Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.92) (envelope-from ) id 1jEePo-0005zQ-EG for pgsql-hackers@arkaria.postgresql.org; Wed, 18 Mar 2020 19:31:45 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1jEePl-0007f4-RY for pgsql-hackers@arkaria.postgresql.org; Wed, 18 Mar 2020 19:31:41 +0000 Received: from makus.postgresql.org ([2001:4800:3e1:1::229]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1jEePl-0007e2-1J for pgsql-hackers@lists.postgresql.org; Wed, 18 Mar 2020 19:31:41 +0000 Received: from mail-wr1-x443.google.com ([2a00:1450:4864:20::443]) by makus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1jEePg-0001gr-8q for pgsql-hackers@postgresql.org; Wed, 18 Mar 2020 19:31:39 +0000 Received: by mail-wr1-x443.google.com with SMTP id i9so4103678wrx.12 for ; Wed, 18 Mar 2020 12:31:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=2ndquadrant-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=NLX71tGDpnb8B4NDA0xJ1l8RC38MV6CVPb8mxIMEThA=; b=yQr2dO6D7iyMHfPC7g+dpDOL5v4cRIib8xgMif5JJmvbn6rxQvFvm8HvL+nPQhqycN 4qzRFfk5RXsJx0D3duNjek2RA10Vek6GqcuDN4Hk9ypkUPHHuKy0ykVZb1DIz+SAt2S4 coB3Jap5M4//iFkYohOVYL2I1xYnF3yNeyUF8V1kxZ9eK8KvqyxDJRozmxmScoRnXQSh XehC/+IUA5bIsM8yGWWpTCC6OubekrKVgdLqyOVd+U+XiZq6cYVOVR2bscFye3CGO64b y0IT+yL7VOJh97gdeNjDFfO5eFS+qNLNoChxzyLttXav7oo0IhI0Cvp833PXn+uB1j1R tgNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=NLX71tGDpnb8B4NDA0xJ1l8RC38MV6CVPb8mxIMEThA=; b=YbdcMz+oF3X/jViM5fNGuZc7mMuoHV668uqPhnFyEytttuo/B+8zsuWm1sOntFLW2s 1RtpGKrfSm2QiRpe3wkCFUuVQh5P1BfOaKUQntj99iloucY+x451Njq7q0lgXqtJhILA WnaCDZcdPvZ9NhFUHuKi1lwUfaua4DjFBJRIk4oeMqr0NkGw0UkZKA2I1YPN7CgUvxbz 3ocNrM0l8nYnjSfaEaOY9LwOjjl7ViGGhO/d8zd71uC6sVp7kxUKuASuwJTQUpHn8MWx MxBJY9VC8zEkhetp6ZwXyWu0YvCXs559eMdVJTm46U8s3WNXGQ5/0rYlLxLNfFPNaiaH XQCA== X-Gm-Message-State: ANhLgQ2DlzVemplAQedue/yFCVox46iGDFM/BKOR24j66nTUnv6oDBPQ 59Hi430oGuNE2bur/PKaIg4xHg== X-Google-Smtp-Source: ADFU+vvpLWVZRZHFyUtEFP3YmpTsSu8C/aCZvowdsKWzTWaQOgSt/7nZ/DsvDPhGK+x+r06mlcsdCw== X-Received: by 2002:adf:eb51:: with SMTP id u17mr7714779wrn.29.1584559892928; Wed, 18 Mar 2020 12:31:32 -0700 (PDT) Received: from localhost (ip-86-49-253-92.net.upcbroadband.cz. [86.49.253.92]) by smtp.gmail.com with ESMTPSA id z6sm10087778wrp.95.2020.03.18.12.31.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Mar 2020 12:31:31 -0700 (PDT) Date: Wed, 18 Mar 2020 20:31:28 +0100 From: Tomas Vondra To: Dean Rasheed Cc: PostgreSQL Hackers Subject: Re: Additional improvements to extended statistics Message-ID: <20200318193128.53soruotqdqnlaoy@development> References: <20200113230008.g67iyk4cs3xbnjju@development> <20200306001556.il6altnuqgjxp55z@development> <20200306125800.wln6p5oltgdiqpxy@development> <20200309000157.ig5tcrynvaqu4ixd@development> <20200309000621.3jhvfxphagyf5bhg@development> <20200314165610.s7p2mgaishsujq5s@development> <20200315000809.ruwpx7ktnpnzly7c@development> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="qmgrvggedyprimol" Content-Disposition: inline In-Reply-To: List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk --qmgrvggedyprimol Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline On Sun, Mar 15, 2020 at 12:37:37PM +0000, Dean Rasheed wrote: >On Sun, 15 Mar 2020 at 00:08, Tomas Vondra wrote: >> >> On Sat, Mar 14, 2020 at 05:56:10PM +0100, Tomas Vondra wrote: >> > >> >Attached is a patch series rebased on top of the current master, after >> >committing the ScalarArrayOpExpr enhancements. I've updated the OR patch >> >to get rid of the code duplication, and barring objections I'll get it >> >committed shortly together with the two parts improving test coverage. >> >> I've pushed the two patches improving test coverage for functional >> dependencies and MCV lists, which seems mostly non-controversial. I'll >> wait a bit more with the two patches actually changing behavior (rebased >> version attached, to keep cputube happy). >> > >Patch 0001 looks to be mostly ready. Just a couple of final comments: > >+ if (is_or) >+ simple_sel = clauselist_selectivity_simple_or(root, >stat_clauses, varRelid, >+ jointype, >sjinfo, NULL, 1.0); >+ else > >Surely that should be passing 0.0 as the final argument, otherwise it >will always just return simple_sel = 1.0. > > >+ * >+ * XXX We can't multiply with current value, because for OR clauses >+ * we start with 0.0, so we simply assign to s1 directly. >+ */ >+ s = statext_clauselist_selectivity(root, clauses, varRelid, >+ jointype, sjinfo, rel, >+ &estimatedclauses, true); > >That final part of the comment is no longer relevant (variable s1 no >longer exists). Probably it could now just be deleted, since I think >there are sufficient comments elsewhere to explain what's going on. > >Otherwise it looks good, and I think this will lead to some very >worthwhile improvements. > Attached is a rebased patch series, addressing both those issues. I've been wondering why none of the regression tests failed because of the 0.0 vs. 1.0 issue, but I think the explanation is pretty simple - to make the tests stable, all the MCV lists we use are "perfect" i.e. it represents 100% of the data. But this selectivity is used to compute selectivity only for the part not represented by the MCV list, i.e. it's not really used. I suppose we could add a test that would use larger MCV item, but I'm afraid that'd be inherently unstable :-( Another thing I was thinking about is the changes to the API. We need to pass information whether the clauses are connected by AND or OR to a number of places, and 0001 does that in two ways. For some functions it adds a new parameter (called is_or), and for other functiosn it creates a new copy of a function. So for example - statext_mcv_clauselist_selectivity - statext_clauselist_selectivity got the new flag, while e.g. clauselist_selectivity gets a new "copy" sibling called clauselist_selectivity_or. There were two reasons for not using flag. First, clauselist_selectivity and similar functions have to do very different stuff for these two cases, so it'd be just one huge if/else block. Second, minimizing breakage of third-party code - pretty much all the extensions I've seen only work with AND clauses, and call clauselist_selectivity. Adding a flag would break that code. (Also, there's a bit of laziness, because this was the simplest thing to do during development.) But I wonder if that's sufficient reason - maybe we should just add the flag in all cases. It might break some code, but the fix is trivial (add a false there). Opinions? regards -- Tomas Vondra http://www.2ndQuadrant.com PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services --qmgrvggedyprimol Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="0001-Improve-estimation-of-OR-clauses-using-exte-20200318.patch" From 4d1b7a071ff7ea27bb991f7999133eb8d34f4720 Mon Sep 17 00:00:00 2001 From: Tomas Vondra Date: Sun, 8 Mar 2020 23:26:50 +0100 Subject: [PATCH 1/2] Improve estimation of OR clauses using extended statistics Until now, OR clauses were estimated using extended statistics only when the whole clause (all the arguments) are compatible. If even just one argument was found to be incompatible, the whole clause was estimated ignoring extended statistics. Estimation errors for OR clauses tend to be fairly mild, so this was considered acceptable, but it may become an issue for OR clauses with more complex arguments, etc. This commit relaxes the restriction, using mostly the same logic as AND clauses. We first apply extended statistics to as many arguments as possible, and then use the (s1 + s2 - s1 * s2) formula to factor in the remaining clauses. The OR clause is still considered incompatible, though. If any argument is unsupported or references variable not covered by the statistics, the whole OR clause is incompatible. The consequence is that e.g. clauses (a = 1) AND (b = 1 OR c = 1 OR d = 1) can't be estimated by statistics on (a,b,c) because the OR clause also references "d". So we'll estimate each of the AND arguments separately, and the extended statistics will be used only to estimate the OR clause. This may be solved by creating statistics including the "d" column, but the issue applies to cases where the clause type is unsupported, e.g. (a = 1) AND (b = 1 OR c = 1 OR mod(d,10) = 0) which can't be solved by adding "d" to the statistics, at least for now. Author: Tomas Vondra Reviewed-by: Dean Rasheed, Thomas Munro Discussion: Discussion: https://www.postgresql.org/message-id/flat/20200113230008.g67iyk4cs3xbnjju@development --- src/backend/optimizer/path/clausesel.c | 141 +++++++++++++++--- src/backend/statistics/extended_stats.c | 36 +++-- src/backend/statistics/mcv.c | 5 +- src/include/optimizer/optimizer.h | 7 + .../statistics/extended_stats_internal.h | 3 +- src/include/statistics/statistics.h | 3 +- src/test/regress/expected/stats_ext.out | 61 +++++++- src/test/regress/sql/stats_ext.sql | 13 +- 8 files changed, 227 insertions(+), 42 deletions(-) diff --git a/src/backend/optimizer/path/clausesel.c b/src/backend/optimizer/path/clausesel.c index a3ebe10592..ce14d47409 100644 --- a/src/backend/optimizer/path/clausesel.c +++ b/src/backend/optimizer/path/clausesel.c @@ -92,7 +92,7 @@ clauselist_selectivity(PlannerInfo *root, */ s1 *= statext_clauselist_selectivity(root, clauses, varRelid, jointype, sjinfo, rel, - &estimatedclauses); + &estimatedclauses, false); } /* @@ -104,6 +104,62 @@ clauselist_selectivity(PlannerInfo *root, estimatedclauses); } +/* + * 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 using regular statistics tracked + * for individual columns. This is done by simply passing the clauses to + * clauselist_selectivity and then combining the selectivities using the + * regular formula (s1+s2 - s1*s2). + */ +static Selectivity +clauselist_selectivity_or(PlannerInfo *root, + List *clauses, + int varRelid, + JoinType jointype, + SpecialJoinInfo *sjinfo) +{ + Selectivity s = 0.0; + 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. + * + * XXX We can't multiply with current value, because for OR clauses + * we start with 0.0, so we simply assign to 's' directly. + */ + s = statext_clauselist_selectivity(root, clauses, varRelid, + jointype, sjinfo, rel, + &estimatedclauses, true); + } + + /* Estimate the rest of the clauses as if they were independent. */ + return clauselist_selectivity_simple_or(root, clauses, varRelid, + jointype, sjinfo, + estimatedclauses, s); +} + /* * clauselist_selectivity_simple - * Compute the selectivity of an implicitly-ANDed list of boolean @@ -351,6 +407,65 @@ clauselist_selectivity_simple(PlannerInfo *root, return s1; } +/* + * clauselist_selectivity_simple_or - + * Compute the selectivity of an implicitly-ORed list of boolean + * expression clauses. The list can be empty, in which case the + * value passed in the last parameter must be returned. + * 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 combine selectivities of the subclauses + * using the formula (s1 + s2 - s1 * s2). It's possible some of the + * clauses are already estimated by other means, in which case we treat + * them as a single logical clause, with the selecitivity passed in the + * last parameter. + */ +Selectivity +clauselist_selectivity_simple_or(PlannerInfo *root, + List *clauses, + int varRelid, + JoinType jointype, + SpecialJoinInfo *sjinfo, + Bitmapset *estimatedclauses, + Selectivity s) +{ + ListCell *lc; + int listidx; + + /* + * Selectivities of the remaining clauses for an OR clause are computed + * as s1+s2 - s1*s2 to account for the probable overlap of selected tuple + * sets. The clauses estimated using extended statistics are effectively + * treated as a single clause. + * + * XXX is this too conservative? + */ + listidx = -1; + foreach(lc, clauses) + { + Selectivity s2; + + listidx++; + + /* skip already estimated clauses */ + if (bms_is_member(listidx, estimatedclauses)) + continue; + + s2 = clause_selectivity(root, + (Node *) lfirst(lc), + varRelid, + jointype, + sjinfo); + + s = s + s2 - s * s2; + } + + return s; +} + /* * addRangeClause --- add a new range clause for clauselist_selectivity * @@ -735,24 +850,14 @@ clause_selectivity(PlannerInfo *root, 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); } else if (is_opclause(clause) || IsA(clause, DistinctExpr)) { diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c index 318fdb8f6d..93d67791c5 100644 --- a/src/backend/statistics/extended_stats.c +++ b/src/backend/statistics/extended_stats.c @@ -1282,16 +1282,17 @@ statext_is_compatible_clause(PlannerInfo *root, Node *clause, Index relid, 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)); @@ -1374,8 +1375,12 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli * 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) + simple_sel = clauselist_selectivity_simple_or(root, stat_clauses, varRelid, + jointype, sjinfo, NULL, 0.0); + else + simple_sel = clauselist_selectivity_simple(root, stat_clauses, varRelid, + jointype, sjinfo, NULL); /* * Now compute the multi-column estimate from the MCV list, along with the @@ -1383,7 +1388,7 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli */ mcv_sel = mcv_clauselist_selectivity(root, stat, stat_clauses, varRelid, jointype, sjinfo, rel, - &mcv_basesel, &mcv_totalsel); + &mcv_basesel, &mcv_totalsel, is_or); /* Estimated