greenplumn appendinfo 源码
greenplumn appendinfo 代码
文件路径：/src/backend/optimizer/util/appendinfo.c
/*-------------------------------------------------------------------------
*
* appendinfo.c
* Routines for mapping between append parent(s) and children
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/optimizer/path/appendinfo.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/appendinfo.h"
#include "parser/parsetree.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/syscache.h"
typedef struct
{
PlannerInfo *root;
int nappinfos;
AppendRelInfo **appinfos;
} adjust_appendrel_attrs_context;
static void make_inh_translation_list(Relation oldrelation,
Relation newrelation,
Index newvarno,
List **translated_vars);
static Node *adjust_appendrel_attrs_mutator(Node *node,
adjust_appendrel_attrs_context *context);
static List *adjust_inherited_tlist(List *tlist,
AppendRelInfo *context);
/*
* make_append_rel_info
* Build an AppendRelInfo for the parent-child pair
*/
AppendRelInfo *
make_append_rel_info(Relation parentrel, Relation childrel,
Index parentRTindex, Index childRTindex)
{
AppendRelInfo *appinfo = makeNode(AppendRelInfo);
appinfo->parent_relid = parentRTindex;
appinfo->child_relid = childRTindex;
appinfo->parent_reltype = parentrel->rd_rel->reltype;
appinfo->child_reltype = childrel->rd_rel->reltype;
make_inh_translation_list(parentrel, childrel, childRTindex,
&appinfo->translated_vars);
appinfo->parent_reloid = RelationGetRelid(parentrel);
return appinfo;
}
/*
* make_inh_translation_list
* Build the list of translations from parent Vars to child Vars for
* an inheritance child.
*
* For paranoia's sake, we match type/collation as well as attribute name.
*/
static void
make_inh_translation_list(Relation oldrelation, Relation newrelation,
Index newvarno,
List **translated_vars)
{
List *vars = NIL;
TupleDesc old_tupdesc = RelationGetDescr(oldrelation);
TupleDesc new_tupdesc = RelationGetDescr(newrelation);
Oid new_relid = RelationGetRelid(newrelation);
int oldnatts = old_tupdesc->natts;
int newnatts = new_tupdesc->natts;
int old_attno;
int new_attno = 0;
for (old_attno = 0; old_attno < oldnatts; old_attno++)
{
Form_pg_attribute att;
char *attname;
Oid atttypid;
int32 atttypmod;
Oid attcollation;
att = TupleDescAttr(old_tupdesc, old_attno);
if (att->attisdropped)
{
/* Just put NULL into this list entry */
vars = lappend(vars, NULL);
continue;
}
attname = NameStr(att->attname);
atttypid = att->atttypid;
atttypmod = att->atttypmod;
attcollation = att->attcollation;
/*
* When we are generating the "translation list" for the parent table
* of an inheritance set, no need to search for matches.
*/
if (oldrelation == newrelation)
{
vars = lappend(vars, makeVar(newvarno,
(AttrNumber) (old_attno + 1),
atttypid,
atttypmod,
attcollation,
0));
continue;
}
/*
* Otherwise we have to search for the matching column by name.
* There's no guarantee it'll have the same column position, because
* of cases like ALTER TABLE ADD COLUMN and multiple inheritance.
* However, in simple cases, the relative order of columns is mostly
* the same in both relations, so try the column of newrelation that
* follows immediately after the one that we just found, and if that
* fails, let syscache handle it.
*/
if (new_attno >= newnatts ||
(att = TupleDescAttr(new_tupdesc, new_attno))->attisdropped ||
strcmp(attname, NameStr(att->attname)) != 0)
{
HeapTuple newtup;
newtup = SearchSysCacheAttName(new_relid, attname);
if (!HeapTupleIsValid(newtup))
elog(ERROR, "could not find inherited attribute \"%s\" of relation \"%s\"",
attname, RelationGetRelationName(newrelation));
new_attno = ((Form_pg_attribute) GETSTRUCT(newtup))->attnum - 1;
ReleaseSysCache(newtup);
att = TupleDescAttr(new_tupdesc, new_attno);
}
/* Found it, check type and collation match */
if (atttypid != att->atttypid || atttypmod != att->atttypmod)
elog(ERROR, "attribute \"%s\" of relation \"%s\" does not match parent's type",
attname, RelationGetRelationName(newrelation));
if (attcollation != att->attcollation)
elog(ERROR, "attribute \"%s\" of relation \"%s\" does not match parent's collation",
attname, RelationGetRelationName(newrelation));
vars = lappend(vars, makeVar(newvarno,
(AttrNumber) (new_attno + 1),
atttypid,
atttypmod,
attcollation,
0));
new_attno++;
}
*translated_vars = vars;
}
/*
* adjust_appendrel_attrs
* Copy the specified query or expression and translate Vars referring to a
* parent rel to refer to the corresponding child rel instead. We also
* update rtindexes appearing outside Vars, such as resultRelation and
* jointree relids.
