* core.c
* Routines copied from PostgreSQL core distribution.
*
+ * The main purpose of this files is having access to static functions in core.
+ * Another purpose is tweaking functions behavior by replacing part of them by
+ * macro definitions. See at the end of pg_hint_plan.c for details. Anyway,
+ * this file *must* contain required functions without making any change.
+ *
+ * This file contains the following functions from corresponding files.
+ *
* src/backend/optimizer/path/allpaths.c
- * set_append_rel_pathlist()
- * generate_mergeappend_paths()
- * accumulate_append_subpath()
- * standard_join_search()
+ *
+ * static functions:
+ * set_plain_rel_pathlist()
+ * add_paths_to_append_rel()
+ * try_partitionwise_join()
+ *
+ * public functions:
+ * standard_join_search(): This funcion is not static. The reason for
+ * including this function is make_rels_by_clause_joins. In order to
+ * avoid generating apparently unwanted join combination, we decided to
+ * change the behavior of make_join_rel, which is called under this
+ * function.
*
* src/backend/optimizer/path/joinrels.c
- * join_search_one_level()
+ *
+ * public functions:
+ * join_search_one_level(): We have to modify this to call my definition of
+ * make_rels_by_clause_joins.
+ *
+ * static functions:
* make_rels_by_clause_joins()
* make_rels_by_clauseless_joins()
* join_is_legal()
* has_join_restriction()
* is_dummy_rel()
- * mark_dummy_rel()
* restriction_is_constant_false()
+ * update_child_rel_info()
+ * build_child_join_sjinfo()
*
- * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
+ *
+ * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*-------------------------------------------------------------------------
*/
+static void populate_joinrel_with_paths(PlannerInfo *root, RelOptInfo *rel1,
+ RelOptInfo *rel2, RelOptInfo *joinrel,
+ SpecialJoinInfo *sjinfo, List *restrictlist);
+
+/*
+ * set_plain_rel_pathlist
+ * Build access paths for a plain relation (no subquery, no inheritance)
+ */
+static void
+set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
+{
+ Relids required_outer;
+
+ /*
+ * We don't support pushing join clauses into the quals of a seqscan, but
+ * it could still have required parameterization due to LATERAL refs in
+ * its tlist.
+ */
+ required_outer = rel->lateral_relids;
+
+ /* Consider sequential scan */
+ add_path(rel, create_seqscan_path(root, rel, required_outer, 0));
+
+ /* If appropriate, consider parallel sequential scan */
+ if (rel->consider_parallel && required_outer == NULL)
+ create_plain_partial_paths(root, rel);
+
+ /* Consider index scans */
+ create_index_paths(root, rel);
+
+ /* Consider TID scans */
+ create_tidscan_paths(root, rel);
+}
+
+
/*
* set_append_rel_pathlist
* Build access paths for an "append relation"
{
int parentRTindex = rti;
List *live_childrels = NIL;
- List *subpaths = NIL;
- List *all_child_pathkeys = NIL;
- List *all_child_outers = NIL;
ListCell *l;
/*
* Generate access paths for each member relation, and remember the
- * cheapest path for each one. Also, identify all pathkeys (orderings)
- * and parameterizations (required_outer sets) available for the member
- * relations.
+ * non-dummy children.
*/
foreach(l, root->append_rel_list)
{
int childRTindex;
RangeTblEntry *childRTE;
RelOptInfo *childrel;
- ListCell *lcp;
/* append_rel_list contains all append rels; ignore others */
if (appinfo->parent_relid != parentRTindex)
childrel = root->simple_rel_array[childRTindex];
/*
+ * If set_append_rel_size() decided the parent appendrel was
+ * parallel-unsafe at some point after visiting this child rel, we
+ * need to propagate the unsafety marking down to the child, so that
+ * we don't generate useless partial paths for it.
+ */
+ if (!rel->consider_parallel)
+ childrel->consider_parallel = false;
+
+ /*
* Compute the child's access paths.
*/
set_rel_pathlist(root, childrel, childRTindex, childRTE);
if (IS_DUMMY_REL(childrel))
continue;
- /*
- * Child is live, so add its cheapest access path to the Append path
- * we are constructing for the parent.
- */
- subpaths = accumulate_append_subpath(subpaths,
- childrel->cheapest_total_path);
-
- /* Remember which childrels are live, for logic below */
- live_childrels = lappend(live_childrels, childrel);
+ /* Bubble up childrel's partitioned children. */
+ if (rel->part_scheme)
+ rel->partitioned_child_rels =
+ list_concat(rel->partitioned_child_rels,
+ list_copy(childrel->partitioned_child_rels));
/*
- * Collect lists of all the available path orderings and
- * parameterizations for all the children. We use these as a
- * heuristic to indicate which sort orderings and parameterizations we
- * should build Append and MergeAppend paths for.
+ * Child is live, so add it to the live_childrels list for use below.
