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/*-------------------------------------------------------------------------
*
* prepunion.c
* Routines to plan set-operation queries. The filename is a leftover
* from a time when only UNIONs were implemented.
*
* There is also some code here to support planning of queries that use
* inheritance (SELECT FROM foo*). This no longer has much connection
* to the processing of UNION queries, but it's still here.
*
*
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.100 2003/07/25 00:01:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/pg_type.h"
#include "nodes/makefuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/plancat.h"
#include "optimizer/planmain.h"
#include "optimizer/planner.h"
#include "optimizer/prep.h"
#include "optimizer/tlist.h"
#include "parser/parse_clause.h"
#include "parser/parse_coerce.h"
#include "parser/parsetree.h"
#include "utils/lsyscache.h"
typedef struct
{
Index old_rt_index;
Index new_rt_index;
Oid old_relid;
Oid new_relid;
} adjust_inherited_attrs_context;
static Plan *recurse_set_operations(Node *setOp, Query *parse,
List *colTypes, bool junkOK,
int flag, List *refnames_tlist);
static Plan *generate_union_plan(SetOperationStmt *op, Query *parse,
List *refnames_tlist);
static Plan *generate_nonunion_plan(SetOperationStmt *op, Query *parse,
List *refnames_tlist);
static List *recurse_union_children(Node *setOp, Query *parse,
SetOperationStmt *top_union,
List *refnames_tlist);
static List *generate_setop_tlist(List *colTypes, int flag,
bool hack_constants,
List *input_tlist,
List *refnames_tlist);
static List *generate_append_tlist(List *colTypes, bool flag,
List *input_plans,
List *refnames_tlist);
static bool tlist_same_datatypes(List *tlist, List *colTypes, bool junkOK);
static Node *adjust_inherited_attrs_mutator(Node *node,
adjust_inherited_attrs_context *context);
static Relids adjust_relid_set(Relids relids, Index oldrelid, Index newrelid);
static List *adjust_inherited_tlist(List *tlist, Oid new_relid);
/*
* plan_set_operations
*
* Plans the queries for a tree of set operations (UNION/INTERSECT/EXCEPT)
*
* This routine only deals with the setOperations tree of the given query.
* Any top-level ORDER BY requested in parse->sortClause will be added
* when we return to grouping_planner.
*/
Plan *
plan_set_operations(Query *parse)
{
SetOperationStmt *topop = (SetOperationStmt *) parse->setOperations;
Node *node;
Query *leftmostQuery;
Assert(topop && IsA(topop, SetOperationStmt));
/* check for unsupported stuff */
Assert(parse->utilityStmt == NULL);
Assert(parse->jointree->fromlist == NIL);
Assert(parse->jointree->quals == NULL);
Assert(parse->groupClause == NIL);
Assert(parse->havingQual == NULL);
Assert(parse->distinctClause == NIL);
/*
* Find the leftmost component Query. We need to use its column names
* for all generated tlists (else SELECT INTO won't work right).
*/
node = topop->larg;
while (node && IsA(node, SetOperationStmt))
node = ((SetOperationStmt *) node)->larg;
Assert(node && IsA(node, RangeTblRef));
leftmostQuery = rt_fetch(((RangeTblRef *) node)->rtindex,
parse->rtable)->subquery;
Assert(leftmostQuery != NULL);
/*
* Recurse on setOperations tree to generate plans for set ops. The
* final output plan should have just the column types shown as the
* output from the top-level node, plus possibly a resjunk working
* column (we can rely on upper-level nodes to deal with that).
