diff --git a/src/backend/optimizer/path/clausesel.c b/src/backend/optimizer/path/clausesel.c new file mode 100644 index 37a735b..b88b29e --- a/src/backend/optimizer/path/clausesel.c +++ b/src/backend/optimizer/path/clausesel.c @@ -44,6 +44,12 @@ static void addRangeClause(RangeQueryCla bool varonleft, bool isLTsel, Selectivity s2); static RelOptInfo *find_single_rel_for_clauses(PlannerInfo *root, List *clauses); +static Selectivity clauselist_selectivity_or(PlannerInfo *root, + List *clauses, + int varRelid, + JoinType jointype, + SpecialJoinInfo *sjinfo, + bool use_extended_stats); /**************************************************************************** * ROUTINES TO COMPUTE SELECTIVITIES @@ -61,64 +67,10 @@ static RelOptInfo *find_single_rel_for_c * * The basic approach is to apply extended statistics first, on as many * clauses as possible, in order to capture cross-column dependencies etc. - * The remaining clauses are then estimated using regular statistics tracked - * for individual columns. This is done by simply passing the clauses to - * clauselist_selectivity_simple. - */ -Selectivity -clauselist_selectivity(PlannerInfo *root, - List *clauses, - int varRelid, - JoinType jointype, - SpecialJoinInfo *sjinfo) -{ - Selectivity s1 = 1.0; - RelOptInfo *rel; - Bitmapset *estimatedclauses = NULL; - - /* - * Determine if these clauses reference a single relation. If so, and if - * it has extended statistics, try to apply those. - */ - rel = find_single_rel_for_clauses(root, clauses); - if (rel && rel->rtekind == RTE_RELATION && rel->statlist != NIL) - { - /* - * Estimate as many clauses as possible using extended statistics. - * - * 'estimatedclauses' tracks the 0-based list position index of - * clauses that we've estimated using extended statistics, and that - * should be ignored. - */ - s1 *= statext_clauselist_selectivity(root, clauses, varRelid, - jointype, sjinfo, rel, - &estimatedclauses); - } - - /* - * Apply normal selectivity estimates for the remaining clauses, passing - * 'estimatedclauses' so that it skips already estimated ones. - */ - return s1 * clauselist_selectivity_simple(root, clauses, varRelid, - jointype, sjinfo, - estimatedclauses); -} - -/* - * clauselist_selectivity_simple - - * Compute the selectivity of an implicitly-ANDed list of boolean - * expression clauses. The list can be empty, in which case 1.0 - * must be returned. List elements may be either RestrictInfos - * or bare expression clauses --- the former is preferred since - * it allows caching of results. The estimatedclauses bitmap tracks - * clauses that have already been estimated by other means. - * - * See clause_selectivity() for the meaning of the additional parameters. - * - * Our basic approach is to take the product of the selectivities of the - * subclauses. However, that's only right if the subclauses have independent - * probabilities, and in reality they are often NOT independent. So, - * we want to be smarter where we can. + * The remaining clauses are then estimated by taking the product of their + * selectivities, but that's only right if they have independent + * probabilities, and in reality they are often NOT independent even if they + * only refer to a single column. So, we want to be smarter where we can. * * We also recognize "range queries", such as "x > 34 AND x < 42". Clauses * are recognized as possible range query components if they are restriction @@ -147,28 +99,68 @@ clauselist_selectivity(PlannerInfo *root * selectivity functions; perhaps some day we can generalize the approach. */ Selectivity -clauselist_selectivity_simple(PlannerInfo *root, - List *clauses, - int varRelid, - JoinType jointype, - SpecialJoinInfo *sjinfo, - Bitmapset *estimatedclauses) +clauselist_selectivity(PlannerInfo *root, + List *clauses, + int varRelid, + JoinType jointype, + SpecialJoinInfo *sjinfo) +{ + return clauselist_selectivity_ext(root, clauses, varRelid, + jointype, sjinfo, true); +} + +/* + * clauselist_selectivity_ext - + * Extended version of clauselist_selectivity(). If "use_extended_stats" + * is false, all extended statistics will be ignored, and only per-column + * statistics will be used. + */ +Selectivity +clauselist_selectivity_ext(PlannerInfo *root, + List *clauses, + int varRelid, + JoinType jointype, + SpecialJoinInfo *sjinfo, + bool use_extended_stats) { Selectivity s1 = 1.0; + RelOptInfo *rel; + Bitmapset *estimatedclauses = NULL; RangeQueryClause *rqlist = NULL; ListCell *l; int listidx; /* - * If there's exactly one clause (and it was not estimated yet), just go - * directly to clause_selectivity(). None of what we might do below is - * relevant. + * If there's exactly one clause, just go directly to + * clause_selectivity_ext(). None of what we might do below is relevant. */ - if (list_length(clauses) == 1 && bms_is_empty(estimatedclauses)) - return clause_selectivity(root, (Node *) linitial(clauses), - varRelid, jointype, sjinfo); + if (list_length(clauses) == 1) + return clause_selectivity_ext(root, (Node *) linitial(clauses), + varRelid, jointype, sjinfo, + use_extended_stats); /* + * Determine if these clauses reference a single relation. If so, and if + * it has extended statistics, try to apply those. + */ + rel = find_single_rel_for_clauses(root, clauses); + if (use_extended_stats && rel && rel->rtekind == RTE_RELATION && rel->statlist != NIL) + { + /* + * Estimate