*/
- foreach(lcp, childrel->pathlist)
- {
- Path *childpath = (Path *) lfirst(lcp);
- List *childkeys = childpath->pathkeys;
- Relids childouter = PATH_REQ_OUTER(childpath);
-
- /* Unsorted paths don't contribute to pathkey list */
- if (childkeys != NIL)
- {
- ListCell *lpk;
- bool found = false;
-
- /* Have we already seen this ordering? */
- foreach(lpk, all_child_pathkeys)
- {
- List *existing_pathkeys = (List *) lfirst(lpk);
-
- if (compare_pathkeys(existing_pathkeys,
- childkeys) == PATHKEYS_EQUAL)
- {
- found = true;
- break;
- }
- }
- if (!found)
- {
- /* No, so add it to all_child_pathkeys */
- all_child_pathkeys = lappend(all_child_pathkeys,
- childkeys);
- }
- }
-
- /* Unparameterized paths don't contribute to param-set list */
- if (childouter)
- {
- ListCell *lco;
- bool found = false;
-
- /* Have we already seen this param set? */
- foreach(lco, all_child_outers)
- {
- Relids existing_outers = (Relids) lfirst(lco);
-
- if (bms_equal(existing_outers, childouter))
- {
- found = true;
- break;
- }
- }
- if (!found)
- {
- /* No, so add it to all_child_outers */
- all_child_outers = lappend(all_child_outers,
- childouter);
- }
- }
- }
- }
-
- /*
- * Next, build an unordered, unparameterized Append path for the rel.
- * (Note: this is correct even if we have zero or one live subpath due to
- * constraint exclusion.)
- */
- add_path(rel, (Path *) create_append_path(rel, subpaths, NULL));
-
- /*
- * Build unparameterized MergeAppend paths based on the collected list of
- * child pathkeys.
- */
- generate_mergeappend_paths(root, rel, live_childrels, all_child_pathkeys);
-
- /*
- * Build Append paths for each parameterization seen among the child rels.
- * (This may look pretty expensive, but in most cases of practical
- * interest, the child rels will expose mostly the same parameterizations,
- * so that not that many cases actually get considered here.)
- *
- * The Append node itself cannot enforce quals, so all qual checking must
- * be done in the child paths. This means that to have a parameterized
- * Append path, we must have the exact same parameterization for each
- * child path; otherwise some children might be failing to check the
- * moved-down quals. To make them match up, we can try to increase the
- * parameterization of lesser-parameterized paths.
- */
- foreach(l, all_child_outers)
- {
- Relids required_outer = (Relids) lfirst(l);
- bool ok = true;
- ListCell *lcr;
-
- /* Select the child paths for an Append with this parameterization */
- subpaths = NIL;
- foreach(lcr, live_childrels)
- {
- RelOptInfo *childrel = (RelOptInfo *) lfirst(lcr);
- Path *cheapest_total;
-
- cheapest_total =
- get_cheapest_path_for_pathkeys(childrel->pathlist,
- NIL,
- required_outer,
- TOTAL_COST);
- Assert(cheapest_total != NULL);
-
- /* Children must have exactly the desired parameterization */
- if (!bms_equal(PATH_REQ_OUTER(cheapest_total), required_outer))
- {
- cheapest_total = reparameterize_path(root, cheapest_total,
- required_outer, 1.0);
- if (cheapest_total == NULL)
- {
- ok = false;
- break;
- }
- }
-
- subpaths = accumulate_append_subpath(subpaths, cheapest_total);
- }
-
- if (ok)
- add_path(rel, (Path *)
- create_append_path(rel, subpaths, required_outer));
+ live_childrels = lappend(live_childrels, childrel);
}
- /* Select cheapest paths */
- set_cheapest(rel);
-}
-
-/*
- * generate_mergeappend_paths
- * Generate MergeAppend paths for an append relation
- *
- * Generate a path for each ordering (pathkey list) appearing in
- * all_child_pathkeys.
- *
- * We consider both cheapest-startup and cheapest-total cases, ie, for each
- * interesting ordering, collect all the cheapest startup subpaths and all the
- * cheapest total paths, and build a MergeAppend path for each case.
- *
- * We don't currently generate any parameterized MergeAppend paths. While
- * it would not take much more code here to do so, it's very unclear that it
- * is worth the planning cycles to investigate such paths: there's little
- * use for an ordered path on the inside of a nestloop. In fact, it's likely
- * that the current coding of add_path would reject such paths out of hand,
- * because add_path gives no credit for sort ordering of parameterized paths,
- * and a parameterized MergeAppend is going to be more expensive than the
- * corresponding parameterized Append path. If we ever try harder to support
- * parameterized mergejoin plans, it might be worth adding support for
- * parameterized MergeAppends to feed such joins. (See notes in
- * optimizer/README for why that might not ever happen, though.)