*/
return recurse_set_operations((Node *) topop, parse,
topop->colTypes, true, -1,
leftmostQuery->targetList);
}
/*
* recurse_set_operations
* Recursively handle one step in a tree of set operations
*
* colTypes: list of type OIDs of expected output columns
* junkOK: if true, child resjunk columns may be left in the result
* flag: if >= 0, add a resjunk output column indicating value of flag
* refnames_tlist: targetlist to take column names from
*/
static Plan *
recurse_set_operations(Node *setOp, Query *parse,
List *colTypes, bool junkOK,
int flag, List *refnames_tlist)
{
if (IsA(setOp, RangeTblRef))
{
RangeTblRef *rtr = (RangeTblRef *) setOp;
RangeTblEntry *rte = rt_fetch(rtr->rtindex, parse->rtable);
Query *subquery = rte->subquery;
Plan *subplan,
*plan;
Assert(subquery != NULL);
/*
* Generate plan for primitive subquery
*/
subplan = subquery_planner(subquery, 0.0 /* default case */ );
/*
* Add a SubqueryScan with the caller-requested targetlist
*/
plan = (Plan *)
make_subqueryscan(generate_setop_tlist(colTypes, flag, true,
subplan->targetlist,
refnames_tlist),
NIL,
rtr->rtindex,
subplan);
return plan;
}
else if (IsA(setOp, SetOperationStmt))
{
SetOperationStmt *op = (SetOperationStmt *) setOp;
Plan *plan;
/* UNIONs are much different from INTERSECT/EXCEPT */
if (op->op == SETOP_UNION)
plan = generate_union_plan(op, parse, refnames_tlist);
else
plan = generate_nonunion_plan(op, parse, refnames_tlist);
/*
* If necessary, add a Result node to project the caller-requested
* output columns.
*
* XXX you don't really want to know about this: setrefs.c will apply
* replace_vars_with_subplan_refs() to the Result node's tlist.
* This would fail if the Vars generated by generate_setop_tlist()
* were not exactly equal() to the corresponding tlist entries of
* the subplan. However, since the subplan was generated by
* generate_union_plan() or generate_nonunion_plan(), and hence
* its tlist was generated by generate_append_tlist(), this will
* work.
*/
if (flag >= 0 ||
!tlist_same_datatypes(plan->targetlist, colTypes, junkOK))
{
plan = (Plan *)
make_result(generate_setop_tlist(colTypes, flag, false,
plan->targetlist,
refnames_tlist),
NULL,
plan);
}
return plan;
}
else
{
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(setOp));
return NULL; /* keep compiler quiet */
}
}
/*
* Generate plan for a UNION or UNION ALL node
*/
static Plan *
generate_union_plan(SetOperationStmt *op, Query *parse,
List *refnames_tlist)
{
List *planlist;
List *tlist;
Plan *plan;
/*
* If any of my children are identical UNION nodes (same op, all-flag,
* and colTypes) then they can be merged into this node so that we
* generate only one Append and Sort for the lot. Recurse to find
* such nodes and compute their children's plans.
*/
planlist = nconc(recurse_union_children(op->larg, parse,
op, refnames_tlist),
recurse_union_children(op->rarg, parse,
op, refnames_tlist));
/*
* Generate tlist for Append plan node.
*
* The tlist for an Append plan isn't important as far as the Append is
* concerned, but we must make it look real anyway for the benefit of
* the next plan level up.
*/
tlist = generate_append_tlist(op->colTypes, false,
planlist, refnames_tlist);
/*
* Append the child results together.
*/
plan = (Plan *) make_append(planlist, false, tlist);
/*
* For UNION ALL, we just need the Append plan. For UNION, need to
* add Sort and Unique nodes to produce unique output.
*/
if (!op->all)
{
List *sortList;
tlist = copyObject(tlist);
sortList = addAllTargetsToSortList(NULL, NIL, tlist, false);
plan = (Plan *) make_sort_from_sortclauses(parse, tlist,
plan, sortList);
plan = (Plan *) make_unique(tlist, plan, sortList);
}
return plan;
}
/*
* Generate plan for an INTERSECT, INTERSECT ALL, EXCEPT, or EXCEPT ALL node
*/
static Plan *
generate_nonunion_plan(SetOperationStmt *op, Query *parse,
List *refnames_tlist)
{
Plan *lplan,
*rplan,
*plan;
List *tlist,
*sortList,
*planlist;
SetOpCmd cmd;
/* Recurse on children, ensuring their outputs are marked */
lplan = recurse_set_operations(op->larg, parse,
op->colTypes, false, 0,
refnames_tlist);
rplan = recurse_set_operations(op->rarg, parse,
op->colTypes, false, 1,
refnames_tlist);
planlist = makeList2(lplan, rplan);
/*
* Generate tlist for Append plan node.
