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postgresql/src/backend/parser/analyze.c

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/*-------------------------------------------------------------------------
*
* analyze.c
* transform the raw parse tree into a query tree
*
* For optimizable statements, we are careful to obtain a suitable lock on
* each referenced table, and other modules of the backend preserve or
* re-obtain these locks before depending on the results. It is therefore
* okay to do significant semantic analysis of these statements. For
* utility commands, no locks are obtained here (and if they were, we could
* not be sure we'd still have them at execution). Hence the general rule
* for utility commands is to just dump them into a Query node untransformed.
* DECLARE CURSOR and EXPLAIN are exceptions because they contain
* optimizable statements.
*
*
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.370 2007/11/15 21:14:36 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/pg_type.h"
#include "nodes/makefuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/var.h"
#include "parser/analyze.h"
#include "parser/parse_agg.h"
#include "parser/parse_clause.h"
#include "parser/parse_coerce.h"
#include "parser/parse_expr.h"
#include "parser/parse_relation.h"
#include "parser/parse_target.h"
#include "parser/parsetree.h"
typedef struct
{
Oid *paramTypes;
int numParams;
} check_parameter_resolution_context;
static Query *transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt);
static Query *transformInsertStmt(ParseState *pstate, InsertStmt *stmt);
static List *transformInsertRow(ParseState *pstate, List *exprlist,
List *stmtcols, List *icolumns, List *attrnos);
static Query *transformSelectStmt(ParseState *pstate, SelectStmt *stmt);
static Query *transformValuesClause(ParseState *pstate, SelectStmt *stmt);
static Query *transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt);
static Node *transformSetOperationTree(ParseState *pstate, SelectStmt *stmt);
static void getSetColTypes(ParseState *pstate, Node *node,
List **colTypes, List **colTypmods);
static void applyColumnNames(List *dst, List *src);
static Query *transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt);
static List *transformReturningList(ParseState *pstate, List *returningList);
static Query *transformDeclareCursorStmt(ParseState *pstate,
DeclareCursorStmt *stmt);
static Query *transformExplainStmt(ParseState *pstate,
ExplainStmt *stmt);
static void transformLockingClause(Query *qry, LockingClause *lc);
static bool check_parameter_resolution_walker(Node *node,
check_parameter_resolution_context *context);
/*
* parse_analyze
* Analyze a raw parse tree and transform it to Query form.
*
* If available, pass the source text from which the raw parse tree was
* generated; it's OK to pass NULL if this is not available.
*
* Optionally, information about $n parameter types can be supplied.
* References to $n indexes not defined by paramTypes[] are disallowed.
*
* The result is a Query node. Optimizable statements require considerable
* transformation, while utility-type statements are simply hung off
* a dummy CMD_UTILITY Query node.
*/
Query *
parse_analyze(Node *parseTree, const char *sourceText,
Oid *paramTypes, int numParams)
{
ParseState *pstate = make_parsestate(NULL);
Query *query;
pstate->p_sourcetext = sourceText;
pstate->p_paramtypes = paramTypes;
pstate->p_numparams = numParams;
pstate->p_variableparams = false;
query = transformStmt(pstate, parseTree);
free_parsestate(pstate);
return query;
}
/*
* parse_analyze_varparams
*
* This variant is used when it's okay to deduce information about $n
* symbol datatypes from context. The passed-in paramTypes[] array can
* be modified or enlarged (via repalloc).
*/
Query *
parse_analyze_varparams(Node *parseTree, const char *sourceText,
Oid **paramTypes, int *numParams)
{
ParseState *pstate = make_parsestate(NULL);
Query *query;
pstate->p_sourcetext = sourceText;
pstate->p_paramtypes = *paramTypes;
pstate->p_numparams = *numParams;
pstate->p_variableparams = true;
query = transformStmt(pstate, parseTree);
*paramTypes = pstate->p_paramtypes;
*numParams = pstate->p_numparams;
free_parsestate(pstate);
/* make sure all is well with parameter types */
if (*numParams > 0)
{
check_parameter_resolution_context context;
context.paramTypes = *paramTypes;
context.numParams = *numParams;
check_parameter_resolution_walker((Node *) query, &context);
}
return query;
}
/*
* parse_sub_analyze
* Entry point for recursively analyzing a sub-statement.