- */
-static void
-generate_mergeappend_paths(PlannerInfo *root, RelOptInfo *rel,
- List *live_childrels,
- List *all_child_pathkeys)
-{
- ListCell *lcp;
-
- foreach(lcp, all_child_pathkeys)
- {
- List *pathkeys = (List *) lfirst(lcp);
- List *startup_subpaths = NIL;
- List *total_subpaths = NIL;
- bool startup_neq_total = false;
- ListCell *lcr;
-
- /* Select the child paths for this ordering... */
- foreach(lcr, live_childrels)
- {
- RelOptInfo *childrel = (RelOptInfo *) lfirst(lcr);
- Path *cheapest_startup,
- *cheapest_total;
-
- /* Locate the right paths, if they are available. */
- cheapest_startup =
- get_cheapest_path_for_pathkeys(childrel->pathlist,
- pathkeys,
- NULL,
- STARTUP_COST);
- cheapest_total =
- get_cheapest_path_for_pathkeys(childrel->pathlist,
- pathkeys,
- NULL,
- TOTAL_COST);
-
- /*
- * If we can't find any paths with the right order just use the
- * cheapest-total path; we'll have to sort it later.
- */
- if (cheapest_startup == NULL || cheapest_total == NULL)
- {
- cheapest_startup = cheapest_total =
- childrel->cheapest_total_path;
- Assert(cheapest_total != NULL);
- }
-
- /*
- * Notice whether we actually have different paths for the
- * "cheapest" and "total" cases; frequently there will be no point
- * in two create_merge_append_path() calls.
- */
- if (cheapest_startup != cheapest_total)
- startup_neq_total = true;
-
- startup_subpaths =
- accumulate_append_subpath(startup_subpaths, cheapest_startup);
- total_subpaths =
- accumulate_append_subpath(total_subpaths, cheapest_total);
- }
-
- /* ... and build the MergeAppend paths */
- add_path(rel, (Path *) create_merge_append_path(root,
- rel,
- startup_subpaths,
- pathkeys,
- NULL));
- if (startup_neq_total)
- add_path(rel, (Path *) create_merge_append_path(root,
- rel,
- total_subpaths,
- pathkeys,
- NULL));
- }
+ /* Add paths to the append relation. */
+ add_paths_to_append_rel(root, rel, live_childrels);
}
-/*
- * accumulate_append_subpath
- * Add a subpath to the list being built for an Append or MergeAppend
- *
- * It's possible that the child is itself an Append path, in which case
- * we can "cut out the middleman" and just add its child paths to our
- * own list. (We don't try to do this earlier because we need to
- * apply both levels of transformation to the quals.)
- */
-static List *
-accumulate_append_subpath(List *subpaths, Path *path)
-{
- if (IsA(path, AppendPath))
- {
- AppendPath *apath = (AppendPath *) path;
-
- /* list_copy is important here to avoid sharing list substructure */
- return list_concat(subpaths, list_copy(apath->subpaths));
- }
- else
- return lappend(subpaths, path);
-}
/*
* standard_join_search
* independent jointree items in the query. This is > 1.
*
* 'initial_rels' is a list of RelOptInfo nodes for each independent
- * jointree item. These are the components to be joined together.
+ * jointree item. These are the components to be joined together.
* Note that levels_needed == list_length(initial_rels).
*
* Returns the final level of join relations, i.e., the relation that is
* needed for these paths need have been instantiated.
*
* Note to plugin authors: the functions invoked during standard_join_search()
- * modify root->join_rel_list and root->join_rel_hash. If you want to do more
+ * modify root->join_rel_list and root->join_rel_hash. If you want to do more
* than one join-order search, you'll probably need to save and restore the
* original states of those data structures. See geqo_eval() for an example.
*/
join_search_one_level(root, lev);
/*
- * Do cleanup work on each just-processed rel.
+ * Run generate_partitionwise_join_paths() and generate_gather_paths()
+ * for each just-processed joinrel. We could not do this earlier
+ * because both regular and partial paths can get added to a
+ * particular joinrel at multiple times within join_search_one_level.
+ *
+ * After that, we're done creating paths for the joinrel, so run
+ * set_cheapest().
*/
foreach(lc, root->join_rel_level[lev])
{
rel = (RelOptInfo *) lfirst(lc);
+ /* Create paths for partitionwise joins. */
+ generate_partitionwise_join_paths(root, rel);
+
+ /*
+ * Except for the topmost scan/join rel, consider gathering
+ * partial paths. We'll do the same for the topmost scan/join rel
+ * once we know the final targetlist (see grouping_planner).
