/*
* have_relevant_joinclause
* Detect whether there is a joinclause that can be used to join
* the two given relations.
*/
bool
have_relevant_joinclause(PlannerInfo *root,
RelOptInfo *rel1, RelOptInfo *rel2)
{
bool result = false;
Relids join_relids;
List *joininfo;
ListCell *l;
join_relids = bms_union(rel1->relids, rel2->relids);
/*
* We could scan either relation's joininfo list; may as well use the
* shorter one.
*/
if (list_length(rel1->joininfo) <= list_length(rel2->joininfo))
joininfo = rel1->joininfo;
else
joininfo = rel2->joininfo;
foreach(l, joininfo)
{
RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
if (bms_is_subset(rinfo->required_relids, join_relids))
{
result = true;
break;
}
}
/*
* clause_sides_match_join
* Determine whether a join clause is of the right form to use in this join.
*
* We already know that the clause is a binary opclause referencing only the
* rels in the current join. The point here is to check whether it has the
* form "outerrel_expr op innerrel_expr" or "innerrel_expr op outerrel_expr",
* rather than mixing outer and inner vars on either side. If it matches,
* we set the transient flag outer_is_left to identify which side is which.
*/
static inline bool
clause_sides_match_join(RestrictInfo *rinfo, RelOptInfo *outerrel,
RelOptInfo *innerrel)
{
if (bms_is_subset(rinfo->left_relids, outerrel->relids) &&
bms_is_subset(rinfo->right_relids, innerrel->relids))
{
/* lefthand side is outer */
rinfo->outer_is_left = true;
return true;
}
else if (bms_is_subset(rinfo->left_relids, innerrel->relids) &&
bms_is_subset(rinfo->right_relids, outerrel->relids))
{
/* righthand side is outer */
rinfo->outer_is_left = false;
return true;
}
return false; /* no good for these input relations */
}
/*
* Does the supplied GpPolicy support unique indexing on the specified
* attributes?
*
* If the table is distributed randomly, no unique indexing is supported.
* Otherwise, the set of columns being indexed should be a superset of the
* policy.
*
* If the proposed index does not match the distribution policy but the relation
* is empty and does not have a primary key or unique index, update the
* distribution policy to match the index definition (MPP-101), as long as it
* doesn't contain expressions.
*/
void
checkPolicyForUniqueIndex(Relation rel, AttrNumber *indattr, int nidxatts,
bool isprimary, bool has_exprs, bool has_pkey,
bool has_ukey)
{
Bitmapset *polbm = NULL;
Bitmapset *indbm = NULL;
int i;
GpPolicy *pol = rel->rd_cdbpolicy;
/*
* Firstly, unique/primary key indexes aren't supported if we're
* distributing randomly.
*/
if (GpPolicyIsRandomly(pol))
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("%s and DISTRIBUTED RANDOMLY are incompatible",
isprimary ? "PRIMARY KEY" : "UNIQUE")));
}
/*
* We use bitmaps to make intersection tests easier. As noted, order is
* not relevant so looping is just painful.
*/
for (i = 0; i < pol->nattrs; i++)
polbm = bms_add_member(polbm, pol->attrs[i]);
for (i = 0; i < nidxatts; i++)
{
if (indattr[i] < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot create %s on system column",
isprimary ? "primary key" : "unique index")));
indbm = bms_add_member(indbm, indattr[i]);
}
Assert(bms_membership(polbm) != BMS_EMPTY_SET);
Assert(bms_membership(indbm) != BMS_EMPTY_SET);
/*
* If the existing policy is not a subset, we must either error out or
* update the distribution policy. It might be tempting to say that even
* when the policy is a subset, we should update it to match the index
* definition. The problem then is that if the user actually wants to
* distribution on (a, b) but then creates an index on (a, b, c) we'll
* change the policy underneath them.
*
* What is really needed is a new field in gp_distribution_policy telling us
* if the policy has been explicitly set.
*/
if (!bms_is_subset(polbm, indbm))
{
if (cdbRelSize(rel) != 0 || has_pkey || has_ukey || has_exprs)
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("%s must contain all columns in the "
"distribution key of relation \"%s\"",
isprimary ? "PRIMARY KEY" : "UNIQUE index",
RelationGetRelationName(rel))));
}
else
{
/* update policy since table is not populated yet. See MPP-101 */
GpPolicy *policy = palloc(sizeof(GpPolicy) +
(sizeof(AttrNumber) * nidxatts));
policy->ptype = POLICYTYPE_PARTITIONED;
policy->nattrs = 0;
for (i = 0; i < nidxatts; i++)
policy->attrs[policy->nattrs++] = indattr[i];
GpPolicyReplace(rel->rd_id, policy);
if (isprimary)
elog(NOTICE, "updating distribution policy to match new primary key");
else
elog(NOTICE, "updating distribution policy to match new unique index");
}
}
}
/*
* join_is_removable
* Determine whether we need not perform the join at all, because
* it will just duplicate its left input.