*/
Query *
parse_sub_analyze(Node *parseTree, ParseState *parentParseState)
{
ParseState *pstate = make_parsestate(parentParseState);
Query *query;
query = transformStmt(pstate, parseTree);
free_parsestate(pstate);
return query;
}
/*
* transformStmt -
* transform a Parse tree into a Query tree.
*/
Query *
transformStmt(ParseState *pstate, Node *parseTree)
{
Query *result;
switch (nodeTag(parseTree))
{
/*
* Optimizable statements
*/
case T_InsertStmt:
result = transformInsertStmt(pstate, (InsertStmt *) parseTree);
break;
case T_DeleteStmt:
result = transformDeleteStmt(pstate, (DeleteStmt *) parseTree);
break;
case T_UpdateStmt:
result = transformUpdateStmt(pstate, (UpdateStmt *) parseTree);
break;
case T_SelectStmt:
{
SelectStmt *n = (SelectStmt *) parseTree;
if (n->valuesLists)
result = transformValuesClause(pstate, n);
else if (n->op == SETOP_NONE)
result = transformSelectStmt(pstate, n);
else
result = transformSetOperationStmt(pstate, n);
}
break;
/*
* Special cases
*/
case T_DeclareCursorStmt:
result = transformDeclareCursorStmt(pstate,
(DeclareCursorStmt *) parseTree);
break;
case T_ExplainStmt:
result = transformExplainStmt(pstate,
(ExplainStmt *) parseTree);
break;
default:
/*
* other statements don't require any transformation; just return
* the original parsetree with a Query node plastered on top.
*/
result = makeNode(Query);
result->commandType = CMD_UTILITY;
result->utilityStmt = (Node *) parseTree;
break;
}
/* Mark as original query until we learn differently */
result->querySource = QSRC_ORIGINAL;
result->canSetTag = true;
return result;
}
/*
* transformDeleteStmt -
* transforms a Delete Statement
*/
static Query *
transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
{
Query *qry = makeNode(Query);
Node *qual;
qry->commandType = CMD_DELETE;
/* set up range table with just the result rel */
qry->resultRelation = setTargetTable(pstate, stmt->relation,
interpretInhOption(stmt->relation->inhOpt),
true,
ACL_DELETE);
qry->distinctClause = NIL;
/*
* The USING clause is non-standard SQL syntax, and is equivalent in
* functionality to the FROM list that can be specified for UPDATE. The
* USING keyword is used rather than FROM because FROM is already a
* keyword in the DELETE syntax.
*/
transformFromClause(pstate, stmt->usingClause);
qual = transformWhereClause(pstate, stmt->whereClause, "WHERE");
qry->returningList = transformReturningList(pstate, stmt->returningList);
/* done building the range table and jointree */
qry->rtable = pstate->p_rtable;
qry->jointree = makeFromExpr(pstate->p_joinlist, qual);
qry->hasSubLinks = pstate->p_hasSubLinks;
qry->hasAggs = pstate->p_hasAggs;
if (pstate->p_hasAggs)
parseCheckAggregates(pstate, qry);
return qry;
}
/*
* transformInsertStmt -
* transform an Insert Statement
*/
static Query *
transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
{
Query *qry = makeNode(Query);
SelectStmt *selectStmt = (SelectStmt *) stmt->selectStmt;
List *exprList = NIL;
bool isGeneralSelect;
List *sub_rtable;
List *sub_relnamespace;
List *sub_varnamespace;
List *icolumns;
List *attrnos;
RangeTblEntry *rte;
RangeTblRef *rtr;
ListCell *icols;
ListCell *attnos;
ListCell *lc;
qry->commandType = CMD_INSERT;
pstate->p_is_insert = true;
/*
* We have three cases to deal with: DEFAULT VALUES (selectStmt == NULL),
* VALUES list, or general SELECT input. We special-case VALUES, both for
* efficiency and so we can handle DEFAULT specifications.
