not_in_anti_join_v1.3.patch
application/octet-stream
Filename: not_in_anti_join_v1.3.patch
Type: application/octet-stream
Part: 0
Message:
Re: NOT IN subquery optimization
Patch
Format: unified
Series: patch v1
| File | + | − |
|---|---|---|
| src/backend/optimizer/plan/subselect.c | 120 | 10 |
| src/backend/optimizer/prep/prepjointree.c | 88 | 19 |
| src/backend/optimizer/util/clauses.c | 395 | 1 |
| src/backend/utils/cache/lsyscache.c | 68 | 0 |
| src/include/optimizer/clauses.h | 3 | 0 |
| src/include/optimizer/subselect.h | 3 | 1 |
| src/include/utils/lsyscache.h | 2 | 0 |
| src/test/regress/expected/subselect.out | 379 | 0 |
| src/test/regress/sql/subselect.sql | 127 | 0 |
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index 555c91f61e..b82ffc002b 100644
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -87,6 +87,9 @@ static bool contain_dml(Node *node);
static bool contain_dml_walker(Node *node, void *context);
static void inline_cte(PlannerInfo *root, CommonTableExpr *cte);
static bool inline_cte_walker(Node *node, inline_cte_walker_context *context);
+static bool is_NOTANY_compatible_with_antijoin(Query *outerquery,
+ SubLink * sublink,
+ Node *notnull_proofs);
static bool simplify_EXISTS_query(PlannerInfo *root, Query *query);
static Query *convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
Node **testexpr, List **paramIds);
@@ -1108,6 +1111,98 @@ inline_cte_walker(Node *node, inline_cte_walker_context *context)
}
+/*
+ * is_NOTANY_compatible_with_antijoin
+ * True if the NOT IN sublink can be safely converted into an ANTI JOIN.
+ * Per SQL spec, NOT IN is not ordinarily equivalent to an anti-join,
+ * however, if we can prove that all of the expressions on both sides of
+ * the, would be, join condition are all certainly not NULL and none of
+ * the join expressions can produce NULLs, then it's safe to convert NOT
+ * IN to an anti-join.
+ *
+ * To ensure that the join expressions cannot be NULL, we can't just check for
+ * strict operators since these only guarantee NULL on NULL input, we need a
+ * guarantee of NOT NULL on NOT NULL input. Fortunately we can just insist
+ * that the operator is a member of a btree or hash opfamily.
+ *
+ * 'outerquery' is the parse of the query that the NOT IN is present in.
+ * 'notnull_proofs' are quals from the same syntactical level as the NOT IN.
+ * These will be used to assist in proving the outer query's would be join
+ * expressions cannot be NULL.
+ *
+ * Note:
+ * This function is quite locked into the NOT IN syntax. Certain assumptions
+ * are made about the structure of the join conditions:
+ *
+ * 1. We assume that when more than 1 join condition exists that these are
+ * AND type conditions, i.e not OR conditions.
+ *
+ * 2. We assume that each join qual is an OpExpr with 2 arguments and the
+ * first arguments in each qual is the one that belongs to the outer side
+ * of the NOT IN clause.
+ */
+static bool
+is_NOTANY_compatible_with_antijoin(Query *outerquery, SubLink *sublink,
+ Node *notnull_proofs)
+{
+ Node *testexpr = sublink->testexpr;
+ List *outerexpr;
+ ListCell *lc;
+
+ /* Extract the outer rel's join condition expressions. */
+
+ /* if it's a single expression */
+ if (IsA(testexpr, OpExpr))
+ {
+ OpExpr *opexpr = (OpExpr *) testexpr;
+
+ Assert(list_length(opexpr->args) == 2);
+
+ /* Reject if op is not part of a btree or hash opfamily */
+ if (!has_merge_or_hash_join_opfamilies(opexpr->opno))
+ return false;
+
+ outerexpr = list_make1(linitial(opexpr->args));
+ }
+
+ /* Extract exprs from multiple expressions ANDed together */
+ else if (IsA(testexpr, BoolExpr))
+ {
+ List *list = ((BoolExpr *) testexpr)->args;
+
+ outerexpr = NIL;
+
+ /* Build a list containing the lefthand expr from each OpExpr */
+ foreach(lc, list)
+ {
+ OpExpr *opexpr = (OpExpr *) lfirst(lc);
+
+ Assert(list_length(opexpr->args) == 2);
+
+ /* Reject if op is not part of a btree or hash opfamily */
+ if (!has_merge_or_hash_join_opfamilies(opexpr->opno))
+ return false;
+
+ outerexpr = lappend(outerexpr, linitial(opexpr->args));
+ }
+ }
+ else
+ elog(ERROR, "unrecognized node type: %d",
+ (int) nodeTag(testexpr));
+
+ Assert(outerexpr != NIL);
+
+ /* Check if any outer expressions can be NULL. */
+ if (!expressions_are_not_nullable(outerquery, outerexpr, notnull_proofs))
+ return false;
+
+ /* Now validate the subquery targetlist to ensure no NULL are possible. */
+ if (!query_outputs_are_not_nullable((Query *) sublink->subselect))
+ return false;
+
+ return true; /* supports ANTI JOIN */
+}
+
/*
* convert_ANY_sublink_to_join: try to convert an ANY SubLink to a join
*
@@ -1117,11 +1212,22 @@ inline_cte_walker(Node *node, inline_cte_walker_context *context)
* If so, form a JoinExpr and return it. Return NULL if the SubLink cannot
* be converted to a join.
*
- * The only non-obvious input parameter is available_rels: this is the set
- * of query rels that can safely be referenced in the sublink expression.
- * (We must restrict this to avoid changing the semantics when a sublink
- * is present in an outer join's ON qual.) The conversion must fail if
- * the converted qual would reference any but these parent-query relids.
+ * If under_not is true, the caller actually found NOT (ANY SubLink),
+ * so that what we must try to build is an ANTI not SEMI join. Per SQL spec,
+ * NOT IN is not ordinarily equivalent to an anti-join, so that by default we
+ * have to fail when under_not. However, if we can prove that all of the
+ * expressions on both sides of the, would be, join condition are all
+ * certainly not NULL and none of the join expressions can produce NULLs, then
+ * it's safe to convert NOT IN to an anti-join. To assist with nullability
+ * proofs for the join conditions on the outside of the join, we make use of
+ *'notnull_proofs'. It is the caller's responsibility to ensure these proofs
+ * come from the same syntactical level as the NOT IN sublink.
+ *
+ * available_rels is the set of query rels that can safely be referenced
+ * in the sublink expression. (We must restrict this to avoid changing the
+ * semantics when a sublink is present in an outer join's ON qual.)
+ * The conversion must fail if the converted qual would reference any but
+ * these parent-query relids.