*
* This is true for a left join for which the join condition cannot match
* more than one inner-side row. (There are other possibly interesting
* cases, but we don't have the infrastructure to prove them.)
*
* Note: there is no need to consider the symmetrical case of duplicating the
* right input, because add_paths_to_joinrel() will be called with each rel
* on the outer side.
*/
static bool
join_is_removable(PlannerInfo *root,
RelOptInfo *joinrel,
RelOptInfo *outerrel,
RelOptInfo *innerrel,
List *restrictlist,
JoinType jointype)
{
List *clause_list = NIL;
ListCell *l;
int attroff;
/*
* Currently, we only know how to remove left joins to a baserel with
* unique indexes. We can check most of these criteria pretty trivially
* to avoid doing useless extra work. But checking whether any of the
* indexes are unique would require iterating over the indexlist, so for
* now we just make sure there are indexes of some sort or other. If none
* of them are unique, join removal will still fail, just slightly later.
*/
if (jointype != JOIN_LEFT ||
innerrel->reloptkind == RELOPT_JOINREL ||
innerrel->rtekind != RTE_RELATION ||
innerrel->indexlist == NIL)
return false;
/*
* We can't remove the join if any inner-rel attributes are used above the
* join.
*
* Note that this test only detects use of inner-rel attributes in higher
* join conditions and the target list. There might be such attributes in
* pushed-down conditions at this join, too. We check that case below.
*
* As a micro-optimization, it seems better to start with max_attr and
* count down rather than starting with min_attr and counting up, on the
* theory that the system attributes are somewhat less likely to be wanted
* and should be tested last.
*/
for (attroff = innerrel->max_attr - innerrel->min_attr;
attroff >= 0;
attroff--)
{
if (!bms_is_subset(innerrel->attr_needed[attroff], joinrel->relids))
return false;
}
/*
* Search for mergejoinable clauses that constrain the inner rel against
* either the outer rel or a pseudoconstant. If an operator is
* mergejoinable then it behaves like equality for some btree opclass, so
* it's what we want. The mergejoinability test also eliminates clauses
* containing volatile functions, which we couldn't depend on.
*/
foreach(l, restrictlist)
{
RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(l);
/*
* If we find a pushed-down clause, it must have come from above the
* outer join and it must contain references to the inner rel. (If it
* had only outer-rel variables, it'd have been pushed down into the
* outer rel.) Therefore, we can conclude that join removal is unsafe
* without any examination of the clause contents.
*/
if (restrictinfo->is_pushed_down)
return false;
/* Ignore if it's not a mergejoinable clause */
if (!restrictinfo->can_join ||
restrictinfo->mergeopfamilies == NIL)
continue; /* not mergejoinable */
/*
* Check if clause has the form "outer op inner" or "inner op outer".
*/
if (!clause_sides_match_join(restrictinfo, outerrel, innerrel))
continue; /* no good for these input relations */
/* OK, add to list */
clause_list = lappend(clause_list, restrictinfo);
}
/*
* make_join_rel
* Find or create a join RelOptInfo that represents the join of
* the two given rels, and add to it path information for paths
* created with the two rels as outer and inner rel.
* (The join rel may already contain paths generated from other
* pairs of rels that add up to the same set of base rels.)
*
* NB: will return NULL if attempted join is not valid. This can happen
* when working with outer joins, or with IN or EXISTS clauses that have been
* turned into joins.
*/
RelOptInfo *
make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
{
Relids joinrelids;
SpecialJoinInfo *sjinfo;
bool reversed;
SpecialJoinInfo sjinfo_data;
RelOptInfo *joinrel;
List *restrictlist;
/* We should never try to join two overlapping sets of rels. */
Assert(!bms_overlap(rel1->relids, rel2->relids));
/* Construct Relids set that identifies the joinrel. */
joinrelids = bms_union(rel1->relids, rel2->relids);
/* Check validity and determine join type. */
if (!join_is_legal(root, rel1, rel2, joinrelids,
&sjinfo, &reversed))
{
/* invalid join path */
bms_free(joinrelids);
return NULL;
}
/* Swap rels if needed to match the join info. */
if (reversed)
{
RelOptInfo *trel = rel1;
rel1 = rel2;
rel2 = trel;
}
/*
* If it's a plain inner join, then we won't have found anything in
* join_info_list. Make up a SpecialJoinInfo so that selectivity
* estimation functions will know what's being joined.