*
* The tlist for an Append plan isn't important as far as the Append is
* concerned, but we must make it look real anyway for the benefit of
* the next plan level up. In fact, it has to be real enough that the
* flag column is shown as a variable not a constant, else setrefs.c
* will get confused.
*/
tlist = generate_append_tlist(op->colTypes, true,
planlist, refnames_tlist);
/*
* Append the child results together.
*/
plan = (Plan *) make_append(planlist, false, tlist);
/*
* Sort the child results, then add a SetOp plan node to generate the
* correct output.
*/
tlist = copyObject(tlist);
sortList = addAllTargetsToSortList(NULL, NIL, tlist, false);
plan = (Plan *) make_sort_from_sortclauses(parse, tlist, plan, sortList);
switch (op->op)
{
case SETOP_INTERSECT:
cmd = op->all ? SETOPCMD_INTERSECT_ALL : SETOPCMD_INTERSECT;
break;
case SETOP_EXCEPT:
cmd = op->all ? SETOPCMD_EXCEPT_ALL : SETOPCMD_EXCEPT;
break;
default:
elog(ERROR, "unrecognized set operation code: %d",
(int) op->op);
cmd = SETOPCMD_INTERSECT; /* keep compiler quiet */
break;
}
plan = (Plan *) make_setop(cmd, tlist, plan, sortList,
length(op->colTypes) + 1);
return plan;
}
/*
* Pull up children of a UNION node that are identically-propertied UNIONs.
*
* NOTE: we can also pull a UNION ALL up into a UNION, since the distinct
* output rows will be lost anyway.
*/
static List *
recurse_union_children(Node *setOp, Query *parse,
SetOperationStmt *top_union,
List *refnames_tlist)
{
if (IsA(setOp, SetOperationStmt))
{
SetOperationStmt *op = (SetOperationStmt *) setOp;
if (op->op == top_union->op &&
(op->all == top_union->all || op->all) &&
equalo(op->colTypes, top_union->colTypes))
{
/* Same UNION, so fold children into parent's subplan list */
return nconc(recurse_union_children(op->larg, parse,
top_union,
refnames_tlist),
recurse_union_children(op->rarg, parse,
top_union,
refnames_tlist));
}
}
/*
* Not same, so plan this child separately.
*
* Note we disallow any resjunk columns in child results. This is
* necessary since the Append node that implements the union won't do
* any projection, and upper levels will get confused if some of our
* output tuples have junk and some don't. This case only arises when
* we have an EXCEPT or INTERSECT as child, else there won't be
* resjunk anyway.
*/
return makeList1(recurse_set_operations(setOp, parse,
top_union->colTypes, false,
-1, refnames_tlist));
}
/*
* Generate targetlist for a set-operation plan node
*
* colTypes: column datatypes for non-junk columns
* flag: -1 if no flag column needed, 0 or 1 to create a const flag column
* hack_constants: true to copy up constants (see comments in code)
* input_tlist: targetlist of this node's input node
* refnames_tlist: targetlist to take column names from
*/
static List *
generate_setop_tlist(List *colTypes, int flag,
bool hack_constants,
List *input_tlist,
List *refnames_tlist)
{
List *tlist = NIL;
int resno = 1;
List *i;
Resdom *resdom;
Node *expr;
foreach(i, colTypes)
{
Oid colType = lfirsto(i);
TargetEntry *inputtle = (TargetEntry *) lfirst(input_tlist);
TargetEntry *reftle = (TargetEntry *) lfirst(refnames_tlist);
int32 colTypmod;
Assert(inputtle->resdom->resno == resno);
Assert(reftle->resdom->resno == resno);
Assert(!inputtle->resdom->resjunk);
Assert(!reftle->resdom->resjunk);
/*
* Generate columns referencing input columns and having
* appropriate data types and column names. Insert datatype
* coercions where necessary.
*
* HACK: constants in the input's targetlist are copied up as-is
* rather than being referenced as subquery outputs. This is
* mainly to ensure that when we try to coerce them to the output
* column's datatype, the right things happen for UNKNOWN
* constants. But do this only at the first level of
* subquery-scan plans; we don't want phony constants appearing in
* the output tlists of upper-level nodes!