+ */
+ if (lev < levels_needed)
+ generate_gather_paths(root, rel, false);
+
/* Find and save the cheapest paths for this rel */
set_cheapest(rel);
}
/*
+ * create_plain_partial_paths
+ * Build partial access paths for parallel scan of a plain relation
+ */
+static void
+create_plain_partial_paths(PlannerInfo *root, RelOptInfo *rel)
+{
+ int parallel_workers;
+
+ parallel_workers = compute_parallel_worker(rel, rel->pages, -1,
+ max_parallel_workers_per_gather);
+
+ /* If any limit was set to zero, the user doesn't want a parallel scan. */
+ if (parallel_workers <= 0)
+ return;
+
+ /* Add an unordered partial path based on a parallel sequential scan. */
+ add_partial_path(rel, create_seqscan_path(root, rel, NULL, parallel_workers));
+}
+
+
+/*
* join_search_one_level
* Consider ways to produce join relations containing exactly 'level'
* jointree items. (This is one step of the dynamic-programming method
if (level == 2) /* consider remaining initial rels */
other_rels = lnext(r);
- else /* consider all initial rels */
+ else /* consider all initial rels */
other_rels = list_head(joinrels[1]);
make_rels_by_clause_joins(root,
/*----------
* When special joins are involved, there may be no legal way
- * to make an N-way join for some values of N. For example consider
+ * to make an N-way join for some values of N. For example consider
*
* SELECT ... FROM t1 WHERE
* x IN (SELECT ... FROM t2,t3 WHERE ...) AND
* to accept failure at level 4 and go on to discover a workable
* bushy plan at level 5.
*
- * However, if there are no special joins then join_is_legal() should
- * never fail, and so the following sanity check is useful.
+ * However, if there are no special joins and no lateral references
+ * then join_is_legal() should never fail, and so the following sanity
+ * check is useful.
*----------
*/
- if (joinrels[level] == NIL && root->join_info_list == NIL)
+ if (joinrels[level] == NIL &&
+ root->join_info_list == NIL &&
+ !root->hasLateralRTEs)
elog(ERROR, "failed to build any %d-way joins", level);
}
}
+
/*
* make_rels_by_clause_joins
* Build joins between the given relation 'old_rel' and other relations
}
}
+
/*
* make_rels_by_clauseless_joins
* Given a relation 'old_rel' and a list of other relations
}
}
+
/*
* join_is_legal
* Determine whether a proposed join is legal given the query's
*
* On success, *sjinfo_p is set to NULL if this is to be a plain inner join,
* else it's set to point to the associated SpecialJoinInfo node. Also,
- * *reversed_p is set TRUE if the given relations need to be swapped to
+ * *reversed_p is set true if the given relations need to be swapped to
* match the SpecialJoinInfo node.
*/
static bool
SpecialJoinInfo *match_sjinfo;
bool reversed;
bool unique_ified;
- bool is_valid_inner;
+ bool must_be_leftjoin;
ListCell *l;
/*
- * Ensure output params are set on failure return. This is just to
+ * Ensure output params are set on failure return. This is just to
* suppress uninitialized-variable warnings from overly anal compilers.
*/
*sjinfo_p = NULL;
/*
* If we have any special joins, the proposed join might be illegal; and
- * in any case we have to determine its join type. Scan the join info
- * list for conflicts.
+ * in any case we have to determine its join type. Scan the join info
+ * list for matches and conflicts.
*/
match_sjinfo = NULL;
reversed = false;
unique_ified = false;
- is_valid_inner = true;
+ must_be_leftjoin = false;
foreach(l, root->join_info_list)
{
* If one input contains min_lefthand and the other contains
* min_righthand, then we can perform the SJ at this join.
*
- * Barf if we get matches to more than one SJ (is that possible?)
+ * Reject if we get matches to more than one SJ; that implies we're
+ * considering something that's not really valid.
*/
if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) &&
bms_is_subset(sjinfo->min_righthand, rel2->relids))
}
else
{
- /*----------
- * Otherwise, the proposed join overlaps the RHS but isn't
- * a valid implementation of this SJ. It might still be
- * a legal join, however. If both inputs overlap the RHS,
- * assume that it's OK. Since the inputs presumably got past
- * this function's checks previously, they can't overlap the
- * LHS and their violations of the RHS boundary must represent
- * SJs that have been determined to commute with this one.
- * We have to allow this to work correctly in cases like
- * (a LEFT JOIN (b JOIN (c LEFT JOIN d)))
- * when the c/d join has been determined to commute with the join
- * to a, and hence d is not part of min_righthand for the upper
- * join. It should be legal to join b to c/d but this will appear
- * as a violation of the upper join's RHS.
- * Furthermore, if one input overlaps the RHS and the other does
- * not, we should still allow the join if it is a valid
- * implementation of some other SJ. We have to allow this to
- * support the associative identity
- * (a LJ b on Pab) LJ c ON Pbc = a LJ (b LJ c ON Pbc) on Pab
- * since joining B directly to C violates the lower SJ's RHS.
- * We assume that make_outerjoininfo() set things up correctly
- * so that we'll only match to some SJ if the join is valid.
- * Set flag here to check at bottom of loop.