*/
if (sjinfo == NULL)
{
sjinfo = &sjinfo_data;
sjinfo->type = T_SpecialJoinInfo;
sjinfo->min_lefthand = rel1->relids;
sjinfo->min_righthand = rel2->relids;
sjinfo->syn_lefthand = rel1->relids;
sjinfo->syn_righthand = rel2->relids;
sjinfo->jointype = JOIN_INNER;
/* we don't bother trying to make the remaining fields valid */
sjinfo->lhs_strict = false;
sjinfo->delay_upper_joins = false;
sjinfo->semi_can_btree = false;
sjinfo->semi_can_hash = false;
sjinfo->semi_operators = NIL;
sjinfo->semi_rhs_exprs = NIL;
}
/*
* Find or build the join RelOptInfo, and compute the restrictlist that
* goes with this particular joining.
*/
joinrel = build_join_rel(root, joinrelids, rel1, rel2, sjinfo,
&restrictlist);
/* !!! START: HERE IS THE PART WHICH ADDED FOR PG_HINT_PLAN !!! */
{
RowsHint *rows_hint = NULL;
int i;
RowsHint *justforme = NULL;
RowsHint *domultiply = NULL;
/* Search for applicable rows hint for this join node */
for (i = 0; i < current_hint->num_hints[HINT_TYPE_ROWS]; i++)
{
rows_hint = current_hint->rows_hints[i];
/*
* Skip this rows_hint if it is invalid from the first or it
* doesn't target any join rels.
*/
if (!rows_hint->joinrelids ||
rows_hint->base.state == HINT_STATE_ERROR)
continue;
if (bms_equal(joinrelids, rows_hint->joinrelids))
{
/*
* This joinrel is just the target of this rows_hint, so tweak
* rows estimation according to the hint.
*/
justforme = rows_hint;
}
else if (!(bms_is_subset(rows_hint->joinrelids, rel1->relids) ||
bms_is_subset(rows_hint->joinrelids, rel2->relids)) &&
bms_is_subset(rows_hint->joinrelids, joinrelids) &&
rows_hint->value_type == RVT_MULTI)
{
/*
* If the rows_hint's target relids is not a subset of both of
* component rels and is a subset of this joinrel, ths hint's
* targets spread over both component rels. This menas that
* this hint has been never applied so far and this joinrel is
* the first (and only) chance to fire in current join tree.
* Only the multiplication hint has the cumulative nature so we
* apply only RVT_MULTI in this way.
*/
domultiply = rows_hint;
}
}
if (justforme)
{
/*
* If a hint just for me is found, no other adjust method is
* useles, but this cannot be more than twice becuase this joinrel
* is already adjusted by this hint.
*/
if (justforme->base.state == HINT_STATE_NOTUSED)
joinrel->rows = adjust_rows(joinrel->rows, justforme);
}
else
{
if (domultiply)
{
/*
* If we have multiple routes up to this joinrel which are not
* applicable this hint, this multiply hint will applied more
* than twice. But there's no means to know of that,
* re-estimate the row number of this joinrel always just
* before applying the hint. This is a bit different from
* normal planner behavior but it doesn't harm so much.
*/
set_joinrel_size_estimates(root, joinrel, rel1, rel2, sjinfo,
restrictlist);
joinrel->rows = adjust_rows(joinrel->rows, domultiply);
}
}
}
/* !!! END: HERE IS THE PART WHICH ADDED FOR PG_HINT_PLAN !!! */
/*
* If we've already proven this join is empty, we needn't consider any
* more paths for it.
*/
if (is_dummy_rel(joinrel))
{
bms_free(joinrelids);
return joinrel;
}
/*
* Consider paths using each rel as both outer and inner. Depending on
* the join type, a provably empty outer or inner rel might mean the join
* is provably empty too; in which case throw away any previously computed
* paths and mark the join as dummy. (We do it this way since it's
* conceivable that dummy-ness of a multi-element join might only be
* noticeable for certain construction paths.)
