress_report(rownum, filename);
+		progress_report(rownum, filename, false);
 	}							/* while (1) */
+	progress_report(rownum, filename, true);
 
 	if (copybuf != NULL)
 		PQfreemem(copybuf);
@@ -1080,8 +1096,7 @@ ReceiveAndUnpackTarFile(PGconn *conn, PGresult *res, int rownum)
 				disconnect_and_exit(1);
 			}
 			totaldone += r;
-			if (showprogress)
-				progress_report(rownum, filename);
+			progress_report(rownum, filename, false);
 
 			current_len_left -= r;
 			if (current_len_left == 0 && current_padding == 0)
@@ -1097,6 +1112,7 @@ ReceiveAndUnpackTarFile(PGconn *conn, PGresult *res, int rownum)
 			}
 		}						/* continuing data in existing file */
 	}							/* loop over all data blocks */
+	progress_report(rownum, filename, true);
 
 	if (file != NULL)
 	{
@@ -1457,8 +1473,7 @@ BaseBackup(void)
 	tablespacecount = PQntuples(res);
 	for (i = 0; i < PQntuples(res); i++)
 	{
-		if (showprogress)
-			totalsize += atol(PQgetvalue(res, i, 2));
+		totalsize += atol(PQgetvalue(res, i, 2));
 
 		/*
 		 * Verify tablespace directories are empty. Don't bother with the
@@ -1505,7 +1520,7 @@ BaseBackup(void)
 
 	if (showprogress)
 	{
-		progress_report(PQntuples(res), NULL);
+		progress_report(PQntuples(res), NULL, true);
 		fprintf(stderr, "\n");	/* Need to move to next line */
 	}
 	PQclear(res);