*/
isGeneralSelect = (selectStmt && selectStmt->valuesLists == NIL);
/*
* If a non-nil rangetable/namespace was passed in, and we are doing
* INSERT/SELECT, arrange to pass the rangetable/namespace down to the
* SELECT. This can only happen if we are inside a CREATE RULE, and in
* that case we want the rule's OLD and NEW rtable entries to appear as
* part of the SELECT's rtable, not as outer references for it. (Kluge!)
* The SELECT's joinlist is not affected however. We must do this before
* adding the target table to the INSERT's rtable.
*/
if (isGeneralSelect)
{
sub_rtable = pstate->p_rtable;
pstate->p_rtable = NIL;
sub_relnamespace = pstate->p_relnamespace;
pstate->p_relnamespace = NIL;
sub_varnamespace = pstate->p_varnamespace;
pstate->p_varnamespace = NIL;
}
else
{
sub_rtable = NIL; /* not used, but keep compiler quiet */
sub_relnamespace = NIL;
sub_varnamespace = NIL;
}
/*
* Must get write lock on INSERT target table before scanning SELECT, else
* we will grab the wrong kind of initial lock if the target table is also
* mentioned in the SELECT part. Note that the target table is not added
* to the joinlist or namespace.
*/
qry->resultRelation = setTargetTable(pstate, stmt->relation,
false, false, ACL_INSERT);
/* Validate stmt->cols list, or build default list if no list given */
icolumns = checkInsertTargets(pstate, stmt->cols, &attrnos);
Assert(list_length(icolumns) == list_length(attrnos));
/*
* Determine which variant of INSERT we have.
*/
if (selectStmt == NULL)
{
/*
* We have INSERT ... DEFAULT VALUES. We can handle this case by
* emitting an empty targetlist --- all columns will be defaulted when
* the planner expands the targetlist.
*/
exprList = NIL;
}
else if (isGeneralSelect)
{
/*
* We make the sub-pstate a child of the outer pstate so that it can
* see any Param definitions supplied from above. Since the outer
* pstate's rtable and namespace are presently empty, there are no
* side-effects of exposing names the sub-SELECT shouldn't be able to
* see.
*/
ParseState *sub_pstate = make_parsestate(pstate);
Query *selectQuery;
/*
* Process the source SELECT.
*
* It is important that this be handled just like a standalone SELECT;
* otherwise the behavior of SELECT within INSERT might be different
* from a stand-alone SELECT. (Indeed, Postgres up through 6.5 had
* bugs of just that nature...)
*/
sub_pstate->p_rtable = sub_rtable;
sub_pstate->p_relnamespace = sub_relnamespace;
sub_pstate->p_varnamespace = sub_varnamespace;
selectQuery = transformStmt(sub_pstate, stmt->selectStmt);
free_parsestate(sub_pstate);
/* The grammar should have produced a SELECT, but it might have INTO */
Assert(IsA(selectQuery, Query));
Assert(selectQuery->commandType == CMD_SELECT);
Assert(selectQuery->utilityStmt == NULL);
if (selectQuery->intoClause)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("INSERT ... SELECT cannot specify INTO")));
/*
* Make the source be a subquery in the INSERT's rangetable, and add
* it to the INSERT's joinlist.
*/
rte = addRangeTableEntryForSubquery(pstate,
selectQuery,
makeAlias("*SELECT*", NIL),
false);
rtr = makeNode(RangeTblRef);
/* assume new rte is at end */
rtr->rtindex = list_length(pstate->p_rtable);
Assert(rte == rt_fetch(rtr->rtindex, pstate->p_rtable));
pstate->p_joinlist = lappend(pstate->p_joinlist, rtr);
/*----------
* Generate an expression list for the INSERT that selects all the
* non-resjunk columns from the subquery. (INSERT's tlist must be
* separate from the subquery's tlist because we may add columns,
* insert datatype coercions, etc.)
