Move ltree parentsel() selectivity function into /contrib/ltree.

3 files changed, 198 insertions, 7 deletions

diff --git a/contrib/ltree/expected/ltree.out b/contrib/ltree/expected/ltree.out
index 3ce1ecf2937..2546490d220 100644
--- a/contrib/ltree/expected/ltree.out
+++ b/contrib/ltree/expected/ltree.out
@@ -2,15 +2,15 @@
 psql:ltree.sql:7: NOTICE:  type "ltree" is not yet defined
 DETAIL:  Creating a shell type definition.
 psql:ltree.sql:12: NOTICE:  argument type ltree is only a shell
-psql:ltree.sql:299: NOTICE:  type "lquery" is not yet defined
+psql:ltree.sql:304: NOTICE:  type "lquery" is not yet defined
 DETAIL:  Creating a shell type definition.
-psql:ltree.sql:304: NOTICE:  argument type lquery is only a shell
-psql:ltree.sql:410: NOTICE:  type "ltxtquery" is not yet defined
+psql:ltree.sql:309: NOTICE:  argument type lquery is only a shell
+psql:ltree.sql:415: NOTICE:  type "ltxtquery" is not yet defined
 DETAIL:  Creating a shell type definition.
-psql:ltree.sql:415: NOTICE:  argument type ltxtquery is only a shell
-psql:ltree.sql:477: NOTICE:  type "ltree_gist" is not yet defined
+psql:ltree.sql:420: NOTICE:  argument type ltxtquery is only a shell
+psql:ltree.sql:482: NOTICE:  type "ltree_gist" is not yet defined
 DETAIL:  Creating a shell type definition.
-psql:ltree.sql:482: NOTICE:  argument type ltree_gist is only a shell
+psql:ltree.sql:487: NOTICE:  argument type ltree_gist is only a shell
 SELECT ''::ltree;
  ltree 
 -------
diff --git a/contrib/ltree/ltree.sql.in b/contrib/ltree/ltree.sql.in
index bdb8bdf52cb..df32c0c501c 100644
--- a/contrib/ltree/ltree.sql.in
+++ b/contrib/ltree/ltree.sql.in
@@ -225,6 +225,11 @@ RETURNS ltree
 AS 'MODULE_PATHNAME'
 LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
 
+CREATE FUNCTION ltreeparentsel(internal, oid, internal, integer)
+RETURNS float8
+AS 'MODULE_PATHNAME'
+LANGUAGE C RETURNS NULL ON NULL INPUT IMMUTABLE;
+
 CREATE OPERATOR @> (
         LEFTARG = ltree,
 	RIGHTARG = ltree,
diff --git a/contrib/ltree/ltree_op.c b/contrib/ltree/ltree_op.c
index ec2d0fbf5de..6b894861dd4 100644
--- a/contrib/ltree/ltree_op.c
+++ b/contrib/ltree/ltree_op.c
@@ -1,12 +1,19 @@
 /*
  * op function for ltree
  * Teodor Sigaev <teodor@stack.net>
- * $PostgreSQL: pgsql/contrib/ltree/ltree_op.c,v 1.9 2006/03/11 04:38:29 momjian Exp $
+ * $PostgreSQL: pgsql/contrib/ltree/ltree_op.c,v 1.10 2006/04/26 22:32:36 momjian Exp $
  */
 
 #include "ltree.h"
 #include <ctype.h>
 
+#include "access/heapam.h"
+#include "catalog/pg_statistic.h"
+#include "nodes/relation.h"
+#include "utils/lsyscache.h"
+#include "utils/selfuncs.h"
+#include "utils/syscache.h"
+
 /* compare functions */
 PG_FUNCTION_INFO_V1(ltree_cmp);
 PG_FUNCTION_INFO_V1(ltree_lt);
@@ -44,6 +51,7 @@ Datum		ltree_textadd(PG_FUNCTION_ARGS);
 Datum		lca(PG_FUNCTION_ARGS);
 Datum		ltree2text(PG_FUNCTION_ARGS);
 Datum		text2ltree(PG_FUNCTION_ARGS);
+Datum		ltreeparentsel(PG_FUNCTION_ARGS);
 
 int
 ltree_compare(const ltree * a, const ltree * b)
@@ -551,3 +559,181 @@ ltree2text(PG_FUNCTION_ARGS)
 
