greenplumn cdbpathlocus 源码
greenplumn cdbpathlocus 代码
文件路径：/src/backend/cdb/cdbpathlocus.c
/*-------------------------------------------------------------------------
*
* cdbpathlocus.c
*
* Portions Copyright (c) 2005-2008, Greenplum inc
* Portions Copyright (c) 2012-Present VMware, Inc. or its affiliates.
*
*
* IDENTIFICATION
* src/backend/cdb/cdbpathlocus.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/gp_distribution_policy.h" /* GpPolicy */
#include "cdb/cdbhash.h"
#include "cdb/cdbpullup.h" /* cdbpullup_findEclassInTargetList() */
#include "nodes/makefuncs.h" /* makeVar() */
#include "nodes/nodeFuncs.h" /* exprType() and exprTypmod() */
#include "nodes/pathnodes.h" /* RelOptInfo */
#include "nodes/plannodes.h" /* Plan */
#include "optimizer/clauses.h"
#include "optimizer/optimizer.h" /* contain_volatile_functions() */
#include "optimizer/pathnode.h" /* Path */
#include "optimizer/paths.h" /* cdb_make_distkey_for_expr() */
#include "optimizer/tlist.h" /* tlist_member() */
#include "parser/parsetree.h" /* rt_fetch() */
#include "utils/lsyscache.h"
#include "cdb/cdbpath.h"
#include "cdb/cdbutil.h"
#include "cdb/cdbvars.h"
#include "cdb/cdbpathlocus.h" /* me */
static List *cdb_build_distribution_keys(PlannerInfo *root,
Index rti,
GpPolicy *policy);
/*
* cdbpathlocus_equal
*
* - Returns false if locus a or locus b is "strewn", meaning that it
* cannot be determined whether it is equal to another partitioned
* distribution.
*
* - Returns true if a and b have the same 'locustype' and 'numsegments',
* and distribution keys that contain the same equivalence classes.
*
* - Returns false otherwise.
*/
bool
cdbpathlocus_equal(CdbPathLocus a, CdbPathLocus b)
{
ListCell *acell;
ListCell *bcell;
ListCell *a_ec_cell;
ListCell *b_ec_cell;
/* Unless a and b have the same numsegments the result is always false */
if (CdbPathLocus_NumSegments(a) !=
CdbPathLocus_NumSegments(b))
return false;
if (CdbPathLocus_IsStrewn(a) ||
CdbPathLocus_IsStrewn(b))
return false;
if (CdbPathLocus_IsEqual(a, b))
return true;
if (a.distkey == NIL ||
b.distkey == NIL ||
list_length(a.distkey) != list_length(b.distkey))
return false;
if ((CdbPathLocus_IsHashed(a) || CdbPathLocus_IsHashedOJ(a)) &&
(CdbPathLocus_IsHashed(b) || CdbPathLocus_IsHashedOJ(b)))
{
forboth(acell, a.distkey, bcell, b.distkey)
{
DistributionKey *adistkey = (DistributionKey *) lfirst(acell);
DistributionKey *bdistkey = (DistributionKey *) lfirst(bcell);
if (adistkey->dk_opfamily != bdistkey->dk_opfamily)
return false;
foreach(b_ec_cell, bdistkey->dk_eclasses)
{
EquivalenceClass *b_ec = (EquivalenceClass *) lfirst(b_ec_cell);
if (!list_member_ptr(adistkey->dk_eclasses, b_ec))
return false;
}
foreach(a_ec_cell, adistkey->dk_eclasses)
{
EquivalenceClass *a_ec = (EquivalenceClass *) lfirst(a_ec_cell);
if (!list_member_ptr(bdistkey->dk_eclasses, a_ec))
return false;
}
}
return true;
}
Assert(false);
return false;
} /* cdbpathlocus_equal */
/*
* cdb_build_distribution_keys
* Build DistributionKeys that match the policy of the given relation.
*/
List *
cdb_build_distribution_keys(PlannerInfo *root, Index rti, GpPolicy *policy)
{
RangeTblEntry *rte = planner_rt_fetch(rti, root);
List *retval = NIL;
int i;
for (i = 0; i < policy->nattrs; ++i)
{
DistributionKey *cdistkey;
/* Find or create a Var node that references the specified column. */
Var *expr;
Oid typeoid;
int32 type_mod;
Oid varcollid;
Oid eqopoid;
Oid opfamily = get_opclass_family(policy->opclasses[i]);
Oid opcintype = get_opclass_input_type(policy->opclasses[i]);
List *mergeopfamilies;
EquivalenceClass *eclass;
get_atttypetypmodcoll(rte->relid, policy->attrs[i], &typeoid, &type_mod, &varcollid);
expr = makeVar(rti, policy->attrs[i], typeoid, type_mod, varcollid, 0);
/*
* Look up the equality operator corresponding to the distribution
* opclass.
