pg_verify_checksums_progress_V11.patch

diff --git a/doc/src/sgml/ref/pg_checksums.sgml b/doc/src/sgml/ref/pg_checksums.sgml
index 6a47dda683..c790170953 100644
--- a/doc/src/sgml/ref/pg_checksums.sgml
+++ b/doc/src/sgml/ref/pg_checksums.sgml
@@ -80,6 +80,19 @@ PostgreSQL documentation
      </varlistentry>
 
      <varlistentry>
+      <term><option>-P</option></term>
+      <term><option>--progress</option></term>
+      <listitem>
+       <para>
+        Enable progress reporting. Turning this on will deliver an approximate
+        progress report during the checksum verification. Sending the
+        <systemitem>SIGUSR1</systemitem> signal will toggle progress reporting
+        on or off during the verification run (not available on Windows).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
        <term><option>-V</option></term>
        <term><option>--version</option></term>
        <listitem>
diff --git a/src/bin/pg_checksums/pg_checksums.c b/src/bin/pg_checksums/pg_checksums.c
index b7ebc11017..a771f67c18 100644
--- a/src/bin/pg_checksums/pg_checksums.c
+++ b/src/bin/pg_checksums/pg_checksums.c
@@ -14,6 +14,8 @@
 #include "postgres_fe.h"
 
 #include <dirent.h>
+#include <signal.h>
+#include <time.h>
 #include <sys/stat.h>
 #include <unistd.h>
 
@@ -21,6 +23,7 @@
 #include "common/controldata_utils.h"
 #include "getopt_long.h"
 #include "pg_getopt.h"
+#include "portability/instr_time.h"
 #include "storage/bufpage.h"
 #include "storage/checksum.h"
 #include "storage/checksum_impl.h"
@@ -34,9 +37,18 @@ static ControlFileData *ControlFile;
 
 static char *only_relfilenode = NULL;
 static bool verbose = false;
+static bool show_progress = false;
 
 static const char *progname;
 
+/*
+ * Progress status information.
+ */
+int64		total_size = 0;
+int64		current_size = 0;
+instr_time	last_progress_update;
+instr_time	scan_started;
+
 static void
 usage(void)
 {
@@ -47,6 +59,7 @@ usage(void)
 	printf(_(" [-D, --pgdata=]DATADIR  data directory\n"));
 	printf(_("  -v, --verbose          output verbose messages\n"));
 	printf(_("  -r RELFILENODE         check only relation with specified relfilenode\n"));
+	printf(_("  -P, --progress         show progress information\n"));
 	printf(_("  -V, --version          output version information, then exit\n"));
 	printf(_("  -?, --help             show this help, then exit\n"));
 	printf(_("\nIf no data directory (DATADIR) is specified, "
@@ -71,6 +84,83 @@ static const char *const skip[] = {
 	NULL,
 };
 
+static void
+toggle_progress_report(int signum)
+{
+
+	/* we handle SIGUSR1 only, and toggle the value of show_progress */
+	if (signum == SIGUSR1)
+	{
+		/*
+		 * Skip to the next line in order to avoid overwriting half of
+		 * the progress report line with the final output.
+		 */
+		if (show_progress && isatty(fileno(stderr)))
+			fprintf(stderr, "\n");
+		show_progress = !show_progress;
+	}
+}
+
+/*
+ * Report current progress status. Parts borrowed from
+ * PostgreSQLs' src/bin/pg_basebackup.c
+ */
+static void
+report_progress(bool force)
+{
+	instr_time	now;
+	double		elapsed;
+	double		total_percent;
+	int64		current_speed;
+
+	char		totalstr[32];
+	char		currentstr[32];
+	char		currspeedstr[32];
+
+	INSTR_TIME_SET_CURRENT(now);
+
+	/* Make sure we report at most once every 400 milliseconds */
+	if ((INSTR_TIME_GET_MILLISEC(now) -
+		 INSTR_TIME_GET_MILLISEC(last_progress_update) < 400) && !force)
+		return;
+
+	/* Save current time */
+	last_progress_update = now;
+
+	/* Elapsed time in milliseconds since start of scan */
+	elapsed = (INSTR_TIME_GET_MILLISEC(now) -
+			   INSTR_TIME_GET_MILLISEC(scan_started));
+
+	/* Calculate current percent done */
+	total_percent = total_size ? 100.0 * current_size / total_size : 0.0;
+
+	/* Don't display larger than 100% */
+	if (total_percent > 100)
+		total_percent = 100;
+
+#define MEGABYTES (1024 * 1024)
+
+	/* The same for total size */
+	if (current_size > total_size)
+		total_size = current_size / MEGABYTES;
+
+	/* Calculate current speed */
+	current_speed = (int64)(current_size / MEGABYTES) / (elapsed / 1000);
+
+	snprintf(totalstr, sizeof(totalstr), INT64_FORMAT,
+			 total_size / MEGABYTES);
+	snprintf(currentstr, sizeof(currentstr), INT64_FORMAT,
+			 current_size / MEGABYTES);
+	snprintf(currspeedstr, sizeof(currspeedstr), INT64_FORMAT,
+			 current_speed);
+
+	fprintf(stderr, "%s/%s MB (%d%%, %s MB/s)",
+			currentstr, totalstr, (int)total_percent, currspeedstr);
+
+	/* Stay on the same line if reporting to a terminal */
+	fprintf(stderr, isatty(fileno(stderr)) ? "\r" : "\n");
+}
+
 static bool
 skipfile(const char *fn)
 {
@@ -121,6 +211,7 @@ scan_file(const char *fn, BlockNumber segmentno)
 			continue;
 