*
* Note: this is only applied after conversion of sublinks to subplans,
* so we don't need to cope with recursion into sub-queries.
*
* Note: this is not hugely different from what pullup_replace_vars() does;
* maybe we should try to fold the two routines together.
*/
Node *
adjust_appendrel_attrs(PlannerInfo *root, Node *node, int nappinfos,
AppendRelInfo **appinfos)
{
Node *result;
adjust_appendrel_attrs_context context;
context.root = root;
context.nappinfos = nappinfos;
context.appinfos = appinfos;
/* If there's nothing to adjust, don't call this function. */
Assert(nappinfos >= 1 && appinfos != NULL);
/*
* Must be prepared to start with a Query or a bare expression tree.
*/
if (node && IsA(node, Query))
{
Query *newnode;
int cnt;
newnode = query_tree_mutator((Query *) node,
adjust_appendrel_attrs_mutator,
(void *) &context,
QTW_IGNORE_RC_SUBQUERIES);
for (cnt = 0; cnt < nappinfos; cnt++)
{
AppendRelInfo *appinfo = appinfos[cnt];
if (newnode->resultRelation == appinfo->parent_relid)
{
newnode->resultRelation = appinfo->child_relid;
/* Fix tlist resnos too, if it's inherited UPDATE */
if (newnode->commandType == CMD_UPDATE)
newnode->targetList =
adjust_inherited_tlist(newnode->targetList,
appinfo);
break;
}
}
result = (Node *) newnode;
}
else
result = adjust_appendrel_attrs_mutator(node, &context);
return result;
}
static Node *
adjust_appendrel_attrs_mutator(Node *node,
adjust_appendrel_attrs_context *context)
{
AppendRelInfo **appinfos = context->appinfos;
int nappinfos = context->nappinfos;
int cnt;
if (node == NULL)
return NULL;
if (IsA(node, Var))
{
Var *var = (Var *) copyObject(node);
AppendRelInfo *appinfo = NULL;
for (cnt = 0; cnt < nappinfos; cnt++)
{
if (var->varno == appinfos[cnt]->parent_relid)
{
appinfo = appinfos[cnt];
break;
}
}
if (var->varlevelsup == 0 && appinfo)
{
var->varno = appinfo->child_relid;
var->varnoold = appinfo->child_relid;
if (var->varattno > 0)
{
Node *newnode;
if (var->varattno > list_length(appinfo->translated_vars))
elog(ERROR, "attribute %d of relation \"%s\" does not exist",
var->varattno, get_rel_name(appinfo->parent_reloid));
newnode = copyObject(list_nth(appinfo->translated_vars,
var->varattno - 1));
if (newnode == NULL)
elog(ERROR, "attribute %d of relation \"%s\" does not exist",
var->varattno, get_rel_name(appinfo->parent_reloid));
return newnode;
}
else if (var->varattno == 0)
{
/*
* Whole-row Var: if we are dealing with named rowtypes, we
* can use a whole-row Var for the child table plus a coercion
* step to convert the tuple layout to the parent's rowtype.
* Otherwise we have to generate a RowExpr.
*/
if (OidIsValid(appinfo->child_reltype))
{
Assert(var->vartype == appinfo->parent_reltype);
if (appinfo->parent_reltype != appinfo->child_reltype)
{
ConvertRowtypeExpr *r = makeNode(ConvertRowtypeExpr);
r->arg = (Expr *) var;
r->resulttype = appinfo->parent_reltype;
r->convertformat = COERCE_IMPLICIT_CAST;
r->location = -1;
/* Make sure the Var node has the right type ID, too */
var->vartype = appinfo->child_reltype;
return (Node *) r;
}
}
else
{
/*
* Build a RowExpr containing the translated variables.
*
* In practice var->vartype will always be RECORDOID here,
* so we need to come up with some suitable column names.
* We use the parent RTE's column names.
*
* Note: we can't get here for inheritance cases, so there
* is no need to worry that translated_vars might contain
* some dummy NULLs.