*/
eqopoid = get_opfamily_member(opfamily, opcintype, opcintype, 1);
/*
* Get Oid of the sort operator that would be used for a sort-merge
* equijoin on a pair of exprs of the same type.
*/
if (eqopoid == InvalidOid || !op_mergejoinable(eqopoid, typeoid))
{
/*
* It's in principle possible that there is no b-tree operator family
* that's compatible with the hash opclass's equality operator. However,
* we cannot construct an EquivalenceClass without the b-tree operator
* family, and therefore cannot build a DistributionKey to represent it.
* Bail out. (That makes the distribution key rather useless.)
*/
return NIL;
}
mergeopfamilies = get_mergejoin_opfamilies(eqopoid);
eclass = get_eclass_for_sort_expr(root, (Expr *) expr,
NULL, /* nullable_relids */ /* GPDB_94_MERGE_FIXME: is NULL ok here? */
mergeopfamilies,
opcintype,
exprCollation((Node *) expr),
0,
bms_make_singleton(rti),
true);
/* Create a distribution key for it. */
cdistkey = makeNode(DistributionKey);
cdistkey->dk_opfamily = opfamily;
cdistkey->dk_eclasses = list_make1(eclass);
retval = lappend(retval, cdistkey);
}
return retval;
}
/*
* cdbpathlocus_for_insert
* Build DistributionKeys that match the policy of the given relation.
*
* This is used for INSERT or split UPDATE, where 'pathtarget' the target list of
* subpath that's producing the rows to be inserted/updated.
*
* As a side-effect, this assigns sortgrouprefs to any volatile expressions
* that are used in the distribution keys.
*
* If the target table is distributed, but the distribution keys cannot be
* represented as Equivalence Classes (because a datatype is missing merge
* opfamilies), returns a NULL locus.
*
* Currently, this function is only invoked by `create_motion_path_for_insert`
* and `create_split_update_path`, and under the condition that policy type
* is always partitioned type.
*/
CdbPathLocus
cdbpathlocus_for_insert(PlannerInfo *root, GpPolicy *policy,
PathTarget *pathtarget)
{
CdbPathLocus targetLocus;
Assert(policy->ptype == POLICYTYPE_PARTITIONED);
/* rows are distributed by hashing on specified columns */
List *distkeys = NIL;
Index maxRef = 0;
bool failed = false;
for (int i = 0; i < list_length(pathtarget->exprs); i++)
maxRef = Max(maxRef, pathtarget->sortgrouprefs[i]);
for (int i = 0; i < policy->nattrs; ++i)
{
AttrNumber attno = policy->attrs[i];
DistributionKey *cdistkey;
Expr *expr;
Oid typeoid;
Oid eqopoid;
Oid opfamily = get_opclass_family(policy->opclasses[i]);
Oid opcintype = get_opclass_input_type(policy->opclasses[i]);
List *mergeopfamilies;
EquivalenceClass *eclass;
expr = list_nth(pathtarget->exprs, attno - 1);
typeoid = exprType((Node *) expr);
/*
* Look up the equality operator corresponding to the distribution
* opclass.
*/
eqopoid = get_opfamily_member(opfamily, opcintype, opcintype, 1);
if (pathtarget->sortgrouprefs[attno - 1] == 0 &&
contain_volatile_functions((Node *) expr))
{
/*
* GPDB_96_MERGE_FIXME: this modifies the subpath's targetlist in place.
* That's a bit ugly.
*/
pathtarget->sortgrouprefs[attno - 1] = ++maxRef;
}
/*
* Get Oid of the sort operator that would be used for a sort-merge
* equijoin on a pair of exprs of the same type.
*/
if (failed || eqopoid == InvalidOid || !op_mergejoinable(eqopoid, typeoid))
{
/*
* It's in principle possible that there is no b-tree operator family
* that's compatible with the hash opclass's equality operator. However,
* we cannot construct an EquivalenceClass without the b-tree operator
* family, and therefore cannot build a DistributionKey to represent it.
* Bail out. (That makes the distribution key rather useless.)
