Fix range-query estimation to not double-exclude NULLs, per gripe from
Ray Ontko 28-June-02. Also, fix prefix_selectivity for NAME lefthand variables (it was bogusly assuming binary compatibility), and adjust make_greater_string() to not call pg_mbcliplen() with invalid multibyte data (this last per bug report that I can't find at the moment, but it was in July '02).
This commit is contained in:
Tom Lane
parent
a3cb8746d9
commit
c0f7dcdac1
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/optimizer/path/clausesel.c,v 1.51 2002/06/20 20:29:29 momjian Exp $
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* $Header: /cvsroot/pgsql/src/backend/optimizer/path/clausesel.c,v 1.52 2002/10/19 02:56:16 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -102,7 +102,9 @@ restrictlist_selectivity(Query *root,
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* see that hisel is the fraction of the range below the high bound, while
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* losel is the fraction above the low bound; so hisel can be interpreted
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* directly as a 0..1 value but we need to convert losel to 1-losel before
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* interpreting it as a value. Then the available range is 1-losel to hisel.)
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* interpreting it as a value. Then the available range is 1-losel to hisel.
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* However, this calculation double-excludes nulls, so really we need
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* hisel + losel + null_frac - 1.)
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* If the calculation yields zero or negative, however, we chicken out and
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* use a default estimate; that probably means that one or both
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* selectivities is a default estimate rather than an actual range value.
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@ -199,6 +201,9 @@ clauselist_selectivity(Query *root,
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/* Successfully matched a pair of range clauses */
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Selectivity s2 = rqlist->hibound + rqlist->lobound - 1.0;
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/* Adjust for double-exclusion of NULLs */
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s2 += nulltestsel(root, IS_NULL, rqlist->var, varRelid);
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/*
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* A zero or slightly negative s2 should be converted into a
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* small positive value; we probably are dealing with a very
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@ -503,12 +508,18 @@ clause_selectivity(Query *root,
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else if (IsA(clause, NullTest))
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{
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/* Use node specific selectivity calculation function */
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s1 = nulltestsel(root, (NullTest *) clause, varRelid);
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s1 = nulltestsel(root,
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((NullTest *) clause)->nulltesttype,
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((NullTest *) clause)->arg,
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varRelid);
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}
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else if (IsA(clause, BooleanTest))
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{
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/* Use node specific selectivity calculation function */
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s1 = booltestsel(root, (BooleanTest *) clause, varRelid);
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s1 = booltestsel(root,
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((BooleanTest *) clause)->booltesttype,
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((BooleanTest *) clause)->arg,
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varRelid);
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}
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else if (IsA(clause, RelabelType))
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{
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@ -15,7 +15,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.118 2002/09/20 03:55:40 momjian Exp $
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* $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.119 2002/10/19 02:56:16 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -1007,10 +1007,9 @@ icnlikesel(PG_FUNCTION_ARGS)
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* booltestsel - Selectivity of BooleanTest Node.
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*/
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Selectivity
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booltestsel(Query *root, BooleanTest *clause, int varRelid)
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booltestsel(Query *root, BoolTestType booltesttype, Node *arg, int varRelid)
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{
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Var *var;
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Node *arg;
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Oid relid;
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HeapTuple statsTuple;
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Datum *values;
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@ -1019,10 +1018,6 @@ booltestsel(Query *root, BooleanTest *clause, int varRelid)
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int nnumbers;
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double selec;
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Assert(clause && IsA(clause, BooleanTest));
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arg = (Node *) clause->arg;
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/*
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* Ignore any binary-compatible relabeling (probably unnecessary, but
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* can't hurt)
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@ -1040,7 +1035,7 @@ booltestsel(Query *root, BooleanTest *clause, int varRelid)
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* the possibility of a NULL value when using clause_selectivity,
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* and just assume the value is either TRUE or FALSE.
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*/
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switch (clause->booltesttype)
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switch (booltesttype)
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{
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case IS_UNKNOWN:
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selec = DEFAULT_UNK_SEL;
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@ -1058,7 +1053,7 @@ booltestsel(Query *root, BooleanTest *clause, int varRelid)
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break;
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default:
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elog(ERROR, "booltestsel: unexpected booltesttype %d",
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(int) clause->booltesttype);
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(int) booltesttype);
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selec = 0.0; /* Keep compiler quiet */
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break;
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}
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@ -1107,7 +1102,7 @@ booltestsel(Query *root, BooleanTest *clause, int varRelid)
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*/
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freq_false = 1.0 - freq_true - freq_null;
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switch (clause->booltesttype)
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switch (booltesttype)
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{
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case IS_UNKNOWN:
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/* select only NULL values */
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@ -1135,7 +1130,7 @@ booltestsel(Query *root, BooleanTest *clause, int varRelid)
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break;
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default:
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elog(ERROR, "booltestsel: unexpected booltesttype %d",
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(int) clause->booltesttype);
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(int) booltesttype);
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selec = 0.0; /* Keep compiler quiet */
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break;
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}
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@ -1151,7 +1146,7 @@ booltestsel(Query *root, BooleanTest *clause, int varRelid)
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* Otherwise adjust for null fraction and assume an even split
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* for boolean tests.
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*/
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switch (clause->booltesttype)
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switch (booltesttype)
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{
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case IS_UNKNOWN:
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@ -1176,7 +1171,7 @@ booltestsel(Query *root, BooleanTest *clause, int varRelid)
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break;
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default:
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elog(ERROR, "booltestsel: unexpected booltesttype %d",
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(int) clause->booltesttype);
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(int) booltesttype);
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selec = 0.0; /* Keep compiler quiet */
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break;
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}
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@ -1190,7 +1185,7 @@ booltestsel(Query *root, BooleanTest *clause, int varRelid)
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* No VACUUM ANALYZE stats available, so use a default value.
