diff options
Diffstat (limited to 'src/backend/optimizer/path/clausesel.c')
| -rw-r--r-- | src/backend/optimizer/path/clausesel.c | 88 |
1 files changed, 43 insertions, 45 deletions
diff --git a/src/backend/optimizer/path/clausesel.c b/src/backend/optimizer/path/clausesel.c index aad977164a7..9a4990898e9 100644 --- a/src/backend/optimizer/path/clausesel.c +++ b/src/backend/optimizer/path/clausesel.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.74 2005/10/11 16:44:40 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.75 2005/10/15 02:49:19 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -82,7 +82,7 @@ static void addRangeClause(RangeQueryClause **rqlist, Node *clause, * hisel + losel + null_frac - 1.) * * If either selectivity is exactly DEFAULT_INEQ_SEL, we forget this equation - * and instead use DEFAULT_RANGE_INEQ_SEL. The same applies if the equation + * and instead use DEFAULT_RANGE_INEQ_SEL. The same applies if the equation * yields an impossible (negative) result. * * A free side-effect is that we can recognize redundant inequalities such @@ -102,9 +102,9 @@ clauselist_selectivity(PlannerInfo *root, ListCell *l; /* - * Initial scan over clauses. Anything that doesn't look like a - * potential rangequery clause gets multiplied into s1 and forgotten. - * Anything that does gets inserted into an rqlist entry. + * Initial scan over clauses. Anything that doesn't look like a potential + * rangequery clause gets multiplied into s1 and forgotten. Anything that + * does gets inserted into an rqlist entry. */ foreach(l, clauses) { @@ -127,10 +127,10 @@ clauselist_selectivity(PlannerInfo *root, rinfo = NULL; /* - * See if it looks like a restriction clause with a pseudoconstant - * on one side. (Anything more complicated than that might not - * behave in the simple way we are expecting.) Most of the tests - * here can be done more efficiently with rinfo than without. + * See if it looks like a restriction clause with a pseudoconstant on + * one side. (Anything more complicated than that might not behave in + * the simple way we are expecting.) Most of the tests here can be + * done more efficiently with rinfo than without. */ if (is_opclause(clause) && list_length(((OpExpr *) clause)->args) == 2) { @@ -142,10 +142,10 @@ clauselist_selectivity(PlannerInfo *root, { ok = (bms_membership(rinfo->clause_relids) == BMS_SINGLETON) && (is_pseudo_constant_clause_relids(lsecond(expr->args), - rinfo->right_relids) || + rinfo->right_relids) || (varonleft = false, - is_pseudo_constant_clause_relids(linitial(expr->args), - rinfo->left_relids))); + is_pseudo_constant_clause_relids(linitial(expr->args), + rinfo->left_relids))); } else { @@ -159,8 +159,8 @@ clauselist_selectivity(PlannerInfo *root, { /* * If it's not a "<" or ">" operator, just merge the - * selectivity in generically. But if it's the right - * oprrest, add the clause to rqlist for later processing. + * selectivity in generically. But if it's the right oprrest, + * add the clause to rqlist for later processing. */ switch (get_oprrest(expr->opno)) { @@ -199,8 +199,8 @@ clauselist_selectivity(PlannerInfo *root, /* * Exact equality to the default value probably means the - * selectivity function punted. This is not airtight but - * should be good enough. + * selectivity function punted. This is not airtight but should + * be good enough. */ if (rqlist->hibound == DEFAULT_INEQ_SEL || rqlist->lobound == DEFAULT_INEQ_SEL) @@ -289,8 +289,8 @@ addRangeClause(RangeQueryClause **rqlist, Node *clause, for (rqelem = *rqlist; rqelem; rqelem = rqelem->next) { /* - * We use full equal() here because the "var" might be a function - * of one or more attributes of the same relation... + * We use full equal() here because the "var" might be a function of + * one or more attributes of the same relation... */ if (!equal(var, rqelem->var)) continue; @@ -423,17 +423,16 @@ clause_selectivity(PlannerInfo *root, rinfo = (RestrictInfo *) clause; /* - * If possible, cache the result of the selectivity calculation - * for the clause. We can cache if varRelid is zero or the clause - * contains only vars of that relid --- otherwise varRelid will - * affect the result, so mustn't cache. We also have to be - * careful about the jointype. It's OK to cache when jointype is - * JOIN_INNER or one of the outer join types (any given outer-join - * clause should always be examined with the same jointype, so - * result won't change). It's not OK to cache when jointype is one - * of the special types associated with IN processing, because the - * same clause may be examined with different jointypes and the - * result should vary. + * If possible, cache the result of the selectivity calculation for + * the clause. We can cache if varRelid is zero or the clause + * contains only vars of that relid --- otherwise varRelid will affect + * the result, so mustn't cache. We also have to be careful about the + * jointype. It's OK to cache when jointype is JOIN_INNER or one of + * the outer join types (any given outer-join clause should always be + * examined with the same jointype, so result won't change). It's not + * OK to cache when jointype is one of the special types associated + * with IN processing, because the same clause may be examined with + * different jointypes and the result should vary. */ if (varRelid == 0 || bms_is_subset_singleton(rinfo->clause_relids, varRelid)) @@ -477,8 +476,8 @@ clause_selectivity(PlannerInfo *root, Var *var = (Var *) clause; /* - * We probably shouldn't ever see an uplevel Var here, but if we - * do, return the default selectivity... + * We probably shouldn't ever see an uplevel Var here, but if we do, + * return the default selectivity... */ if (var->varlevelsup == 0 && (varRelid == 0 || varRelid == (int) var->varno)) @@ -488,23 +487,23 @@ clause_selectivity(PlannerInfo *root, if (rte->rtekind == RTE_SUBQUERY) { /* - * XXX not smart about subquery references... any way to - * do better? + * XXX not smart about subquery references... any way to do + * better? */ s1 = 0.5; } else { /* - * A Var at the top of a clause must be a bool Var. This - * is equivalent to the clause reln.attribute = 't', so we + * A Var at the top of a clause must be a bool Var. This is + * equivalent to the clause reln.attribute = 't', so we * compute the selectivity as if that is what we have. */ s1 = restriction_selectivity(root, BooleanEqualOperator, list_make2(var, - makeBoolConst(true, - false)), + makeBoolConst(true, + false)), varRelid); } } @@ -534,7 +533,7 @@ clause_selectivity(PlannerInfo *root, { /* inverse of the selectivity of the underlying clause */ s1 = 1.0 - clause_selectivity(root, - (Node *) get_notclausearg((Expr *) clause), + (Node *) get_notclausearg((Expr *) clause), varRelid, jointype); } @@ -576,17 +575,16 @@ clause_selectivity(PlannerInfo *root, { /* * If we are considering a nestloop join then all clauses are - * restriction clauses, since we are only interested in the - * one relation. + * restriction clauses, since we are only interested in the one + * relation. */ is_join_clause = false; } else { /* - * Otherwise, it's a join if there's more than one relation - * used. We can optimize this calculation if an rinfo was - * passed. + * Otherwise, it's a join if there's more than one relation used. + * We can optimize this calculation if an rinfo was passed. */ if (rinfo) is_join_clause = (bms_membership(rinfo->clause_relids) == @@ -613,8 +611,8 @@ clause_selectivity(PlannerInfo *root, else if (is_funcclause(clause)) { /* - * This is not an operator, so we guess at the selectivity. THIS - * IS A HACK TO GET V4 OUT THE DOOR. FUNCS SHOULD BE ABLE TO HAVE + * This is not an operator, so we guess at the selectivity. THIS IS A + * HACK TO GET V4 OUT THE DOOR. FUNCS SHOULD BE ABLE TO HAVE * SELECTIVITIES THEMSELVES. -- JMH 7/9/92 */ s1 = (Selectivity) 0.3333333; |