v6-0004-Add-pg_export_stats.patch

From fa020383ac1811fb02997b53f0551a8d3ae26329 Mon Sep 17 00:00:00 2001
From: Corey Huinker <corey.huinker@gmail.com>
Date: Tue, 20 Feb 2024 01:14:54 -0500
Subject: [PATCH v6 4/4] Add pg_export_stats.

This is a command-line utility that connects to a database and exports
statistics from all user relations and user statistics objects, printing
SQL statements designed to re-import those statistics into a like-named
object.
---
 src/fe_utils/stats_export.c       |   2 +-
 src/bin/scripts/.gitignore        |   1 +
 src/bin/scripts/Makefile          |   3 +-
 src/bin/scripts/pg_export_stats.c | 267 ++++++++++++++++++++++++++++++
 4 files changed, 271 insertions(+), 2 deletions(-)
 create mode 100644 src/bin/scripts/pg_export_stats.c

diff --git a/src/fe_utils/stats_export.c b/src/fe_utils/stats_export.c
index 1815793c9d..09b4eb240d 100644
--- a/src/fe_utils/stats_export.c
+++ b/src/fe_utils/stats_export.c
@@ -835,7 +835,7 @@ stats_export_print_rel_import(FILE *outf,
 
 	fprintf(outf,
 			"SELECT pg_catalog.pg_import_rel_stats(r.oid, %s::jsonb, %s, %s) "
-			"FROM pg_catalog.pg_catalog.pg_class AS r "
+			"FROM pg_catalog.pg_class AS r "
 			"JOIN pg_catalog.pg_namespace AS n ON n.oid = r.relnamespace "
 			"WHERE n.nspname = %s "
 			"AND r.relname = %s;\n\n",
diff --git a/src/bin/scripts/.gitignore b/src/bin/scripts/.gitignore
index 0f23fe0004..76704a3ad4 100644
--- a/src/bin/scripts/.gitignore
+++ b/src/bin/scripts/.gitignore
@@ -6,5 +6,6 @@
 /reindexdb
 /vacuumdb
 /pg_isready
+/pg_export_stats
 
 /tmp_check/
diff --git a/src/bin/scripts/Makefile b/src/bin/scripts/Makefile
index 9633c99136..dd54faaf2a 100644
--- a/src/bin/scripts/Makefile
+++ b/src/bin/scripts/Makefile
@@ -16,7 +16,7 @@ subdir = src/bin/scripts
 top_builddir = ../../..
 include $(top_builddir)/src/Makefile.global
 
-PROGRAMS = createdb createuser dropdb dropuser clusterdb vacuumdb reindexdb pg_isready
+PROGRAMS = createdb createuser dropdb dropuser clusterdb vacuumdb reindexdb pg_isready pg_export_stats
 
 override CPPFLAGS := -I$(libpq_srcdir) $(CPPFLAGS)
 LDFLAGS_INTERNAL += -L$(top_builddir)/src/fe_utils -lpgfeutils $(libpq_pgport)
@@ -41,6 +41,7 @@ install: all installdirs
 	$(INSTALL_PROGRAM) vacuumdb$(X)   '$(DESTDIR)$(bindir)'/vacuumdb$(X)
 	$(INSTALL_PROGRAM) reindexdb$(X)  '$(DESTDIR)$(bindir)'/reindexdb$(X)
 	$(INSTALL_PROGRAM) pg_isready$(X) '$(DESTDIR)$(bindir)'/pg_isready$(X)
+	$(INSTALL_PROGRAM) pg_export_stats$(X) '$(DESTDIR)$(bindir)'/pg_export_stats$(X)
 