*/
if (hack_constants && inputtle->expr && IsA(inputtle->expr, Const))
expr = (Node *) inputtle->expr;
else
expr = (Node *) makeVar(0,
inputtle->resdom->resno,
inputtle->resdom->restype,
inputtle->resdom->restypmod,
0);
if (inputtle->resdom->restype == colType)
{
/* no coercion needed, and believe the input typmod */
colTypmod = inputtle->resdom->restypmod;
}
else
{
expr = coerce_to_common_type(NULL, /* no UNKNOWNs here */
expr,
colType,
"UNION/INTERSECT/EXCEPT");
colTypmod = -1;
}
resdom = makeResdom((AttrNumber) resno++,
colType,
colTypmod,
pstrdup(reftle->resdom->resname),
false);
tlist = lappend(tlist, makeTargetEntry(resdom, (Expr *) expr));
input_tlist = lnext(input_tlist);
refnames_tlist = lnext(refnames_tlist);
}
if (flag >= 0)
{
/* Add a resjunk flag column */
resdom = makeResdom((AttrNumber) resno++,
INT4OID,
-1,
pstrdup("flag"),
true);
/* flag value is the given constant */
expr = (Node *) makeConst(INT4OID,
sizeof(int4),
Int32GetDatum(flag),
false,
true);
tlist = lappend(tlist, makeTargetEntry(resdom, (Expr *) expr));
}
return tlist;
}
/*
* Generate targetlist for a set-operation Append node
*
* colTypes: column datatypes for non-junk columns
* flag: true to create a flag column copied up from subplans
* input_plans: list of sub-plans of the Append
* refnames_tlist: targetlist to take column names from
*
* The entries in the Append's targetlist should always be simple Vars;
* we just have to make sure they have the right datatypes and typmods.
*/
static List *
generate_append_tlist(List *colTypes, bool flag,
List *input_plans,
List *refnames_tlist)
{
List *tlist = NIL;
int resno = 1;
List *curColType;
int colindex;
Resdom *resdom;
Node *expr;
List *planl;
int32 *colTypmods;
/*
* First extract typmods to use.
*
* If the inputs all agree on type and typmod of a particular column, use
* that typmod; else use -1.
*/
colTypmods = (int32 *) palloc(length(colTypes) * sizeof(int32));
foreach(planl, input_plans)
{
Plan *subplan = (Plan *) lfirst(planl);
List *subtlist;
curColType = colTypes;
colindex = 0;
foreach(subtlist, subplan->targetlist)
{
TargetEntry *subtle = (TargetEntry *) lfirst(subtlist);
if (subtle->resdom->resjunk)
continue;
Assert(curColType != NIL);
if (subtle->resdom->restype == lfirsto(curColType))
{
/* If first subplan, copy the typmod; else compare */
if (planl == input_plans)
colTypmods[colindex] = subtle->resdom->restypmod;
else if (subtle->resdom->restypmod != colTypmods[colindex])
colTypmods[colindex] = -1;
}
else
{
/* types disagree, so force typmod to -1 */
colTypmods[colindex] = -1;
}
curColType = lnext(curColType);
colindex++;
}
Assert(curColType == NIL);
}
/*
* Now we can build the tlist for the Append.
*/
colindex = 0;
foreach(curColType, colTypes)
{
Oid colType = lfirsto(curColType);
int32 colTypmod = colTypmods[colindex++];
TargetEntry *reftle = (TargetEntry *) lfirst(refnames_tlist);
Assert(reftle->resdom->resno == resno);
Assert(!reftle->resdom->resjunk);
expr = (Node *) makeVar(0,
resno,
colType,
colTypmod,
0);
resdom = makeResdom((AttrNumber) resno++,
colType,
colTypmod,
pstrdup(reftle->resdom->resname),
false);
tlist = lappend(tlist, makeTargetEntry(resdom, (Expr *) expr));
refnames_tlist = lnext(refnames_tlist);
}
if (flag)
{
/* Add a resjunk flag column */
resdom = makeResdom((AttrNumber) resno++,
INT4OID,
-1,
pstrdup("flag"),
true);
/* flag value is shown as copied up from subplan */
expr = (Node *) makeVar(0,
resdom->resno,
INT4OID,
-1,
0);
tlist = lappend(tlist, makeTargetEntry(resdom, (Expr *) expr));
}
pfree(colTypmods);
return tlist;
}
/*
* Does tlist have same datatypes as requested colTypes?