*/
failed = true;
continue;
}
mergeopfamilies = get_mergejoin_opfamilies(eqopoid);
eclass = get_eclass_for_sort_expr(root, (Expr *) expr,
NULL, /* nullable_relids */ /* GPDB_94_MERGE_FIXME: is NULL ok here? */
mergeopfamilies,
opcintype,
exprCollation((Node *) expr),
pathtarget->sortgrouprefs[attno - 1],
NULL,
true);
/* Create a distribution key for it. */
cdistkey = makeNode(DistributionKey);
cdistkey->dk_opfamily = opfamily;
cdistkey->dk_eclasses = list_make1(eclass);
distkeys = lappend(distkeys, cdistkey);
}
if (failed)
{
CdbPathLocus_MakeNull(&targetLocus);
}
else if (distkeys)
CdbPathLocus_MakeHashed(&targetLocus, distkeys, policy->numsegments);
else
{
/* DISTRIBUTED RANDOMLY */
CdbPathLocus_MakeStrewn(&targetLocus, policy->numsegments);
}
return targetLocus;
}
/*
* cdbpathlocus_from_policy
*
* Returns a locus describing the distribution of a policy
*/
CdbPathLocus
cdbpathlocus_from_policy(struct PlannerInfo *root, Index rti, GpPolicy *policy)
{
CdbPathLocus result;
if (Gp_role != GP_ROLE_DISPATCH)
{
CdbPathLocus_MakeEntry(&result);
return result;
}
if (GpPolicyIsPartitioned(policy))
{
/* Are the rows distributed by hashing on specified columns? */
if (policy->nattrs > 0)
{
List *distkeys = cdb_build_distribution_keys(root,
rti,
policy);
if (distkeys)
CdbPathLocus_MakeHashed(&result, distkeys, policy->numsegments);
else
{
/*
* It's possible that we fail to build a DistributionKey
* representation for the distribution policy.
*/
CdbPathLocus_MakeStrewn(&result, policy->numsegments);
}
}
/* Rows are distributed on an unknown criterion (uniformly, we hope!) */
else
CdbPathLocus_MakeStrewn(&result, policy->numsegments);
}
else if (GpPolicyIsReplicated(policy))
{
CdbPathLocus_MakeSegmentGeneral(&result, policy->numsegments);
}
/* Normal catalog access */
else
CdbPathLocus_MakeEntry(&result);
return result;
} /* cdbpathlocus_from_baserel */
/*
* cdbpathlocus_from_baserel
*
* Returns a locus describing the distribution of a base relation.
*/
CdbPathLocus
cdbpathlocus_from_baserel(struct PlannerInfo *root,
struct RelOptInfo *rel)
{
return cdbpathlocus_from_policy(root, rel->relid, rel->cdbpolicy);
} /* cdbpathlocus_from_baserel */
/*
* cdbpathlocus_from_exprs
*
* Returns a locus specifying hashed distribution on a list of exprs.
*/
CdbPathLocus
cdbpathlocus_from_exprs(struct PlannerInfo *root,
RelOptInfo *rel,
List *hash_on_exprs,
List *hash_opfamilies,
List *hash_sortrefs,
int numsegments)
{
CdbPathLocus locus;
List *distkeys = NIL;
ListCell *le, *lof, *lsr;
forthree(le, hash_on_exprs, lof, hash_opfamilies, lsr, hash_sortrefs)
{
Node *expr = (Node *) lfirst(le);
Oid opfamily = lfirst_oid(lof);
int sortref = lfirst_int(lsr);
DistributionKey *distkey;
distkey = cdb_make_distkey_for_expr(root, rel, expr, opfamily, sortref);
distkeys = lappend(distkeys, distkey);
}
CdbPathLocus_MakeHashed(&locus, distkeys, numsegments);
return locus;
} /* cdbpathlocus_from_exprs */
/*
* cdbpathlocus_from_subquery
*
* Returns a locus describing the distribution of a subquery.
* The subquery plan should have been generated already.
*
* 'subqplan' is the subquery plan.
* 'subqrelid' is the subquery RTE index in the current query level, for
* building Var nodes that reference the subquery's result columns.