*
* Also, a provably constant-false join restriction typically means that
* we can skip evaluating one or both sides of the join. We do this by
* marking the appropriate rel as dummy. For outer joins, a
* constant-false restriction that is pushed down still means the whole
* join is dummy, while a non-pushed-down one means that no inner rows
* will join so we can treat the inner rel as dummy.
*
* We need only consider the jointypes that appear in join_info_list, plus
* JOIN_INNER.
*/
switch (sjinfo->jointype)
{
case JOIN_INNER:
if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
restriction_is_constant_false(restrictlist, false))
{
mark_dummy_rel(joinrel);
break;
}
add_paths_to_joinrel(root, joinrel, rel1, rel2,
JOIN_INNER, sjinfo,
restrictlist);
add_paths_to_joinrel(root, joinrel, rel2, rel1,
JOIN_INNER, sjinfo,
restrictlist);
break;
case JOIN_LEFT:
if (is_dummy_rel(rel1) ||
restriction_is_constant_false(restrictlist, true))
{
mark_dummy_rel(joinrel);
break;
}
if (restriction_is_constant_false(restrictlist, false) &&
bms_is_subset(rel2->relids, sjinfo->syn_righthand))
mark_dummy_rel(rel2);
add_paths_to_joinrel(root, joinrel, rel1, rel2,
JOIN_LEFT, sjinfo,
restrictlist);
add_paths_to_joinrel(root, joinrel, rel2, rel1,
JOIN_RIGHT, sjinfo,
restrictlist);
break;
case JOIN_FULL:
if ((is_dummy_rel(rel1) && is_dummy_rel(rel2)) ||
restriction_is_constant_false(restrictlist, true))
{
mark_dummy_rel(joinrel);
break;
}
add_paths_to_joinrel(root, joinrel, rel1, rel2,
JOIN_FULL, sjinfo,
restrictlist);
add_paths_to_joinrel(root, joinrel, rel2, rel1,
JOIN_FULL, sjinfo,
restrictlist);
/*
* If there are join quals that aren't mergeable or hashable, we
* may not be able to build any valid plan. Complain here so that
* we can give a somewhat-useful error message. (Since we have no
* flexibility of planning for a full join, there's no chance of
* succeeding later with another pair of input rels.)
*/
if (joinrel->pathlist == NIL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("FULL JOIN is only supported with merge-joinable or hash-joinable join conditions")));
break;
case JOIN_SEMI:
/*
* We might have a normal semijoin, or a case where we don't have
* enough rels to do the semijoin but can unique-ify the RHS and
* then do an innerjoin (see comments in join_is_legal). In the
* latter case we can't apply JOIN_SEMI joining.
*/
if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
bms_is_subset(sjinfo->min_righthand, rel2->relids))
{
if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
restriction_is_constant_false(restrictlist, false))
{
mark_dummy_rel(joinrel);
break;
}
add_paths_to_joinrel(root, joinrel, rel1, rel2,
JOIN_SEMI, sjinfo,
restrictlist);
}
/*
* If we know how to unique-ify the RHS and one input rel is
* exactly the RHS (not a superset) we can consider unique-ifying
* it and then doing a regular join. (The create_unique_path
* check here is probably redundant with what join_is_legal did,
* but if so the check is cheap because it's cached. So test
* anyway to be sure.)
*/
if (bms_equal(sjinfo->syn_righthand, rel2->relids) &&
create_unique_path(root, rel2, rel2->cheapest_total_path,
sjinfo) != NULL)
{
if (is_dummy_rel(rel1) || is_dummy_rel(rel2) ||
restriction_is_constant_false(restrictlist, false))
{
mark_dummy_rel(joinrel);
break;
}
add_paths_to_joinrel(root, joinrel, rel1, rel2,
JOIN_UNIQUE_INNER, sjinfo,
restrictlist);
add_paths_to_joinrel(root, joinrel, rel2, rel1,
JOIN_UNIQUE_OUTER, sjinfo,
restrictlist);
}
break;
case JOIN_ANTI:
if (is_dummy_rel(rel1) ||
restriction_is_constant_false(restrictlist, true))
{
mark_dummy_rel(joinrel);
break;
}
if (restriction_is_constant_false(restrictlist, false) &&
bms_is_subset(rel2->relids, sjinfo->syn_righthand))
mark_dummy_rel(rel2);
add_paths_to_joinrel(root, joinrel, rel1, rel2,
JOIN_ANTI, sjinfo,
restrictlist);
break;
default:
/* other values not expected here */
elog(ERROR, "unrecognized join type: %d", (int) sjinfo->jointype);
break;
}
bms_free(joinrelids);
return joinrel;
}
