/*
* have_relevant_joinclause
* Detect whether there is a joinclause that involves
* the two given relations.
*
* Note: the joinclause does not have to be evaluatable with only these two
* relations. This is intentional. For example consider
* SELECT * FROM a, b, c WHERE a.x = (b.y + c.z)
* If a is much larger than the other tables, it may be worthwhile to
* cross-join b and c and then use an inner indexscan on a.x. Therefore
* we should consider this joinclause as reason to join b to c, even though
* it can't be applied at that join step.
*/
bool
have_relevant_joinclause(PlannerInfo *root,
RelOptInfo *rel1, RelOptInfo *rel2)
{
bool result = false;
List *joininfo;
Relids other_relids;
ListCell *l;
/*
* 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;
other_relids = rel2->relids;
}
else
{
joininfo = rel2->joininfo;
other_relids = rel1->relids;
}
foreach(l, joininfo)
{
RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
if (bms_overlap(other_relids, rinfo->required_relids))
{
result = true;
break;
}
}
/*
* Checks if any of the 'attnums' is a partition key attribute for rel
*
* Sets *used_in_expr if any of the 'attnums' is found to be referenced in some
* partition key expression. It's possible for a column to be both used
* directly and as part of an expression; if that happens, *used_in_expr may
* end up as either true or false. That's OK for current uses of this
* function, because *used_in_expr is only used to tailor the error message
* text.
*/
bool
has_partition_attrs(Relation rel, Bitmapset *attnums, bool *used_in_expr)
{
PartitionKey key;
int partnatts;
List *partexprs;
ListCell *partexprs_item;
int i;
if (attnums == NULL || rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
return false;
key = RelationGetPartitionKey(rel);
partnatts = get_partition_natts(key);
partexprs = get_partition_exprs(key);
partexprs_item = list_head(partexprs);
for (i = 0; i < partnatts; i++)
{
AttrNumber partattno = get_partition_col_attnum(key, i);
if (partattno != 0)
{
if (bms_is_member(partattno - FirstLowInvalidHeapAttributeNumber,
attnums))
{
if (used_in_expr)
*used_in_expr = false;
return true;
}
}
else
{
/* Arbitrary expression */
Node *expr = (Node *) lfirst(partexprs_item);
Bitmapset *expr_attrs = NULL;
/* Find all attributes referenced */
pull_varattnos(expr, 1, &expr_attrs);
partexprs_item = lnext(partexprs_item);
if (bms_overlap(attnums, expr_attrs))
{
if (used_in_expr)
*used_in_expr = true;
return true;
}
}
}
return false;
}
static inline bool
allow_star_schema_join(PlannerInfo *root,
Path *outer_path,
Path *inner_path)
{
Relids innerparams = PATH_REQ_OUTER(inner_path);
Relids outerrelids = outer_path->parent->relids;
/*
* It's a star-schema case if the outer rel provides some but not all of
* the inner rel's parameterization.
*/
return (bms_overlap(innerparams, outerrelids) &&
bms_nonempty_difference(innerparams, outerrelids));
}
/*
* 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;
}
/*
* make_restrictinfo_internal
*
* Common code for the main entry points and the recursive cases.
*/
static RestrictInfo *
make_restrictinfo_internal(Expr *clause,
Expr *orclause,
bool is_pushed_down,
bool outerjoin_delayed,
bool pseudoconstant,
Index security_level,
Relids required_relids,
Relids outer_relids,
Relids nullable_relids)
{
RestrictInfo *restrictinfo = makeNode(RestrictInfo);
restrictinfo->clause = clause;
restrictinfo->orclause = orclause;
restrictinfo->is_pushed_down = is_pushed_down;
restrictinfo->outerjoin_delayed = outerjoin_delayed;
restrictinfo->pseudoconstant = pseudoconstant;
restrictinfo->can_join = false; /* may get set below */
restrictinfo->security_level = security_level;
restrictinfo->outer_relids = outer_relids;
restrictinfo->nullable_relids = nullable_relids;
/*
* If it's potentially delayable by lower-level security quals, figure out
* whether it's leakproof. We can skip testing this for level-zero quals,
* since they would never get delayed on security grounds anyway.
*/
if (security_level > 0)
restrictinfo->leakproof = !contain_leaked_vars((Node *) clause);
else
restrictinfo->leakproof = false; /* really, "don't know" */
/*
* If it's a binary opclause, set up left/right relids info. In any case
* set up the total clause relids info.
*/
if (is_opclause(clause) && list_length(((OpExpr *) clause)->args) == 2)
{
restrictinfo->left_relids = pull_varnos(get_leftop(clause));
restrictinfo->right_relids = pull_varnos(get_rightop(clause));
restrictinfo->clause_relids = bms_union(restrictinfo->left_relids,
restrictinfo->right_relids);
/*
* Does it look like a normal join clause, i.e., a binary operator
* relating expressions that come from distinct relations? If so we
* might be able to use it in a join algorithm. Note that this is a
* purely syntactic test that is made regardless of context.
*/
if (!bms_is_empty(restrictinfo->left_relids) &&
!bms_is_empty(restrictinfo->right_relids) &&
!bms_overlap(restrictinfo->left_relids,
restrictinfo->right_relids))
{
restrictinfo->can_join = true;
/* pseudoconstant should certainly not be true */
Assert(!restrictinfo->pseudoconstant);
}
}
else
{
/* Not a binary opclause, so mark left/right relid sets as empty */
restrictinfo->left_relids = NULL;
restrictinfo->right_relids = NULL;
/* and get the total relid set the hard way */
restrictinfo->clause_relids = pull_varnos((Node *) clause);
}
/* required_relids defaults to clause_relids */
if (required_relids != NULL)
restrictinfo->required_relids = required_relids;
else
restrictinfo->required_relids = restrictinfo->clause_relids;
/*
* Fill in all the cacheable fields with "not yet set" markers. None of
* these will be computed until/unless needed. Note in particular that we
* don't mark a binary opclause as mergejoinable or hashjoinable here;
* that happens only if it appears in the right context (top level of a
* joinclause list).
*/
restrictinfo->parent_ec = NULL;
restrictinfo->eval_cost.startup = -1;
restrictinfo->norm_selec = -1;
restrictinfo->outer_selec = -1;
restrictinfo->mergeopfamilies = NIL;
restrictinfo->left_ec = NULL;
restrictinfo->right_ec = NULL;
restrictinfo->left_em = NULL;
restrictinfo->right_em = NULL;
restrictinfo->scansel_cache = NIL;
restrictinfo->outer_is_left = false;
restrictinfo->hashjoinoperator = InvalidOid;
restrictinfo->left_bucketsize = -1;
restrictinfo->right_bucketsize = -1;
restrictinfo->left_mcvfreq = -1;
restrictinfo->right_mcvfreq = -1;
return restrictinfo;
}