*/
CdbPathLocus
cdbpathlocus_from_subquery(struct PlannerInfo *root,
RelOptInfo *rel,
Path *subpath)
{
CdbPathLocus locus;
if (CdbPathLocus_IsHashed(subpath->locus) ||
CdbPathLocus_IsHashedOJ(subpath->locus))
{
bool failed = false;
List *distkeys = NIL;
int numsegments = subpath->locus.numsegments;
ListCell *dk_cell;
List *usable_subtlist = NIL;
List *new_vars = NIL;
ListCell *lc;
ListCell *lc2 = NULL;
RelOptInfo *parentrel = NULL;
/*
* If the subquery we're pulling up is a child of an append rel,
* the pathkey should refer to the parent rel's Vars, not the child.
* Normally, the planner puts the parent and child expressions in an
* equivalence class for any potentially useful expressions, but that's
* done earlier in the planning already.
*/
if (rel->reloptkind == RELOPT_OTHER_MEMBER_REL)
{
if (root->append_rel_array == NULL || root->append_rel_array[rel->relid] == NULL)
elog(ERROR, "child rel %u not found in append_rel_array", rel->relid);
/* Direct looking for AppendRelInfos by relid in the append_rel_array */
AppendRelInfo *appendrel = root->append_rel_array[rel->relid];
Index parent_relid = appendrel->parent_relid;
parentrel = root->simple_rel_array[parent_relid];
Assert(list_length(parentrel->reltarget->exprs) == list_length(rel->reltarget->exprs));
}
if (parentrel)
lc2 = list_head(parentrel->reltarget->exprs);
foreach (lc, rel->reltarget->exprs)
{
Expr *expr = (Expr *) lfirst(lc);
Var *var;
Expr *subexpr;
Expr *parentexpr = NULL;
if (parentrel)
{
parentexpr = lfirst(lc2);
lc2 = lnext(lc2);
}
if (!IsA(expr, Var))
continue;
var = (Var *) expr;
/* ignore whole-row vars */
if (var->varattno == 0)
continue;
subexpr = list_nth(subpath->pathtarget->exprs, var->varattno - 1);
usable_subtlist = lappend(usable_subtlist,
makeTargetEntry(subexpr,
list_length(usable_subtlist) + 1,
NULL,
false));
new_vars = lappend(new_vars, parentrel ? parentexpr : expr);
}
foreach (dk_cell, subpath->locus.distkey)
{
DistributionKey *sub_dk = (DistributionKey *) lfirst(dk_cell);
ListCell *ec_cell;
DistributionKey *outer_dk = NULL;
foreach (ec_cell, sub_dk->dk_eclasses)
{
EquivalenceClass *sub_ec = (EquivalenceClass *) lfirst(ec_cell);
EquivalenceClass *outer_ec;
outer_ec = cdb_pull_up_eclass(root,
sub_ec,
rel->relids,
usable_subtlist,
new_vars,
-1 /* not used */);
if (outer_ec)
{
outer_dk = makeNode(DistributionKey);
outer_dk->dk_eclasses = list_make1(outer_ec);
outer_dk->dk_opfamily = sub_dk->dk_opfamily;
break;
}
}
if (outer_dk == NULL)
{
failed = true;
break;
}
distkeys = lappend(distkeys, outer_dk);
}
if (failed)
CdbPathLocus_MakeStrewn(&locus, numsegments);
else if (CdbPathLocus_IsHashed(subpath->locus))
CdbPathLocus_MakeHashed(&locus, distkeys, numsegments);
else
{
Assert(CdbPathLocus_IsHashedOJ(subpath->locus));
CdbPathLocus_MakeHashedOJ(&locus, distkeys, numsegments);
}
}
else
locus = subpath->locus;
return locus;
} /* cdbpathlocus_from_subquery */
/*
* cdbpathlocus_get_distkey_exprs
*
* Returns a List with one Expr for each distkey column. Each item either is
* in the given targetlist, or has no Var nodes that are not in the targetlist;
* and uses only rels in the given set of relids. Returns NIL if the
* distkey cannot be expressed in terms of the given relids and targetlist.