*
* On success, the returned JoinExpr has larg = NULL and rarg = the jointree
* item representing the pulled-up subquery. The caller must set larg to
@@ -1144,7 +1250,8 @@ inline_cte_walker(Node *node, inline_cte_walker_context *context)
*/
JoinExpr *
convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
- Relids available_rels)
+ bool under_not, Relids available_rels,
+ Node *notnull_proofs)
{
JoinExpr *result;
Query *parse = root->parse;
@@ -1159,6 +1266,11 @@ convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
Assert(sublink->subLinkType == ANY_SUBLINK);
+ /* Check if NOT IN can be converted to an anti-join. */
+ if (under_not &&
+ !is_NOTANY_compatible_with_antijoin(parse, sublink, notnull_proofs))
+ return NULL;
+
/*
* The sub-select must not refer to any Vars of the parent query. (Vars of
* higher levels should be okay, though.)
@@ -1228,7 +1340,7 @@ convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
* And finally, build the JoinExpr node.
*/
result = makeNode(JoinExpr);
- result->jointype = JOIN_SEMI;
+ result->jointype = under_not ? JOIN_ANTI : JOIN_SEMI;
result->isNatural = false;
result->larg = NULL; /* caller must fill this in */
result->rarg = (Node *) rtr;
@@ -1243,9 +1355,7 @@ convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
/*
* convert_EXISTS_sublink_to_join: try to convert an EXISTS SubLink to a join
*
- * The API of this function is identical to convert_ANY_sublink_to_join's,
- * except that we also support the case where the caller has found NOT EXISTS,
- * so we need an additional input parameter "under_not".
+ * The API of this function is identical to convert_ANY_sublink_to_join's.
*/
JoinExpr *
convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index aebe162713..27a7fafcf4 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -64,7 +64,8 @@ static Node *pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
Relids *relids);
static Node *pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
Node **jtlink1, Relids available_rels1,
- Node **jtlink2, Relids available_rels2);
+ Node **jtlink2, Relids available_rels2,
+ Node *notnull_proofs);
static Node *pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
JoinExpr *lowest_outer_join,
JoinExpr *lowest_nulling_outer_join,
@@ -261,7 +262,7 @@ pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
/* Now process qual --- all children are available for use */
newf->quals = pull_up_sublinks_qual_recurse(root, f->quals,
&jtlink, frelids,
- NULL, NULL);
+ NULL, NULL, f->quals);
/*
* Note that the result will be either newf, or a stack of JoinExprs
@@ -315,13 +316,13 @@ pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
&jtlink,
bms_union(leftrelids,
rightrelids),
- NULL, NULL);
+ NULL, NULL, j->quals);
break;
case JOIN_LEFT:
j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
&j->rarg,
rightrelids,
- NULL, NULL);
+ NULL, NULL, j->quals);
break;
case JOIN_FULL:
/* can't do anything with full-join quals */
@@ -330,7 +331,7 @@ pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
&j->larg,
leftrelids,
- NULL, NULL);
+ NULL, NULL, j->quals);
break;
default:
elog(ERROR, "unrecognized join type: %d",
@@ -370,12 +371,17 @@ pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
* and/or jtlink2 in the order we encounter them. We rely on subsequent
* optimization to rearrange the stack if appropriate.
*
+ * notnull_proofs, if not passed as NULL, is used to help prove that the
+ * would be outer rel's join condition exprs cannot be NULL when we attempt
+ * to convert NOT IN to use an antijoin.
+ *
* Returns the replacement qual node, or NULL if the qual should be removed.
*/
static Node *
pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
Node **jtlink1, Relids available_rels1,
- Node **jtlink2, Relids available_rels2)
+ Node **jtlink2, Relids available_rels2,
+ Node *notnull_proofs)
{
if (node == NULL)
return NULL;
@@ -388,8 +394,8 @@ pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
/* Is it a convertible ANY or EXISTS clause? */
if (sublink->subLinkType == ANY_SUBLINK)
{
- if ((j = convert_ANY_sublink_to_join(root, sublink,
- available_rels1)) != NULL)
+ if ((j = convert_ANY_sublink_to_join(root, sublink, false,
+ available_rels1, NULL)) != NULL)
{
/* Yes; insert the new join node into the join tree */
j->larg = *jtlink1;
@@ -409,13 +415,14 @@ pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
&j->larg,
available_rels1,
&j->rarg,
- child_rels);
+ child_rels,
+ notnull_proofs);
/* Return NULL representing constant TRUE */
return NULL;
}
if (available_rels2 != NULL &&
- (j = convert_ANY_sublink_to_join(root, sublink,
- available_rels2)) != NULL)
+ (j = convert_ANY_sublink_to_join(root, sublink, false,
+ available_rels2, NULL)) != NULL)
{
/* Yes; insert the new join node into the join tree */
j->larg = *jtlink2;
@@ -435,7 +442,8 @@ pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
&j->larg,
available_rels2,
&j->rarg,
- child_rels);
+ child_rels,
+ notnull_proofs);
/* Return NULL representing constant TRUE */
return NULL;
}
@@ -463,7 +471,8 @@ pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
&j->larg,
available_rels1,
&j->rarg,
- child_rels);
+ child_rels,
+ notnull_proofs);
/* Return NULL representing constant TRUE */
return NULL;
}
@@ -489,7 +498,8 @@ pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
&j->larg,
available_rels2,
&j->rarg,
- child_rels);
+ child_rels,
+ notnull_proofs);
/* Return NULL representing constant TRUE */
return NULL;
}
@@ -499,14 +509,70 @@ pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
}
if (is_notclause(node))
{
- /* If the immediate argument of NOT is EXISTS, try to convert */
+ /* If the immediate argument of NOT is ANY or EXISTS, try to convert */
SubLink *sublink = (SubLink *) get_notclausearg((Expr *) node);
JoinExpr *j;
Relids child_rels;
if (sublink && IsA(sublink, SubLink))
{
- if (sublink->subLinkType == EXISTS_SUBLINK)
+ if (sublink->subLinkType == ANY_SUBLINK)
+ {
+ if ((j = convert_ANY_sublink_to_join(root, sublink, true,
+ available_rels1, notnull_proofs)) != NULL)
+ {
+ /* Yes; insert the new join node into the join tree */
+ j->larg = *jtlink1;
+ *jtlink1 = (Node *) j;
+ /* Recursively process pulled-up jointree nodes */
+ j->rarg = pull_up_sublinks_jointree_recurse(root,
+ j->rarg,
+ &child_rels);
+
+ /*
+ * Now recursively process the pulled-up quals. Because
+ * we are underneath a NOT, we can't pull up sublinks that
+ * reference the left-hand stuff, but it's still okay to
+ * pull up sublinks referencing j->rarg.