selectivity of values not covered by MCV matches */ other_sel = simple_sel - mcv_basesel; @@ -1397,8 +1402,11 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli stat_sel = mcv_sel + other_sel; CLAMP_PROBABILITY(stat_sel); - /* Factor the estimate from this MCV to the oveall estimate. */ - sel *= stat_sel; + /* Factor the estimate from this MCV to the overall estimate. */ + if (is_or) + sel = sel + stat_sel - sel * stat_sel; + else + sel *= stat_sel; } return sel; @@ -1411,13 +1419,21 @@ statext_mcv_clauselist_selectivity(PlannerInfo *root, List *clauses, int varReli 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 index 3147d8fedc..343011178b 100644 --- a/src/backend/statistics/mcv.c +++ b/src/backend/statistics/mcv.c @@ -1902,7 +1902,8 @@ mcv_clauselist_selectivity(PlannerInfo *root, StatisticExtInfo *stat, List *clauses, int varRelid, JoinType jointype, SpecialJoinInfo *sjinfo, RelOptInfo *rel, - Selectivity *basesel, Selectivity *totalsel) + Selectivity *basesel, Selectivity *totalsel, + bool is_or) { int i; MCVList *mcv; @@ -1915,7 +1916,7 @@ mcv_clauselist_selectivity(PlannerInfo *root, StatisticExtInfo *stat, mcv = statext_mcv_load(stat->statOid); /* build a match bitmap for the clauses */ - matches = mcv_get_match_bitmap(root, clauses, stat->keys, mcv, false); + matches = mcv_get_match_bitmap(root, clauses, stat->keys, mcv, is_or); /* sum frequencies for all the matching MCV items */ *basesel = 0.0; diff --git a/src/include/optimizer/optimizer.h b/src/include/optimizer/optimizer.h index 5283995df8..67adcd4485 100644 --- a/src/include/optimizer/optimizer.h +++ b/src/include/optimizer/optimizer.h @@ -64,6 +64,13 @@ extern Selectivity clauselist_selectivity_simple(PlannerInfo *root, JoinType jointype, SpecialJoinInfo *sjinfo, Bitmapset *estimatedclauses); +extern Selectivity clauselist_selectivity_simple_or(PlannerInfo *root, + List *clauses, + int varRelid, + JoinType jointype, + SpecialJoinInfo *sjinfo, + Bitmapset *estimatedclauses, + Selectivity s); extern Selectivity clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid, diff --git a/src/include/statistics/extended_stats_internal.h b/src/include/statistics/extended_stats_internal.h index 2b14ab238c..6c039a81c2 100644 --- a/src/include/statistics/extended_stats_internal.h +++ b/src/include/statistics/extended_stats_internal.h @@ -107,6 +107,7 @@ extern Selectivity mcv_clauselist_selectivity(PlannerInfo *root, SpecialJoinInfo *sjinfo, RelOptInfo *rel, Selectivity *basesel, - Selectivity *totalsel); + Selectivity *totalsel, + bool is_or); #endif /* EXTENDED_STATS_INTERNAL_H */ diff --git a/src/include/statistics/statistics.h b/src/include/statistics/statistics.h index f5d9b6c73a..e18c9a6539 100644 --- a/src/include/statistics/statistics.h +++ b/src/include/statistics/statistics.h @@ -116,7 +116,8 @@ extern Selectivity statext_clauselist_selectivity(PlannerInfo *root, 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 index bd6d8be434..3aba4a37c6 100644 --- a/src/test/regress/expected/stats_ext.out +++ b/src/test/regress/expected/stats_ext.out @@ -1075,6 +1075,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ' 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 -----------+-------- @@ -1135,13 +1141,6 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY 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 @@ -1464,12 +1463,36 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AN 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; @@ -1486,12 +1509,36 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AN 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 +-----------+-------- + 1571 | 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 index 897ed3051c..54ceb1f4ee 100644 --- a/src/test/regress/sql/stats_ext.sql +++ b/src/test/regress/sql/stats_ext.sql @@ -547,6 +547,8 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE 4 >= a AND ''0 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)'); @@ -567,9 +569,6 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY 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); @@ -781,7 +780,11 @@ 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; @@ -791,7 +794,11 @@ 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; -- 2.21.1 --qmgrvggedyprimol Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="0002-Support-clauses-of-the-form-Var-op-Var-20200318.patch" From deb998bcbaac39ce90b6ad47b4828e2857ae1a57 Mon