*/
void
cdbpathlocus_get_distkey_exprs(CdbPathLocus locus,
Bitmapset *relids,
List *targetlist,
List **exprs_p,
List **opfamilies_p)
{
List *result_exprs = NIL;
List *result_opfamilies = NIL;
ListCell *distkeycell;
Assert(cdbpathlocus_is_valid(locus));
*exprs_p = NIL;
*opfamilies_p = NIL;
if (CdbPathLocus_IsHashed(locus) || CdbPathLocus_IsHashedOJ(locus))
{
foreach(distkeycell, locus.distkey)
{
DistributionKey *distkey = (DistributionKey *) lfirst(distkeycell);
ListCell *ec_cell;
Expr *item = NULL;
foreach(ec_cell, distkey->dk_eclasses)
{
EquivalenceClass *dk_eclass = (EquivalenceClass *) lfirst(ec_cell);
item = cdbpullup_findEclassInTargetList(dk_eclass, targetlist,
distkey->dk_opfamily);
if (item)
break;
}
if (!item)
return;
result_exprs = lappend(result_exprs, item);
result_opfamilies = lappend_oid(result_opfamilies, distkey->dk_opfamily);
}
*exprs_p = result_exprs;
*opfamilies_p = result_opfamilies;
}
} /* cdbpathlocus_get_distkey_exprs */
/*
* cdbpathlocus_pull_above_projection
*
* Given a targetlist, and a locus evaluable before the projection is
* applied, returns an equivalent locus evaluable after the projection.
* Returns a strewn locus if the necessary inputs are not projected.
*
* 'relids' is the set of relids that may occur in the targetlist exprs.
* 'targetlist' specifies the projection. It is a List of TargetEntry
* or merely a List of Expr.
* 'newvarlist' is an optional List of Expr, in 1-1 correspondence with
* 'targetlist'. If specified, instead of creating a Var node to
* reference a targetlist item, we plug in a copy of the corresponding
* newvarlist item.
* 'newrelid' is the RTE index of the projected result, for finding or
* building Var nodes that reference the projected columns.
* Ignored if 'newvarlist' is specified.
*/
CdbPathLocus
cdbpathlocus_pull_above_projection(struct PlannerInfo *root,
CdbPathLocus locus,
Bitmapset *relids,
List *targetlist,
List *newvarlist,
Index newrelid)
{
CdbPathLocus newlocus;
Assert(cdbpathlocus_is_valid(locus));
if (CdbPathLocus_IsHashed(locus) || CdbPathLocus_IsHashedOJ(locus))
{
ListCell *distkeycell;
List *newdistkeys = NIL;
int numsegments;
/*
* Keep the numsegments unchanged.
*/
numsegments = CdbPathLocus_NumSegments(locus);
/* For each column of the distribution key... */
foreach(distkeycell, locus.distkey)
{
DistributionKey *olddistkey = (DistributionKey *) lfirst(distkeycell);
DistributionKey *newdistkey = NULL;
/* Get DistributionKey for key expr rewritten in terms of projection cols. */
ListCell *ec_cell;
EquivalenceClass *new_ec = NULL;
foreach(ec_cell, olddistkey->dk_eclasses)
{
EquivalenceClass *old_ec = (EquivalenceClass *) lfirst(ec_cell);
new_ec = cdb_pull_up_eclass(root,
old_ec,
relids,
targetlist,
newvarlist,
newrelid);
if (new_ec)
break;
}
/*
* NB: Targetlist might include columns from both sides of outer
* join "=" comparison, in which case cdb_pull_up_distribution_keys might
* succeed on keys from more than one distkeylist. The
* pulled-up locus could then be a HashedOJ locus, perhaps saving
* a Motion when an outer join is followed by UNION ALL followed
* by a join or aggregate. For now, don't bother.
*/
/*
* Fail if can't evaluate distribution key in the context of this
* targetlist.
*/
if (!new_ec)
{
CdbPathLocus_MakeStrewn(&newlocus, numsegments);
return newlocus;
}
newdistkey = makeNode(DistributionKey);
newdistkey->dk_eclasses = list_make1(new_ec);
newdistkey->dk_opfamily = olddistkey->dk_opfamily;
/* Assemble new distkeys. */
newdistkeys = lappend(newdistkeys, newdistkey);
}
/* Build new locus. */
if (CdbPathLocus_IsHashed(locus))
CdbPathLocus_MakeHashed(&newlocus, newdistkeys, numsegments);
else
CdbPathLocus_MakeHashedOJ(&newlocus, newdistkeys, numsegments);
return newlocus;
}
else
return locus;
} /* cdbpathlocus_pull_above_projection */
/*
* cdbpathlocus_join
*
* Determine locus to describe the result of a join. Any necessary Motion has
* already been applied to the sources.
*/
CdbPathLocus
cdbpathlocus_join(JoinType jointype, CdbPathLocus a, CdbPathLocus b)
{
ListCell *acell;
ListCell *bcell;
CdbPathLocus resultlocus = {0};
int numsegments;
Assert(cdbpathlocus_is_valid(a));
Assert(cdbpathlocus_is_valid(b));
/* Do both input rels have same locus? */
if (cdbpathlocus_equal(a, b))
return a;
/*
* SingleQE may have different segment counts.
