From 954228712310e78e12f48070df066f984dc977f5 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 7 Nov 2007 21:00:37 +0000
Subject: [PATCH] Fix patternsel() and callers to do the right thing for NOT
LIKE and the other negated-match operators. patternsel had been using the
supplied operator as though it were a positive-match operator, and thus
obtaining a wrong result, which was even more wrong after the caller
subtracted it from 1. Seems cleanest to give patternsel an explicit "negate"
argument so that it knows what's going on. Also install the same
factorization scheme for pattern join selectivity estimators; even though
they are just stubs at the moment, this may keep someone from making the same
type of mistake when they get filled out. Per report from Greg Mullane.
Backpatch to 8.2 --- previous releases do not show the problem because
patternsel() doesn't actually use the operator directly.
---
src/backend/utils/adt/selfuncs.c | 109 +++++++++++++++----------------
1 file changed, 52 insertions(+), 57 deletions(-)
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index ad9f662b68d..5bf04d052a6 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -15,7 +15,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.236 2007/08/31 23:35:22 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.237 2007/11/07 21:00:37 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -901,7 +901,7 @@ scalargtsel(PG_FUNCTION_ARGS)
* patternsel - Generic code for pattern-match selectivity.
*/
static double
-patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype)
+patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype, bool negate)
{
PlannerInfo *root = (PlannerInfo *) PG_GETARG_POINTER(0);
Oid operator = PG_GETARG_OID(1);
@@ -921,23 +921,40 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype)
Const *rest = NULL;
double result;
+ /*
+ * If this is for a NOT LIKE or similar operator, get the corresponding
+ * positive-match operator and work with that. Set result to the
+ * correct default estimate, too.
+ */
+ if (negate)
+ {
+ operator = get_negator(operator);
+ if (!OidIsValid(operator))
+ elog(ERROR, "patternsel called for operator without a negator");
+ result = 1.0 - DEFAULT_MATCH_SEL;
+ }
+ else
+ {
+ result = DEFAULT_MATCH_SEL;
+ }
+
/*
* If expression is not variable op constant, then punt and return a
* default estimate.
*/
if (!get_restriction_variable(root, args, varRelid,
&vardata, &other, &varonleft))
- return DEFAULT_MATCH_SEL;
+ return result;
if (!varonleft || !IsA(other, Const))
{
ReleaseVariableStats(vardata);
- return DEFAULT_MATCH_SEL;
+ return result;
}
variable = (Node *) linitial(args);
/*
* If the constant is NULL, assume operator is strict and return zero, ie,
- * operator will never return TRUE.
+ * operator will never return TRUE. (It's zero even for a negator op.)
*/
if (((Const *) other)->constisnull)
{
@@ -956,7 +973,7 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype)
if (consttype != TEXTOID && consttype != BYTEAOID)
{
ReleaseVariableStats(vardata);
- return DEFAULT_MATCH_SEL;
+ return result;
}
/*
@@ -988,7 +1005,7 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype)
break;
default:
ReleaseVariableStats(vardata);
- return DEFAULT_MATCH_SEL;
+ return result;
}
/* divide pattern into fixed prefix and remainder */
@@ -1017,7 +1034,7 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype)
elog(ERROR, "unrecognized consttype: %u",
prefix->consttype);
ReleaseVariableStats(vardata);
- return DEFAULT_MATCH_SEL;
+ return result;
}
prefix = string_to_const(prefixstr, vartype);
pfree(prefixstr);
@@ -1125,7 +1142,7 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype)
ReleaseVariableStats(vardata);
- return result;
+ return negate ? (1.0 - result) : result;
}
/*
@@ -1134,7 +1151,7 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype)
Datum
regexeqsel(PG_FUNCTION_ARGS)
{
- PG_RETURN_FLOAT8(patternsel(fcinfo, Pattern_Type_Regex));
+ PG_RETURN_FLOAT8(patternsel(fcinfo, Pattern_Type_Regex, false));
}
/*
@@ -1143,7 +1160,7 @@ regexeqsel(PG_FUNCTION_ARGS)
Datum
icregexeqsel(PG_FUNCTION_ARGS)
{
- PG_RETURN_FLOAT8(patternsel(fcinfo, Pattern_Type_Regex_IC));