*
* HACK: unknown-type constants and params in the SELECT's targetlist
* are copied up as-is rather than being referenced as subquery
* outputs. This is to ensure that when we try to coerce them to
* the target column's datatype, the right things happen (see
* special cases in coerce_type). Otherwise, this fails:
* INSERT INTO foo SELECT 'bar', ... FROM baz
*----------
*/
exprList = NIL;
foreach(lc, selectQuery->targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(lc);
Expr *expr;
if (tle->resjunk)
continue;
if (tle->expr &&
(IsA(tle->expr, Const) ||IsA(tle->expr, Param)) &&
exprType((Node *) tle->expr) == UNKNOWNOID)
expr = tle->expr;
else
expr = (Expr *) makeVar(rtr->rtindex,
tle->resno,
exprType((Node *) tle->expr),
exprTypmod((Node *) tle->expr),
0);
exprList = lappend(exprList, expr);
}
/* Prepare row for assignment to target table */
exprList = transformInsertRow(pstate, exprList,
stmt->cols,
icolumns, attrnos);
}
else if (list_length(selectStmt->valuesLists) > 1)
{
/*
* Process INSERT ... VALUES with multiple VALUES sublists. We
* generate a VALUES RTE holding the transformed expression lists, and
* build up a targetlist containing Vars that reference the VALUES
* RTE.
*/
List *exprsLists = NIL;
int sublist_length = -1;
foreach(lc, selectStmt->valuesLists)
{
List *sublist = (List *) lfirst(lc);
/* Do basic expression transformation (same as a ROW() expr) */
sublist = transformExpressionList(pstate, sublist);
/*
* All the sublists must be the same length, *after*
* transformation (which might expand '*' into multiple items).
* The VALUES RTE can't handle anything different.
*/
if (sublist_length < 0)
{
/* Remember post-transformation length of first sublist */
sublist_length = list_length(sublist);
}
else if (sublist_length != list_length(sublist))
{
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("VALUES lists must all be the same length")));
}
/* Prepare row for assignment to target table */
sublist = transformInsertRow(pstate, sublist,
stmt->cols,
icolumns, attrnos);
exprsLists = lappend(exprsLists, sublist);
}
/*
* There mustn't have been any table references in the expressions,
* else strange things would happen, like Cartesian products of those
* tables with the VALUES list ...
*/
if (pstate->p_joinlist != NIL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("VALUES must not contain table references")));
/*
* Another thing we can't currently support is NEW/OLD references in
* rules --- seems we'd need something like SQL99's LATERAL construct
* to ensure that the values would be available while evaluating the
* VALUES RTE. This is a shame. FIXME
*/
if (list_length(pstate->p_rtable) != 1 &&
contain_vars_of_level((Node *) exprsLists, 0))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("VALUES must not contain OLD or NEW references"),
errhint("Use SELECT ... UNION ALL ... instead.")));
/*
* Generate the VALUES RTE
*/
rte = addRangeTableEntryForValues(pstate, exprsLists, NULL, true);
rtr = makeNode(RangeTblRef);
/* assume new rte is at end */
rtr->rtindex = list_length(pstate->p_rtable);
Assert(rte == rt_fetch(rtr->rtindex, pstate->p_rtable));
pstate->p_joinlist = lappend(pstate->p_joinlist, rtr);
/*
* Generate list of Vars referencing the RTE
*/
expandRTE(rte, rtr->rtindex, 0, false, NULL, &exprList);
}
else
{
/*----------
* Process INSERT ... VALUES with a single VALUES sublist.
* We treat this separately for efficiency and for historical
* compatibility --- specifically, allowing table references,
* such as
* INSERT INTO foo VALUES(bar.*)
*
* The sublist is just computed directly as the Query's targetlist,
* with no VALUES RTE. So it works just like SELECT without FROM.
