diff options
| -rw-r--r-- | src/backend/utils/adt/selfuncs.c | 163 |
1 files changed, 103 insertions, 60 deletions
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c index 6e491bbc21e..52d0e48995a 100644 --- a/src/backend/utils/adt/selfuncs.c +++ b/src/backend/utils/adt/selfuncs.c @@ -154,12 +154,13 @@ get_relation_stats_hook_type get_relation_stats_hook = NULL; get_index_stats_hook_type get_index_stats_hook = NULL; +static double eqsel_internal(PG_FUNCTION_ARGS, bool negate); static double var_eq_const(VariableStatData *vardata, Oid operator, Datum constval, bool constisnull, - bool varonleft); + bool varonleft, bool negate); static double var_eq_non_const(VariableStatData *vardata, Oid operator, Node *other, - bool varonleft); + bool varonleft, bool negate); static double ineq_histogram_selectivity(PlannerInfo *root, VariableStatData *vardata, FmgrInfo *opproc, bool isgt, @@ -227,6 +228,15 @@ static List *add_predicate_to_quals(IndexOptInfo *index, List *indexQuals); Datum eqsel(PG_FUNCTION_ARGS) { + PG_RETURN_FLOAT8((float8) eqsel_internal(fcinfo, false)); +} + +/* + * Common code for eqsel() and neqsel() + */ +static double +eqsel_internal(PG_FUNCTION_ARGS, bool negate) +{ PlannerInfo *root = (PlannerInfo *) PG_GETARG_POINTER(0); Oid operator = PG_GETARG_OID(1); List *args = (List *) PG_GETARG_POINTER(2); @@ -237,12 +247,26 @@ eqsel(PG_FUNCTION_ARGS) double selec; /* + * When asked about <>, we do the estimation using the corresponding = + * operator, then convert to <> via "1.0 - eq_selectivity - nullfrac". + */ + if (negate) + { + operator = get_negator(operator); + if (!OidIsValid(operator)) + { + /* Use default selectivity (should we raise an error instead?) */ + return 1.0 - DEFAULT_EQ_SEL; + } + } + + /* * 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_EQ_SEL); + return negate ? (1.0 - DEFAULT_EQ_SEL) : DEFAULT_EQ_SEL; /* * We can do a lot better if the something is a constant. (Note: the @@ -253,14 +277,14 @@ eqsel(PG_FUNCTION_ARGS) selec = var_eq_const(&vardata, operator, ((Const *) other)->constvalue, ((Const *) other)->constisnull, - varonleft); + varonleft, negate); else selec = var_eq_non_const(&vardata, operator, other, - varonleft); + varonleft, negate); ReleaseVariableStats(vardata); - PG_RETURN_FLOAT8((float8) selec); + return selec; } /* @@ -271,20 +295,33 @@ eqsel(PG_FUNCTION_ARGS) static double var_eq_const(VariableStatData *vardata, Oid operator, Datum constval, bool constisnull, - bool varonleft) + bool varonleft, bool negate) { double selec; + double nullfrac = 0.0; bool isdefault; Oid opfuncoid; /* * 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 (constisnull) return 0.0; /* + * Grab the nullfrac for use below. Note we allow use of nullfrac + * regardless of security check. + */ + if (HeapTupleIsValid(vardata->statsTuple)) + { + Form_pg_statistic stats; + + stats = (Form_pg_statistic) GETSTRUCT(vardata->statsTuple); + nullfrac = stats->stanullfrac; + } + + /* * If we matched the var to a unique index or DISTINCT clause, assume * there is exactly one match regardless of anything else. (This is * slightly bogus, since the index or clause's equality operator might be @@ -292,11 +329,12 @@ var_eq_const(VariableStatData *vardata, Oid operator, * ignoring the information.) */ if (vardata->isunique && vardata->rel && vardata->rel->tuples >= 1.0) - return 1.0 / vardata->rel->tuples; - - if (HeapTupleIsValid(vardata->statsTuple) && - statistic_proc_security_check(vardata, - (opfuncoid = get_opcode(operator)))) + { + selec = 1.0 / vardata->rel->tuples; + } + else if (HeapTupleIsValid(vardata->statsTuple) && + statistic_proc_security_check(vardata, + (opfuncoid = get_opcode(operator)))) { Form_pg_statistic stats; AttStatsSlot sslot; @@ -363,7 +401,7 @@ var_eq_const(VariableStatData *vardata, Oid operator, for (i = 0; i < sslot.nnumbers; i++) sumcommon += sslot.numbers[i]; - selec = 1.0 - sumcommon - stats->stanullfrac; + selec = 1.0 - sumcommon - nullfrac; CLAMP_PROBABILITY(selec); /* @@ -396,6 +434,10 @@ var_eq_const(VariableStatData *vardata, Oid operator, selec = 1.0 / get_variable_numdistinct(vardata, &isdefault); } + /* now adjust if we wanted <> rather than = */ + if (negate) + selec = 1.0 - selec - nullfrac; + /* result should be in range, but make sure... */ CLAMP_PROBABILITY(selec); @@ -408,12 +450,24 @@ var_eq_const(VariableStatData *vardata, Oid operator, static double var_eq_non_const(VariableStatData *vardata, Oid operator, Node *other, - bool varonleft) + bool varonleft, bool negate) { double selec; + double nullfrac = 0.0; bool isdefault; /* + * Grab the nullfrac for use below. + */ + if (HeapTupleIsValid(vardata->statsTuple)) + { + Form_pg_statistic stats; + + stats = (Form_pg_statistic) GETSTRUCT(vardata->statsTuple); + nullfrac = stats->stanullfrac; + } + + /* * If we matched the var to a unique index or DISTINCT clause, assume * there is exactly one match regardless