*
* Resjunk columns are ignored if junkOK is true; otherwise presence of
* a resjunk column will always cause a 'false' result.
*/
static bool
tlist_same_datatypes(List *tlist, List *colTypes, bool junkOK)
{
List *i;
foreach(i, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(i);
if (tle->resdom->resjunk)
{
if (!junkOK)
return false;
}
else
{
if (colTypes == NIL)
return false;
if (tle->resdom->restype != lfirsto(colTypes))
return false;
colTypes = lnext(colTypes);
}
}
if (colTypes != NIL)
return false;
return true;
}
/*
* find_all_inheritors -
* Returns a list of relation OIDs including the given rel plus
* all relations that inherit from it, directly or indirectly.
*/
List *
find_all_inheritors(Oid parentrel)
{
List *examined_relids = NIL;
List *unexamined_relids = makeListo1(parentrel);
/*
* While the queue of unexamined relids is nonempty, remove the first
* element, mark it examined, and find its direct descendants. NB:
* cannot use foreach(), since we modify the queue inside loop.
*/
while (unexamined_relids != NIL)
{
Oid currentrel = lfirsto(unexamined_relids);
List *currentchildren;
unexamined_relids = lnext(unexamined_relids);
examined_relids = lappendo(examined_relids, currentrel);
currentchildren = find_inheritance_children(currentrel);
/*
* Add to the queue only those children not already seen. This
* avoids making duplicate entries in case of multiple inheritance
* paths from the same parent. (It'll also keep us from getting
* into an infinite loop, though theoretically there can't be any
* cycles in the inheritance graph anyway.)
*/
currentchildren = set_differenceo(currentchildren, examined_relids);
unexamined_relids = set_uniono(unexamined_relids, currentchildren);
}
return examined_relids;
}
/*
* expand_inherited_rtentry
* Check whether a rangetable entry represents an inheritance set.
* If so, add entries for all the child tables to the query's
* rangetable, and return an integer list of RT indexes for the
* whole inheritance set (parent and children).
* If not, return NIL.
*
* When dup_parent is false, the initially given RT index is part of the
* returned list (if any). When dup_parent is true, the given RT index
* is *not* in the returned list; a duplicate RTE will be made for the
* parent table.
*
* A childless table is never considered to be an inheritance set; therefore
* the result will never be a one-element list. It'll be either empty
* or have two or more elements.
*
* NOTE: after this routine executes, the specified RTE will always have
* its inh flag cleared, whether or not there were any children. This
* ensures we won't expand the same RTE twice, which would otherwise occur
* for the case of an inherited UPDATE/DELETE target relation.
*
* XXX probably should convert the result type to Relids?
*/
List *
expand_inherited_rtentry(Query *parse, Index rti, bool dup_parent)
{
RangeTblEntry *rte = rt_fetch(rti, parse->rtable);
Oid parentOID;
List *inhOIDs;
List *inhRTIs;
List *l;
/* Does RT entry allow inheritance? */
if (!rte->inh)
return NIL;
Assert(rte->rtekind == RTE_RELATION);
/* Always clear the parent's inh flag, see above comments */
rte->inh = false;
/* Fast path for common case of childless table */
parentOID = rte->relid;
if (!has_subclass(parentOID))
return NIL;
/* Scan for all members of inheritance set */
inhOIDs = find_all_inheritors(parentOID);
/*
* Check that there's at least one descendant, else treat as no-child
* case. This could happen despite above has_subclass() check, if
* table once had a child but no longer does.
*/
if (lnext(inhOIDs) == NIL)
return NIL;
/* OK, it's an inheritance set; expand it */
if (dup_parent)
inhRTIs = NIL;
else
inhRTIs = makeListi1(rti); /* include original RTE in result */
foreach(l, inhOIDs)
{
Oid childOID = lfirsto(l);
RangeTblEntry *childrte;
Index childRTindex;
/* parent will be in the list too; skip it if not dup requested */
if (childOID == parentOID && !dup_parent)
continue;
/*
* Build an RTE for the child, and attach to query's rangetable
* list. We copy most fields of the parent's RTE, but replace
* relation real name and OID. Note that inh will be false at
* this point.
