initdbmaxbuffers.patch

diff --git a/doc/src/sgml/ref/initdb.sgml b/doc/src/sgml/ref/initdb.sgml
index 08ee37e..69cf625 100644
--- a/doc/src/sgml/ref/initdb.sgml
+++ b/doc/src/sgml/ref/initdb.sgml
@@ -220,6 +220,17 @@ PostgreSQL documentation
      </varlistentry>
 
      <varlistentry>
+      <term><option>--max-shared-buffers=<replaceable>memory</replaceable></option></term>
+      <listitem>
+       <para>
+        Specify the maximum amount of memory to try for setting <option>shared_buffers</option>.
+        The default is 128Mb. It can be specified in Gigabytes (e.g. 8Gb), 
+        Megabytes (e.g. 32Mb) or blocks (with no suffix).
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
       <term><option>-N</option></term>
       <term><option>--nosync</option></term>
       <listitem>
diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index 4292231..44243b9 100644
--- a/src/bin/initdb/initdb.c
+++ b/src/bin/initdb/initdb.c
@@ -120,6 +120,7 @@ static bool noclean = false;
 static bool do_sync = true;
 static bool show_setting = false;
 static char *xlog_dir = "";
+static int max_shared_buffers = 16384;
 
 
 /* internal vars */
@@ -227,6 +228,7 @@ static bool check_locale_name(int category, const char *locale,
 static bool check_locale_encoding(const char *locale, int encoding);
 static void setlocales(void);
 static void usage(const char *progname);
+static void set_max_shared_buffers(const char * arg);
 
 #ifdef WIN32
 static int	CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo);
@@ -1071,7 +1073,7 @@ test_config_settings(void)
 	static const int trial_conns[] = {
 		100, 50, 40, 30, 20, 10
 	};
-	static const int trial_bufs[] = {
+	static const int preset_trial_bufs[] = {
 		16384, 8192, 4096, 3584, 3072, 2560, 2048, 1536,
 		1000, 900, 800, 700, 600, 500,
 		400, 300, 200, 100, 50
@@ -1079,14 +1081,40 @@ test_config_settings(void)
 
 	char		cmd[MAXPGPATH];
 	const int	connslen = sizeof(trial_conns) / sizeof(int);
-	const int	bufslen = sizeof(trial_bufs) / sizeof(int);
+	const int	preset_bufslen = sizeof(preset_trial_bufs) / sizeof(int);
+	int         *trial_bufs;
 	int			i,
+		        max_bufs = preset_trial_bufs[0],
+		        n_extra = 1,
+		        bufslen = 1,
 				status,
 				test_conns,
 				test_buffs,
 				ok_buffers = 0;
 
+	while (max_bufs * 2 < max_shared_buffers)
+	{
+		n_extra++;
+		max_bufs *= 2;
+	}
+
+	trial_bufs = pg_malloc((preset_bufslen + n_extra) * sizeof(int));
+
+	trial_bufs[0] = max_shared_buffers;
+
+	while (max_bufs > preset_trial_bufs[0])
+	{
+		trial_bufs[bufslen++] = max_bufs;
+		max_bufs = max_bufs / 2;
+	}
 
+	for (i= 0; i < preset_bufslen; i++)
+	{
+		if (preset_trial_bufs[i] >= max_shared_buffers)
+			continue;
+		trial_bufs[bufslen++] = preset_trial_bufs[i];
+	}
+	
 	printf(_("selecting default max_connections ... "));
 	fflush(stdout);
 
@@ -1122,7 +1150,8 @@ test_config_settings(void)
 	for (i = 0; i < bufslen; i++)
 	{
 		/* Use same amount of memory, independent of BLCKSZ */
-		test_buffs = (trial_bufs[i] * 8192) / BLCKSZ;
+		/* Avoid overflow by doing the operations in the right order */
+		test_buffs = BLCKSZ <= 8192 ? trial_bufs[i] * (8192 / BLCKSZ) : trial_bufs[i] / (BLCKSZ / 8192);
 		if (test_buffs <= ok_buffers)
 		{
 			test_buffs = ok_buffers;
@@ -1143,7 +1172,9 @@ test_config_settings(void)
 	}
 	n_buffers = test_buffs;
 