of anything else. (This is * slightly bogus, since the index or clause's equality operator might be @@ -421,9 +475,10 @@ var_eq_non_const(VariableStatData *vardata, Oid operator, * ignoring the information.) */ if (vardata->isunique && vardata->rel && vardata->rel->tuples >= 1.0) - return 1.0 / vardata->rel->tuples; - - if (HeapTupleIsValid(vardata->statsTuple)) + { + selec = 1.0 / vardata->rel->tuples; + } + else if (HeapTupleIsValid(vardata->statsTuple)) { Form_pg_statistic stats; double ndistinct; @@ -441,7 +496,7 @@ var_eq_non_const(VariableStatData *vardata, Oid operator, * values, regardless of their frequency in the table. Is that a good * idea?) */ - selec = 1.0 - stats->stanullfrac; + selec = 1.0 - nullfrac; ndistinct = get_variable_numdistinct(vardata, &isdefault); if (ndistinct > 1) selec /= ndistinct; @@ -469,6 +524,10 @@ var_eq_non_const(VariableStatData *vardata, Oid operator, selec = 1.0 / get_variable_numdistinct(vardata, &isdefault); } + /* now adjust if we wanted <> rather than = */ + if (negate) + selec = 1.0 - selec - nullfrac; + /* result should be in range, but make sure... */ CLAMP_PROBABILITY(selec); @@ -485,33 +544,7 @@ var_eq_non_const(VariableStatData *vardata, Oid operator, Datum neqsel(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); - Oid eqop; - float8 result; - - /* - * We want 1 - eqsel() where the equality operator is the one associated - * with this != operator, that is, its negator. - */ - eqop = get_negator(operator); - if (eqop) - { - result = DatumGetFloat8(DirectFunctionCall4(eqsel, - PointerGetDatum(root), - ObjectIdGetDatum(eqop), - PointerGetDatum(args), - Int32GetDatum(varRelid))); - } - else - { - /* Use default selectivity (should we raise an error instead?) */ - result = DEFAULT_EQ_SEL; - } - result = 1.0 - result; - PG_RETURN_FLOAT8(result); + PG_RETURN_FLOAT8((float8) eqsel_internal(fcinfo, true)); } /* @@ -1114,6 +1147,7 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype, bool negate) Const *patt; Const *prefix = NULL; Selectivity rest_selec = 0; + double nullfrac = 0.0; double result; /* @@ -1203,6 +1237,17 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype, bool negate) } /* + * Grab the nullfrac for use below. + */ + if (HeapTupleIsValid(vardata.statsTuple)) + { + Form_pg_statistic stats; + + stats = (Form_pg_statistic) GETSTRUCT(vardata.statsTuple); + nullfrac = stats->stanullfrac; + } + + /* * Pull out any fixed prefix implied by the pattern, and estimate the * fractional selectivity of the remainder of the pattern. Unlike many of * the other functions in this file, we use the pattern operator's actual @@ -1252,7 +1297,7 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype, bool negate) if (eqopr == InvalidOid) elog(ERROR, "no = operator for opfamily %u", opfamily); result = var_eq_const(&vardata, eqopr, prefix->constvalue, - false, true); + false, true, false); } else { @@ -1275,8 +1320,7 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype, bool negate) Selectivity selec; int hist_size; FmgrInfo opproc; - double nullfrac, - mcv_selec, + double mcv_selec, sumcommon; /* Try to use the histogram entries to get selectivity */ @@ -1328,11 +1372,6 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype, bool negate) mcv_selec = mcv_selectivity(&vardata, &opproc, constval, true, &sumcommon); - if (HeapTupleIsValid(vardata.statsTuple)) - nullfrac = ((Form_pg_statistic) GETSTRUCT(vardata.statsTuple))->stanullfrac; - else - nullfrac = 0.0; - /* * Now merge the results from the MCV and histogram calculations, * realizing that the histogram covers only the non-null values that @@ -1340,12 +1379,16 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype, bool negate) */ selec *= 1.0 - nullfrac - sumcommon; selec += mcv_selec; - - /* result should be in range, but make sure... */ - CLAMP_PROBABILITY(selec); result = selec; } + /* now adjust if we wanted not-match rather than match */ + if (negate) + result = 1.0 - result - nullfrac; + + /* result should be in range, but make sure... */ + CLAMP_PROBABILITY(result); + if (prefix) { pfree(DatumGetPointer(prefix->constvalue)); @@ -1354,7 +1397,7 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype, bool negate) ReleaseVariableStats(vardata); - return negate ? (1.0 - result) : result; + return result; } /* @@ -1451,7 +1494,7 @@ boolvarsel(PlannerInfo *root, Node *arg, int varRelid) * compute the selectivity as if that is what we have. */ selec = var_eq_const(&vardata, BooleanEqualOperator, - BoolGetDatum(true), false, true); + BoolGetDatum(true), false, true, false); } else if (is_funcclause(arg)) { @@ -5788,7 +5831,7 @@ prefix_selectivity(PlannerInfo *root, VariableStatData *vardata, if (cmpopr == InvalidOid) elog(ERROR, "no = operator for opfamily %u", opfamily); eq_sel = var_eq_const(vardata, cmpopr, prefixcon->constvalue, - false, true); + false, true, false); prefixsel = Max(prefixsel, eq_sel); |