 	PG_RETURN_POINTER(out);
 }
+
+
+#define DEFAULT_PARENT_SEL 0.001
+
+/*
+ *	ltreeparentsel - Selectivity of parent relationship for ltree data types.
+ */
+Datum
+ltreeparentsel(PG_FUNCTION_ARGS)
+{
+	PlannerInfo *root = (PlannerInfo *) PG_GETARG_POINTER(0);
+	Oid			operator = PG_GETARG_OID(1);
+	List	   *args = (List *) PG_GETARG_POINTER(2);
+	int			varRelid = PG_GETARG_INT32(3);
+	VariableStatData vardata;
+	Node	   *other;
+	bool		varonleft;
+	Datum	   *values;
+	int			nvalues;
+	float4	   *numbers;
+	int			nnumbers;
+	double		selec = 0.0;
+
+	/*
+	 * If expression is not variable <@ something or something <@ variable,
+	 * then punt and return a default estimate.
+	 */
+	if (!get_restriction_variable(root, args, varRelid,
+								  &vardata, &other, &varonleft))
+		PG_RETURN_FLOAT8(DEFAULT_PARENT_SEL);
+
+	/*
+	 * If the something is a NULL constant, assume operator is strict and
+	 * return zero, ie, operator will never return TRUE.
+	 */
+	if (IsA(other, Const) &&
+		((Const *) other)->constisnull)
+	{
+		ReleaseVariableStats(vardata);
+		PG_RETURN_FLOAT8(0.0);
+	}
+
+	if (HeapTupleIsValid(vardata.statsTuple))
+	{
+		Form_pg_statistic stats;
+		double		mcvsum = 0.0;
+		double		mcvsel = 0.0;
+		double		hissel = 0.0;
+
+		stats = (Form_pg_statistic) GETSTRUCT(vardata.statsTuple);
+
+		if (IsA(other, Const))
+		{
+			/* Variable is being compared to a known non-null constant */
+			Datum		constval = ((Const *) other)->constvalue;
+			bool		match = false;
+			int			i;
+
+			/*
+			 * Is the constant "<@" to any of the column's most common values?
+			 */
+			if (get_attstatsslot(vardata.statsTuple,
+								 vardata.atttype, vardata.atttypmod,
+								 STATISTIC_KIND_MCV, InvalidOid,
+								 &values, &nvalues,
+								 &numbers, &nnumbers))
+			{
+				FmgrInfo	contproc;
+
+				fmgr_info(get_opcode(operator), &contproc);
+
+				for (i = 0; i < nvalues; i++)
+				{
+					/* be careful to apply operator right way 'round */
+					if (varonleft)
+						match = DatumGetBool(FunctionCall2(&contproc,
+														   values[i],
+														   constval));
+					else
+						match = DatumGetBool(FunctionCall2(&contproc,
+														   constval,
+														   values[i]));
+
+					/* calculate total selectivity of all most-common-values */
+					mcvsum += numbers[i];
+
+					/* calculate selectivity of matching most-common-values */
+					if (match)
+						mcvsel += numbers[i];
+				}
+			}
+			else
+			{
+				/* no most-common-values info available */
+				values = NULL;
+				numbers = NULL;
+				i = nvalues = nnumbers = 0;
+			}
+
+			free_attstatsslot(vardata.atttype, values, nvalues, NULL, 0);
+
+			/*
+			 * Is the constant "<@" to any of the column's histogram values?
+			 */
+			if (get_attstatsslot(vardata.statsTuple,
+								 vardata.atttype, vardata.atttypmod,
+								 STATISTIC_KIND_HISTOGRAM, InvalidOid,
+								 &values, &nvalues,
+								 NULL, NULL))
+			{
+				FmgrInfo	contproc;
+
+				fmgr_info(get_opcode(operator), &contproc);
+
+				for (i = 0; i < nvalues; i++)
+				{
+					/* be careful to apply operator right way 'round */
+					if (varonleft)
+						match = DatumGetBool(FunctionCall2(&contproc,
+														   values[i],
+														   constval));
+					else
+						match = DatumGetBool(FunctionCall2(&contproc,
+														   constval,
+														   values[i]));
+					/* count matching histogram values */
+					if (match)
+						hissel++;
+				}
+
+				if (hissel > 0.0)
+				{
+					/*
+					 * some matching values found inside histogram, divide
+					 * matching entries number by total histogram entries to
+					 * get the histogram related selectivity
+					 */
+					hissel /= nvalues;
+				}
+			}
+			else
+			{
+				/* no histogram info available */
+				values = NULL;
+				i = nvalues = 0;
+			}
+
+			free_attstatsslot(vardata.atttype, values, nvalues,
+							  NULL, 0);
+
+
+			/*
+			 * calculate selectivity based on MCV and histogram result
+			 * histogram selectivity needs to be scaled down if there are any
+			 * most-common-values
+			 */
+			selec = mcvsel + hissel * (1.0 - mcvsum);
+
+			/*
+			 * don't return 0.0 selectivity unless all table values are inside
+			 * mcv
+			 */
+			if (selec == 0.0 && mcvsum != 1.0)
+				selec = DEFAULT_PARENT_SEL;
+		}
+		else
+			selec = DEFAULT_PARENT_SEL;
+	}
+	else
+		selec = DEFAULT_PARENT_SEL;
+
+	ReleaseVariableStats(vardata);
+
+	/* result should be in range, but make sure... */
+	CLAMP_PROBABILITY(selec);
+
+	PG_RETURN_FLOAT8((float8) selec);
+}