Sep 17 00:00:00 2001 From: Tomas Vondra Date: Tue, 17 Mar 2020 02:57:12 +0100 Subject: [PATCH 2/2] Support clauses of the form Var op Var --- src/backend/statistics/extended_stats.c | 67 ++++++++++++----- src/backend/statistics/mcv.c | 71 +++++++++++++++++- .../statistics/extended_stats_internal.h | 2 +- src/test/regress/expected/stats_ext.out | 72 +++++++++++++++++++ src/test/regress/sql/stats_ext.sql | 22 ++++++ 5 files changed, 215 insertions(+), 19 deletions(-) diff --git a/src/backend/statistics/extended_stats.c b/src/backend/statistics/extended_stats.c index 93d67791c5..f8947d9097 100644 --- a/src/backend/statistics/extended_stats.c +++ b/src/backend/statistics/extended_stats.c @@ -987,14 +987,18 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause, { RangeTblEntry *rte = root->simple_rte_array[relid]; OpExpr *expr = (OpExpr *) clause; - Var *var; + Var *var, + *var2; /* Only expressions with two arguments are considered compatible. */ if (list_length(expr->args) != 2) return false; - /* Check if the expression has the right shape (one Var, one Const) */ - if (!examine_clause_args(expr->args, &var, NULL, NULL)) + /* + * Check if the expression has the right shape (one Var and one Const, + * or two Vars). + */ + if (!examine_clause_args(expr->args, &var, &var2, NULL, NULL)) return false; /* @@ -1034,7 +1038,20 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause, !get_func_leakproof(get_opcode(expr->opno))) return false; - return statext_is_compatible_clause_internal(root, (Node *) var, + /* + * Check compatibility of the first Var - we get this one for both + * types of supported expressions (Var op Const) and (Var op Var). + */ + if (!statext_is_compatible_clause_internal(root, (Node *) var, + relid, attnums)) + return false; + + /* For (Var op Const) we don't get the second Var, and we're done. */ + if (!var2) + return true; + + /* For (Var op Var) check compatibility of the second Var. */ + return statext_is_compatible_clause_internal(root, (Node *) var2, relid, attnums); } @@ -1050,7 +1067,7 @@ statext_is_compatible_clause_internal(PlannerInfo *root, Node *clause, return false; /* Check if the expression has the right shape (one Var, one Const) */ - if (!examine_clause_args(expr->args, &var, NULL, NULL)) + if (!examine_clause_args(expr->args, &var, NULL, NULL, NULL)) return false; /* @@ -1456,22 +1473,24 @@ statext_clauselist_selectivity(PlannerInfo *root, List *clauses, int varRelid, } /* - * examine_opclause_expression + * examine_clause_args * Split expression into Var and Const parts. * - * Attempts to match the arguments to either (Var op Const) or (Const op Var), - * possibly with a RelabelType on top. When the expression matches this form, - * returns true, otherwise returns false. + * Attempts to match the arguments to either (Var op Const) or (Const op Var) + * or (Var op Var), possibly with a RelabelType on top. When the expression + * matches this form, returns true, otherwise returns false. * * Optionally returns pointers to the extracted Var/Const nodes, when passed * non-null pointers (varp, cstp and varonleftp). The varonleftp flag specifies * on which side of the operator we found the Var node. */ bool -examine_clause_args(List *args, Var **varp, Const **cstp, bool *varonleftp) +examine_clause_args(List *args, Var **var1p, Var **var2p, Const **cstp, + bool *varonleftp) { - Var *var; - Const *cst; + Var *var1 = NULL; + Var *var2 = NULL; + Const *cst = NULL; bool varonleft; Node *leftop, *rightop; @@ -1491,22 +1510,38 @@ examine_clause_args(List *args, Var **varp, Const **cstp, bool *varonleftp) if (IsA(leftop, Var) && IsA(rightop, Const)) { - var = (Var *) leftop; + var1 = (Var *) leftop; cst = (Const *) rightop; varonleft = true; } else if (IsA(leftop, Const) && IsA(rightop, Var)) { - var = (Var *) rightop; + var1 = (Var *) rightop; cst = (Const *) leftop; varonleft = false; } + else if (IsA(leftop, Var) && IsA(rightop, Var)) + { + var1 = (Var *) leftop; + var2 = (Var *) rightop; + varonleft = false; + + /* + * Both variables have to be for the same relation (otherwise it's + * a join clause, and we don't deal with those yet. + */ + if (var1->varno != var2->varno) + return false; + } else return false; /* return pointers to the extracted parts if requested */ - if (varp) - *varp = var; + if (var1p) + *var1p = var1; + + if (var2p) + *var2p = var2; if (cstp) *cstp = cst; diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c