+ */
+ j->quals = pull_up_sublinks_qual_recurse(root,
+ j->quals,
+ &j->rarg,
+ child_rels,
+ NULL, NULL,
+ notnull_proofs);
+ /* Return NULL representing constant TRUE */
+ return NULL;
+ }
+ if (available_rels2 != NULL &&
+ (j = convert_ANY_sublink_to_join(root, sublink, true,
+ available_rels2, notnull_proofs)) != NULL)
+ {
+ /* Yes; insert the new join node into the join tree */
+ j->larg = *jtlink2;
+ *jtlink2 = (Node *) j;
+ /* Recursively process pulled-up jointree nodes */
+ j->rarg = pull_up_sublinks_jointree_recurse(root,
+ j->rarg,
+ &child_rels);
+
+ /*
+ * Now recursively process the pulled-up quals. Because
+ * we are underneath a NOT, we can't pull up sublinks that
+ * reference the left-hand stuff, but it's still okay to
+ * pull up sublinks referencing j->rarg.
+ */
+ j->quals = pull_up_sublinks_qual_recurse(root,
+ j->quals,
+ &j->rarg,
+ child_rels,
+ NULL, NULL,
+ notnull_proofs);
+ /* Return NULL representing constant TRUE */
+ return NULL;
+ }
+ }
+ else if (sublink->subLinkType == EXISTS_SUBLINK)
{
if ((j = convert_EXISTS_sublink_to_join(root, sublink, true,
available_rels1)) != NULL)
@@ -529,7 +595,8 @@ pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
j->quals,
&j->rarg,
child_rels,
- NULL, NULL);
+ NULL, NULL,
+ notnull_proofs);
/* Return NULL representing constant TRUE */
return NULL;
}
@@ -555,7 +622,8 @@ pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
j->quals,
&j->rarg,
child_rels,
- NULL, NULL);
+ NULL, NULL,
+ notnull_proofs);
/* Return NULL representing constant TRUE */
return NULL;
}
@@ -580,7 +648,8 @@ pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
jtlink1,
available_rels1,
jtlink2,
- available_rels2);
+ available_rels2,
+ notnull_proofs);
if (newclause)
newclauses = lappend(newclauses, newclause);
}
diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c
index 501b0e9e2d..b79a99c885 100644
--- a/src/backend/optimizer/util/clauses.c
+++ b/src/backend/optimizer/util/clauses.c
@@ -42,6 +42,7 @@
#include "parser/parse_agg.h"
#include "parser/parse_coerce.h"
#include "parser/parse_func.h"
+#include "parser/parsetree.h"
#include "rewrite/rewriteManip.h"
#include "tcop/tcopprot.h"
#include "utils/acl.h"
@@ -113,6 +114,8 @@ static bool contain_context_dependent_node_walker(Node *node, int *flags);
static bool contain_leaked_vars_walker(Node *node, void *context);
static Relids find_nonnullable_rels_walker(Node *node, bool top_level);
static List *find_nonnullable_vars_walker(Node *node, bool top_level);
+static void find_innerjoined_rels(Node *jtnode,
+ Relids *innerjoined_rels, List **usable_quals);
static bool is_strict_saop(ScalarArrayOpExpr *expr, bool falseOK);
static Node *eval_const_expressions_mutator(Node *node,
eval_const_expressions_context *context);
@@ -1467,6 +1470,10 @@ contain_leaked_vars_walker(Node *node, void *context)
context);
}
+/*****************************************************************************
+ * Nullability analysis
+ *****************************************************************************/
+
/*
* find_nonnullable_rels
* Determine which base rels are forced nonnullable by given clause.
@@ -1710,7 +1717,7 @@ find_nonnullable_rels_walker(Node *node, bool top_level)
* but here we assume that the input is a Boolean expression, and wish to
* see if NULL inputs will provably cause a FALSE-or-NULL result. We expect
* the expression to have been AND/OR flattened and converted to implicit-AND
- * format.
+ * format (but the results are still good if it wasn't AND/OR flattened).
*
* The result is a palloc'd List, but we have not copied the member Var nodes.
* Also, we don't bother trying to eliminate duplicate entries.
@@ -2011,6 +2018,393 @@ find_forced_null_var(Node *node)
return NULL;
}
+/*
+ * expressions_are_not_nullable
+ * Return TRUE if all 'exprs' are certainly not NULL.
+ *
+ * The reason this takes a Query, and not just a list of expressions, is so
+ * that we can determine which relations are INNER JOINed and make use of the
+ * query's WHERE/ON clauses to help prove that inner joined rel's Vars cannot
+ * be NULL in the absense of a NOT NULL constraint.
+ *
+ * 'query' is the query that the 'exprs' belong to.
+ * 'notnull_proofs' can be passed to assist in proving the non-nullability of
+ * 'exprs'. These may be used for outer joined Vars or for Vars that allow
+ * NULLs to help determine if each 'exprs' cannot be NULL. It is the callers
+ * responsibility to ensure 'notnull_proofs' come from the same syntactical
+ * level as 'exprs'.
+ *
+ * In current usage, the passed exprs haven't yet been through any planner
+ * processing. This means that applying find_nonnullable_vars() on them isn't
+ * really ideal: for lack of const-simplification, we might be unable to prove
+ * not-nullness in some cases where we could have proved it afterwards.
+ * However, we should not get any false positive results.
+ *
+ * Here we can err on the side of conservatism: if we're not sure then it's
+ * okay to return FALSE.
+ */
+bool
+expressions_are_not_nullable(Query *query, List *exprs, Node *notnull_proofs)
+{
+ Relids innerjoined_rels = NULL;
+ List *innerjoined_useful_quals = NIL;
+ bool computed_innerjoined_rels = false;
+ List *nonnullable_vars = NIL;
+ bool computed_nonnullable_vars = false;
+ List *nonnullable_inner_vars = NIL;
+ bool computed_nonnullable_inner_vars = false;
+ ListCell *lc;
+
+ foreach(lc, exprs)
+ {
+ Expr *expr = (Expr *) lfirst(lc);
+
+ /*
+ * For the most part we don't try to deal with anything more complex
+ * than Consts and Vars; but it seems worthwhile to look through
+ * binary relabelings, since we know those don't introduce nulls.
+ */
+ while (expr && IsA(expr, RelabelType))
+ expr = ((RelabelType *) expr)->arg;
+
+ if (expr == NULL) /* paranoia */
+ return false;
+
+ if (IsA(expr, Const))
+ {
+ /* Consts are easy: they're either null or not. */
+ if (((Const *) expr)->constisnull)
+ return false;
+ }
+ else if (IsA(expr, Var))
+ {
+ Var *var = (Var *) expr;
+
+ /* Currently, we punt for any nonlocal Vars */
+ if (var->varlevelsup != 0)
+ return false;
+
+ /*
+ * Since the subquery hasn't yet been through expression
+ * preprocessing, we must apply flatten_join_alias_vars to the
+ * given Var, and to any Vars found by find_nonnullable_vars, to
+ * avoid being fooled by join aliases. If we get something other
+ * than a plain Var out of the substitution, punt.