+ PG_RETURN_FLOAT8(patternsel(fcinfo, Pattern_Type_Regex_IC, false));
}
/*
@@ -1152,7 +1169,7 @@ icregexeqsel(PG_FUNCTION_ARGS)
Datum
likesel(PG_FUNCTION_ARGS)
{
- PG_RETURN_FLOAT8(patternsel(fcinfo, Pattern_Type_Like));
+ PG_RETURN_FLOAT8(patternsel(fcinfo, Pattern_Type_Like, false));
}
/*
@@ -1161,7 +1178,7 @@ likesel(PG_FUNCTION_ARGS)
Datum
iclikesel(PG_FUNCTION_ARGS)
{
- PG_RETURN_FLOAT8(patternsel(fcinfo, Pattern_Type_Like_IC));
+ PG_RETURN_FLOAT8(patternsel(fcinfo, Pattern_Type_Like_IC, false));
}
/*
@@ -1170,11 +1187,7 @@ iclikesel(PG_FUNCTION_ARGS)
Datum
regexnesel(PG_FUNCTION_ARGS)
{
- double result;
-
- result = patternsel(fcinfo, Pattern_Type_Regex);
- result = 1.0 - result;
- PG_RETURN_FLOAT8(result);
+ PG_RETURN_FLOAT8(patternsel(fcinfo, Pattern_Type_Regex, true));
}
/*
@@ -1183,11 +1196,7 @@ regexnesel(PG_FUNCTION_ARGS)
Datum
icregexnesel(PG_FUNCTION_ARGS)
{
- double result;
-
- result = patternsel(fcinfo, Pattern_Type_Regex_IC);
- result = 1.0 - result;
- PG_RETURN_FLOAT8(result);
+ PG_RETURN_FLOAT8(patternsel(fcinfo, Pattern_Type_Regex_IC, true));
}
/*
@@ -1196,11 +1205,7 @@ icregexnesel(PG_FUNCTION_ARGS)
Datum
nlikesel(PG_FUNCTION_ARGS)
{
- double result;
-
- result = patternsel(fcinfo, Pattern_Type_Like);
- result = 1.0 - result;
- PG_RETURN_FLOAT8(result);
+ PG_RETURN_FLOAT8(patternsel(fcinfo, Pattern_Type_Like, true));
}
/*
@@ -1209,11 +1214,7 @@ nlikesel(PG_FUNCTION_ARGS)
Datum
icnlikesel(PG_FUNCTION_ARGS)
{
- double result;
-
- result = patternsel(fcinfo, Pattern_Type_Like_IC);
- result = 1.0 - result;
- PG_RETURN_FLOAT8(result);
+ PG_RETURN_FLOAT8(patternsel(fcinfo, Pattern_Type_Like_IC, true));
}
/*
@@ -2081,13 +2082,23 @@ scalargtjoinsel(PG_FUNCTION_ARGS)
PG_RETURN_FLOAT8(DEFAULT_INEQ_SEL);
}
+/*
+ * patternjoinsel - Generic code for pattern-match join selectivity.
+ */
+static double
+patternjoinsel(PG_FUNCTION_ARGS, Pattern_Type ptype, bool negate)
+{
+ /* For the moment we just punt. */
+ return negate ? (1.0 - DEFAULT_MATCH_SEL) : DEFAULT_MATCH_SEL;
+}
+
/*
* regexeqjoinsel - Join selectivity of regular-expression pattern match.
*/
Datum
regexeqjoinsel(PG_FUNCTION_ARGS)
{
- PG_RETURN_FLOAT8(DEFAULT_MATCH_SEL);
+ PG_RETURN_FLOAT8(patternjoinsel(fcinfo, Pattern_Type_Regex, false));
}
/*
@@ -2096,7 +2107,7 @@ regexeqjoinsel(PG_FUNCTION_ARGS)
Datum
icregexeqjoinsel(PG_FUNCTION_ARGS)
{
- PG_RETURN_FLOAT8(DEFAULT_MATCH_SEL);
+ PG_RETURN_FLOAT8(patternjoinsel(fcinfo, Pattern_Type_Regex_IC, false));
}
/*
@@ -2105,7 +2116,7 @@ icregexeqjoinsel(PG_FUNCTION_ARGS)
Datum
likejoinsel(PG_FUNCTION_ARGS)
{
- PG_RETURN_FLOAT8(DEFAULT_MATCH_SEL);
+ PG_RETURN_FLOAT8(patternjoinsel(fcinfo, Pattern_Type_Like, false));
}
/*
@@ -2114,7 +2125,7 @@ likejoinsel(PG_FUNCTION_ARGS)
Datum
iclikejoinsel(PG_FUNCTION_ARGS)
{
- PG_RETURN_FLOAT8(DEFAULT_MATCH_SEL);
+ PG_RETURN_FLOAT8(patternjoinsel(fcinfo, Pattern_Type_Like_IC, false));
}
/*
@@ -2123,11 +2134,7 @@ iclikejoinsel(PG_FUNCTION_ARGS)
Datum
regexnejoinsel(PG_FUNCTION_ARGS)
{
- float8 result;
-
- result = DatumGetFloat8(regexeqjoinsel(fcinfo));
- result = 1.0 - result;
- PG_RETURN_FLOAT8(result);
+ PG_RETURN_FLOAT8(patternjoinsel(fcinfo, Pattern_Type_Regex, true));
}
/*
@@ -2136,11 +2143,7 @@ regexnejoinsel(PG_FUNCTION_ARGS)
Datum
icregexnejoinsel(PG_FUNCTION_ARGS)
{
- float8 result;
-
- result = DatumGetFloat8(icregexeqjoinsel(fcinfo));
- result = 1.0 - result;
- PG_RETURN_FLOAT8(result);
+ PG_RETURN_FLOAT8(patternjoinsel(fcinfo, Pattern_Type_Regex_IC, true));
}
/*
@@ -2149,11 +2152,7 @@ icregexnejoinsel(PG_FUNCTION_ARGS)
Datum
nlikejoinsel(PG_FUNCTION_ARGS)
{
- float8 result;
-
- result = DatumGetFloat8(likejoinsel(fcinfo));
- result = 1.0 - result;
- PG_RETURN_FLOAT8(result);
+ PG_RETURN_FLOAT8(patternjoinsel(fcinfo, Pattern_Type_Like, true));
}
/*
@@ -2162,11 +2161,7 @@ nlikejoinsel(PG_FUNCTION_ARGS)
Datum
icnlikejoinsel(PG_FUNCTION_ARGS)
{
- float8 result;
-
- result = DatumGetFloat8(iclikejoinsel(fcinfo));
- result = 1.0 - result;
- PG_RETURN_FLOAT8(result);
+ PG_RETURN_FLOAT8(patternjoinsel(fcinfo, Pattern_Type_Like_IC, true));
}
/*
--
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