 		csum = pg_checksum_page(buf.data, blockno + segmentno * RELSEG_SIZE);
+		current_size += r;
 		if (csum != header->pd_checksum)
 		{
 			if (ControlFile->data_checksum_version == PG_DATA_CHECKSUM_VERSION)
@@ -128,6 +219,9 @@ scan_file(const char *fn, BlockNumber segmentno)
 						progname, fn, blockno, csum, header->pd_checksum);
 			badblocks++;
 		}
+
+		if (show_progress)
+			report_progress(false);
 	}
 
 	if (verbose)
@@ -137,9 +231,10 @@ scan_file(const char *fn, BlockNumber segmentno)
 	close(f);
 }
 
-static void
-scan_directory(const char *basedir, const char *subdir)
+static int64
+scan_directory(const char *basedir, const char *subdir, bool sizeonly)
 {
+	int64		dirsize = 0;
 	char		path[MAXPGPATH];
 	DIR		   *dir;
 	struct dirent *de;
@@ -218,16 +313,20 @@ scan_directory(const char *basedir, const char *subdir)
 				/* Relfilenode not to be included */
 				continue;
 
-			scan_file(fn, segmentno);
+			dirsize += st.st_size;
+
+			if (!sizeonly)
+				scan_file(fn, segmentno);
 		}
 #ifndef WIN32
 		else if (S_ISDIR(st.st_mode) || S_ISLNK(st.st_mode))
 #else
 		else if (S_ISDIR(st.st_mode) || pgwin32_is_junction(fn))
 #endif
-			scan_directory(path, de->d_name);
+			dirsize += scan_directory(path, de->d_name, sizeonly);
 	}
 	closedir(dir);
+	return dirsize;
 }
 
 int
@@ -235,6 +334,7 @@ main(int argc, char *argv[])
 {
 	static struct option long_options[] = {
 		{"pgdata", required_argument, NULL, 'D'},
+		{"progress", no_argument, NULL, 'P'},
 		{"verbose", no_argument, NULL, 'v'},
 		{NULL, 0, NULL, 0}
 	};
@@ -262,7 +362,7 @@ main(int argc, char *argv[])
 		}
 	}
 
-	while ((c = getopt_long(argc, argv, "D:r:v", long_options, &option_index)) != -1)
+	while ((c = getopt_long(argc, argv, "D:r:vP", long_options, &option_index)) != -1)
 	{
 		switch (c)
 		{
@@ -280,6 +380,9 @@ main(int argc, char *argv[])
 				}
 				only_relfilenode = pstrdup(optarg);
 				break;
+			case 'P':
+				show_progress = true;
+				break;
 			default:
 				fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 				exit(1);
@@ -349,10 +452,45 @@ main(int argc, char *argv[])
 		exit(1);
 	}
 
+
+#ifndef WIN32
+	/*
+	 * Assign SIGUSR1 signal handler to toggle progress status information
+	 */
+	pqsignal(SIGUSR1, toggle_progress_report);
+#endif
+
+	/*
+	 * As progress status information may be requested even after start of
+	 * operation, we need to scan the directory tree(s) twice, once to get
+	 * the idea how much data we need to scan and finally to do the real
+	 * legwork.
+	 */
+	total_size = scan_directory(DataDir, "global", true);
+	total_size += scan_directory(DataDir, "base", true);
+	total_size += scan_directory(DataDir, "pg_tblspc", true);
+
+	/*
+	 * Remember start time. Required to calculate the current speed in
+	 * report_progress()
+	 */
+	INSTR_TIME_SET_CURRENT(scan_started);
+
 	/* Scan all files */
-	scan_directory(DataDir, "global");
-	scan_directory(DataDir, "base");
-	scan_directory(DataDir, "pg_tblspc");
+	scan_directory(DataDir, "global", false);
+	scan_directory(DataDir, "base", false);
+	scan_directory(DataDir, "pg_tblspc", false);
+
+	/*
+	 * Done. Move to next line in case progress information was shown.
+	 * Otherwise we clutter the summary output.
+	 */
+	if (show_progress)
+	{
+		report_progress(true);
+		if (isatty(fileno(stderr)))
+			fprintf(stderr, "\n");
+	}
 
 	printf(_("Checksum scan completed\n"));
 	printf(_("Data checksum version: %d\n"), ControlFile->data_checksum_version);