*/
if (CdbPathLocus_IsSingleQE(a) &&
CdbPathLocus_IsSingleQE(b))
{
CdbPathLocus_MakeSingleQE(&resultlocus,
CdbPathLocus_CommonSegments(a, b));
return resultlocus;
}
if (CdbPathLocus_IsGeneral(a))
return b;
if (CdbPathLocus_IsGeneral(b))
return a;
/*
* If one rel is replicated, result stays with the other rel,
* but need to ensure the result is on the common segments.
*/
if (CdbPathLocus_IsReplicated(a))
{
b.numsegments = CdbPathLocus_CommonSegments(a, b);
return b;
}
if (CdbPathLocus_IsReplicated(b))
{
a.numsegments = CdbPathLocus_CommonSegments(a, b);
return a;
}
/*
* If one rel is segmentgeneral, result stays with the other rel,
* but need to ensure the result is on the common segments.
*
* NB: the code check SegmentGeneral and replicated is quite similar,
* but we have to put check-segmentgeneral below. Consider one
* is segmentgeneral and the other is replicated, only by this order
* we can be sure that this function never return a locus of
* Replicated.
* update a replicated table join with a partitioned locus table will
* reach here.
*/
if (CdbPathLocus_IsSegmentGeneral(a))
{
b.numsegments = CdbPathLocus_CommonSegments(a, b);
return b;
}
if (CdbPathLocus_IsSegmentGeneral(b))
{
a.numsegments = CdbPathLocus_CommonSegments(a, b);
return a;
}
/*
* Both sides must be Hashed (or HashedOJ), then. And the distribution
* keys should be compatible; otherwise the caller should not be building
* a join directly between these two rels (a Motion would be needed).
*/
if (!(CdbPathLocus_IsHashed(a) || CdbPathLocus_IsHashedOJ(a)))
elog(ERROR, "could not be construct join with non-hashed path");
if (!(CdbPathLocus_IsHashed(b) || CdbPathLocus_IsHashedOJ(b)))
elog(ERROR, "could not be construct join with non-hashed path");
if (a.distkey == NIL ||
list_length(a.distkey) != list_length(b.distkey))
elog(ERROR, "could not construct hashed join locus with incompatible distribution keys");
if (CdbPathLocus_NumSegments(a) != CdbPathLocus_NumSegments(b))
elog(ERROR, "could not construct hashed join locus with different number of segments");
numsegments = CdbPathLocus_NumSegments(a);
/*
* For a LEFT/RIGHT OUTER JOIN, we can use key of the outer, non-nullable
* side as is. There should not be any more joins with the nullable side
* above this join rel, so the inner side's keys are not interesting above
* this.
*/
if (jointype == JOIN_LEFT ||
jointype == JOIN_LASJ_NOTIN ||
jointype == JOIN_ANTI)
{
resultlocus = a;
}
else if (jointype == JOIN_RIGHT)
{
resultlocus = b;
}
else
{
/*
* Not a LEFT/RIGHT JOIN. We don't usually get here with INNER JOINs
* either, because if you have an INNER JOIN on a equality predicate,
* they should form an EquivalenceClass, so that the distribution keys
* on both sides of the join refer to the same EquivalenceClass, and
* we exit already at the top of this function, at the
* "if(cdbpathlocus_equal(a, b)" test. The usual case that we get here
* is a FULL JOIN.
*
* I'm not sure what non-FULL corner cases there are that lead here.
* But it's safe to create a HashedOJ locus for them, anyway, because
* the promise of a HashedOJ is weaker than Hashed.
*/
/* Zip the two distkey lists together to make a HashedOJ locus. */
List *newdistkeys = NIL;
forboth(acell, a.distkey, bcell, b.distkey)
{
DistributionKey *adistkey = (DistributionKey *) lfirst(acell);
DistributionKey *bdistkey = (DistributionKey *) lfirst(bcell);
DistributionKey *newdistkey;
Assert(adistkey->dk_opfamily == bdistkey->dk_opfamily);
newdistkey = makeNode(DistributionKey);
newdistkey->dk_eclasses = list_union_ptr(adistkey->dk_eclasses,
bdistkey->dk_eclasses);
newdistkey->dk_opfamily = adistkey->dk_opfamily;
newdistkeys = lappend(newdistkeys, newdistkey);
}
CdbPathLocus_MakeHashedOJ(&resultlocus, newdistkeys, numsegments);
}
Assert(cdbpathlocus_is_valid(resultlocus));
return resultlocus;
} /* cdbpathlocus_join */
/*
* cdbpathlocus_is_hashed_on_exprs
*
* This function tests whether grouping on a given set of exprs can be done
* in place without motion.