as many clauses as possible using extended statistics. + * + * 'estimatedclauses' is populated with the 0-based list position + * index of clauses estimated here, and that should be ignored below. + */ + s1 = statext_clauselist_selectivity(root, clauses, varRelid, + jointype, sjinfo, rel, + &estimatedclauses, false); + } + + /* + * Apply normal selectivity estimates for remaining clauses. We'll be + * careful to skip any clauses which were already estimated above. + * * 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. @@ -189,8 +181,9 @@ clauselist_selectivity_simple(PlannerInf if (bms_is_member(listidx, estimatedclauses)) continue; - /* Always compute the selectivity using clause_selectivity */ - s2 = clause_selectivity(root, clause, varRelid, jointype, sjinfo); + /* Compute the selectivity of this clause in isolation */ + s2 = clause_selectivity_ext(root, clause, varRelid, jointype, sjinfo, + use_extended_stats); /* * Check for being passed a RestrictInfo. @@ -351,6 +344,83 @@ clauselist_selectivity_simple(PlannerInf } /* + * clauselist_selectivity_or - + * Compute the selectivity of an implicitly-ORed list of boolean + * expression clauses. The list can be empty, in which case 0.0 + * must be returned. List elements may be either RestrictInfos + * or bare expression clauses --- the former is preferred since + * it allows caching of results. + * + * See clause_selectivity() for the meaning of the additional parameters. + * + * The basic approach is to apply extended statistics first, on as many + * clauses as possible, in order to capture cross-column dependencies etc. + * The remaining clauses are then estimated as if they were independent. + */ +static Selectivity +clauselist_selectivity_or(PlannerInfo *root, + List *clauses, + int varRelid, + JoinType jointype, + SpecialJoinInfo *sjinfo, + bool use_extended_stats) +{ + Selectivity s1 = 0.0; + RelOptInfo *rel; + Bitmapset *estimatedclauses = NULL; + ListCell *lc; + int listidx; + + /* + * Determine if these clauses reference a single relation. If so, and if + * it has extended statistics, try to apply those. + */ + rel = find_single_rel_for_clauses(root, clauses); + if (use_extended_stats && rel && rel->rtekind == RTE_RELATION && rel->statlist != NIL) + { + /* + * Estimate as many clauses as possible using extended statistics. + * + * 'estimatedclauses' is populated with the 0-based list position + * index of clauses estimated here, and that should be ignored below. + */ + s1 = statext_clauselist_selectivity(root, clauses, varRelid, + jointype, sjinfo, rel, + &estimatedclauses, true); + } + + /* + * Estimate the remaining clauses as if they were independent. + * + * Selectivities for an OR clause are computed as s1+s2 - s1*s2 to account + * for the probable overlap of selected tuple sets. + * + * XXX is this too conservative? + */ + listidx = -1; + foreach(lc, clauses) + { + Selectivity s2; + + listidx++; + + /* + * Skip this clause if it's already been estimated by some other + * statistics above. + */ + if (bms_is_member(listidx, estimatedclauses)) + continue; + + s2 = clause_selectivity_ext(root, (Node *) lfirst(lc), varRelid, + jointype, sjinfo, use_extended_stats); + + s1 = s1 + s2 - s1 * s2; + } + + return s1; +} + +/* * addRangeClause --- add a new range clause for clauselist_selectivity * * Here is where we try to match up pairs of range-query clauses @@ -602,6 +672,24 @@ clause_selectivity(PlannerInfo *root, JoinType jointype, SpecialJoinInfo *sjinfo) { + return clause_selectivity_ext(root, clause, varRelid, + jointype, sjinfo, true); +} + +/* + * clause_selectivity_ext - + * Extended version of clause_selectivity(). If "use_extended_stats" is + * false, all extended statistics will be ignored, and only per-column + * statistics will be used. + */ +Selectivity +clause_selectivity_ext(PlannerInfo *root, + Node *clause, + int varRelid, + JoinType jointype, + SpecialJoinInfo *sjinfo, + bool use_extended_stats) +{ Selectivity s1 = 0.5; /* default for any unhandled clause type */ RestrictInfo *rinfo = NULL; bool cacheable = false; @@ -716,42 +804,35 @@ clause_selectivity(PlannerInfo *root, else if (is_notclause(clause)) { /* inverse of the selectivity of the underlying clause */ - s1 = 1.0 - clause_selectivity(root, - (Node *) get_notclausearg((Expr *) clause), - varRelid, - jointype, - sjinfo); + s1 = 1.0 - clause_selectivity_ext(root, + (Node *) get_notclausearg((Expr *) clause), + varRelid, + jointype, + sjinfo, + use_extended_stats); } else if (is_andclause(clause)) { /* share code with clauselist_selectivity() */ - s1 = clauselist_selectivity(root, - ((BoolExpr *) clause)->args, - varRelid, - jointype, - sjinfo); + s1 = clauselist_selectivity_ext(root, + ((BoolExpr *) clause)->args, + varRelid, + jointype, + sjinfo, + use_extended_stats); } else if (is_orclause(clause)) { /* - * Selectivities for an OR clause are computed as s1+s2 - s1*s2 to - * account for the probable overlap of selected tuple sets. - * - * XXX is this too conservative? + * Almost the same thing as clauselist_selectivity, but with the + * clauses connected by OR. */ - ListCell *arg; - - s1 = 0.0; - foreach(arg, ((BoolExpr *) clause)->args) - { - Selectivity s2 = clause_selectivity(root, - (Node *) lfirst(arg), - varRelid, - jointype, - sjinfo); - - s1 = s1 + s2 - s1 * s2; - } + s1 = clauselist_selectivity_or(root, + ((BoolExpr *) clause)->args, + varRelid, + jointype, + sjinfo, + use_extended_stats); } else if (is_opclause(clause) || IsA(clause, DistinctExpr)) { @@ -852,20 +933,22 @@ clause_selectivity(PlannerInfo *root, else if (IsA(clause, RelabelType)) { /* Not sure this case is needed, but it can't hurt */ - s1 = clause_selectivity(root, - (Node *) ((RelabelType *) clause)->arg, - varRelid, - jointype, - sjinfo); + s1 = clause_selectivity_ext(root, + (Node *) ((RelabelType *) clause)->arg, + varRelid, + jointype, + sjinfo, + use_extended_stats); } else if (IsA(clause, CoerceToDomain)) { /* Not sure this case is needed, but it can't hurt */ - s1 = clause_selectivity(root, - (Node *) ((CoerceToDomain *) clause)->arg, - varRelid, - jointype, - sjinfo); + s1 = clause_selectivity_ext(root, + (Node *) ((CoerceToDomain *) clause)->arg, + varRelid, + jointype, + sjinfo, + use_extended_stats); } else { diff --git a/src/backend/statistics/dependencies.c b/src/backend/statistics/dependencies.c new file mode 100644 index d950b4e..b1abcde --- a/src/backend/statistics/dependencies.c +++ b/src/backend/statistics/dependencies.c @@ -1073,8 +1073,8 @@ clauselist_apply_dependencies(PlannerInf } } - simple_sel = clauselist_selectivity_simple(root, attr_clauses, varRelid, - jointype, sjinfo, NULL); + simple_sel = clauselist_selectivity_ext(root, attr_clauses, varRelid, + jointype, sjinfo, false); attr_sel[attidx++] = simple_sel; } diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c new file mode 100644 index 3632692..8d3cd09 --- a/src/backend/statistics/extended_stats.c +++ b/src/backend/statistics/extended_stats.c @@ -1239,10 +1239,10 @@ statext_is_compatible_clause(PlannerInfo * One of the main challenges with using MCV lists is how to extrapolate the * estimate to the data not covered by the MCV list. To do that, we compute * not only the "MCV selectivity" (selectivities for MCV items matching the - * supplied clauses), but also a couple of derived selectivities: + * supplied clauses), but also the following related selectivities: * - * - simple selectivity: Computed without extended statistic, i.e. as if the - * columns/clauses were independent + * - simple selectivity: Computed without extended statistics, i.e. as if the + * columns/clauses were independent. * * - base selectivity: Similar to simple selectivity, but is computed using * the extended statistic by adding up the base frequencies (that we compute @@ -1250,30 +1250,9 @@ statext_is_compatible_clause(PlannerInfo * * - total selectivity: Selectivity covered by the whole MCV list. * - * - other selectivity: A selectivity estimate for data not covered by the MCV - * list (i.e. satisfying the clauses, but not common enough to make it into - * the MCV list) - * - * Note: While simple and base selectivities are defined in a quite similar - * way, the values are computed differently and are not therefore equal. The - * simple selectivity is computed as a product of per-clause estimates, while - * the base selectivity is computed by adding up base frequencies of matching - * items of the multi-column MCV list. So the values may differ for two main - * reasons - (a) the MCV list may not cover 100% of the data and (b) some of - * the MCV items did not match the estimated clauses. - * - * As both (a) and (b) reduce the base selectivity value, it generally holds - * that (simple_selectivity >= base_selectivity). If the MCV list covers all - * the data, the values may be equal. - * - * So, (simple_selectivity - base_selectivity) is an estimate for the part - * not covered by the MCV list, and (mcv_selectivity - base_selectivity) may - * be seen as a correction for the part covered by the MCV list. Those two - * statements are actually equivalent. - * - * Note: Due to rounding errors and minor differences in how the estimates - * are computed, the inequality may not always hold. Which is why we clamp - * the selectivities to prevent strange estimate (negative etc.). + * These are passed to mcv_combine_selectivities() which combines them to + * produce a selectivity estimate that makes use of both per-column statistics + * and the multi-column MCV statistics. * * 'estimatedclauses' is an input/output parameter. We set bits for the * 0-based 'clauses' indexes we estimate for and also skip clause items that @@ -1282,16 +1261,17 @@ statext_is_compatible_clause(PlannerInfo static Selectivity statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid, JoinType jointype, SpecialJoinInfo *sjinfo, - RelOptInfo *rel, Bitmapset **estimatedclauses) + RelOptInfo *rel, Bitmapset **estimatedclauses, + bool is_or) { ListCell *l; Bitmapset **list_attnums; int listidx; - Selectivity sel = 1.0; + Selectivity sel = (is_or) ? 