*/
childrte = copyObject(rte);
childrte->relid = childOID;
parse->rtable = lappend(parse->rtable, childrte);
childRTindex = length(parse->rtable);
inhRTIs = lappendi(inhRTIs, childRTindex);
}
return inhRTIs;
}
/*
* adjust_inherited_attrs
* Copy the specified query or expression and translate Vars referring
* to old_rt_index to refer to new_rt_index.
*
* We also adjust varattno to match the new table by column name, rather
* than column number. This hack makes it possible for child tables to have
* different column positions for the "same" attribute as a parent, which
* helps ALTER TABLE ADD COLUMN. Unfortunately this isn't nearly enough to
* make it work transparently; there are other places where things fall down
* if children and parents don't have the same column numbers for inherited
* attributes. It'd be better to rip this code out and fix ALTER TABLE...
*/
Node *
adjust_inherited_attrs(Node *node,
Index old_rt_index, Oid old_relid,
Index new_rt_index, Oid new_relid)
{
adjust_inherited_attrs_context context;
/* Handle simple case simply... */
if (old_rt_index == new_rt_index)
{
Assert(old_relid == new_relid);
return copyObject(node);
}
context.old_rt_index = old_rt_index;
context.new_rt_index = new_rt_index;
context.old_relid = old_relid;
context.new_relid = new_relid;
/*
* Must be prepared to start with a Query or a bare expression tree.
*/
if (node && IsA(node, Query))
{
Query *newnode;
newnode = query_tree_mutator((Query *) node,
adjust_inherited_attrs_mutator,
(void *) &context,
QTW_IGNORE_RT_SUBQUERIES);
if (newnode->resultRelation == old_rt_index)
{
newnode->resultRelation = new_rt_index;
/* Fix tlist resnos too, if it's inherited UPDATE */
if (newnode->commandType == CMD_UPDATE)
newnode->targetList =
adjust_inherited_tlist(newnode->targetList,
new_relid);
}
return (Node *) newnode;
}
else
return adjust_inherited_attrs_mutator(node, &context);
}
static Node *
adjust_inherited_attrs_mutator(Node *node,
adjust_inherited_attrs_context *context)
{
if (node == NULL)
return NULL;
if (IsA(node, Var))
{
Var *var = (Var *) copyObject(node);
if (var->varlevelsup == 0 &&
var->varno == context->old_rt_index)
{
var->varno = context->new_rt_index;
var->varnoold = context->new_rt_index;
if (var->varattno > 0)
{
char *attname = get_attname(context->old_relid,
var->varattno);
var->varattno = get_attnum(context->new_relid, attname);
if (var->varattno == InvalidAttrNumber)
elog(ERROR, "attribute \"%s\" of relation \"%s\" does not exist",
attname, get_rel_name(context->new_relid));
var->varoattno = var->varattno;
pfree(attname);
}
}
return (Node *) var;
}
if (IsA(node, RangeTblRef))
{
RangeTblRef *rtr = (RangeTblRef *) copyObject(node);
if (rtr->rtindex == context->old_rt_index)
rtr->rtindex = context->new_rt_index;
return (Node *) rtr;
}
if (IsA(node, JoinExpr))
{
/* Copy the JoinExpr node with correct mutation of subnodes */
JoinExpr *j;
j = (JoinExpr *) expression_tree_mutator(node,
adjust_inherited_attrs_mutator,
(void *) context);
/* now fix JoinExpr's rtindex */
if (j->rtindex == context->old_rt_index)
j->rtindex = context->new_rt_index;
return (Node *) j;
}
if (IsA(node, InClauseInfo))
{
/* Copy the InClauseInfo node with correct mutation of subnodes */
InClauseInfo *ininfo;
ininfo = (InClauseInfo *) expression_tree_mutator(node,
adjust_inherited_attrs_mutator,
(void *) context);
/* now fix InClauseInfo's relid sets */
ininfo->lefthand = adjust_relid_set(ininfo->lefthand,
context->old_rt_index,
context->new_rt_index);
ininfo->righthand = adjust_relid_set(ininfo->righthand,
context->old_rt_index,
context->new_rt_index);
return (Node *) ininfo;
}
/*
* We have to process RestrictInfo nodes specially.