*
* For a hashed locus, returns false if the distkey has a column whose
* equivalence class contains no expr belonging to the given list.
*
* If 'ignore_constants' is true, any constants in the locus are ignored.
*/
bool
cdbpathlocus_is_hashed_on_exprs(CdbPathLocus locus, List *exprlist,
bool ignore_constants)
{
ListCell *distkeycell;
Assert(cdbpathlocus_is_valid(locus));
if (CdbPathLocus_IsHashed(locus) || CdbPathLocus_IsHashedOJ(locus))
{
foreach(distkeycell, locus.distkey)
{
DistributionKey *distkey = (DistributionKey *) lfirst(distkeycell);
ListCell *distkeyeccell;
bool found = false;
foreach(distkeyeccell, distkey->dk_eclasses)
{
/* Does some expr in distkey match some item in exprlist? */
EquivalenceClass *dk_eclass = (EquivalenceClass *) lfirst(distkeyeccell);
ListCell *i;
if (ignore_constants && CdbEquivClassIsConstant(dk_eclass))
{
found = true;
break;
}
foreach(i, dk_eclass->ec_members)
{
EquivalenceMember *em = (EquivalenceMember *) lfirst(i);
if (list_member(exprlist, em->em_expr))
{
found = true;
break;
}
}
if (found)
break;
}
if (!found)
return false;
}
/* Every column of the distkey contains an expr in exprlist. */
return true;
}
else
return !CdbPathLocus_IsStrewn(locus);
} /* cdbpathlocus_is_hashed_on_exprs */
/*
* cdbpathlocus_is_hashed_on_eclasses
*
* This function tests whether grouping on a given set of exprs can be done
* in place without motion.
*
* For a hashed locus, returns false if the distribution key has any column whose
* equivalence class is not in 'eclasses' list.
*
* If 'ignore_constants' is true, any constants in the locus are ignored.
*/
bool
cdbpathlocus_is_hashed_on_eclasses(CdbPathLocus locus, List *eclasses,
bool ignore_constants)
{
ListCell *distkeycell;
Assert(cdbpathlocus_is_valid(locus));
if (CdbPathLocus_IsHashed(locus) || CdbPathLocus_IsHashedOJ(locus))
{
foreach(distkeycell, locus.distkey)
{
DistributionKey *distkey = (DistributionKey *) lfirst(distkeycell);
ListCell *distkeyeccell;
bool found = false;
foreach(distkeyeccell, distkey->dk_eclasses)
{
/* Does distkey have an eclass that's not in 'eclasses'? */
EquivalenceClass *dk_ec = (EquivalenceClass *) lfirst(distkeyeccell);
ListCell *eccell;
while (dk_ec->ec_merged != NULL)
dk_ec = dk_ec->ec_merged;
if (ignore_constants && CdbEquivClassIsConstant(dk_ec))
{
found = true;
break;
}
foreach(eccell, eclasses)
{
EquivalenceClass *ec = (EquivalenceClass *) lfirst(eccell);
while (ec->ec_merged != NULL)
ec = ec->ec_merged;
if (ec == dk_ec)
{
found = true;
break;
}
}
if (found)
break;
}
if (!found)
return false;
}
/* Every column of the distribution key contains an expr in exprlist. */
return true;
}
else
return !CdbPathLocus_IsStrewn(locus);
} /* cdbpathlocus_is_hashed_on_exprs */
/*
* cdbpathlocus_is_hashed_on_tlist
*
* This function tests whether grouping on a given set of exprs can be done
* in place without motion.
*
* For a hashed locus, returns false if the distkey has a column whose
* equivalence class contains no expr belonging to the given list.
*
* If 'ignore_constants' is true, any constants in the locus are ignored.