*/
RowExpr *rowexpr;
List *fields;
RangeTblEntry *rte;
rte = rt_fetch(appinfo->parent_relid,
context->root->parse->rtable);
fields = copyObject(appinfo->translated_vars);
rowexpr = makeNode(RowExpr);
rowexpr->args = fields;
rowexpr->row_typeid = var->vartype;
rowexpr->row_format = COERCE_IMPLICIT_CAST;
rowexpr->colnames = copyObject(rte->eref->colnames);
rowexpr->location = -1;
return (Node *) rowexpr;
}
}
/* system attributes don't need any other translation */
}
return (Node *) var;
}
if (IsA(node, CurrentOfExpr))
{
CurrentOfExpr *cexpr = (CurrentOfExpr *) copyObject(node);
for (cnt = 0; cnt < nappinfos; cnt++)
{
AppendRelInfo *appinfo = appinfos[cnt];
if (cexpr->cvarno == appinfo->parent_relid)
{
cexpr->cvarno = appinfo->child_relid;
break;
}
}
return (Node *) cexpr;
}
if (IsA(node, RangeTblRef))
{
RangeTblRef *rtr = (RangeTblRef *) copyObject(node);
for (cnt = 0; cnt < nappinfos; cnt++)
{
AppendRelInfo *appinfo = appinfos[cnt];
if (rtr->rtindex == appinfo->parent_relid)
{
rtr->rtindex = appinfo->child_relid;
break;
}
}
return (Node *) rtr;
}
if (IsA(node, JoinExpr))
{
/* Copy the JoinExpr node with correct mutation of subnodes */
JoinExpr *j;
AppendRelInfo *appinfo;
j = (JoinExpr *) expression_tree_mutator(node,
adjust_appendrel_attrs_mutator,
(void *) context);
/* now fix JoinExpr's rtindex (probably never happens) */
for (cnt = 0; cnt < nappinfos; cnt++)
{
appinfo = appinfos[cnt];
if (j->rtindex == appinfo->parent_relid)
{
j->rtindex = appinfo->child_relid;
break;
}
}
return (Node *) j;
}
if (IsA(node, PlaceHolderVar))
{
/* Copy the PlaceHolderVar node with correct mutation of subnodes */
PlaceHolderVar *phv;
phv = (PlaceHolderVar *) expression_tree_mutator(node,
adjust_appendrel_attrs_mutator,
(void *) context);
/* now fix PlaceHolderVar's relid sets */
if (phv->phlevelsup == 0)
phv->phrels = adjust_child_relids(phv->phrels, context->nappinfos,
context->appinfos);
return (Node *) phv;
}
/* Shouldn't need to handle planner auxiliary nodes here */
Assert(!IsA(node, SpecialJoinInfo));
Assert(!IsA(node, AppendRelInfo));
Assert(!IsA(node, PlaceHolderInfo));
Assert(!IsA(node, MinMaxAggInfo));
/*
* We have to process RestrictInfo nodes specially. (Note: although
* set_append_rel_pathlist will hide RestrictInfos in the parent's
* baserestrictinfo list from us, it doesn't hide those in joininfo.)
*/
if (IsA(node, RestrictInfo))
{
RestrictInfo *oldinfo = (RestrictInfo *) node;
RestrictInfo *newinfo = makeNode(RestrictInfo);
/* Copy all flat-copiable fields */
memcpy(newinfo, oldinfo, sizeof(RestrictInfo));
/* Recursively fix the clause itself */
newinfo->clause = (Expr *)
adjust_appendrel_attrs_mutator((Node *) oldinfo->clause, context);
/* and the modified version, if an OR clause */
newinfo->orclause = (Expr *)
adjust_appendrel_attrs_mutator((Node *) oldinfo->orclause, context);
/* adjust relid sets too */
newinfo->clause_relids = adjust_child_relids(oldinfo->clause_relids,
context->nappinfos,
context->appinfos);
newinfo->required_relids = adjust_child_relids(oldinfo->required_relids,
context->nappinfos,
context->appinfos);
newinfo->outer_relids = adjust_child_relids(oldinfo->outer_relids,
context->nappinfos,
context->appinfos);
newinfo->nullable_relids = adjust_child_relids(oldinfo->nullable_relids,
context->nappinfos,
context->appinfos);
newinfo->left_relids = adjust_child_relids(oldinfo->left_relids,
context->nappinfos,
context->appinfos);
newinfo->right_relids = adjust_child_relids(oldinfo->right_relids,
context->nappinfos,
context->appinfos);
/*
* Reset cached derivative fields, since these might need to have
* different values when considering the child relation. Note we
* don't reset left_ec/right_ec: each child variable is implicitly
* equivalent to its parent, so still a member of the same EC if any.