- *----------
+ /*
+ * Otherwise, the proposed join overlaps the RHS but isn't a valid
+ * implementation of this SJ. But don't panic quite yet: the RHS
+ * violation might have occurred previously, in one or both input
+ * relations, in which case we must have previously decided that
+ * it was OK to commute some other SJ with this one. If we need
+ * to perform this join to finish building up the RHS, rejecting
+ * it could lead to not finding any plan at all. (This can occur
+ * because of the heuristics elsewhere in this file that postpone
+ * clauseless joins: we might not consider doing a clauseless join
+ * within the RHS until after we've performed other, validly
+ * commutable SJs with one or both sides of the clauseless join.)
+ * This consideration boils down to the rule that if both inputs
+ * overlap the RHS, we can allow the join --- they are either
+ * fully within the RHS, or represent previously-allowed joins to
+ * rels outside it.
*/
- if (sjinfo->jointype != JOIN_SEMI &&
- bms_overlap(rel1->relids, sjinfo->min_righthand) &&
+ if (bms_overlap(rel1->relids, sjinfo->min_righthand) &&
bms_overlap(rel2->relids, sjinfo->min_righthand))
- {
- /* seems OK */
- Assert(!bms_overlap(joinrelids, sjinfo->min_lefthand));
- }
- else
- is_valid_inner = false;
+ continue; /* assume valid previous violation of RHS */
+
+ /*
+ * The proposed join could still be legal, but only if we're
+ * allowed to associate it into the RHS of this SJ. That means
+ * this SJ must be a LEFT join (not SEMI or ANTI, and certainly
+ * not FULL) and the proposed join must not overlap the LHS.
+ */
+ if (sjinfo->jointype != JOIN_LEFT ||
+ bms_overlap(joinrelids, sjinfo->min_lefthand))
+ return false; /* invalid join path */
+
+ /*
+ * To be valid, the proposed join must be a LEFT join; otherwise
+ * it can't associate into this SJ's RHS. But we may not yet have
+ * found the SpecialJoinInfo matching the proposed join, so we
+ * can't test that yet. Remember the requirement for later.
+ */
+ must_be_leftjoin = true;
}
}
/*
- * Fail if violated some SJ's RHS and didn't match to another SJ. However,
- * "matching" to a semijoin we are implementing by unique-ification
- * doesn't count (think: it's really an inner join).
+ * Fail if violated any SJ's RHS and didn't match to a LEFT SJ: the
+ * proposed join can't associate into an SJ's RHS.
+ *
+ * Also, fail if the proposed join's predicate isn't strict; we're
+ * essentially checking to see if we can apply outer-join identity 3, and
+ * that's a requirement. (This check may be redundant with checks in
+ * make_outerjoininfo, but I'm not quite sure, and it's cheap to test.)
*/
- if (!is_valid_inner &&
- (match_sjinfo == NULL || unique_ified))
+ if (must_be_leftjoin &&
+ (match_sjinfo == NULL ||
+ match_sjinfo->jointype != JOIN_LEFT ||
+ !match_sjinfo->lhs_strict))
return false; /* invalid join path */
+ /*
+ * We also have to check for constraints imposed by LATERAL references.
+ */
+ if (root->hasLateralRTEs)
+ {
+ bool lateral_fwd;
+ bool lateral_rev;
+ Relids join_lateral_rels;
+
+ /*
+ * The proposed rels could each contain lateral references to the
+ * other, in which case the join is impossible. If there are lateral
+ * references in just one direction, then the join has to be done with
+ * a nestloop with the lateral referencer on the inside. If the join
+ * matches an SJ that cannot be implemented by such a nestloop, the
+ * join is impossible.
+ *
+ * Also, if the lateral reference is only indirect, we should reject
+ * the join; whatever rel(s) the reference chain goes through must be
+ * joined to first.
+ *
+ * Another case that might keep us from building a valid plan is the
+ * implementation restriction described by have_dangerous_phv().
+ */
+ lateral_fwd = bms_overlap(rel1->relids, rel2->lateral_relids);
+ lateral_rev = bms_overlap(rel2->relids, rel1->lateral_relids);
+ if (lateral_fwd && lateral_rev)
+ return false; /* have lateral refs in both directions */
+ if (lateral_fwd)
+ {
+ /* has to be implemented as nestloop with rel1 on left */
+ if (match_sjinfo &&
+ (reversed ||
+ unique_ified ||
+ match_sjinfo->jointype == JOIN_FULL))
+ return false; /* not implementable as nestloop */
+ /* check there is a direct reference from rel2 to rel1 */
+ if (!bms_overlap(rel1->relids, rel2->direct_lateral_relids))
+ return false; /* only indirect refs, so reject */
+ /* check we won't have a dangerous PHV */
+ if (have_dangerous_phv(root, rel1->relids, rel2->lateral_relids))
+ return false; /* might be unable to handle required PHV */
+ }
+ else if (lateral_rev)
+ {
+ /* has to be implemented as nestloop with rel2 on left */
+ if (match_sjinfo &&
+ (!reversed ||
+ unique_ified ||
+ match_sjinfo->jointype == JOIN_FULL))
+ return false; /* not implementable as nestloop */
+ /* check there is a direct reference from rel1 to rel2 */
+ if (!bms_overlap(rel2->relids, rel1->direct_lateral_relids))
+ return false; /* only indirect refs, so reject */
+ /* check we won't have a dangerous PHV */
+ if (have_dangerous_phv(root, rel2->relids, rel1->lateral_relids))
+ return false; /* might be unable to handle required PHV */
+ }
+
+ /*
+ * LATERAL references could also cause problems later on if we accept
+ * this join: if the join's minimum parameterization includes any rels
+ * that would have to be on the inside of an outer join with this join
+ * rel, then it's never going to be possible to build the complete
+ * query using this join. We should reject this join not only because
+ * it'll save work, but because if we don't, the clauseless-join
+ * heuristics might think that legality of this join means that some
+ * other join rel need not be formed, and that could lead to failure
+ * to find any plan at all. We have to consider not only rels that
+ * are directly on the inner side of an OJ with the joinrel, but also
+ * ones that are indirectly so, so search to find all such rels.