*----------
*/
List *valuesLists = selectStmt->valuesLists;
Assert(list_length(valuesLists) == 1);
/* Do basic expression transformation (same as a ROW() expr) */
exprList = transformExpressionList(pstate,
(List *) linitial(valuesLists));
/* Prepare row for assignment to target table */
exprList = transformInsertRow(pstate, exprList,
stmt->cols,
icolumns, attrnos);
}
/*
* Generate query's target list using the computed list of expressions.
*/
qry->targetList = NIL;
icols = list_head(icolumns);
attnos = list_head(attrnos);
foreach(lc, exprList)
{
Expr *expr = (Expr *) lfirst(lc);
ResTarget *col;
TargetEntry *tle;
col = (ResTarget *) lfirst(icols);
Assert(IsA(col, ResTarget));
tle = makeTargetEntry(expr,
(AttrNumber) lfirst_int(attnos),
col->name,
false);
qry->targetList = lappend(qry->targetList, tle);
icols = lnext(icols);
attnos = lnext(attnos);
}
/*
* If we have a RETURNING clause, we need to add the target relation to
* the query namespace before processing it, so that Var references in
* RETURNING will work. Also, remove any namespace entries added in a
* sub-SELECT or VALUES list.
*/
if (stmt->returningList)
{
pstate->p_relnamespace = NIL;
pstate->p_varnamespace = NIL;
addRTEtoQuery(pstate, pstate->p_target_rangetblentry,
false, true, true);
qry->returningList = transformReturningList(pstate,
stmt->returningList);
}
/* done building the range table and jointree */
qry->rtable = pstate->p_rtable;
qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);
qry->hasSubLinks = pstate->p_hasSubLinks;
/* aggregates not allowed (but subselects are okay) */
if (pstate->p_hasAggs)
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in VALUES")));
return qry;
}
/*
* Prepare an INSERT row for assignment to the target table.
*
* The row might be either a VALUES row, or variables referencing a
* sub-SELECT output.
*/
static List *
transformInsertRow(ParseState *pstate, List *exprlist,
List *stmtcols, List *icolumns, List *attrnos)
{
List *result;
ListCell *lc;
ListCell *icols;
ListCell *attnos;
/*
* Check length of expr list. It must not have more expressions than
* there are target columns. We allow fewer, but only if no explicit
* columns list was given (the remaining columns are implicitly
* defaulted). Note we must check this *after* transformation because
* that could expand '*' into multiple items.
*/
if (list_length(exprlist) > list_length(icolumns))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("INSERT has more expressions than target columns")));
if (stmtcols != NIL &&
list_length(exprlist) < list_length(icolumns))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("INSERT has more target columns than expressions")));
/*
* Prepare columns for assignment to target table.
*/
result = NIL;
icols = list_head(icolumns);
attnos = list_head(attrnos);
foreach(lc, exprlist)
{
Expr *expr = (Expr *) lfirst(lc);
ResTarget *col;
col = (ResTarget *) lfirst(icols);
Assert(IsA(col, ResTarget));
expr = transformAssignedExpr(pstate, expr,
col->name,
lfirst_int(attnos),
col->indirection,
col->location);
result = lappend(result, expr);
icols = lnext(icols);
attnos = lnext(attnos);
}
return result;
}
/*
* transformSelectStmt -
* transforms a Select Statement
*
* Note: this covers only cases with no set operations and no VALUES lists;
* see below for the other cases.
*/
static Query *
transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
{
Query *qry = makeNode(Query);
Node *qual;
ListCell *l;
qry->commandType = CMD_SELECT;
/* make FOR UPDATE/FOR SHARE info available to addRangeTableEntry */
pstate->p_locking_clause = stmt->lockingClause;
/* process the FROM clause */
transformFromClause(pstate, stmt->fromClause);
/* transform targetlist */
qry->targetList = transformTargetList(pstate, stmt->targetList);
/* mark column origins */
markTargetListOrigins(pstate, qry->targetList);
/* transform WHERE */
qual = transformWhereClause(pstate, stmt->whereClause, "WHERE");
/*
* Initial processing of HAVING clause is just like WHERE clause.