+ */
+ var = (Var *) flatten_join_alias_vars(query, (Node *) var);
+
+ if (!IsA(var, Var))
+ return false;
+ Assert(var->varlevelsup == 0);
+
+ /*
+ * We don't bother to compute innerjoined_rels until we've found a
+ * Var we must analyze.
+ */
+ if (!computed_innerjoined_rels)
+ {
+ find_innerjoined_rels((Node *) query->jointree,
+ &innerjoined_rels,
+ &innerjoined_useful_quals);
+ computed_innerjoined_rels = true;
+ }
+
+ /* Check if the Var is from an INNER JOINed rel */
+ if (bms_is_member(var->varno, innerjoined_rels))
+ {
+ RangeTblEntry *rte = rt_fetch(var->varno, query->rtable);
+
+ /*
+ * If Var is from a plain relation and its column is marked
+ * NOT NULL according to the catalogs, it can't produce NULL.
+ */
+ if (rte->rtekind == RTE_RELATION &&
+ get_attnotnull(rte->relid, var->varattno))
+ continue; /* cannot produce NULL */
+
+ /*
+ * Otherwise check for the existance of quals which filter
+ * out NULL values for this Var. We may need to compute the
+ * nonnullable_inner_vars, if not done already.
+ */
+ if (!computed_nonnullable_inner_vars)
+ {
+ nonnullable_inner_vars =
+ find_nonnullable_vars((Node *) innerjoined_useful_quals);
+ nonnullable_inner_vars = (List *)
+ flatten_join_alias_vars(query,
+ (Node *) nonnullable_inner_vars);
+ /* We don't bother removing any non-Vars from the result */
+ computed_nonnullable_inner_vars = true;
+ }
+
+ if (list_member(nonnullable_inner_vars, var))
+ continue; /* cannot produce NULL */
+ }
+
+ /*
+ * Even if that didn't work, we can conclude that the Var is not
+ * nullable if find_nonnullable_vars can find a "var IS NOT NULL"
+ * or similarly strict condition among the notnull_proofs.
+ * Compute the list of Vars having such quals if we didn't
+ * already.
+ */
+ if (!computed_nonnullable_vars)
+ {
+ nonnullable_vars = find_nonnullable_vars(notnull_proofs);
+ nonnullable_vars = (List *)
+ flatten_join_alias_vars(query,
+ (Node *) nonnullable_vars);
+ /* We don't bother removing any non-Vars from the result */
+ computed_nonnullable_vars = true;
+ }
+
+ if (!list_member(nonnullable_vars, var))
+ return false; /* we failed to prove the Var non-null */
+ }
+ else
+ {
+ /* Not a Const or Var; punt */
+ return false;
+ }
+ }
+
+ return true; /* exprs cannot emit NULLs */
+}
+
+/*
+ * query_outputs_are_not_nullable
+ * Returns TRUE if the output values of the Query are certainly not NULL.
+ * All output columns must return non-NULL to answer TRUE.
+ *
+ * The reason this takes a Query, and not just an individual tlist expression,
+ * is so that we can make use of the query's WHERE/ON clauses to prove it does
+ * not return nulls.
+ *
+ * In current usage, the passed sub-Query hasn't yet been through any planner
+ * processing. This means that applying find_nonnullable_vars() to its WHERE
+ * clauses isn't really ideal: for lack of const-simplification, we might be
+ * unable to prove not-nullness in some cases where we could have proved it
+ * afterwards. However, we should not get any false positive results.
+ *
+ * Like the other forms of nullability analysis above, we can err on the
+ * side of conservatism: if we're not sure, it's okay to return FALSE.
+ */
+bool
+query_outputs_are_not_nullable(Query *query)
+{
+ Relids innerjoined_rels = NULL;
+ bool computed_innerjoined_rels = false;
+ List *usable_quals = NIL;
+ List *nonnullable_vars = NIL;
+ bool computed_nonnullable_vars = false;
+ ListCell *tl;
+
+ /*
+ * If the query contains set operations, punt. The set ops themselves
+ * couldn't introduce nulls that weren't in their inputs, but the tlist
+ * present in the top-level query is just dummy and won't give us useful
+ * info. We could get an answer by recursing to examine each leaf query,
+ * but for the moment it doesn't seem worth the extra complication.
+ *
+ * Note that we needn't consider other top-level operators such as
+ * DISTINCT, GROUP BY, etc, as those will not introduce nulls either.
+ */
+ if (query->setOperations)
+ return false;
+
+ /*
+ * Examine each targetlist entry to prove that it can't produce NULL.
+ */
+ foreach(tl, query->targetList)
+ {
+ TargetEntry *tle = (TargetEntry *) lfirst(tl);
+ Expr *expr = tle->expr;
+
+ /* Resjunk columns can be ignored: they don't produce output values */
+ if (tle->resjunk)
+ continue;
+
+ /*
+ * For the most part we don't try to deal with anything more complex
+ * than Consts and Vars; but it seems worthwhile to look through
+ * binary relabelings, since we know those don't introduce nulls.
+ */
+ while (expr && IsA(expr, RelabelType))
+ expr = ((RelabelType *) expr)->arg;
+
+ if (expr == NULL) /* paranoia */
+ return false;
+
+ if (IsA(expr, Const))
+ {
+ /* Consts are easy: they're either null or not. */
+ if (((Const *) expr)->constisnull)
+ return false;
+ }
+ else if (IsA(expr, Var))
+ {
+ Var *var = (Var *) expr;
+
+ /* Currently, we punt for any nonlocal Vars */
+ if (var->varlevelsup != 0)
+ return false;
+
+ /*
+ * Since the subquery hasn't yet been through expression
+ * preprocessing, we must apply flatten_join_alias_vars to the
+ * given Var, and to any Vars found by find_nonnullable_vars, to
+ * avoid being fooled by join aliases. If we get something other
+ * than a plain Var out of the substitution, punt.
+ */
+ var = (Var *) flatten_join_alias_vars(query, (Node *) var);
+
+ if (!IsA(var, Var))
+ return false;
+ Assert(var->varlevelsup == 0);
+
+ /*
+ * We don't bother to compute innerjoined_rels and usable_quals
+ * until we've found a Var we must analyze.
+ */
+ if (!computed_innerjoined_rels)
+ {
+ find_innerjoined_rels((Node *) query->jointree,
+ &innerjoined_rels, &usable_quals);
+ computed_innerjoined_rels = true;
+ }
+
+ /*
+ * If Var is from a plain relation, and that relation is not on
+ * the nullable side of any outer join, and its column is marked
+ * NOT NULL according to the catalogs, it can't produce NULL.