+ */
+ join_lateral_rels = min_join_parameterization(root, joinrelids,
+ rel1, rel2);
+ if (join_lateral_rels)
+ {
+ Relids join_plus_rhs = bms_copy(joinrelids);
+ bool more;
+
+ do
+ {
+ more = false;
+ foreach(l, root->join_info_list)
+ {
+ SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
+
+ if (bms_overlap(sjinfo->min_lefthand, join_plus_rhs) &&
+ !bms_is_subset(sjinfo->min_righthand, join_plus_rhs))
+ {
+ join_plus_rhs = bms_add_members(join_plus_rhs,
+ sjinfo->min_righthand);
+ more = true;
+ }
+ /* full joins constrain both sides symmetrically */
+ if (sjinfo->jointype == JOIN_FULL &&
+ bms_overlap(sjinfo->min_righthand, join_plus_rhs) &&
+ !bms_is_subset(sjinfo->min_lefthand, join_plus_rhs))
+ {
+ join_plus_rhs = bms_add_members(join_plus_rhs,
+ sjinfo->min_lefthand);
+ more = true;
+ }
+ }
+ } while (more);
+ if (bms_overlap(join_plus_rhs, join_lateral_rels))
+ return false; /* will not be able to join to some RHS rel */
+ }
+ }
+
/* Otherwise, it's a valid join */
*sjinfo_p = match_sjinfo;
*reversed_p = reversed;
return true;
}
+
/*
* has_join_restriction
- * Detect whether the specified relation has join-order restrictions
- * due to being inside an outer join or an IN (sub-SELECT).
+ * Detect whether the specified relation has join-order restrictions,
+ * due to being inside an outer join or an IN (sub-SELECT),
+ * or participating in any LATERAL references or multi-rel PHVs.
*
* Essentially, this tests whether have_join_order_restriction() could
* succeed with this rel and some other one. It's OK if we sometimes
- * say "true" incorrectly. (Therefore, we don't bother with the relatively
+ * say "true" incorrectly. (Therefore, we don't bother with the relatively
* expensive has_legal_joinclause test.)
*/
static bool
{
ListCell *l;
+ if (rel->lateral_relids != NULL || rel->lateral_referencers != NULL)
+ return true;
+
+ foreach(l, root->placeholder_list)
+ {
+ PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l);
+
+ if (bms_is_subset(rel->relids, phinfo->ph_eval_at) &&
+ !bms_equal(rel->relids, phinfo->ph_eval_at))
+ return true;
+ }
+
foreach(l, root->join_info_list)
{
SpecialJoinInfo *sjinfo = (SpecialJoinInfo *) lfirst(l);
return false;
}
+
/*
* is_dummy_rel --- has relation been proven empty?
*/
* dummy.
*
* Also, when called during GEQO join planning, we are in a short-lived
- * memory context. We must make sure that the dummy path attached to a
+ * memory context. We must make sure that the dummy path attached to a
* baserel survives the GEQO cycle, else the baserel is trashed for future
* GEQO cycles. On the other hand, when we are marking a joinrel during GEQO,
* we don't want the dummy path to clutter the main planning context. Upshot
* is that the best solution is to explicitly make the dummy path in the same
* context the given RelOptInfo is in.
*/
-static void
+void
mark_dummy_rel(RelOptInfo *rel)
{
MemoryContext oldcontext;
/* Evict any previously chosen paths */
rel->pathlist = NIL;
+ rel->partial_pathlist = NIL;
/* Set up the dummy path */
- add_path(rel, (Path *) create_append_path(rel, NIL, NULL));
+ add_path(rel, (Path *) create_append_path(NULL, rel, NIL, NIL, NULL,
+ 0, false, NIL, -1));
/* Set or update cheapest_total_path and related fields */
set_cheapest(rel);
MemoryContextSwitchTo(oldcontext);
}
+
/*
* restriction_is_constant_false --- is a restrictlist just FALSE?
*
* decide there's no match for an outer row, which is pretty stupid. So,
* we need to detect the case.