*/
qry->havingQual = transformWhereClause(pstate, stmt->havingClause,
"HAVING");
/*
* Transform sorting/grouping stuff. Do ORDER BY first because both
* transformGroupClause and transformDistinctClause need the results.
*/
qry->sortClause = transformSortClause(pstate,
stmt->sortClause,
&qry->targetList,
true /* fix unknowns */ );
qry->groupClause = transformGroupClause(pstate,
stmt->groupClause,
&qry->targetList,
qry->sortClause);
qry->distinctClause = transformDistinctClause(pstate,
stmt->distinctClause,
&qry->targetList,
&qry->sortClause);
qry->limitOffset = transformLimitClause(pstate, stmt->limitOffset,
"OFFSET");
qry->limitCount = transformLimitClause(pstate, stmt->limitCount,
"LIMIT");
/* handle any SELECT INTO/CREATE TABLE AS spec */
if (stmt->intoClause)
{
qry->intoClause = stmt->intoClause;
if (stmt->intoClause->colNames)
applyColumnNames(qry->targetList, stmt->intoClause->colNames);
}
qry->rtable = pstate->p_rtable;
qry->jointree = makeFromExpr(pstate->p_joinlist, qual);
qry->hasSubLinks = pstate->p_hasSubLinks;
qry->hasAggs = pstate->p_hasAggs;
if (pstate->p_hasAggs || qry->groupClause || qry->havingQual)
parseCheckAggregates(pstate, qry);
foreach(l, stmt->lockingClause)
{
transformLockingClause(qry, (LockingClause *) lfirst(l));
}
return qry;
}
/*
* transformValuesClause -
* transforms a VALUES clause that's being used as a standalone SELECT
*
* We build a Query containing a VALUES RTE, rather as if one had written
* SELECT * FROM (VALUES ...)
*/
static Query *
transformValuesClause(ParseState *pstate, SelectStmt *stmt)
{
Query *qry = makeNode(Query);
List *exprsLists = NIL;
List **coltype_lists = NULL;
Oid *coltypes = NULL;
int sublist_length = -1;
List *newExprsLists;
RangeTblEntry *rte;
RangeTblRef *rtr;
ListCell *lc;
ListCell *lc2;
int i;
qry->commandType = CMD_SELECT;
/* Most SELECT stuff doesn't apply in a VALUES clause */
Assert(stmt->distinctClause == NIL);
Assert(stmt->targetList == NIL);
Assert(stmt->fromClause == NIL);
Assert(stmt->whereClause == NULL);
Assert(stmt->groupClause == NIL);
Assert(stmt->havingClause == NULL);
Assert(stmt->op == SETOP_NONE);
/*
* For each row of VALUES, transform the raw expressions and gather type
* information. This is also a handy place to reject DEFAULT nodes, which
* the grammar allows for simplicity.
*/
foreach(lc, stmt->valuesLists)
{
List *sublist = (List *) lfirst(lc);
/* Do basic expression transformation (same as a ROW() expr) */
sublist = transformExpressionList(pstate, sublist);
/*
* All the sublists must be the same length, *after* transformation
* (which might expand '*' into multiple items). The VALUES RTE can't
* handle anything different.
*/
if (sublist_length < 0)
{
/* Remember post-transformation length of first sublist */
sublist_length = list_length(sublist);
/* and allocate arrays for column-type info */
coltype_lists = (List **) palloc0(sublist_length * sizeof(List *));
coltypes = (Oid *) palloc0(sublist_length * sizeof(Oid));
}
else if (sublist_length != list_length(sublist))
{
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("VALUES lists must all be the same length")));
}
exprsLists = lappend(exprsLists, sublist);
i = 0;
foreach(lc2, sublist)
{
Node *col = (Node *) lfirst(lc2);
if (IsA(col, SetToDefault))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("DEFAULT can only appear in a VALUES list within INSERT")));
coltype_lists[i] = lappend_oid(coltype_lists[i], exprType(col));
i++;
}
}
/*
* Now resolve the common types of the columns, and coerce everything to
* those types.