+ */
+ if (bms_is_member(var->varno, innerjoined_rels))
+ {
+ RangeTblEntry *rte = rt_fetch(var->varno, query->rtable);
+
+ if (rte->rtekind == RTE_RELATION &&
+ get_attnotnull(rte->relid, var->varattno))
+ continue; /* cannot produce NULL */
+ }
+
+ /*
+ * Even if that didn't work, we can conclude that the Var is not
+ * nullable if find_nonnullable_vars can find a "var IS NOT NULL"
+ * or similarly strict condition among the usable_quals. Compute
+ * the list of Vars having such quals if we didn't already.
+ */
+ if (!computed_nonnullable_vars)
+ {
+ nonnullable_vars = find_nonnullable_vars((Node *) usable_quals);
+ nonnullable_vars = (List *)
+ flatten_join_alias_vars(query,
+ (Node *) nonnullable_vars);
+ /* We don't bother removing any non-Vars from the result */
+ computed_nonnullable_vars = true;
+ }
+
+ if (!list_member(nonnullable_vars, var))
+ return false; /* we failed to prove the Var non-null */
+ }
+ else
+ {
+ /* Not a Const or Var; punt */
+ return false;
+ }
+ }
+
+ return true; /* query cannot emit NULLs */
+}
+
+/*
+ * find_innerjoined_rels
+ * Traverse jointree to locate non-outerjoined-rels and quals above them
+ *
+ * We fill innerjoined_rels with the relids of all rels that are not below
+ * the nullable side of any outer join (which would cause their Vars to be
+ * possibly NULL regardless of what's in the catalogs). In the same scan,
+ * we locate all WHERE and JOIN/ON quals that constrain these rels add them to
+ * the usable_quals list (forming a list with implicit-AND semantics).
+ *
+ * Top-level caller must initialize innerjoined_rels/usable_quals to NULL/NIL.
+ */
+static void
+find_innerjoined_rels(Node *jtnode,
+ Relids *innerjoined_rels, List **usable_quals)
+{
+ if (jtnode == NULL)
+ return;
+ if (IsA(jtnode, RangeTblRef))
+ {
+ int varno = ((RangeTblRef *) jtnode)->rtindex;
+
+ *innerjoined_rels = bms_add_member(*innerjoined_rels, varno);
+ }
+ else if (IsA(jtnode, FromExpr))
+ {
+ FromExpr *f = (FromExpr *) jtnode;
+ ListCell *lc;
+
+ /* All elements of the FROM list are allowable */
+ foreach(lc, f->fromlist)
+ find_innerjoined_rels((Node *) lfirst(lc),
+ innerjoined_rels, usable_quals);
+ /* ... and its WHERE quals are too */
+ if (f->quals)
+ *usable_quals = lappend(*usable_quals, f->quals);
+ }
+ else if (IsA(jtnode, JoinExpr))
+ {
+ JoinExpr *j = (JoinExpr *) jtnode;
+
+ switch (j->jointype)
+ {
+ case JOIN_INNER:
+ /* visit both children */
+ find_innerjoined_rels(j->larg,
+ innerjoined_rels, usable_quals);
+ find_innerjoined_rels(j->rarg,
+ innerjoined_rels, usable_quals);
+ /* and grab the ON quals too */
+ if (j->quals)
+ *usable_quals = lappend(*usable_quals, j->quals);
+ break;
+
+ case JOIN_LEFT:
+ case JOIN_SEMI:
+ case JOIN_ANTI:
+
+ /*
+ * Only the left input is possibly non-nullable; furthermore,
+ * the quals of this join don't constrain the left input.
+ * Note: we probably can't see SEMI or ANTI joins at this
+ * point, but if we do, we can treat them like LEFT joins.
+ */
+ find_innerjoined_rels(j->larg,
+ innerjoined_rels, usable_quals);
+ break;
+
+ case JOIN_RIGHT:
+ /* Reverse of the above case */
+ find_innerjoined_rels(j->rarg,
+ innerjoined_rels, usable_quals);
+ break;
+
+ case JOIN_FULL:
+ /* Neither side is non-nullable, so stop descending */
+ break;
+
+ default:
+ elog(ERROR, "unrecognized join type: %d",
+ (int) j->jointype);
+ }
+ }
+ else
+ elog(ERROR, "unrecognized node type: %d",
+ (int) nodeTag(jtnode));
+}
+
/*
* Can we treat a ScalarArrayOpExpr as strict?
*
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index e88c45d268..7b665f0afe 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -388,6 +388,45 @@ get_mergejoin_opfamilies(Oid opno)
return result;
}
+/*
+ * has_merge_or_hash_join_opfamilies
+ * TRUE iif 'opno' belongs to any btree or hash opfamily's equality
+ * strategy.
+ */
+bool
+has_merge_or_hash_join_opfamilies(Oid opno)
+{
+ bool result = false;
+ CatCList *catlist;
+ int i;
+
+ /*
+ * Search pg_amop to see if the target operator is registered as the "="
+ * operator of any btree opfamily.
+ */
+ catlist = SearchSysCacheList1(AMOPOPID, ObjectIdGetDatum(opno));
+
+ for (i = 0; i < catlist->n_members; i++)
+ {
+ HeapTuple tuple = &catlist->members[i]->tuple;
+ Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
+
+ /* must be btree or hash equality */
+ if ((aform->amopmethod == BTREE_AM_OID &&
+ aform->amopstrategy == BTEqualStrategyNumber) ||
+ (aform->amopmethod == HASH_AM_OID &&
+ aform->amopstrategy == HTEqualStrategyNumber))
+ {
+ result = true;
+ break;
+ }
+ }
+
+ ReleaseSysCacheList(catlist);
+
+ return result;
+}
+
/*
* get_compatible_hash_operators
* Get the OID(s) of hash equality operator(s) compatible with the given
@@ -878,6 +917,35 @@ get_atttypetypmodcoll(Oid relid, AttrNumber attnum,
ReleaseSysCache(tp);
}
+/*
+ * get_attnotnull
+ *
+ * Given the relation id and the attribute number,
+ * return the "attnotnull" field from the attribute relation.
+ *
+ * Returns false if the attr doesn't exist (or is dropped).