*
- * If only_pushed_down is TRUE, then consider only pushed-down quals.
+ * If only_pushed_down is true, then consider only quals that are pushed-down
+ * from the point of view of the joinrel.
*/
static bool
-restriction_is_constant_false(List *restrictlist, bool only_pushed_down)
+restriction_is_constant_false(List *restrictlist,
+ RelOptInfo *joinrel,
+ bool only_pushed_down)
{
ListCell *lc;
*/
foreach(lc, restrictlist)
{
- RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
+ RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
- Assert(IsA(rinfo, RestrictInfo));
- if (only_pushed_down && !rinfo->is_pushed_down)
+ if (only_pushed_down && !RINFO_IS_PUSHED_DOWN(rinfo, joinrel->relids))
continue;
if (rinfo->clause && IsA(rinfo->clause, Const))
}
return false;
}
+
+
+/*
+ * Set up tlist expressions for the childrel, and add EC members referencing
+ * the childrel.
+ */
+static void
+update_child_rel_info(PlannerInfo *root,
+ RelOptInfo *rel, RelOptInfo *childrel)
+{
+ AppendRelInfo *appinfo = root->append_rel_array[childrel->relid];
+
+ /* Make child tlist expressions */
+ childrel->reltarget->exprs = (List *)
+ adjust_appendrel_attrs(root,
+ (Node *) rel->reltarget->exprs,
+ 1, &appinfo);
+
+ /* Make child entries in the EquivalenceClass as well */
+ if (rel->has_eclass_joins || has_useful_pathkeys(root, rel))
+ add_child_rel_equivalences(root, appinfo, rel, childrel);
+ childrel->has_eclass_joins = rel->has_eclass_joins;
+}
+
+/*
+ * Construct the SpecialJoinInfo for a child-join by translating
+ * SpecialJoinInfo for the join between parents. left_relids and right_relids
+ * are the relids of left and right side of the join respectively.
+ */
+static SpecialJoinInfo *
+build_child_join_sjinfo(PlannerInfo *root, SpecialJoinInfo *parent_sjinfo,
+ Relids left_relids, Relids right_relids)
+{
+ SpecialJoinInfo *sjinfo = makeNode(SpecialJoinInfo);
+ AppendRelInfo **left_appinfos;
+ int left_nappinfos;
+ AppendRelInfo **right_appinfos;
+ int right_nappinfos;
+
+ memcpy(sjinfo, parent_sjinfo, sizeof(SpecialJoinInfo));
+ left_appinfos = find_appinfos_by_relids(root, left_relids,
+ &left_nappinfos);
+ right_appinfos = find_appinfos_by_relids(root, right_relids,
+ &right_nappinfos);
+
+ sjinfo->min_lefthand = adjust_child_relids(sjinfo->min_lefthand,
+ left_nappinfos, left_appinfos);
+ sjinfo->min_righthand = adjust_child_relids(sjinfo->min_righthand,
+ right_nappinfos,
+ right_appinfos);
+ sjinfo->syn_lefthand = adjust_child_relids(sjinfo->syn_lefthand,
+ left_nappinfos, left_appinfos);
+ sjinfo->syn_righthand = adjust_child_relids(sjinfo->syn_righthand,
+ right_nappinfos,
+ right_appinfos);
+ sjinfo->semi_rhs_exprs = (List *) adjust_appendrel_attrs(root,
+ (Node *) sjinfo->semi_rhs_exprs,
+ right_nappinfos,
+ right_appinfos);
+
+ pfree(left_appinfos);
+ pfree(right_appinfos);
+
+ return sjinfo;
+}
+
+/*
+ * Assess whether join between given two partitioned relations can be broken
+ * down into joins between matching partitions; a technique called
+ * "partitionwise join"
+ *
+ * Partitionwise join is possible when a. Joining relations have same
+ * partitioning scheme b. There exists an equi-join between the partition keys
+ * of the two relations.
+ *
+ * Partitionwise join is planned as follows (details: optimizer/README.)
+ *
+ * 1. Create the RelOptInfos for joins between matching partitions i.e
+ * child-joins and add paths to them.
+ *
+ * 2. Construct Append or MergeAppend paths across the set of child joins.
+ * This second phase is implemented by generate_partitionwise_join_paths().
+ *
+ * The RelOptInfo, SpecialJoinInfo and restrictlist for each child join are
+ * obtained by translating the respective parent join structures.
+ */
+static void
+try_partitionwise_join(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
+ RelOptInfo *joinrel, SpecialJoinInfo *parent_sjinfo,
+ List *parent_restrictlist)
+{
+ bool rel1_is_simple = IS_SIMPLE_REL(rel1);
+ bool rel2_is_simple = IS_SIMPLE_REL(rel2);
+ int nparts;
+ int cnt_parts;
+
+ /* Guard against stack overflow due to overly deep partition hierarchy. */
+ check_stack_depth();
+
+ /* Nothing to do, if the join relation is not partitioned. */
+ if (!IS_PARTITIONED_REL(joinrel))
+ return;
+
+ /* The join relation should have consider_partitionwise_join set. */
+ Assert(joinrel->consider_partitionwise_join);
+
+ /*
+ * Since this join relation is partitioned, all the base relations
+ * participating in this join must be partitioned and so are all the
+ * intermediate join relations.