*/
newinfo->eval_cost.startup = -1;
newinfo->norm_selec = -1;
newinfo->outer_selec = -1;
newinfo->left_em = NULL;
newinfo->right_em = NULL;
newinfo->scansel_cache = NIL;
newinfo->left_bucketsize = -1;
newinfo->right_bucketsize = -1;
newinfo->left_mcvfreq = -1;
newinfo->right_mcvfreq = -1;
return (Node *) newinfo;
}
/*
* NOTE: we do not need to recurse into sublinks, because they should
* already have been converted to subplans before we see them.
*/
Assert(!IsA(node, SubLink));
Assert(!IsA(node, Query));
node = expression_tree_mutator(node, adjust_appendrel_attrs_mutator,
(void *) context);
/*
* In GPDB, if you have two SubPlans referring to the same initplan, we
* require two separate copies of the subplan, one for each SubPlan
* reference. That's because even if a plan is otherwise the same, we
* may want to later apply different flow to different SubPlans
* referring it. Any subplan that is left unused, because we created
* the new copy here, will be removed by remove_unused_subplans().
*/
if (IsA(node, SubPlan))
{
SubPlan *sp = (SubPlan *) node;
if (!sp->is_initplan)
{
PlannerInfo *root = context->root;
Plan *newsubplan = (Plan *) copyObject(planner_subplan_get_plan(root, sp));
PlannerInfo *newsubroot = makeNode(PlannerInfo);
memcpy(newsubroot, planner_subplan_get_root(root, sp), sizeof(PlannerInfo));
/*
* Add the subplan and its subroot to the global lists.
*/
root->glob->subplans = lappend(root->glob->subplans, newsubplan);
root->glob->subroots = lappend(root->glob->subroots, newsubroot);
/*
* expression_tree_mutator made a copy of the SubPlan already, so
* we can modify it directly.
*/
sp->plan_id = list_length(root->glob->subplans);
sp->plan_name = psprintf("%s (copy %d)", sp->plan_name, sp->plan_id);
}
}
return node;
}
/*
* adjust_appendrel_attrs_multilevel
* Apply Var translations from a toplevel appendrel parent down to a child.
*
* In some cases we need to translate expressions referencing a parent relation
* to reference an appendrel child that's multiple levels removed from it.
*/
Node *
adjust_appendrel_attrs_multilevel(PlannerInfo *root, Node *node,
Relids child_relids,
Relids top_parent_relids)
{
AppendRelInfo **appinfos;
Bitmapset *parent_relids = NULL;
int nappinfos;
int cnt;
Assert(bms_num_members(child_relids) == bms_num_members(top_parent_relids));
appinfos = find_appinfos_by_relids(root, child_relids, &nappinfos);
/* Construct relids set for the immediate parent of given child. */
for (cnt = 0; cnt < nappinfos; cnt++)
{
AppendRelInfo *appinfo = appinfos[cnt];
parent_relids = bms_add_member(parent_relids, appinfo->parent_relid);
}
/* Recurse if immediate parent is not the top parent. */
if (!bms_equal(parent_relids, top_parent_relids))
node = adjust_appendrel_attrs_multilevel(root, node, parent_relids,
top_parent_relids);
/* Now translate for this child */
node = adjust_appendrel_attrs(root, node, nappinfos, appinfos);
pfree(appinfos);
return node;
}
/*
* Substitute child relids for parent relids in a Relid set. The array of
* appinfos specifies the substitutions to be performed.
*/
Relids
adjust_child_relids(Relids relids, int nappinfos, AppendRelInfo **appinfos)
{
Bitmapset *result = NULL;
int cnt;
for (cnt = 0; cnt < nappinfos; cnt++)
{
AppendRelInfo *appinfo = appinfos[cnt];
/* Remove parent, add child */
if (bms_is_member(appinfo->parent_relid, relids))
{
/* Make a copy if we are changing the set. */
if (!result)
result = bms_copy(relids);
result = bms_del_member(result, appinfo->parent_relid);
result = bms_add_member(result, appinfo->child_relid);
}
}
/* If we made any changes, return the modified copy. */
if (result)
return result;
/* Otherwise, return the original set without modification. */
return relids;
}
/*
* Replace any relid present in top_parent_relids with its child in
* child_relids. Members of child_relids can be multiple levels below top
* parent in the partition hierarchy.
*/
Relids
adjust_child_relids_multilevel(PlannerInfo *root, Relids relids,
Relids child_relids, Relids top_parent_relids)
{
AppendRelInfo **appinfos;
int nappinfos;
Relids parent_relids = NULL;
Relids result;
Relids tmp_result = NULL;
int cnt;
/*
* If the given relids set doesn't contain any of the top parent relids,
* it will remain unchanged.