+ */
+bool
+get_attnotnull(Oid relid, AttrNumber attnum)
+{
+ HeapTuple tp;
+
+ tp = SearchSysCache2(ATTNUM,
+ ObjectIdGetDatum(relid),
+ Int16GetDatum(attnum));
+ if (HeapTupleIsValid(tp))
+ {
+ Form_pg_attribute att_tup = (Form_pg_attribute) GETSTRUCT(tp);
+ bool result;
+
+ result = att_tup->attnotnull;
+ ReleaseSysCache(tp);
+ return result;
+ }
+ else
+ return false;
+}
+
/* ---------- COLLATION CACHE ---------- */
/*
diff --git a/src/include/optimizer/clauses.h b/src/include/optimizer/clauses.h
index 5e10fb1d50..b4d189eabc 100644
--- a/src/include/optimizer/clauses.h
+++ b/src/include/optimizer/clauses.h
@@ -44,6 +44,9 @@ extern Relids find_nonnullable_rels(Node *clause);
extern List *find_nonnullable_vars(Node *clause);
extern List *find_forced_null_vars(Node *clause);
extern Var *find_forced_null_var(Node *clause);
+extern bool expressions_are_not_nullable(Query *query, List *exprs,
+ Node *notnull_proofs);
+extern bool query_outputs_are_not_nullable(Query *query);
extern bool is_pseudo_constant_clause(Node *clause);
extern bool is_pseudo_constant_clause_relids(Node *clause, Relids relids);
diff --git a/src/include/optimizer/subselect.h b/src/include/optimizer/subselect.h
index 2d2c3bcbc0..48216a6277 100644
--- a/src/include/optimizer/subselect.h
+++ b/src/include/optimizer/subselect.h
@@ -19,7 +19,9 @@
extern void SS_process_ctes(PlannerInfo *root);
extern JoinExpr *convert_ANY_sublink_to_join(PlannerInfo *root,
SubLink *sublink,
- Relids available_rels);
+ bool under_not,
+ Relids available_rels,
+ Node *notnull_proofs);
extern JoinExpr *convert_EXISTS_sublink_to_join(PlannerInfo *root,
SubLink *sublink,
bool under_not,
diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h
index 16b0b1d2dc..ad1897962c 100644
--- a/src/include/utils/lsyscache.h
+++ b/src/include/utils/lsyscache.h
@@ -76,6 +76,7 @@ extern bool get_ordering_op_properties(Oid opno,
extern Oid get_equality_op_for_ordering_op(Oid opno, bool *reverse);
extern Oid get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type);
extern List *get_mergejoin_opfamilies(Oid opno);
+extern bool has_merge_or_hash_join_opfamilies(Oid opno);
extern bool get_compatible_hash_operators(Oid opno,
Oid *lhs_opno, Oid *rhs_opno);
extern bool get_op_hash_functions(Oid opno,
@@ -89,6 +90,7 @@ extern AttrNumber get_attnum(Oid relid, const char *attname);
extern Oid get_atttype(Oid relid, AttrNumber attnum);
extern void get_atttypetypmodcoll(Oid relid, AttrNumber attnum,
Oid *typid, int32 *typmod, Oid *collid);
+extern bool get_attnotnull(Oid relid, AttrNumber attnum);
extern char *get_collation_name(Oid colloid);
extern char *get_constraint_name(Oid conoid);
extern char *get_language_name(Oid langoid, bool missing_ok);
diff --git a/src/test/regress/expected/subselect.out b/src/test/regress/expected/subselect.out
index fe5fc64480..8917ba35d6 100644
--- a/src/test/regress/expected/subselect.out
+++ b/src/test/regress/expected/subselect.out
@@ -1323,3 +1323,382 @@ select * from x for update;
Output: subselect_tbl.f1, subselect_tbl.f2, subselect_tbl.f3
(2 rows)
+--
+-- Check NOT IN performs an ANTI JOIN when NULLs are not possible
+-- on either side of the, would be, join condition.
+--
+BEGIN;
+CREATE TEMP TABLE a (id INT PRIMARY KEY);
+CREATE TEMP TABLE b (x INT NOT NULL, y INT);
+CREATE TEMP TABLE c (z INT NOT NULL);
+INSERT INTO b VALUES(1,1),(2,2),(3,NULL);
+-- No ANTI JOIN, b.x is from an outer join
+EXPLAIN (COSTS OFF)
+SELECT * FROM a
+LEFT OUTER JOIN b ON a.id = b.x
+WHERE b.x NOT IN(SELECT z FROM c);
+ QUERY PLAN
+------------------------------------
+ Hash Right Join
+ Hash Cond: (b.x = a.id)
+ Filter: (NOT (hashed SubPlan 1))
+ -> Seq Scan on b
+ -> Hash
+ -> Seq Scan on a
+ SubPlan 1
+ -> Seq Scan on c
+(8 rows)
+
+-- ANTI JOIN, b.x is from an outer join but b.x > 100
+-- forces the join not to produce NULL on the righthand
+-- side.
+EXPLAIN (COSTS OFF)
+SELECT * FROM a
+LEFT OUTER JOIN b ON a.id = b.x
+WHERE b.x NOT IN(SELECT z FROM c)
+ AND b.x > 100;
+ QUERY PLAN
+---------------------------------
+ Hash Join
+ Hash Cond: (b.x = a.id)
+ -> Hash Anti Join
+ Hash Cond: (b.x = c.z)
+ -> Seq Scan on b
+ Filter: (x > 100)
+ -> Hash
+ -> Seq Scan on c
+ -> Hash
+ -> Seq Scan on a
+(10 rows)
+
+-- No ANTI JOIN, b.x is from an outer join
+EXPLAIN (COSTS OFF)
+SELECT * FROM a
+FULL OUTER JOIN b ON a.id = b.x
+WHERE b.x NOT IN(SELECT y FROM c);
+ QUERY PLAN
+-----------------------------
+ Hash Full Join
+ Hash Cond: (b.x = a.id)
+ Filter: (NOT (SubPlan 1))
+ -> Seq Scan on b
+ -> Hash
+ -> Seq Scan on a
+ SubPlan 1
+ -> Seq Scan on c
+(8 rows)
+
+-- No ANTI JOIN. y can have NULLs
+EXPLAIN (COSTS OFF)
+SELECT * FROM b WHERE y NOT IN (SELECT z FROM c);
+ QUERY PLAN
+------------------------------------
+ Seq Scan on b
+ Filter: (NOT (hashed SubPlan 1))
+ SubPlan 1
+ -> Seq Scan on c
+(4 rows)
+
+-- c is an empty relation so should cause no filtering on b
+SELECT * FROM b WHERE y NOT IN (SELECT z FROM c);
+ x | y
+---+---
+ 1 | 1
+ 2 | 2
+ 3 |
+(3 rows)
+
+INSERT INTO c VALUES(1);
+-- Records where y is NULL should be filtered out.
+SELECT * FROM b WHERE y NOT IN (SELECT z FROM c);
+ x | y
+---+---
+ 2 | 2
+(1 row)
+
+-- No ANTI JOIN, y can be NULL
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT y FROM b);
+ QUERY PLAN
+------------------------------------
+ Seq Scan on a
+ Filter: (NOT (hashed SubPlan 1))
+ SubPlan 1
+ -> Seq Scan on b
+(4 rows)
+
+-- No ANTI JOIN, x is NOT NULL, but we don't know if + 1 will change that.
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT x+1 FROM b);
+ QUERY PLAN
+------------------------------------
+ Seq Scan on a
+ Filter: (NOT (hashed SubPlan 1))
+ SubPlan 1
+ -> Seq Scan on b
+(4 rows)
+
+-- ANTI JOIN 1 is a Const that is not null.
