1 files changed, 47 insertions, 0 deletions
diff --git a/src/include/statistics/statistics.h b/src/include/statistics/statistics.h
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+++ b/src/include/statistics/statistics.h
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+/*-------------------------------------------------------------------------
+ *
+ * statistics.h
+ *	  Extended statistics and selectivity estimation functions.
+ *
+ * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/statistics/statistics.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STATISTICS_H
+#define STATISTICS_H
+
+#include "commands/vacuum.h"
+
+#define STATS_MAX_DIMENSIONS	8		/* max number of attributes */
+
+/* Multivariate distinct coefficients */
+#define STATS_NDISTINCT_MAGIC		0xA352BFA4	/* struct identifier */
+#define STATS_NDISTINCT_TYPE_BASIC	1	/* struct version */
+
+/* MVDistinctItem represents a single combination of columns */
+typedef struct MVNDistinctItem
+{
+	double		ndistinct;		/* ndistinct value for this combination */
+	Bitmapset  *attrs;			/* attr numbers of items */
+} MVNDistinctItem;
+
+/* A MVNDistinct object, comprising all possible combinations of columns */
+typedef struct MVNDistinct
+{
+	uint32		magic;			/* magic constant marker */
+	uint32		type;			/* type of ndistinct (BASIC) */
+	uint32		nitems;			/* number of items in the statistic */
+	MVNDistinctItem items[FLEXIBLE_ARRAY_MEMBER];
+} MVNDistinct;
+
+extern MVNDistinct *statext_ndistinct_load(Oid mvoid);
+
+extern void BuildRelationExtStatistics(Relation onerel, double totalrows,
+						   int numrows, HeapTuple *rows,
+						   int natts, VacAttrStats **vacattrstats);
+extern bool statext_is_kind_built(HeapTuple htup, char kind);
+
+#endif   /* STATISTICS_H */