0.0 : 1.0; /* check if there's any stats that might be useful for us. */ if (!has_stats_of_kind(rel->statlist, STATS_EXT_MCV)) - return 1.0; + return sel; list_attnums = (Bitmapset **) palloc(sizeof(Bitmapset *) * list_length(clauses)); @@ -1327,12 +1307,7 @@ statext_mcv_clauselist_selectivity(Plann { StatisticExtInfo *stat; List *stat_clauses; - Selectivity simple_sel, - mcv_sel, - mcv_basesel, - mcv_totalsel, - other_sel, - stat_sel; + Bitmapset *simple_clauses; /* find the best suited statistics object for these attnums */ stat = choose_best_statistics(rel->statlist, STATS_EXT_MCV, @@ -1351,6 +1326,9 @@ statext_mcv_clauselist_selectivity(Plann /* now filter the clauses to be estimated using the selected MCV */ stat_clauses = NIL; + /* record which clauses are simple (single column) */ + simple_clauses = NULL; + listidx = 0; foreach(l, clauses) { @@ -1361,6 +1339,10 @@ statext_mcv_clauselist_selectivity(Plann if (list_attnums[listidx] != NULL && bms_is_subset(list_attnums[listidx], stat->keys)) { + if (bms_membership(list_attnums[listidx]) == BMS_SINGLETON) + simple_clauses = bms_add_member(simple_clauses, + list_length(stat_clauses)); + stat_clauses = lappend(stat_clauses, (Node *) lfirst(l)); *estimatedclauses = bms_add_member(*estimatedclauses, listidx); @@ -1371,40 +1353,131 @@ statext_mcv_clauselist_selectivity(Plann listidx++; } - /* - * First compute "simple" selectivity, i.e. without the extended - * statistics, and essentially assuming independence of the - * columns/clauses. We'll then use the various selectivities computed - * from MCV list to improve it. - */ - simple_sel = clauselist_selectivity_simple(root, stat_clauses, varRelid, - jointype, sjinfo, NULL); + if (is_or) + { + bool *or_matches = NULL; + Selectivity simple_or_sel = 0.0; + MCVList *mcv_list; - /* - * Now compute the multi-column estimate from the MCV list, along with - * the other selectivities (base & total selectivity). - */ - mcv_sel = mcv_clauselist_selectivity(root, stat, stat_clauses, varRelid, - jointype, sjinfo, rel, - &mcv_basesel, &mcv_totalsel); + /* Load the MCV list stored in the statistics object */ + mcv_list = statext_mcv_load(stat->statOid); - /* Estimated selectivity of values not covered by MCV matches */ - other_sel = simple_sel - mcv_basesel; - CLAMP_PROBABILITY(other_sel); + /* + * Compute the selectivity of the ORed list of clauses by + * estimating each in turn and combining them using the formula + * P(A OR B) = P(A) + P(B) - P(A AND B). This allows us to use + * the multivariate MCV stats to better estimate each term. + * + * Each time we iterate this formula, the clause "A" above is + * equal to all the clauses processed so far, combined with "OR". + */ + listidx = 0; + foreach(l, stat_clauses) + { + Node *clause = (Node *) lfirst(l); + Selectivity simple_sel, + overlap_simple_sel, + mcv_sel, + mcv_basesel, + overlap_mcvsel, + overlap_basesel, + mcv_totalsel, + clause_sel, + overlap_sel; - /* The non-MCV selectivity can't exceed the 1 - mcv_totalsel. */ - if (other_sel > 1.0 - mcv_totalsel) - other_sel = 1.0 - mcv_totalsel; + /* + * "Simple" selectivity of the next clause and its overlap + * with any of the previous clauses. These are our initial + * estimates of P(B) and P(A AND B), assuming independence of + * columns/clauses. + */ + simple_sel = clause_selectivity_ext(root, clause, varRelid, + jointype, sjinfo, false); - /* - * Overall selectivity is the combination of MCV and non-MCV - * estimates. - */ - stat_sel = mcv_sel + other_sel; - CLAMP_PROBABILITY(stat_sel); + overlap_simple_sel = simple_or_sel * simple_sel; - /* Factor the estimate from this MCV to the overall estimate. */ - sel *= stat_sel; + /* + * New "simple" selectivity of all clauses seen so far, + * assuming independence. + */ + simple_or_sel += simple_sel - overlap_simple_sel; + CLAMP_PROBABILITY(simple_or_sel); + + /* + * Multi-column estimate of this clause using MCV statistics, + * along with base and total selectivities, and corresponding + * selectivities for the overlap term P(A AND B). + */ + mcv_sel = mcv_clause_selectivity_or(root, stat, mcv_list, + clause, &or_matches, + &mcv_basesel, + &overlap_mcvsel, + &overlap_basesel, + &mcv_totalsel); + + /* + * Combine the simple and multi-column estimates. + * + * If this clause is a simple single-column clause, then we + * just use the simple selectivity estimate for it, since the + * multi-column statistics are unlikely to improve on that + * (and in fact could make it worse). For the overlap, we + * always make use of the multi-column statistics. + */ + if (bms_is_member(listidx, simple_clauses)) + clause_sel = simple_sel; + else + clause_sel = mcv_combine_selectivities(simple_sel, + mcv_sel, + mcv_basesel, + mcv_totalsel); + + overlap_sel = mcv_combine_selectivities(overlap_simple_sel, + overlap_mcvsel, + overlap_basesel, + mcv_totalsel); + + /* Factor these into the overall result */ + sel += clause_sel - overlap_sel; + CLAMP_PROBABILITY(sel); + + listidx++; + } + } + else /* Implicitly-ANDed list of clauses */ + { + Selectivity simple_sel, + mcv_sel, + mcv_basesel, + mcv_totalsel, + stat_sel; + + /* + * "Simple" selectivity, i.e. without any extended statistics, + * essentially assuming independence of the columns/clauses. + */ + simple_sel = clauselist_selectivity_ext(root, stat_clauses, + varRelid, jointype, + sjinfo, false); + + /* + * Multi-column estimate using MCV statistics, along with base and + * total selectivities. + */ + mcv_sel = mcv_clauselist_selectivity(root, stat, stat_clauses, + varRelid, jointype, sjinfo, + rel, &mcv_basesel, + &mcv_totalsel); + + /* Combine the simple and multi-column estimates. */ + stat_sel = mcv_combine_selectivities(simple_sel, + mcv_sel, + mcv_basesel, + mcv_totalsel); + + /* Factor this into the overall result */ + sel *= stat_sel; + } } return sel; @@ -1417,13 +1490,21 @@ statext_mcv_clauselist_selectivity(Plann Selectivity statext_clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid, JoinType jointype, SpecialJoinInfo *sjinfo, - RelOptInfo *rel, Bitmapset **estimatedclauses) + RelOptInfo *rel, Bitmapset **estimatedclauses, + bool is_or) { Selectivity sel; /* First, try estimating clauses using a multivariate MCV list. */ sel = statext_mcv_clauselist_selectivity(root, clauses, varRelid, jointype, - sjinfo, rel, estimatedclauses); + sjinfo, rel, estimatedclauses, is_or); + + /* + * Functional dependencies only work for clauses connected by AND, so for + * OR clauses we're done. + */ + if (is_or) + return sel; /* * Then, apply functional dependencies on the remaining clauses by calling diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c new file mode 100644 index 6a262f1..fae792a --- a/src/backend/statistics/mcv.c +++ b/src/backend/statistics/mcv.c @@ -32,6 +32,7 @@ #include "utils/fmgroids.h" #include "utils/fmgrprotos.h" #include "utils/lsyscache.h" +#include "utils/selfuncs.h" #include "utils/syscache.h" #include "utils/typcache.h" @@ -1889,15 +1890,79 @@ mcv_get_match_bitmap(PlannerInfo *root, /* + * mcv_combine_selectivities + * Combine per-column and multi-column MCV selectivity estimates. + * + * simple_sel is a "simple" selectivity estimate (produced without using any + * extended statistics, essentially assuming independence of columns/clauses). + * + * mcv_sel and mcv_basesel are sums of the frequencies and base frequencies of + * all matching MCV items. The difference (mcv_sel - mcv_basesel) is then + * essentially interpreted as a correction to be added to simple_sel, as + * described below. + * + * mcv_totalsel is the sum of the frequencies of all MCV items (not just the + * matching ones). This is used as an upper bound on the portion of the + * selectivity estimates not covered by the MCV statistics. + * + * Note: While simple and base selectivities are defined in a quite similar + * way, the values are computed differently and are not therefore equal. The + * simple selectivity is computed as a product of per-clause estimates, while + * the base selectivity is computed by adding up base frequencies of matching + * items of the multi-column MCV list. So the values may differ for two main + * reasons - (a) the MCV list may not cover 100% of the data and (b) some of + * the MCV items did not match the estimated clauses. + * + * As both (a) and (b) reduce the base selectivity value, it generally holds + * that (simple_sel >= mcv_basesel). If the MCV list covers all the data, the + * values may be equal. + * + * So, other_sel = (simple_sel - mcv_basesel) is an estimate for the part not + * covered by the MCV list, and (mcv_sel - mcv_basesel) may be seen as a + * correction for the part covered by the MCV list. Those two statements are + * actually equivalent. + */ +Selectivity +mcv_combine_selectivities(Selectivity simple_sel, + Selectivity mcv_sel, + Selectivity mcv_basesel, + Selectivity mcv_totalsel) +{ + Selectivity other_sel; + Selectivity sel; + + /* estimated selectivity of values not covered by MCV matches */ + other_sel = simple_sel - mcv_basesel; + CLAMP_PROBABILITY(other_sel); + + /* this non-MCV selectivity cannot exceed 1 - mcv_totalsel */ + if (other_sel > 1.0 - mcv_totalsel) + other_sel = 1.0 - mcv_totalsel; + + /* overall selectivity is the sum of the MCV and non-MCV parts */ + sel = mcv_sel + other_sel; + CLAMP_PROBABILITY(sel); + + return sel; +} + + +/* * mcv_clauselist_selectivity - * Return the selectivity estimate computed using an MCV list. + * Use MCV statistics to estimate the selectivity of an implicitly-ANDed + * list of clauses. * - * First builds a bitmap of MCV items matching the clauses, and then sums - * the frequencies of matching items. + * This determines which MCV items match every clause in the list and returns + * the sum of the frequencies of those items. * - * It also produces two additional interesting selectivities - total - * selectivity of all the MCV items (not just the matching ones), and the - * base frequency computed on the assumption of independence. + * In addition, it returns the sum of the base frequencies of each of those + * items (that is the sum of the selectivities that each item would have if + * the columns were independent of one another), and the total selectivity of + * all the MCV items (not just the matching ones). These are expected to be + * used together with a "simple" selectivity estimate (one based only on + * per-column statistics) to produce an overall selectivity estimate that + * makes use of both per-column and multi-column statistics --- see + * mcv_combine_selectivities(). */ Selectivity mcv_clauselist_selectivity(PlannerInfo *root, StatisticExtInfo *stat, @@ -1928,7 +1993,6 @@ mcv_clauselist_selectivity(PlannerInfo * if (matches[i] != false) { - /* XXX Shouldn't the basesel be outside the if condition? */ *basesel += mcv->items[i].base_frequency; s += mcv->items[i].frequency; } @@ -1936,3 +2000,94 @@ mcv_clauselist_selectivity(PlannerInfo * return s; } + + +/* + * mcv_clause_selectivity_or + * Use MCV statistics to estimate the selectivity of a clause that + * appears in an ORed list of clauses. + * + * As with mcv_clauselist_selectivity() this determines which MCV items match + * the clause and returns both the sum of the frequencies and the sum of the + * base frequencies of those items, as well as the sum of the frequencies of + * all MCV items (not just the matching ones) so that this information can be + * used by mcv_combine_selectivities() to produce a selectivity estimate that + * makes use of