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT 1 FROM b);
+ QUERY PLAN
+---------------------------
+ Nested Loop Anti Join
+ Join Filter: (a.id = 1)
+ -> Seq Scan on a
+ -> Materialize
+ -> Seq Scan on b
+(5 rows)
+
+-- No ANTI JOIN, results contain a NULL Const
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT NULL::int FROM b);
+ QUERY PLAN
+------------------------------------
+ Seq Scan on a
+ Filter: (NOT (hashed SubPlan 1))
+ SubPlan 1
+ -> Seq Scan on b
+(4 rows)
+
+-- ANTI JOIN y = 1 means y can't be NULL
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT y FROM b WHERE y = 1);
+ QUERY PLAN
+-------------------------------
+ Hash Anti Join
+ Hash Cond: (a.id = b.y)
+ -> Seq Scan on a
+ -> Hash
+ -> Seq Scan on b
+ Filter: (y = 1)
+(6 rows)
+
+-- No ANTI JOIN, OR condition does not ensure y = 1
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT y FROM b WHERE y = 1 OR x = 1);
+ QUERY PLAN
+----------------------------------------
+ Seq Scan on a
+ Filter: (NOT (hashed SubPlan 1))
+ SubPlan 1
+ -> Seq Scan on b
+ Filter: ((y = 1) OR (x = 1))
+(5 rows)
+
+-- No ANTI JOIN, OR condition does not ensure y = 1 or y = 2
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT y FROM b WHERE (y = 1 OR x = 1) AND (y = 2 OR x = 2));
+ QUERY PLAN
+-------------------------------------------------------------------
+ Seq Scan on a
+ Filter: (NOT (hashed SubPlan 1))
+ SubPlan 1
+ -> Seq Scan on b
+ Filter: (((y = 1) OR (x = 1)) AND ((y = 2) OR (x = 2)))
+(5 rows)
+
+-- ANTI JOIN y must be 2, so can't be NULL
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT y FROM b WHERE (y = 1 OR x = 1) AND y = 2);
+ QUERY PLAN
+----------------------------------------------------------
+ Hash Anti Join
+ Hash Cond: (a.id = b.y)
+ -> Seq Scan on a
+ -> Hash
+ -> Seq Scan on b
+ Filter: ((y = 2) AND ((y = 1) OR (x = 1)))
+(6 rows)
+
+-- ANTI JOIN y can be 1 or 2, but can't be null.
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT y FROM b WHERE (y = 1 OR y = 2));
+ QUERY PLAN
+--------------------------------------------
+ Hash Anti Join
+ Hash Cond: (a.id = b.y)
+ -> Seq Scan on a
+ -> Hash
+ -> Seq Scan on b
+ Filter: ((y = 1) OR (y = 2))
+(6 rows)
+
+-- No ANTI JOIN c.z is from a left outer join so it can have nulls.
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT c.z FROM b LEFT JOIN c ON b.x = c.z);
+ QUERY PLAN
+------------------------------------
+ Seq Scan on a
+ Filter: (NOT (hashed SubPlan 1))
+ SubPlan 1
+ -> Merge Left Join
+ Merge Cond: (b.x = c.z)
+ -> Sort
+ Sort Key: b.x
+ -> Seq Scan on b
+ -> Sort
+ Sort Key: c.z
+ -> Seq Scan on c
+(11 rows)
+
+-- ANTI JOIN, c.z is not from an outer join
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT c.z FROM b RIGHT JOIN c ON b.x = c.z);
+ QUERY PLAN
+-----------------------------------------
+ Merge Anti Join
+ Merge Cond: (a.id = c.z)
+ -> Index Only Scan using a_pkey on a
+ -> Merge Left Join
+ Merge Cond: (c.z = b.x)
+ -> Sort
+ Sort Key: c.z
+ -> Seq Scan on c
+ -> Sort
+ Sort Key: b.x
+ -> Seq Scan on b
+(11 rows)
+
+-- No ANTI JOIN, b.x is from an outer join
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT b.x FROM b RIGHT JOIN c ON b.x = c.z);
+ QUERY PLAN
+------------------------------------
+ Seq Scan on a
+ Filter: (NOT (hashed SubPlan 1))
+ SubPlan 1
+ -> Merge Right Join
+ Merge Cond: (b.x = c.z)
+ -> Sort
+ Sort Key: b.x
+ -> Seq Scan on b
+ -> Sort
+ Sort Key: c.z
+ -> Seq Scan on c
+(11 rows)
+
+-- No ANTI JOIN, c.z is from an outer join
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT c.z FROM b FULL JOIN c ON b.x = c.z);
+ QUERY PLAN
+------------------------------------
+ Seq Scan on a
+ Filter: (NOT (hashed SubPlan 1))
+ SubPlan 1
+ -> Merge Full Join
+ Merge Cond: (b.x = c.z)
+ -> Sort
+ Sort Key: b.x
+ -> Seq Scan on b
+ -> Sort
+ Sort Key: c.z
+ -> Seq Scan on c
+(11 rows)
+
+-- No ANTI JOIN, b.x is from an outer join
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT b.x FROM b FULL JOIN c ON b.x = c.z);
+ QUERY PLAN
+------------------------------------
+ Seq Scan on a
+ Filter: (NOT (hashed SubPlan 1))
+ SubPlan 1
+ -> Merge Full Join
+ Merge Cond: (b.x = c.z)
+ -> Sort
+ Sort Key: b.x
+ -> Seq Scan on b
+ -> Sort
+ Sort Key: c.z
+ -> Seq Scan on c
+(11 rows)
+
+-- ANTI JOIN, c.z is from an inner join and has a NOT NULL constraint.
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT c.z FROM b INNER JOIN c ON b.x = c.z);
+ QUERY PLAN
+-----------------------------------------
+ Merge Anti Join
+ Merge Cond: (a.id = c.z)
+ -> Index Only Scan using a_pkey on a
+ -> Merge Join
+ Merge Cond: (b.x = c.z)
+ -> Sort
+ Sort Key: b.x
+ -> Seq Scan on b
+ -> Sort
+ Sort Key: c.z
+ -> Seq Scan on c
+(11 rows)
+
+-- ANTI JOIN, c.z must be 1
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT c.z FROM b LEFT JOIN c ON b.x = c.z WHERE c.z = 1);
+ QUERY PLAN
+-------------------------------------------
+ Hash Anti Join
+ Hash Cond: (a.id = c.z)
+ -> Seq Scan on a
+ -> Hash
+ -> Nested Loop
+ -> Seq Scan on c
+ Filter: (z = 1)
+ -> Materialize
+ -> Seq Scan on b
+ Filter: (x = 1)
+(10 rows)
+
+-- ANTI JOIN, c.z can't be NULL
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT c.z FROM b LEFT JOIN c ON b.x = c.z WHERE c.z IS NOT NULL);
+ QUERY PLAN
+---------------------------------------------
+ Merge Anti Join
+ Merge Cond: (a.id = c.z)
+ -> Index Only Scan using a_pkey on a
+ -> Merge Join
+ Merge Cond: (b.x = c.z)
+ -> Sort
+ Sort Key: b.x
+ -> Seq Scan on b
+ -> Sort
+ Sort Key: c.z
+ -> Seq Scan on c
+ Filter: (z IS NOT NULL)
+(12 rows)
+
+-- ANTI JOIN, b.y cannot be NULL due to the join condition b.y = c.z
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT b.y FROM b INNER JOIN c ON b.y = c.z);
+ QUERY PLAN
+-----------------------------------------
+ Merge Anti Join
+ Merge Cond: (a.id = b.y)
+ -> Index Only Scan using a_pkey on a
+ -> Merge Join
+ Merge Cond: (b.y = c.z)
+ -> Sort
+ Sort Key: b.y
+ -> Seq Scan on b
+ -> Sort
+ Sort Key: c.z
+ -> Seq Scan on c
+(11 rows)
+
+-- No ANTI JOIN when the type's '=' operator is not a member of a btree or
+-- hash opfamily.