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* (Note: not much point in recursing to clause_selectivity here.)
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*/
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switch (clause->booltesttype)
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switch (booltesttype)
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{
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case IS_UNKNOWN:
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selec = DEFAULT_UNK_SEL;
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@ -1206,7 +1201,7 @@ booltestsel(Query *root, BooleanTest *clause, int varRelid)
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break;
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default:
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elog(ERROR, "booltestsel: unexpected booltesttype %d",
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(int) clause->booltesttype);
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(int) booltesttype);
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selec = 0.0; /* Keep compiler quiet */
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break;
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}
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@ -1222,19 +1217,16 @@ booltestsel(Query *root, BooleanTest *clause, int varRelid)
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* nulltestsel - Selectivity of NullTest Node.
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*/
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Selectivity
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nulltestsel(Query *root, NullTest *clause, int varRelid)
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nulltestsel(Query *root, NullTestType nulltesttype, Node *arg, int varRelid)
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{
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Var *var;
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Node *arg;
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Oid relid;
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HeapTuple statsTuple;
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double selec;
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double defselec;
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double freq_null;
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Assert(clause && IsA(clause, NullTest));
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switch (clause->nulltesttype)
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switch (nulltesttype)
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{
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case IS_NULL:
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defselec = DEFAULT_UNK_SEL;
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@ -1244,25 +1236,22 @@ nulltestsel(Query *root, NullTest *clause, int varRelid)
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break;
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default:
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elog(ERROR, "nulltestsel: unexpected nulltesttype %d",
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(int) clause->nulltesttype);
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(int) nulltesttype);
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return (Selectivity) 0; /* keep compiler quiet */
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}
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arg = (Node *) clause->arg;
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/*
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* Ignore any binary-compatible relabeling
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*/
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if (IsA(arg, RelabelType))
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arg = ((RelabelType *) arg)->arg;
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if (IsA(arg, Var) &&(varRelid == 0 || varRelid == ((Var *) arg)->varno))
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if (IsA(arg, Var) &&
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(varRelid == 0 || varRelid == ((Var *) arg)->varno))
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var = (Var *) arg;
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else
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{
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/*
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* punt if non-Var argument
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*/
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/* punt if non-Var argument */
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return (Selectivity) defselec;
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}
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@ -1282,7 +1271,7 @@ nulltestsel(Query *root, NullTest *clause, int varRelid)
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stats = (Form_pg_statistic) GETSTRUCT(statsTuple);
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freq_null = stats->stanullfrac;
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switch (clause->nulltesttype)
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switch (nulltesttype)
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{
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case IS_NULL:
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@ -1301,7 +1290,7 @@ nulltestsel(Query *root, NullTest *clause, int varRelid)
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break;
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default:
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elog(ERROR, "nulltestsel: unexpected nulltesttype %d",
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(int) clause->nulltesttype);
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(int) nulltesttype);
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return (Selectivity) 0; /* keep compiler quiet */
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}
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@ -2978,6 +2967,10 @@ prefix_selectivity(Query *root, Var *var, Const *prefixcon)
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else
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prefix = DatumGetCString(DirectFunctionCall1(byteaout, prefixcon->constvalue));
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/* If var is type NAME, must adjust type of comparison constant */
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if (var->vartype == NAMEOID)
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prefixcon = string_to_const(prefix, NAMEOID);
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cmpargs = makeList2(var, prefixcon);
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/* Assume scalargtsel is appropriate for all supported types */
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prefixsel = DatumGetFloat8(DirectFunctionCall4(scalargtsel,
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@ -3014,6 +3007,9 @@ prefix_selectivity(Query *root, Var *var, Const *prefixcon)
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*/
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prefixsel = topsel + prefixsel - 1.0;
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/* Adjust for double-exclusion of NULLs */
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prefixsel += nulltestsel(root, IS_NULL, (Node *) var, var->varno);
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/*
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* A zero or slightly negative prefixsel should be converted into
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* a small positive value; we probably are dealing with a very
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@ -3351,6 +3347,7 @@ make_greater_string(const Const *str_const)
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while (len > 0)
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{
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unsigned char *lastchar = (unsigned char *) (workstr + len - 1);
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unsigned char savelastchar = *lastchar;
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/*
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* Try to generate a larger string by incrementing the last byte.
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@ -3369,6 +3366,9 @@ make_greater_string(const Const *str_const)
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}
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}
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/* restore last byte so we don't confuse pg_mbcliplen */
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*lastchar = savelastchar;
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/*
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* Truncate off the last character, which might be more than 1
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* byte, depending on the character encoding.
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@ -8,7 +8,7 @@
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* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: selfuncs.h,v 1.8 2002/09/04 20:31:46 momjian Exp $
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* $Id: selfuncs.h,v 1.9 2002/10/19 02:56:16 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -66,8 +66,10 @@ extern Datum icregexnejoinsel(PG_FUNCTION_ARGS);
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extern Datum nlikejoinsel(PG_FUNCTION_ARGS);
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extern Datum icnlikejoinsel(PG_FUNCTION_ARGS);
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extern Selectivity booltestsel(Query *root, BooleanTest *clause, int varRelid);
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extern Selectivity nulltestsel(Query *root, NullTest *clause, int varRelid);
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extern Selectivity booltestsel(Query *root, BoolTestType booltesttype,
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Node *arg, int varRelid);
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extern Selectivity nulltestsel(Query *root, NullTestType nulltesttype,
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Node *arg, int varRelid);
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extern void mergejoinscansel(Query *root, Node *clause,
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Selectivity *leftscan,
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