both per-column and multi-column statistics. + * + * Additionally, we return information to help compute the overall selectivity + * of the ORed list of clauses assumed to contain this clause. This function + * is intended to be called for each clause in the ORed list of clauses, + * allowing the overall selectivity to be computed using the following + * algorithm: + * + * Suppose P[n] = P(C[1] OR C[2] OR ... OR C[n]) is the combined selectivity + * of the first n clauses in the list. Then the combined selectivity taking + * into account the next clause C[n+1] can be written as + * + * P[n+1] = P[n] + P(C[n+1]) - P((C[1] OR ... OR C[n]) AND C[n+1]) + * + * The final term above represents the overlap between the clauses examined so + * far and the (n+1)'th clause. To estimate its selectivity, we track the + * match bitmap for the ORed list of clauses examined so far and examine its + * intersection with the match bitmap for the (n+1)'th clause. + * + * We then also return the sums of the MCV item frequencies and base + * frequencies for the match bitmap intersection corresponding to the overlap + * term above, so that they can be combined with a simple selectivity estimate + * for that term. + * + * The parameter "or_matches" is an in/out parameter tracking the match bitmap + * for the clauses examined so far. The caller is expected to set it to NULL + * the first time it calls this function. + */ +Selectivity +mcv_clause_selectivity_or(PlannerInfo *root, StatisticExtInfo *stat, + MCVList *mcv, Node *clause, bool **or_matches, + Selectivity *basesel, Selectivity *overlap_mcvsel, + Selectivity *overlap_basesel, Selectivity *totalsel) +{ + Selectivity s = 0.0; + bool *new_matches; + int i; + + /* build the OR-matches bitmap, if not built already */ + if (*or_matches == NULL) + *or_matches = palloc0(sizeof(bool) * mcv->nitems); + + /* build the match bitmap for the new clause */ + new_matches = mcv_get_match_bitmap(root, list_make1(clause), stat->keys, + mcv, false); + + /* + * Sum the frequencies for all the MCV items matching this clause and also + * those matching the overlap between this clause and any of the preceding + * clauses as described above. + */ + *basesel = 0.0; + *overlap_mcvsel = 0.0; + *overlap_basesel = 0.0; + *totalsel = 0.0; + for (i = 0; i < mcv->nitems; i++) + { + *totalsel += mcv->items[i].frequency; + + if (new_matches[i]) + { + s += mcv->items[i].frequency; + *basesel += mcv->items[i].base_frequency; + + if ((*or_matches)[i]) + { + *overlap_mcvsel += mcv->items[i].frequency; + *overlap_basesel += mcv->items[i].base_frequency; + } + } + + /* update the OR-matches bitmap for the next clause */ + (*or_matches)[i] = (*or_matches)[i] || new_matches[i]; + } + + pfree(new_matches); + + return s; +} diff --git a/src/include/optimizer/optimizer.h b/src/include/optimizer/optimizer.h new file mode 100644 index 3e41710..dea0e73 --- a/src/include/optimizer/optimizer.h +++ b/src/include/optimizer/optimizer.h @@ -58,17 +58,23 @@ extern Selectivity clause_selectivity(Pl int varRelid, JoinType jointype, SpecialJoinInfo *sjinfo); -extern Selectivity clauselist_selectivity_simple(PlannerInfo *root, - List *clauses, - int varRelid, - JoinType jointype, - SpecialJoinInfo *sjinfo, - Bitmapset *estimatedclauses); +extern Selectivity clause_selectivity_ext(PlannerInfo *root, + Node *clause, + int varRelid, + JoinType jointype, + SpecialJoinInfo *sjinfo, + bool use_extended_stats); extern Selectivity clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid, JoinType jointype, SpecialJoinInfo *sjinfo); +extern Selectivity clauselist_selectivity_ext(PlannerInfo *root, + List *clauses, + int varRelid, + JoinType jointype, + SpecialJoinInfo *sjinfo, + bool use_extended_stats); /* in path/costsize.c: */ diff --git a/src/include/statistics/extended_stats_internal.h b/src/include/statistics/extended_stats_internal.h new file mode 100644 index 61e6969..02bf6a0 --- a/src/include/statistics/extended_stats_internal.h +++ b/src/include/statistics/extended_stats_internal.h @@ -99,6 +99,11 @@ extern SortItem *build_sorted_items(int extern bool examine_clause_args(List *args, Var **varp, Const **cstp, bool *varonleftp); +extern Selectivity mcv_combine_selectivities(Selectivity simple_sel, + Selectivity mcv_sel, + Selectivity mcv_basesel, + Selectivity mcv_totalsel); + extern Selectivity mcv_clauselist_selectivity(PlannerInfo *root, StatisticExtInfo *stat, List *clauses, @@ -109,4 +114,14 @@ extern Selectivity mcv_clauselist_select Selectivity *basesel, Selectivity *totalsel); +extern Selectivity mcv_clause_selectivity_or(PlannerInfo *root, + StatisticExtInfo *stat, + MCVList *mcv, + Node *clause, + bool **or_matches, + Selectivity *basesel, + Selectivity *overlap_mcvsel, + Selectivity *overlap_basesel, + Selectivity *totalsel); + #endif /* EXTENDED_STATS_INTERNAL_H */ diff --git a/src/include/statistics/statistics.h b/src/include/statistics/statistics.h new file mode 100644 index 50fce49..c9ed211 --- a/src/include/statistics/statistics.h +++ b/src/include/statistics/statistics.h @@ -116,7 +116,8 @@ extern Selectivity statext_clauselist_se JoinType jointype, SpecialJoinInfo *sjinfo, RelOptInfo *rel, - Bitmapset **estimatedclauses); + Bitmapset **estimatedclauses, + bool is_or); extern bool has_stats_of_kind(List *stats, char requiredkind); extern StatisticExtInfo *choose_best_statistics(List *stats, char