index 343011178b..3e58d36d68 100644 --- a/src/backend/statistics/mcv.c +++ b/src/backend/statistics/mcv.c @@ -1581,13 +1581,17 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses, /* valid only after examine_clause_args returns true */ Var *var; + Var *var2; Const *cst; bool varonleft; fmgr_info(get_opcode(expr->opno), &opproc); /* extract the var and const from the expression */ - if (examine_clause_args(expr->args, &var, &cst, &varonleft)) + if (!examine_clause_args(expr->args, &var, &var2, &cst, &varonleft)) + continue; + + if (cst) /* Var op Const */ { int idx; @@ -1651,6 +1655,68 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses, matches[i] = RESULT_MERGE(matches[i], is_or, match); } } + else /* Var op Var */ + { + int idx; + int idx2; + + Assert(var2); + + /* match the attribute to a dimension of the statistic */ + idx = bms_member_index(keys, var->varattno); + idx2 = bms_member_index(keys, var2->varattno); + + /* + * Walk through the MCV items and evaluate the current clause. + * We can skip items that were already ruled out, and + * terminate if there are no remaining MCV items that might + * possibly match. + */ + for (i = 0; i < mcvlist->nitems; i++) + { + bool match = true; + MCVItem *item = &mcvlist->items[i]; + + /* + * When either of the MCV items is NULL we can treat this + * as a mismatch. We must not call the operator because + * of strictness. + */ + if (item->isnull[idx] || item->isnull[idx2]) + { + matches[i] = RESULT_MERGE(matches[i], is_or, false); + continue; + } + + /* + * Skip MCV items that can't change result in the bitmap. + * Once the value gets false for AND-lists, or true for + * OR-lists, we don't need to look at more clauses. + */ + if (RESULT_IS_FINAL(matches[i], is_or)) + continue; + + /* + * First check whether the constant is below the lower + * boundary (in that case we can skip the bucket, because + * there's no overlap). + * + * We don't store collations used to build the statistics, + * but we can use the collation for the attribute itself, + * as stored in varcollid. We do reset the statistics after + * a type change (including collation change), so this is + * OK. We may need to relax this after allowing extended + * statistics on expressions. + */ + match = DatumGetBool(FunctionCall2Coll(&opproc, + var->varcollid, + item->values[idx], + item->values[idx2])); + + /* update the match bitmap with the result */ + matches[i] = RESULT_MERGE(matches[i], is_or, match); + } + } } else if (IsA(clause, ScalarArrayOpExpr)) { @@ -1665,7 +1731,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses, fmgr_info(get_opcode(expr->opno), &opproc); /* extract the var and const from the expression */ - if (examine_clause_args(expr->args, &var, &cst, &varonleft)) + if (examine_clause_args(expr->args, &var, NULL, &cst, &varonleft)) { int idx; @@ -1679,6 +1745,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses, /* ScalarArrayOpExpr has the Var always on the left */ Assert(varonleft); + Assert(cst); if (!cst->constisnull) { diff --git a/src/include/statistics/extended_stats_internal.h b/src/include/statistics/extended_stats_internal.h index 6c039a81c2..ee34a897c8 100644 --- a/src/include/statistics/extended_stats_internal.h +++ b/src/include/statistics/extended_stats_internal.h @@ -96,7 +96,7 @@ extern SortItem *build_sorted_items(int numrows, int *nitems, HeapTuple *rows, TupleDesc tdesc, MultiSortSupport mss, int numattrs, AttrNumber *attnums); -extern bool examine_clause_args(List *args, Var **varp, +extern bool examine_clause_args(List *args, Var **var1p, Var **var2p, Const **cstp, bool *varonleftp); extern Selectivity mcv_clauselist_selectivity(PlannerInfo *root, diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out index 3aba4a37c6..481be40141 100644 --- a/src/test/regress/expected/stats_ext.out +++ b/src/test/regress/expected/stats_ext.out @@ -940,6 +940,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ' 343 | 200 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c'); + estimated | actual +-----------+-------- + 1667 | 3750 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c'); + estimated | actual +-----------+-------- + 1667 | 0 +(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 -----------+-------- @@ -1081,6 +1093,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ' 200 | 200 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a > c'); + estimated | actual +-----------+-------- + 3750 | 3750 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c'); + estimated | actual +-----------+-------- + 1 | 0 +(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 -----------+-------- @@ -1284,6 +1308,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND 3750 | 2500 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d'); + estimated | actual +-----------+-------- + 25 | 2500 +(1 row) + -- create statistics CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, d FROM mcv_lists; ANALYZE mcv_lists; @@ -1317,6 +1347,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND 2500 | 2500 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d'); + estimated | actual +-----------+-------- + 2500 | 2500 +(1 row) + -- mcv with pass-by-ref fixlen types, e.g. uuid CREATE TABLE mcv_lists_uuid ( a UUID, @@ -1408,6 +1444,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND 1094 | 0 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b'); + estimated | actual +-----------+-------- + 9950 | 2500 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c'); + estimated | actual +-----------+-------- + 50 | 2500 +(1 row) + CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c FROM mcv_lists_bool; ANALYZE mcv_lists_bool; @@ -1435,6 +1483,18 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND 1 | 0 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b'); + estimated | actual +-----------+-------- + 2500 | 2500 +(1 row) + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c'); + estimated | actual +-----------+-------- + 2500 | 2500 +(1 row) + -- check the ability to use multiple MCV lists CREATE TABLE mcv_lists_multi ( a INTEGER, @@ -1493,6 +1553,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR 2649 | 1572 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d'); + estimated | actual +-----------+-------- + 1 | 5000 +(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; @@ -1539,6 +1605,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 OR 1571 | 1572 (1 row) +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d'); + estimated | actual +-----------+-------- + 5000 | 5000 +(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 index 54ceb1f4ee..f5e4468129 100644 --- a/src/test/regress/sql/stats_ext.sql +++ b/src/test/regress/sql/stats_ext.sql @@ -498,6 +498,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ' 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 > c'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c'); + 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)'); @@ -549,6 +553,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ' 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 > c'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < c'); + 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)'); @@ -656,6 +664,8 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ' SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND (b = ''x'' OR d = ''x'')'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d'); + -- create statistics CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, d FROM mcv_lists; @@ -674,6 +684,8 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 OR b = ' SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND (b = ''x'' OR d = ''x'')'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = d'); + -- mcv with pass-by-ref fixlen types, e.g. uuid CREATE TABLE mcv_lists_uuid ( a UUID, @@ -746,6 +758,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c'); + CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c FROM mcv_lists_bool; @@ -759,6 +775,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND b AND NOT c'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b'); + +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a = b AND b = c'); + -- check the ability to use multiple MCV lists CREATE TABLE mcv_lists_multi ( a INTEGER, @@ -785,6 +805,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 OR 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'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d'); -- create separate MCV statistics CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi; @@ -799,6 +820,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE b = 0 OR 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'); +SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = b AND c = d'); DROP TABLE mcv_lists_multi; -- 2.21.1 --qmgrvggedyprimol--