diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/optimizer/path/clausesel.c | 25 | ||||
| -rw-r--r-- | src/backend/optimizer/util/clauses.c | 28 | ||||
| -rw-r--r-- | src/backend/optimizer/util/plancat.c | 8 | ||||
| -rw-r--r-- | src/backend/utils/adt/selfuncs.c | 32 | ||||
| -rw-r--r-- | src/backend/utils/cache/lsyscache.c | 10 |
5 files changed, 66 insertions, 37 deletions
diff --git a/src/backend/optimizer/path/clausesel.c b/src/backend/optimizer/path/clausesel.c index 23998a54bff..5264d508342 100644 --- a/src/backend/optimizer/path/clausesel.c +++ b/src/backend/optimizer/path/clausesel.c @@ -7,7 +7,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/clausesel.c,v 1.25 1999/07/25 23:07:24 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/clausesel.c,v 1.26 1999/09/09 02:35:47 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -230,24 +230,24 @@ compute_clause_selec(Query *root, Node *clause) int flag; get_relattval(clause, 0, &relidx, &attno, &constval, &flag); - if (relidx <= 0 || attno <= 0) + if (relidx && attno) + s1 = (Cost) restriction_selectivity(oprrest, + opno, + getrelid(relidx, + root->rtable), + attno, + constval, + flag); + else { /* - * attno can be Invalid if the clause had a function in it, + * attno can be 0 if the clause had a function in it, * i.e. WHERE myFunc(f) = 10 * * XXX should be FIXED to use function selectivity */ s1 = (Cost) (0.5); } - else - s1 = (Cost) restriction_selectivity(oprrest, - opno, - getrelid(relidx, - root->rtable), - attno, - constval, - flag); } } else @@ -274,7 +274,8 @@ compute_clause_selec(Query *root, Node *clause) attno2; get_rels_atts(clause, &relid1, &attno1, &relid2, &attno2); - if (relid1 > 0 && relid2 > 0 && attno1 > 0 && attno2 > 0) + if (relid1 && relid2 && attno1 && attno2) + s1 = (Cost) join_selectivity(oprjoin, opno, getrelid(relid1, diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c index 1ab09217c59..876a0dafb72 100644 --- a/src/backend/optimizer/util/clauses.c +++ b/src/backend/optimizer/util/clauses.c @@ -7,7 +7,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.50 1999/08/26 05:09:05 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.51 1999/09/09 02:35:53 tgl Exp $ * * HISTORY * AUTHOR DATE MAJOR EVENT @@ -116,7 +116,10 @@ make_opclause(Oper *op, Var *leftop, Var *rightop) * * Returns the left operand of a clause of the form (op expr expr) * or (op expr) - * NB: it is assumed (for now) that all expr must be Var nodes + * + * NB: for historical reasons, the result is declared Var *, even + * though many callers can cope with results that are not Vars. + * The result really ought to be declared Expr * or Node *. */ Var * get_leftop(Expr *clause) @@ -549,8 +552,11 @@ NumRelids(Node *clause) * if the "something" is a constant, the value of the constant * flags indicating whether a constant was found, and on which side. * Default values are returned if the expression is too complicated, - * specifically -1 for the relid and attno, 0 for the constant value. - * Note that InvalidAttrNumber is *not* -1, but 0. + * specifically 0 for the relid and attno, 0 for the constant value. + * + * Note that negative attno values are *not* invalid, but represent + * system attributes such as OID. It's sufficient to check for relid=0 + * to determine whether the routine succeeded. */ void get_relattval(Node *clause, @@ -610,8 +616,8 @@ get_relattval(Node *clause, { /* Duh, it's too complicated for me... */ default_results: - *relid = -1; - *attno = -1; + *relid = 0; + *attno = 0; *constval = 0; *flag = 0; return; @@ -663,7 +669,7 @@ static int is_single_func(Node *node) * for a joinclause. * * If the clause is not of the form (var op var) or if any of the vars - * refer to nested attributes, then -1's are returned. + * refer to nested attributes, then zeroes are returned. * */ void @@ -674,10 +680,10 @@ get_rels_atts(Node *clause, AttrNumber *attno2) { /* set default values */ - *relid1 = -1; - *attno1 = -1; - *relid2 = -1; - *attno2 = -1; + *relid1 = 0; + *attno1 = 0; + *relid2 = 0; + *attno2 = 0; if (is_opclause(clause)) { diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c index a428e027f61..9ca188bce62 100644 --- a/src/backend/optimizer/util/plancat.c +++ b/src/backend/optimizer/util/plancat.