+CREATE TEMP TABLE l1 (a LINE NOT NULL);
+CREATE TEMP TABLE l2 (b LINE NOT NULL);
+EXPLAIN (COSTS OFF)
+SELECT * FROM l1 WHERE a NOT IN(SELECT b FROM l2);
+ QUERY PLAN
+------------------------------
+ Seq Scan on l1
+ Filter: (NOT (SubPlan 1))
+ SubPlan 1
+ -> Materialize
+ -> Seq Scan on l2
+(5 rows)
+
+ROLLBACK;
diff --git a/src/test/regress/sql/subselect.sql b/src/test/regress/sql/subselect.sql
index b5931ee700..3d9a2efa33 100644
--- a/src/test/regress/sql/subselect.sql
+++ b/src/test/regress/sql/subselect.sql
@@ -692,3 +692,130 @@ select * from (with x as (select 2 as y) select * from x) ss;
explain (verbose, costs off)
with x as (select * from subselect_tbl)
select * from x for update;
+
+--
+-- Check NOT IN performs an ANTI JOIN when NULLs are not possible
+-- on either side of the, would be, join condition.
+--
+
+BEGIN;
+
+CREATE TEMP TABLE a (id INT PRIMARY KEY);
+CREATE TEMP TABLE b (x INT NOT NULL, y INT);
+CREATE TEMP TABLE c (z INT NOT NULL);
+
+INSERT INTO b VALUES(1,1),(2,2),(3,NULL);
+
+-- No ANTI JOIN, b.x is from an outer join
+EXPLAIN (COSTS OFF)
+SELECT * FROM a
+LEFT OUTER JOIN b ON a.id = b.x
+WHERE b.x NOT IN(SELECT z FROM c);
+
+-- ANTI JOIN, b.x is from an outer join but b.x > 100
+-- forces the join not to produce NULL on the righthand
+-- side.
+EXPLAIN (COSTS OFF)
+SELECT * FROM a
+LEFT OUTER JOIN b ON a.id = b.x
+WHERE b.x NOT IN(SELECT z FROM c)
+ AND b.x > 100;
+
+-- No ANTI JOIN, b.x is from an outer join
+EXPLAIN (COSTS OFF)
+SELECT * FROM a
+FULL OUTER JOIN b ON a.id = b.x
+WHERE b.x NOT IN(SELECT y FROM c);
+
+-- No ANTI JOIN. y can have NULLs
+EXPLAIN (COSTS OFF)
+SELECT * FROM b WHERE y NOT IN (SELECT z FROM c);
+
+-- c is an empty relation so should cause no filtering on b
+SELECT * FROM b WHERE y NOT IN (SELECT z FROM c);
+
+INSERT INTO c VALUES(1);
+
+-- Records where y is NULL should be filtered out.
+SELECT * FROM b WHERE y NOT IN (SELECT z FROM c);
+
+-- No ANTI JOIN, y can be NULL
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT y FROM b);
+
+-- No ANTI JOIN, x is NOT NULL, but we don't know if + 1 will change that.
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT x+1 FROM b);
+
+-- ANTI JOIN 1 is a Const that is not null.
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT 1 FROM b);
+
+-- No ANTI JOIN, results contain a NULL Const
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT NULL::int FROM b);
+
+-- ANTI JOIN y = 1 means y can't be NULL
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT y FROM b WHERE y = 1);
+
+-- No ANTI JOIN, OR condition does not ensure y = 1
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT y FROM b WHERE y = 1 OR x = 1);
+
+-- No ANTI JOIN, OR condition does not ensure y = 1 or y = 2
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT y FROM b WHERE (y = 1 OR x = 1) AND (y = 2 OR x = 2));
+
+-- ANTI JOIN y must be 2, so can't be NULL
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT y FROM b WHERE (y = 1 OR x = 1) AND y = 2);
+
+-- ANTI JOIN y can be 1 or 2, but can't be null.
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT y FROM b WHERE (y = 1 OR y = 2));
+
+-- No ANTI JOIN c.z is from a left outer join so it can have nulls.
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT c.z FROM b LEFT JOIN c ON b.x = c.z);
+
+-- ANTI JOIN, c.z is not from an outer join
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT c.z FROM b RIGHT JOIN c ON b.x = c.z);
+
+-- No ANTI JOIN, b.x is from an outer join
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT b.x FROM b RIGHT JOIN c ON b.x = c.z);
+
+-- No ANTI JOIN, c.z is from an outer join
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT c.z FROM b FULL JOIN c ON b.x = c.z);
+
+-- No ANTI JOIN, b.x is from an outer join
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT b.x FROM b FULL JOIN c ON b.x = c.z);
+
+-- ANTI JOIN, c.z is from an inner join and has a NOT NULL constraint.
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT c.z FROM b INNER JOIN c ON b.x = c.z);
+
+-- ANTI JOIN, c.z must be 1
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT c.z FROM b LEFT JOIN c ON b.x = c.z WHERE c.z = 1);
+
+-- ANTI JOIN, c.z can't be NULL
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT c.z FROM b LEFT JOIN c ON b.x = c.z WHERE c.z IS NOT NULL);
+
+-- ANTI JOIN, b.y cannot be NULL due to the join condition b.y = c.z
+EXPLAIN (COSTS OFF)
+SELECT * FROM a WHERE id NOT IN (SELECT b.y FROM b INNER JOIN c ON b.y = c.z);
+
+-- No ANTI JOIN when the type's '=' operator is not a member of a btree or
+-- hash opfamily.
+CREATE TEMP TABLE l1 (a LINE NOT NULL);
+CREATE TEMP TABLE l2 (b LINE NOT NULL);
+EXPLAIN (COSTS OFF)
+SELECT * FROM l1 WHERE a NOT IN(SELECT b FROM l2);
+
+ROLLBACK;