Move information about pgstats kinds into its own header pgstat_kind.h

This includes all the definitions for the various PGSTAT_KIND_* values,
the range allowed for custom stats kinds and some macros related all
that.

One use-case behind this split is the possibility to use this
information for frontend tools, without having to rely on pgstat.h and a
backend footprint.

Author: Michael Paquier
Reviewed-by: Bertrand Drouvot
Discussion: https://postgr.es/m/[email protected]

2 files changed, 73 insertions, 56 deletions

diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 7cd9396aced..3c411ae5194 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -18,6 +18,7 @@
 #include "replication/conflict.h"
 #include "utils/backend_progress.h" /* for backward compatibility */
 #include "utils/backend_status.h"	/* for backward compatibility */
+#include "utils/pgstat_kind.h"
 #include "utils/relcache.h"
 #include "utils/wait_event.h"	/* for backward compatibility */
 
@@ -33,62 +34,6 @@
 /* Default directory to store temporary statistics data in */
 #define PG_STAT_TMP_DIR		"pg_stat_tmp"
 
-/* The types of statistics entries */
-#define PgStat_Kind uint32
-
-/* Range of IDs allowed, for built-in and custom kinds */
-#define PGSTAT_KIND_MIN	1		/* Minimum ID allowed */
-#define PGSTAT_KIND_MAX	256		/* Maximum ID allowed */
-
-/* use 0 for INVALID, to catch zero-initialized data */
-#define PGSTAT_KIND_INVALID 0
-
-/* stats for variable-numbered objects */
-#define PGSTAT_KIND_DATABASE	1	/* database-wide statistics */
-#define PGSTAT_KIND_RELATION	2	/* per-table statistics */
-#define PGSTAT_KIND_FUNCTION	3	/* per-function statistics */
-#define PGSTAT_KIND_REPLSLOT	4	/* per-slot statistics */
-#define PGSTAT_KIND_SUBSCRIPTION	5	/* per-subscription statistics */
-#define PGSTAT_KIND_BACKEND	6	/* per-backend statistics */
-
-/* stats for fixed-numbered objects */
-#define PGSTAT_KIND_ARCHIVER	7
-#define PGSTAT_KIND_BGWRITER	8
-#define PGSTAT_KIND_CHECKPOINTER	9
-#define PGSTAT_KIND_IO	10
-#define PGSTAT_KIND_SLRU	11
-#define PGSTAT_KIND_WAL	12
-
-#define PGSTAT_KIND_BUILTIN_MIN PGSTAT_KIND_DATABASE
-#define PGSTAT_KIND_BUILTIN_MAX PGSTAT_KIND_WAL
-#define PGSTAT_KIND_BUILTIN_SIZE (PGSTAT_KIND_BUILTIN_MAX + 1)
-
-/* Custom stats kinds */
-
-/* Range of IDs allowed for custom stats kinds */
-#define PGSTAT_KIND_CUSTOM_MIN	128
-#define PGSTAT_KIND_CUSTOM_MAX	PGSTAT_KIND_MAX
-#define PGSTAT_KIND_CUSTOM_SIZE	(PGSTAT_KIND_CUSTOM_MAX - PGSTAT_KIND_CUSTOM_MIN + 1)
-
-/*
- * PgStat_Kind to use for extensions that require an ID, but are still in
- * development and have not reserved their own unique kind ID yet. See:
- * https://wiki.postgresql.org/wiki/CustomCumulativeStats
- */
-#define PGSTAT_KIND_EXPERIMENTAL	128
-
-static inline bool
-pgstat_is_kind_builtin(PgStat_Kind kind)
-{