-	if ((n_buffers * (BLCKSZ / 1024)) % 1024 == 0)
+	if ((n_buffers * (BLCKSZ / 1024)) % (1024 * 1024) == 0)
+		printf("%dGB\n", (n_buffers * (BLCKSZ / 1024)) / (1024 * 1024));
+	else if ((n_buffers * (BLCKSZ / 1024)) % 1024 == 0)
 		printf("%dMB\n", (n_buffers * (BLCKSZ / 1024)) / 1024);
 	else
 		printf("%dkB\n", n_buffers * (BLCKSZ / 1024));
@@ -2740,9 +2771,11 @@ usage(const char *progname)
 			 "                            set default locale in the respective category for\n"
 			 "                            new databases (default taken from environment)\n"));
 	printf(_("      --no-locale           equivalent to --locale=C\n"));
+	printf(_("      --max-shared-buffers=MEMORY\n"
+			 "                            maximum shared buffers setting to try, default 128Mb\n"));
 	printf(_("      --pwfile=FILE         read password for the new superuser from file\n"));
 	printf(_("  -T, --text-search-config=CFG\n"
-		 "                            default text search configuration\n"));
+		     "                            default text search configuration\n"));
 	printf(_("  -U, --username=NAME       database superuser name\n"));
 	printf(_("  -W, --pwprompt            prompt for a password for the new superuser\n"));
 	printf(_("  -X, --xlogdir=XLOGDIR     location for the transaction log directory\n"));
@@ -2810,6 +2843,36 @@ check_need_password(const char *authmethodlocal, const char *authmethodhost)
 	}
 }
 
+static void 
+set_max_shared_buffers(const char * arg)
+{
+	long int bufs;
+	char * endptr;
+	bufs = strtol(arg, &endptr, 10);
+
+	if (pg_strcasecmp(endptr,"MB") == 0)
+	{
+		printf("endptr: '%s'\n",endptr);
+		/* convert megabytes to 8k pages */
+		bufs *= ((1024 * 1024) / 8192);
+	}
+	else if (pg_strcasecmp(endptr,"GB") == 0)
+	{
+		/* convert gigabytes to buffers */
+		bufs *= ((1024 * 1024 * 1024) / 8192);
+		printf("endptr: '%s' bufs = %ld\n",endptr,bufs);
+	}
+	else if (*endptr != '\0')
+	{
+		/* no other specified units allowed */
+		fprintf(stderr, _("Invalid specification for chared buffers: '%s', only MB or GB allowed\n"),
+				arg);
+		exit(1);
+	}
+	max_shared_buffers = (int) bufs;
+}
+
+
 int
 main(int argc, char *argv[])
 {
@@ -2828,6 +2891,7 @@ main(int argc, char *argv[])
 		{"lc-time", required_argument, NULL, 6},
 		{"lc-messages", required_argument, NULL, 7},
 		{"no-locale", no_argument, NULL, 8},
+		{"max-shared-buffers", required_argument, NULL, 12},
 		{"text-search-config", required_argument, NULL, 'T'},
 		{"auth", required_argument, NULL, 'A'},
 		{"auth-local", required_argument, NULL, 10},
@@ -2972,6 +3036,9 @@ main(int argc, char *argv[])
 			case 9:
 				pwfilename = xstrdup(optarg);
 				break;
+			case 12:
+				set_max_shared_buffers(optarg);
+				break;
 			case 's':
 				show_setting = true;
 				break;
diff --git a/src/test/regress/pg_regress.c b/src/test/regress/pg_regress.c
index 7d89318..d0f2622 100644
--- a/src/test/regress/pg_regress.c
+++ b/src/test/regress/pg_regress.c
@@ -2150,7 +2150,7 @@ regression_main(int argc, char *argv[], init_function ifunc, test_function tfunc
 		/* initdb */
 		header(_("initializing database system"));
 		snprintf(buf, sizeof(buf),
-				 SYSTEMQUOTE "\"%s/initdb\" -D \"%s/data\" -L \"%s\" --noclean%s%s > \"%s/log/initdb.log\" 2>&1" SYSTEMQUOTE,
+				 SYSTEMQUOTE "\"%s/initdb\" -D \"%s/data\" -L \"%s\" --max-shared-buffers=32mb --noclean%s%s > \"%s/log/initdb.log\" 2>&1" SYSTEMQUOTE,
 				 bindir, temp_install, datadir,
 				 debug ? " --debug" : "",
 				 nolocale ? " --no-locale" : "",