requiredkind, Bitmapset **clause_attnums, diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out new file mode 100644 index 4c3edd2..dbbe984 --- a/src/test/regress/expected/stats_ext.out +++ b/src/test/regress/expected/stats_ext.out @@ -1113,6 +1113,12 @@ SELECT * FROM check_estimated_rows('SELE 200 | 200 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL'); + estimated | actual +-----------+-------- + 200 | 200 +(1 row) + SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52) AND b IN ( ''1'', ''2'')'); estimated | actual -----------+-------- @@ -1173,13 +1179,6 @@ SELECT * FROM check_estimated_rows('SELE 100 | 100 (1 row) --- we can't use the statistic for OR clauses that are not fully covered (missing 'd' attribute) -SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL'); - estimated | actual ------------+-------- - 343 | 200 -(1 row) - -- check change of unrelated column type does not reset the MCV statistics ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64); SELECT d.stxdmcv IS NOT NULL @@ -1477,6 +1476,134 @@ SELECT * FROM check_estimated_rows('SELE 1 | 0 (1 row) +-- mcv covering just a small fraction of data +CREATE TABLE mcv_lists_partial ( + a INT, + b INT, + c INT +); +-- 10 frequent groups, each with 100 elements +INSERT INTO mcv_lists_partial (a, b, c) + SELECT + mod(i,10), + mod(i,10), + mod(i,10) + FROM generate_series(0,999) s(i); +-- 100 groups that will make it to the MCV list (includes the 10 frequent ones) +INSERT INTO mcv_lists_partial (a, b, c) + SELECT + i, + i, + i + FROM generate_series(0,99) s(i); +-- 4000 groups in total, most of which won't make it (just a single item) +INSERT INTO mcv_lists_partial (a, b, c) + SELECT + i, + i, + i + FROM generate_series(0,3999) s(i); +ANALYZE mcv_lists_partial; +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 AND b = 0 AND c = 0'); + estimated | actual +-----------+-------- + 1 | 102 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 OR b = 0 OR c = 0'); + estimated | actual +-----------+-------- + 300 | 102 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 10 AND b = 10 AND c = 10'); + estimated | actual +-----------+-------- + 1 | 2 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 10 OR b = 10 OR c = 10'); + estimated | actual +-----------+-------- + 6 | 2 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 AND b = 0 AND c = 10'); + estimated | actual +-----------+-------- + 1 | 0 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 OR b = 0 OR c = 10'); + estimated | actual +-----------+-------- + 204 | 104 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE (a = 0 AND b = 0 AND c = 0) OR (a = 1 AND b = 1 AND c = 1) OR (a = 2 AND b = 2 AND c = 2)'); + estimated | actual +-----------+-------- + 1 | 306 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE (a = 0 AND b = 0) OR (a = 0 AND c = 0) OR (b = 0 AND c = 0)'); + estimated | actual +-----------+-------- + 6 | 102 +(1 row) + +CREATE STATISTICS mcv_lists_partial_stats (mcv) ON a, b, c + FROM mcv_lists_partial; +ANALYZE mcv_lists_partial; +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 AND b = 0 AND c = 0'); + estimated | actual +-----------+-------- + 102 | 102 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 OR b = 0 OR c = 0'); + estimated | actual +-----------+-------- + 96 | 102 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 10 AND b = 10 AND c = 10'); + estimated | actual +-----------+-------- + 2 | 2 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 10 OR b = 10 OR c = 10'); + estimated | actual +-----------+-------- + 2 | 2 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 AND b = 0 AND c = 10'); + estimated | actual +-----------+-------- + 1 | 0 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 OR b = 0 OR c = 10'); + estimated | actual +-----------+-------- + 102 | 104 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE (a = 0 AND b = 0 AND c = 0) OR (a = 1 AND b = 1 AND c = 1) OR (a = 2 AND b = 2 AND c = 2)'); + estimated | actual +-----------+-------- + 300 | 306 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE (a = 0 AND b = 0) OR (a = 0 AND c = 0) OR (b = 0 AND c = 0)'); + estimated | actual +-----------+-------- + 306 | 102 +(1 row) + +DROP TABLE mcv_lists_partial; -- check the ability to use multiple MCV lists CREATE TABLE mcv_lists_multi ( a INTEGER, @@ -1506,12 +1633,36 @@ SELECT * FROM check_estimated_rows('SELE 102 | 714 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 AND c = 0'); + estimated | actual +-----------+-------- + 143 | 142 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 OR c = 0'); + estimated | actual +-----------+-------- + 1571 | 1572 +(1 row) + SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0'); estimated | actual -----------+-------- 4 | 142 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE (a = 0 AND b = 0) OR (c = 0 AND d = 0)'); + estimated | actual +-----------+-------- + 298 | 1572 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR b = 0 OR c = 0 OR d = 0'); + estimated | actual +-----------+-------- + 2649 | 1572 +(1 row) + -- create separate MCV statistics CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi; CREATE STATISTICS mcv_lists_multi_2 (mcv) ON c, d FROM mcv_lists_multi; @@ -1528,12 +1679,36 @@ SELECT * FROM check_estimated_rows('SELE 714 | 714 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 AND c = 0'); + estimated | actual +-----------+-------- + 143 | 142 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 OR c = 0'); + estimated | actual +-----------+-------- + 1571 | 1572 +(1 row) + SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0'); estimated | actual -----------+-------- 143 | 142 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE (a = 0 AND b = 0) OR (c = 0 AND d = 0)'); + estimated | actual +-----------+-------- + 1571 | 1572 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR b = 0 OR c = 0 OR d = 0'); + estimated | actual +-----------+-------- + 1714 | 1572 +(1 row) + DROP TABLE mcv_lists_multi; -- Permission tests. Users should not be able to see specific data values in -- the extended statistics, if they lack permission to see those values in diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql new file mode 100644 index 9781e59..7912e73 --- a/src/test/regress/sql/stats_ext.sql +++ b/src/test/regress/sql/stats_ext.sql @@ -561,6 +561,8 @@ SELECT * FROM check_estimated_rows('SELE SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL'); + SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52) AND b IN ( ''1'', ''2'')'); SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (1, 2, 51, 52, NULL) AND b IN ( ''1'', ''2'', NULL)'); @@ -581,9 +583,6 @@ SELECT * FROM check_estimated_rows('SELE SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY[4, 5]) AND b IN (''1'', ''2'', NULL, ''3'') AND c > ANY (ARRAY[1, 2, NULL, 3])'); --- we can't use the statistic for OR clauses that are not fully covered (missing 'd' attribute) -SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ''1'' OR c = 1 OR d IS NOT NULL'); - -- check change of unrelated column type does not reset the MCV statistics ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64); @@ -777,6 +776,78 @@ SELECT * FROM check_estimated_rows('SELE SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c'); +-- mcv covering just a small fraction of data +CREATE TABLE mcv_lists_partial ( + a INT, + b INT, + c INT +); + +-- 10 frequent groups, each with 100 elements +INSERT INTO mcv_lists_partial (a, b, c) + SELECT + mod(i,10), + mod(i,10), + mod(i,10) + FROM generate_series(0,999) s(i); + +-- 100 groups that will make it to the MCV list (includes the 10 frequent ones) +INSERT INTO mcv_lists_partial (a, b, c) + SELECT + i, + i, + i + FROM generate_series(0,99) s(i); + +-- 4000 groups in total, most of which won't make it (just a single item) +INSERT INTO mcv_lists_partial (a, b, c) + SELECT + i, + i, + i + FROM generate_series(0,3999) s(i); + +ANALYZE mcv_lists_partial; + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 AND b = 0 AND c = 0'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 OR b = 0 OR c = 0'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 10 AND b = 10 AND c = 10'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 10 OR b = 10 OR c = 10'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 AND b = 0 AND c = 10'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 OR b = 0 OR c = 10'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE (a = 0 AND b = 0 AND c = 0) OR (a = 1 AND b = 1 AND c = 1) OR (a = 2 AND b = 2 AND c = 2)'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE (a = 0 AND b = 0) OR (a = 0 AND c = 0) OR (b = 0 AND c = 0)'); + +CREATE STATISTICS mcv_lists_partial_stats (mcv) ON a, b, c + FROM mcv_lists_partial; + +ANALYZE mcv_lists_partial; + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 AND b = 0 AND c = 0'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 OR b = 0 OR c = 0'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 10 AND b = 10 AND c = 10'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 10 OR b = 10 OR c = 10'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 AND b = 0 AND c = 10'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE a = 0 OR b = 0 OR c = 10'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE (a = 0 AND b = 0 AND c = 0) OR (a = 1 AND b = 1 AND c = 1) OR (a = 2 AND b = 2 AND c = 2)'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_partial WHERE (a = 0 AND b = 0) OR (a = 0 AND c = 0) OR (b = 0 AND c = 0)'); + +DROP TABLE mcv_lists_partial; + -- check the ability to use multiple MCV lists CREATE TABLE mcv_lists_multi ( a INTEGER, @@ -799,7 +870,11 @@ ANALYZE mcv_lists_multi; -- estimates without any mcv statistics SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0'); SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AND d = 0'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 AND c = 0'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 OR c = 0'); SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE (a = 0 AND b = 0) OR (c = 0 AND d = 0)'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR b = 0 OR c = 0 OR d = 0'); -- create separate MCV statistics CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi; @@ -809,7 +884,11 @@ ANALYZE mcv_lists_multi; SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0'); SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AND d = 0'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 AND c = 0'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 OR c = 0'); SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE (a = 0 AND b = 0) OR (c = 0 AND d = 0)'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR b = 0 OR c = 0 OR d = 0'); DROP TABLE mcv_lists_multi;