*/
if (!bms_overlap(relids, top_parent_relids))
return relids;
appinfos = find_appinfos_by_relids(root, child_relids, &nappinfos);
/* Construct relids set for the immediate parent of the given child. */
for (cnt = 0; cnt < nappinfos; cnt++)
{
AppendRelInfo *appinfo = appinfos[cnt];
parent_relids = bms_add_member(parent_relids, appinfo->parent_relid);
}
/* Recurse if immediate parent is not the top parent. */
if (!bms_equal(parent_relids, top_parent_relids))
{
tmp_result = adjust_child_relids_multilevel(root, relids,
parent_relids,
top_parent_relids);
relids = tmp_result;
}
result = adjust_child_relids(relids, nappinfos, appinfos);
/* Free memory consumed by any intermediate result. */
if (tmp_result)
bms_free(tmp_result);
bms_free(parent_relids);
pfree(appinfos);
return result;
}
/*
* Adjust the targetlist entries of an inherited UPDATE operation
*
* The expressions have already been fixed, but we have to make sure that
* the target resnos match the child table (they may not, in the case of
* a column that was added after-the-fact by ALTER TABLE). In some cases
* this can force us to re-order the tlist to preserve resno ordering.
* (We do all this work in special cases so that preptlist.c is fast for
* the typical case.)
*
* The given tlist has already been through expression_tree_mutator;
* therefore the TargetEntry nodes are fresh copies that it's okay to
* scribble on.
*
* Note that this is not needed for INSERT because INSERT isn't inheritable.
*/
static List *
adjust_inherited_tlist(List *tlist, AppendRelInfo *context)
{
bool changed_it = false;
ListCell *tl;
List *new_tlist;
bool more;
int attrno;
/* This should only happen for an inheritance case, not UNION ALL */
Assert(OidIsValid(context->parent_reloid));
/* Scan tlist and update resnos to match attnums of child rel */
foreach(tl, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(tl);
Var *childvar;
if (tle->resjunk)
continue; /* ignore junk items */
/* Look up the translation of this column: it must be a Var */
if (tle->resno <= 0 ||
tle->resno > list_length(context->translated_vars))
elog(ERROR, "attribute %d of relation \"%s\" does not exist",
tle->resno, get_rel_name(context->parent_reloid));
childvar = (Var *) list_nth(context->translated_vars, tle->resno - 1);
if (childvar == NULL || !IsA(childvar, Var))
elog(ERROR, "attribute %d of relation \"%s\" does not exist",
tle->resno, get_rel_name(context->parent_reloid));
if (tle->resno != childvar->varattno)
{
tle->resno = childvar->varattno;
changed_it = true;
}
}
/*
* If we changed anything, re-sort the tlist by resno, and make sure
* resjunk entries have resnos above the last real resno. The sort
* algorithm is a bit stupid, but for such a seldom-taken path, small is
* probably better than fast.
*/
if (!changed_it)
return tlist;
new_tlist = NIL;
more = true;
for (attrno = 1; more; attrno++)
{
more = false;
foreach(tl, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(tl);
if (tle->resjunk)
continue; /* ignore junk items */
if (tle->resno == attrno)
new_tlist = lappend(new_tlist, tle);
else if (tle->resno > attrno)
more = true;
}
}
foreach(tl, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(tl);
if (!tle->resjunk)
continue; /* here, ignore non-junk items */
tle->resno = attrno;
new_tlist = lappend(new_tlist, tle);
attrno++;
}
return new_tlist;
}
/*
* find_appinfos_by_relids
* Find AppendRelInfo structures for all relations specified by relids.
*
* The AppendRelInfos are returned in an array, which can be pfree'd by the
* caller. *nappinfos is set to the number of entries in the array.
*/
AppendRelInfo **
find_appinfos_by_relids(PlannerInfo *root, Relids relids, int *nappinfos)
{
AppendRelInfo **appinfos;
int cnt = 0;
int i;
*nappinfos = bms_num_members(relids);
appinfos = (AppendRelInfo **) palloc(sizeof(AppendRelInfo *) * *nappinfos);
i = -1;
while ((i = bms_next_member(relids, i)) >= 0)
{
AppendRelInfo *appinfo = root->append_rel_array[i];
if (!appinfo)
elog(ERROR, "child rel %d not found in append_rel_array", i);
appinfos[cnt++] = appinfo;
}
return appinfos;
}
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