-	return kind >= PGSTAT_KIND_BUILTIN_MIN && kind <= PGSTAT_KIND_BUILTIN_MAX;
-}
-
-static inline bool
-pgstat_is_kind_custom(PgStat_Kind kind)
-{
-	return kind >= PGSTAT_KIND_CUSTOM_MIN && kind <= PGSTAT_KIND_CUSTOM_MAX;
-}
-
 /* Values for track_functions GUC variable --- order is significant! */
 typedef enum TrackFunctionsLevel
 {
diff --git a/src/include/utils/pgstat_kind.h b/src/include/utils/pgstat_kind.h
new file mode 100644
index 00000000000..f44169fd5a3
--- /dev/null
+++ b/src/include/utils/pgstat_kind.h
@@ -0,0 +1,72 @@
+/* ----------
+ *	pgstat_kind.h
+ *
+ *	Definitions related to the statistics kinds for the PostgreSQL
+ *	cumulative statistics system.  Can be included in backend or
+ *	frontend code.
+ *
+ *	Copyright (c) 2001-2025, PostgreSQL Global Development Group
+ *
+ *	src/include/utils/pgstat_kind.h
+ * ----------
+ */
+#ifndef PGSTAT_KIND_H
+#define PGSTAT_KIND_H
+
+/* The types of statistics entries */
+#define PgStat_Kind uint32
+
+/* Range of IDs allowed, for built-in and custom kinds */
+#define PGSTAT_KIND_MIN	1		/* Minimum ID allowed */
+#define PGSTAT_KIND_MAX	256		/* Maximum ID allowed */
+
+/* use 0 for INVALID, to catch zero-initialized data */
+#define PGSTAT_KIND_INVALID 0
+
+/* stats for variable-numbered objects */
+#define PGSTAT_KIND_DATABASE	1	/* database-wide statistics */
+#define PGSTAT_KIND_RELATION	2	/* per-table statistics */
+#define PGSTAT_KIND_FUNCTION	3	/* per-function statistics */
+#define PGSTAT_KIND_REPLSLOT	4	/* per-slot statistics */
+#define PGSTAT_KIND_SUBSCRIPTION	5	/* per-subscription statistics */
+#define PGSTAT_KIND_BACKEND	6	/* per-backend statistics */
+
+/* stats for fixed-numbered objects */
+#define PGSTAT_KIND_ARCHIVER	7
+#define PGSTAT_KIND_BGWRITER	8
+#define PGSTAT_KIND_CHECKPOINTER	9
+#define PGSTAT_KIND_IO	10
+#define PGSTAT_KIND_SLRU	11
+#define PGSTAT_KIND_WAL	12
+
+#define PGSTAT_KIND_BUILTIN_MIN PGSTAT_KIND_DATABASE
+#define PGSTAT_KIND_BUILTIN_MAX PGSTAT_KIND_WAL
+#define PGSTAT_KIND_BUILTIN_SIZE (PGSTAT_KIND_BUILTIN_MAX + 1)
+
+/* Custom stats kinds */
+
+/* Range of IDs allowed for custom stats kinds */
+#define PGSTAT_KIND_CUSTOM_MIN	128
+#define PGSTAT_KIND_CUSTOM_MAX	PGSTAT_KIND_MAX
+#define PGSTAT_KIND_CUSTOM_SIZE	(PGSTAT_KIND_CUSTOM_MAX - PGSTAT_KIND_CUSTOM_MIN + 1)
+
+/*
+ * PgStat_Kind to use for extensions that require an ID, but are still in
+ * development and have not reserved their own unique kind ID yet. See:
+ * https://wiki.postgresql.org/wiki/CustomCumulativeStats
+ */
+#define PGSTAT_KIND_EXPERIMENTAL	128
+
+static inline bool
+pgstat_is_kind_builtin(PgStat_Kind kind)
+{
+	return kind >= PGSTAT_KIND_BUILTIN_MIN && kind <= PGSTAT_KIND_BUILTIN_MAX;
+}
+
+static inline bool
+pgstat_is_kind_custom(PgStat_Kind kind)
+{
+	return kind >= PGSTAT_KIND_CUSTOM_MIN && kind <= PGSTAT_KIND_CUSTOM_MAX;
+}
+
+#endif							/* PGSTAT_KIND_H */