*/
bool
cdbpathlocus_is_hashed_on_tlist(CdbPathLocus locus, List *tlist,
bool ignore_constants)
{
ListCell *distkeycell;
Assert(cdbpathlocus_is_valid(locus));
if (CdbPathLocus_IsHashed(locus) || CdbPathLocus_IsHashedOJ(locus))
{
foreach(distkeycell, locus.distkey)
{
DistributionKey *distkey = (DistributionKey *) lfirst(distkeycell);
ListCell *distkeyeccell;
foreach(distkeyeccell, distkey->dk_eclasses)
{
/* Does some expr in distkey match some item in exprlist? */
EquivalenceClass *dk_eclass = (EquivalenceClass *) lfirst(distkeyeccell);
ListCell *i;
bool found = false;
if (ignore_constants && CdbEquivClassIsConstant(dk_eclass))
{
found = true;
continue;
}
if (dk_eclass->ec_sortref != 0)
{
foreach(i, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(i);
if (tle->ressortgroupref == dk_eclass->ec_sortref)
{
found = true;
break;
}
}
}
else
{
foreach(i, dk_eclass->ec_members)
{
EquivalenceMember *em = (EquivalenceMember *) lfirst(i);
ListCell *ltl;
foreach(ltl, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(ltl);
if (equal(tle->expr, em->em_expr))
{
found = true;
break;
}
}
if (found)
break;
}
}
if (!found)
return false;
}
}
/* Every column of the distkey contains an expr in exprlist. */
return true;
}
else
return !CdbPathLocus_IsStrewn(locus);
}
/*
* cdbpathlocus_is_hashed_on_relids
*
* Used when a subquery predicate (such as "x IN (SELECT ...)") has been
* flattened into a join with the tables of the current query. A row of
* the cross-product of the current query's tables might join with more
* than one row from the subquery and thus be duplicated. Removing such
* duplicates after the join is called deduping. If a row's duplicates
* might occur in more than one partition, a Motion operator will be
* needed to bring them together. This function tests whether the join
* result (whose locus is given) can be deduped in place without motion.
*
* For a hashed locus, returns false if the distkey has a column whose
* equivalence class contains no Var node belonging to the given set of
* relids. Caller should specify the relids of the non-subquery tables.
*/
bool
cdbpathlocus_is_hashed_on_relids(CdbPathLocus locus, Bitmapset *relids)
{
Assert(cdbpathlocus_is_valid(locus));
if (CdbPathLocus_IsHashed(locus) || CdbPathLocus_IsHashedOJ(locus))
{
ListCell *lc1;
foreach(lc1, locus.distkey)
{
DistributionKey *distkey = (DistributionKey *) lfirst(lc1);
bool found = false;
ListCell *lc2;
foreach(lc2, distkey->dk_eclasses)
{
/* Does distribution key contain a Var whose varno is in relids? */
EquivalenceClass *dk_eclass = (EquivalenceClass *) lfirst(lc2);
ListCell *lc3;
foreach(lc3, dk_eclass->ec_members)
{
EquivalenceMember *em = (EquivalenceMember *) lfirst(lc3);
if (IsA(em->em_expr, Var) && bms_is_subset(em->em_relids, relids))
{
found = true;
break;
}
}
if (found)
break;
}
if (!found)
return false;
}
/*
* Every column of the distkey contains a Var whose varno is in
* relids.
*/
return true;
}
else
return !CdbPathLocus_IsStrewn(locus);
} /* cdbpathlocus_is_hashed_on_relids */
/*
* cdbpathlocus_is_valid
*
* Returns true if locus appears structurally valid.
*/
bool
cdbpathlocus_is_valid(CdbPathLocus locus)
{
ListCell *distkeycell;
if (!CdbLocusType_IsValid(locus.locustype))
goto bad;
if (!CdbPathLocus_IsHashed(locus) && !CdbPathLocus_IsHashedOJ(locus) && locus.distkey != NIL)
goto bad;
if (CdbPathLocus_IsHashed(locus) || CdbPathLocus_IsHashedOJ(locus))
{
if (locus.distkey == NIL)
goto bad;
if (!IsA(locus.distkey, List))
goto bad;
foreach(distkeycell, locus.distkey)
{
DistributionKey *item = (DistributionKey *) lfirst(distkeycell);
if (!item || !IsA(item, DistributionKey))
goto bad;
if (!OidIsValid(item->dk_opfamily))
goto bad;
}
}
/* Check that 'numsegments' is valid */
if (!CdbPathLocus_IsGeneral(locus) &&
!CdbPathLocus_IsEntry(locus) &&
!CdbPathLocus_IsOuterQuery(locus) &&
locus.numsegments == -1)
goto bad;
return true;
bad:
return false;
} /* cdbpathlocus_is_valid */
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