+ */
+ Assert(IS_PARTITIONED_REL(rel1) && IS_PARTITIONED_REL(rel2));
+ Assert(REL_HAS_ALL_PART_PROPS(rel1) && REL_HAS_ALL_PART_PROPS(rel2));
+
+ /* The joining relations should have consider_partitionwise_join set. */
+ Assert(rel1->consider_partitionwise_join &&
+ rel2->consider_partitionwise_join);
+
+ /*
+ * The partition scheme of the join relation should match that of the
+ * joining relations.
+ */
+ Assert(joinrel->part_scheme == rel1->part_scheme &&
+ joinrel->part_scheme == rel2->part_scheme);
+
+ /*
+ * Since we allow partitionwise join only when the partition bounds of the
+ * joining relations exactly match, the partition bounds of the join
+ * should match those of the joining relations.
+ */
+ Assert(partition_bounds_equal(joinrel->part_scheme->partnatts,
+ joinrel->part_scheme->parttyplen,
+ joinrel->part_scheme->parttypbyval,
+ joinrel->boundinfo, rel1->boundinfo));
+ Assert(partition_bounds_equal(joinrel->part_scheme->partnatts,
+ joinrel->part_scheme->parttyplen,
+ joinrel->part_scheme->parttypbyval,
+ joinrel->boundinfo, rel2->boundinfo));
+
+ nparts = joinrel->nparts;
+
+ /*
+ * Create child-join relations for this partitioned join, if those don't
+ * exist. Add paths to child-joins for a pair of child relations
+ * corresponding to the given pair of parent relations.
+ */
+ for (cnt_parts = 0; cnt_parts < nparts; cnt_parts++)
+ {
+ RelOptInfo *child_rel1 = rel1->part_rels[cnt_parts];
+ RelOptInfo *child_rel2 = rel2->part_rels[cnt_parts];
+ SpecialJoinInfo *child_sjinfo;
+ List *child_restrictlist;
+ RelOptInfo *child_joinrel;
+ Relids child_joinrelids;
+ AppendRelInfo **appinfos;
+ int nappinfos;
+
+ /*
+ * If a child table has consider_partitionwise_join=false, it means
+ * that it's a dummy relation for which we skipped setting up tlist
+ * expressions and adding EC members in set_append_rel_size(), so do
+ * that now for use later.
+ */
+ if (rel1_is_simple && !child_rel1->consider_partitionwise_join)
+ {
+ Assert(child_rel1->reloptkind == RELOPT_OTHER_MEMBER_REL);
+ Assert(IS_DUMMY_REL(child_rel1));
+ update_child_rel_info(root, rel1, child_rel1);
+ child_rel1->consider_partitionwise_join = true;
+ }
+ if (rel2_is_simple && !child_rel2->consider_partitionwise_join)
+ {
+ Assert(child_rel2->reloptkind == RELOPT_OTHER_MEMBER_REL);
+ Assert(IS_DUMMY_REL(child_rel2));
+ update_child_rel_info(root, rel2, child_rel2);
+ child_rel2->consider_partitionwise_join = true;
+ }
+
+ /* We should never try to join two overlapping sets of rels. */
+ Assert(!bms_overlap(child_rel1->relids, child_rel2->relids));
+ child_joinrelids = bms_union(child_rel1->relids, child_rel2->relids);
+ appinfos = find_appinfos_by_relids(root, child_joinrelids, &nappinfos);
+
+ /*
+ * Construct SpecialJoinInfo from parent join relations's
+ * SpecialJoinInfo.
+ */
+ child_sjinfo = build_child_join_sjinfo(root, parent_sjinfo,
+ child_rel1->relids,
+ child_rel2->relids);
+
+ /*
+ * Construct restrictions applicable to the child join from those
+ * applicable to the parent join.
+ */
+ child_restrictlist =
+ (List *) adjust_appendrel_attrs(root,
+ (Node *) parent_restrictlist,
+ nappinfos, appinfos);
+ pfree(appinfos);
+
+ child_joinrel = joinrel->part_rels[cnt_parts];
+ if (!child_joinrel)
+ {
+ child_joinrel = build_child_join_rel(root, child_rel1, child_rel2,
+ joinrel, child_restrictlist,
+ child_sjinfo,
+ child_sjinfo->jointype);
+ joinrel->part_rels[cnt_parts] = child_joinrel;
+ }
+
+ Assert(bms_equal(child_joinrel->relids, child_joinrelids));
+
+ populate_joinrel_with_paths(root, child_rel1, child_rel2,
+ child_joinrel, child_sjinfo,
+ child_restrictlist);
+ }
+}
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