*/
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_inherited_attrs_mutator((Node *) oldinfo->clause, context);
/*
* We do NOT want to copy the original subclauseindices list, since
* the new rel will have different indices. The list will be rebuilt
* when needed during later planning.
*/
newinfo->subclauseindices = NIL;
/*
* Adjust left/right relid sets too.
*/
newinfo->left_relids = adjust_relid_set(oldinfo->left_relids,
context->old_rt_index,
context->new_rt_index);
newinfo->right_relids = adjust_relid_set(oldinfo->right_relids,
context->old_rt_index,
context->new_rt_index);
newinfo->eval_cost.startup = -1; /* reset these too */
newinfo->this_selec = -1;
newinfo->left_pathkey = NIL; /* and these */
newinfo->right_pathkey = NIL;
newinfo->left_mergescansel = -1;
newinfo->right_mergescansel = -1;
newinfo->left_bucketsize = -1;
newinfo->right_bucketsize = -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));
/*
* BUT: although we don't need to recurse into subplans, we do need to
* make sure that they are copied, not just referenced as
* expression_tree_mutator will do by default. Otherwise we'll have
* the same subplan node referenced from each arm of the inheritance
* APPEND plan, which will cause trouble in the executor. This is a
* kluge that should go away when we redesign querytrees.
*/
if (is_subplan(node))
{
SubPlan *subplan;
/* Copy the node and process subplan args */
node = expression_tree_mutator(node, adjust_inherited_attrs_mutator,
(void *) context);
/* Make sure we have separate copies of subplan and its rtable */
subplan = (SubPlan *) node;
subplan->plan = copyObject(subplan->plan);
subplan->rtable = copyObject(subplan->rtable);
return node;
}
return expression_tree_mutator(node, adjust_inherited_attrs_mutator,
(void *) context);
}
/*
* Substitute newrelid for oldrelid in a Relid set
*/
static Relids
adjust_relid_set(Relids relids, Index oldrelid, Index newrelid)
{
if (bms_is_member(oldrelid, relids))
{
/* Ensure we have a modifiable copy */
relids = bms_copy(relids);
/* Remove old, add new */
relids = bms_del_member(relids, oldrelid);
relids = bms_add_member(relids, newrelid);
}
return relids;
}
/*
* 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. But the Resdom nodes have not been copied; make new ones
* if we need to change them!
*
* Note that this is not needed for INSERT because INSERT isn't inheritable.
*/
static List *
adjust_inherited_tlist(List *tlist, Oid new_relid)
{
bool changed_it = false;
List *tl;
List *new_tlist;
bool more;
int attrno;
/* Scan tlist and update resnos to match attnums of new_relid */
foreach(tl, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(tl);
Resdom *resdom = tle->resdom;
if (resdom->resjunk)
continue; /* ignore junk items */
attrno = get_attnum(new_relid, resdom->resname);
if (attrno == InvalidAttrNumber)
elog(ERROR, "attribute \"%s\" of relation \"%s\" does not exist",
resdom->resname, get_rel_name(new_relid));
if (resdom->resno != attrno)
{
resdom = (Resdom *) copyObject((Node *) resdom);
resdom->resno = attrno;
tle->resdom = resdom;
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);
Resdom *resdom = tle->resdom;
if (resdom->resjunk)
continue; /* ignore junk items */
if (resdom->resno == attrno)
new_tlist = lappend(new_tlist, tle);
else if (resdom->resno > attrno)
more = true;
}
}
foreach(tl, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(tl);
Resdom *resdom = tle->resdom;
if (!resdom->resjunk)
continue; /* here, ignore non-junk items */
if (resdom->resno != attrno)
{
resdom = (Resdom *) copyObject((Node *) resdom);
resdom->resno = attrno;
tle->resdom = resdom;
}
new_tlist = lappend(new_tlist, tle);
attrno++;
}
return new_tlist;
}