 installdirs:
 	$(MKDIR_P) '$(DESTDIR)$(bindir)'
diff --git a/src/bin/scripts/pg_export_stats.c b/src/bin/scripts/pg_export_stats.c
new file mode 100644
index 0000000000..7fce1ef515
--- /dev/null
+++ b/src/bin/scripts/pg_export_stats.c
@@ -0,0 +1,267 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_export_stats
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/bin/scripts/pg_export_stats.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres_fe.h"
+#include "common.h"
+#include "common/logging.h"
+#include "fe_utils/cancel.h"
+#include "fe_utils/option_utils.h"
+#include "fe_utils/query_utils.h"
+#include "fe_utils/simple_list.h"
+#include "fe_utils/stats_export.h"
+#include "fe_utils/string_utils.h"
+
+static void help(const char *progname);
+
+int
+main(int argc, char *argv[])
+{
+	static struct option long_options[] = {
+		{"host", required_argument, NULL, 'h'},
+		{"port", required_argument, NULL, 'p'},
+		{"username", required_argument, NULL, 'U'},
+		{"no-password", no_argument, NULL, 'w'},
+		{"password", no_argument, NULL, 'W'},
+		{"echo", no_argument, NULL, 'e'},
+		{"dbname", required_argument, NULL, 'd'},
+		{"validate", no_argument, NULL, 'v'},
+		{"require-match", no_argument, NULL, 'm'},
+		{NULL, 0, NULL, 0}
+	};
+
+	const char *progname;
+	int			optindex;
+	int			c;
+
+	bool		validate = false;
+	bool		require_match = false;
+	const char *dbname = NULL;
+	char	   *host = NULL;
+	char	   *port = NULL;
+	char	   *username = NULL;
+	enum trivalue prompt_password = TRI_DEFAULT;
+	ConnParams	cparams;
+	bool		echo = false;
+
+	PQExpBufferData sql;
+
+	PGconn	   *conn;
+	int			server_version_num;
+
+	PGresult   *result;
+
+	ExecStatusType result_status;
+
+	pg_logging_init(argv[0]);
+	progname = get_progname(argv[0]);
+	set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pgscripts"));
+
+	handle_help_version_opts(argc, argv, "pg_export_stats", help);
+
+	while ((c = getopt_long(argc, argv, "d:eh:mp:U:vwW", long_options, &optindex)) != -1)
+	{
+		switch (c)
+		{
+			case 'd':
+				dbname = pg_strdup(optarg);
+				break;
+			case 'e':
+				echo = true;
+				break;
+			case 'h':
+				host = pg_strdup(optarg);
+				break;
+			case 'm':
+				require_match = true;
+				break;
+			case 'p':
+				port = pg_strdup(optarg);
+				break;
+			case 'U':
+				username = pg_strdup(optarg);
+				break;
+			case 'v':
+				validate = true;
+				break;
+			case 'w':
+				prompt_password = TRI_NO;
+				break;
+			case 'W':
+				prompt_password = TRI_YES;
+				break;
+			default:
+				/* getopt_long already emitted a complaint */
+				pg_log_error_hint("Try \"%s --help\" for more information.", progname);
+				exit(1);
+		}
+	}
+
+	/*
+	 * Non-option argument specifies database name as long as it wasn't
+	 * already specified with -d / --dbname
+	 */
+	if (optind < argc && dbname == NULL)
+	{
+		dbname = argv[optind];
+		optind++;
+	}
+
+	if (optind < argc)
+	{
+		pg_log_error("too many command-line arguments (first is \"%s\")",
+					 argv[optind]);
+		pg_log_error_hint("Try \"%s --help\" for more information.", progname);
+		exit(1);
+	}
+
+	/* fill cparams except for dbname, which is set below */
+	cparams.pghost = host;
+	cparams.pgport = port;
+	cparams.pguser = username;
+	cparams.prompt_password = prompt_password;
+	cparams.override_dbname = NULL;
+
+	setup_cancel_handler(NULL);
+
+	if (dbname == NULL)
+	{
+		if (getenv("PGDATABASE"))
+			dbname = getenv("PGDATABASE");
+		else if (getenv("PGUSER"))
+			dbname = getenv("PGUSER");
+		else
+			dbname = get_user_name_or_exit(progname);
+	}
+
+	cparams.dbname = dbname;
+
+	conn = connectDatabase(&cparams, progname, echo, false, true);
+
+	server_version_num = PQserverVersion(conn);
+
+	initPQExpBuffer(&sql);
+
+	/*
+	 * Query catalog for relations, export statistics from each of them,
+	 * and generate a SQL statement to re-import those statistics.