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.36 1999/07/25 23:07:26 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.37 1999/09/09 02:35:53 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -288,7 +288,7 @@ index_selectivity(Query *root, } /* - * restriction_selectivity in lisp system. + * restriction_selectivity * * NOTE: The routine is now merged with RestrictionClauseSelectivity * as defined in plancat.c @@ -298,7 +298,7 @@ index_selectivity(Query *root, * operator relation, by calling the function manager. * * XXX The assumption in the selectivity procedures is that if the - * relation OIDs or attribute numbers are -1, then the clause + * relation OIDs or attribute numbers are 0, then the clause * isn't of the form (op var const). */ Cost @@ -337,7 +337,7 @@ restriction_selectivity(Oid functionObjectId, * information. * * XXX The assumption in the selectivity procedures is that if the - * relation OIDs or attribute numbers are -1, then the clause + * relation OIDs or attribute numbers are 0, then the clause * isn't of the form (op var var). */ Cost diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c index 883da87a275..1b2d58c075e 100644 --- a/src/backend/utils/adt/selfuncs.c +++ b/src/backend/utils/adt/selfuncs.c @@ -10,7 +10,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.39 1999/08/21 00:56:18 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.40 1999/09/09 02:35:58 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -31,7 +31,7 @@ #include "utils/syscache.h" /* N is not a valid var/constant or relation id */ -#define NONVALUE(N) ((N) == -1) +#define NONVALUE(N) ((N) == 0) /* are we looking at a functional index selectivity request? */ #define FunctionalSelectivity(nIndKeys,attNum) ((attNum)==InvalidAttrNumber) @@ -170,7 +170,9 @@ eqsel(Oid opid, else { /* No VACUUM ANALYZE stats available, so make a guess using - * the disbursion stat (if we have that, which is unlikely...) + * the disbursion stat (if we have that, which is unlikely + * for a normal attribute; but for a system attribute we may + * be able to estimate it). */ selec = get_attdisbursion(relid, attno, 0.01); } @@ -366,7 +368,7 @@ eqjoinsel(Oid opid, float64 result; float64data num1, num2, - max; + min; result = (float64) palloc(sizeof(float64data)); if (NONVALUE(attno1) || NONVALUE(relid1) || @@ -376,11 +378,23 @@ eqjoinsel(Oid opid, { num1 = get_attdisbursion(relid1, attno1, 0.01); num2 = get_attdisbursion(relid2, attno2, 0.01); - max = (num1 > num2) ? num1 : num2; - if (max <= 0) - *result = 1.0; - else - *result = max; + /* + * The join selectivity cannot be more than num2, since each + * tuple in table 1 could match no more than num2 fraction of + * tuples in table 2 (and that's only if the table-1 tuple + * matches the most common value in table 2, so probably it's + * less). By the same reasoning it is not more than num1. + * The min is therefore an upper bound. + * + * XXX can we make a better estimate here? Using the nullfrac + * statistic might be helpful, for example. Assuming the operator + * is strict (does not succeed for null inputs) then the selectivity + * couldn't be more than (1-nullfrac1)*(1-nullfrac2), which might + * be usefully small if there are many nulls. How about applying + * the operator to the most common values? + */ + min = (num1 < num2) ? num1 : num2; + *result = min; } return result; } diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c index 4f9cd3fefa7..75994a31f27 100644 --- a/src/backend/utils/cache/lsyscache.c +++ b/src/backend/utils/cache/lsyscache.c @@ -6,7 +6,7 @@ * Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.33 1999/08/16 02:06:25 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.34 1999/09/09 02:36:04 tgl Exp $ * * NOTES * Eventually, the index information should go through here, too. @@ -224,6 +224,14 @@ get_attdisbursion(Oid relid, AttrNumber attnum, double min_estimate) return 1.0 / (double) ntuples; /* + * VACUUM ANALYZE does not compute disbursion for system attributes, + * but some of them can reasonably be assumed unique anyway. + */ + if (attnum == ObjectIdAttributeNumber || + attnum == SelfItemPointerAttributeNumber) + return 1.0 / (double) ntuples; + + /* * VACUUM ANALYZE has not been run for this table. * Produce an estimate = 1/numtuples. This may produce * unreasonably small estimates for large tables, so limit |