+	 */
+	appendPQExpBufferStr(&sql,
+		"SELECT quote_literal(b.nspname), quote_literal(b.relname), "
+		"       quote_literal(b.stats_json) "
+		"FROM ( SELECT n.nspname, r.relname, ");
+
+	appendPQExpBufferStr(&sql, stats_export_rel_query(server_version_num));
+
+	appendPQExpBufferStr(&sql,
+		"WHERE r.relkind IN ('r', 'm', 'f', 'p', 'i') "
+		"AND r.relpersistence = 'p' "
+		"AND n.nspname NOT IN ('pg_catalog', 'pg_toast', 'information_schema') "
+		"ORDER BY n.nspname, r.relname"
+		") AS b");
+
+	if (echo)
+		printf("%s\n", sql.data);
+
+	result = PQexec(conn, sql.data);
+	result_status = PQresultStatus(result);
+
+	if (result_status != PGRES_TUPLES_OK)
+		pg_fatal("malformed catalog query: %s", PQerrorMessage(conn));
+	else
+	{
+		int nrows = PQntuples(result);
+		int i;
+
+		for (i = 0; i < nrows; i++)
+			stats_export_print_rel_import(stdout,
+										  PQgetvalue(result, i, 0),
+										  PQgetvalue(result, i, 1),
+										  PQgetvalue(result, i, 2),
+										  validate,
+										  require_match);
+	}
+
+	PQclear(result);
+	resetPQExpBuffer(&sql);
+
+	/*
+	 * Query catalog for statistics objects, export statistics from each of
+	 * them, and generate a SQL statement to re-import those statistics.
+	 */
+	appendPQExpBufferStr(&sql,
+		"SELECT quote_literal(b.nspname), quote_literal(b.relname), "
+		"       quote_literal(b.stxname), quote_literal(b.ext_stats_json) "
+		"FROM ( SELECT n.nspname, r.relname, e.stxname, ");
+
+	appendPQExpBufferStr(&sql, stats_export_ext_query(server_version_num));
+
+	appendPQExpBufferStr(&sql,
+		"WHERE r.relkind IN ('r', 'm', 'f', 'p', 'i') "
+		"AND r.relpersistence = 'p' "
+		"AND n.nspname NOT IN ('pg_catalog', 'pg_toast', 'information_schema') "
+		"ORDER BY n.nspname, r.relname, e.stxname "
+		") AS b ");
+
+	if (echo)
+		printf("%s\n", sql.data);
+
+	result = PQexec(conn, sql.data);
+	result_status = PQresultStatus(result);
+
+	if (result_status != PGRES_TUPLES_OK)
+		pg_fatal("malformed catalog query: %s", PQerrorMessage(conn));
+	else
+	{
+		int nrows = PQntuples(result);
+		int i;
+
+		for (i = 0; i < nrows; i++)
+			stats_export_print_ext_import(stdout,
+										  PQgetvalue(result, i, 0),
+										  PQgetvalue(result, i, 1),
+										  PQgetvalue(result, i, 2),
+										  PQgetvalue(result, i, 3),
+										  validate,
+										  require_match);
+	}
+
+	PQclear(result);
+
+	PQfinish(conn);
+	termPQExpBuffer(&sql);
+	exit(0);
+}
+
+
+static void
+help(const char *progname)
+{
+	printf(_("%s export statistics for all objects in a database.\n\n"), progname);
+	printf(_("Usage:\n"));
+	printf(_("  %s [OPTION]... [DBNAME]\n"), progname);
+	printf(_("\nOptions:\n"));
+	printf(_("  -d, --dbname=DBNAME       database to export\n"));
+	printf(_("  -e, --echo                show the commands being sent to the server\n"));
+	printf(_("  -V, --version             output version information, then exit\n"));
+	printf(_("  -?, --help                show this help, then exit\n"));
+	printf(_("  -v, --validate            Import calls generated should set the validate flag\n"));
+	printf(_("  -m, --require-match       Import calls generated should set the require_match flag\n"));
+	printf(_("\nConnection options:\n"));
+	printf(_("  -h, --host=HOSTNAME       database server host or socket directory\n"));
+	printf(_("  -p, --port=PORT           database server port\n"));
+	printf(_("  -U, --username=USERNAME   user name to connect as\n"));
+	printf(_("  -w, --no-password         never prompt for password\n"));
+	printf(_("  -W, --password            force password prompt\n"));
+	printf(_("  --maintenance-db=DBNAME   alternate maintenance database\n"));
+	printf(_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
+	printf(_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL);
+}
-- 
2.43.2