*/
for (i = 0; i < sublist_length; i++)
{
coltypes[i] = select_common_type(coltype_lists[i], "VALUES");
}
newExprsLists = NIL;
foreach(lc, exprsLists)
{
List *sublist = (List *) lfirst(lc);
List *newsublist = NIL;
i = 0;
foreach(lc2, sublist)
{
Node *col = (Node *) lfirst(lc2);
col = coerce_to_common_type(pstate, col, coltypes[i], "VALUES");
newsublist = lappend(newsublist, col);
i++;
}
newExprsLists = lappend(newExprsLists, newsublist);
}
/*
* Generate the VALUES RTE
*/
rte = addRangeTableEntryForValues(pstate, newExprsLists, NULL, true);
rtr = makeNode(RangeTblRef);
/* assume new rte is at end */
rtr->rtindex = list_length(pstate->p_rtable);
Assert(rte == rt_fetch(rtr->rtindex, pstate->p_rtable));
pstate->p_joinlist = lappend(pstate->p_joinlist, rtr);
pstate->p_varnamespace = lappend(pstate->p_varnamespace, rte);
/*
* Generate a targetlist as though expanding "*"
*/
Assert(pstate->p_next_resno == 1);
qry->targetList = expandRelAttrs(pstate, rte, rtr->rtindex, 0);
/*
* The grammar allows attaching ORDER BY, LIMIT, and FOR UPDATE to a
* VALUES, so cope.
*/
qry->sortClause = transformSortClause(pstate,
stmt->sortClause,
&qry->targetList,
true /* fix unknowns */ );
qry->limitOffset = transformLimitClause(pstate, stmt->limitOffset,
"OFFSET");
qry->limitCount = transformLimitClause(pstate, stmt->limitCount,
"LIMIT");
if (stmt->lockingClause)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE cannot be applied to VALUES")));
/* handle any CREATE TABLE AS spec */
if (stmt->intoClause)
{
qry->intoClause = stmt->intoClause;
if (stmt->intoClause->colNames)
applyColumnNames(qry->targetList, stmt->intoClause->colNames);
}
/*
* There mustn't have been any table references in the expressions, else
* strange things would happen, like Cartesian products of those tables
* with the VALUES list. We have to check this after parsing ORDER BY et
* al since those could insert more junk.
*/
if (list_length(pstate->p_joinlist) != 1)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("VALUES must not contain table references")));
/*
* Another thing we can't currently support is NEW/OLD references in rules
* --- seems we'd need something like SQL99's LATERAL construct to ensure
* that the values would be available while evaluating the VALUES RTE.
* This is a shame. FIXME
*/
if (list_length(pstate->p_rtable) != 1 &&
contain_vars_of_level((Node *) newExprsLists, 0))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("VALUES must not contain OLD or NEW references"),
errhint("Use SELECT ... UNION ALL ... instead.")));
qry->rtable = pstate->p_rtable;
qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);
qry->hasSubLinks = pstate->p_hasSubLinks;
/* aggregates not allowed (but subselects are okay) */
if (pstate->p_hasAggs)
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in VALUES")));
return qry;
}
/*
* transformSetOperationStmt -
* transforms a set-operations tree
*
* A set-operation tree is just a SELECT, but with UNION/INTERSECT/EXCEPT
* structure to it. We must transform each leaf SELECT and build up a top-
* level Query that contains the leaf SELECTs as subqueries in its rangetable.
* The tree of set operations is converted into the setOperations field of
* the top-level Query.
*/
static Query *
transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
{
Query *qry = makeNode(Query);
SelectStmt *leftmostSelect;
int leftmostRTI;
Query *leftmostQuery;
SetOperationStmt *sostmt;
List *intoColNames = NIL;
List *sortClause;
Node *limitOffset;
Node *limitCount;
List *lockingClause;
Node *node;
ListCell *left_tlist,
*lct,
*lcm,
*l;
List *targetvars,
*targetnames,
*sv_relnamespace,
*sv_varnamespace,
*sv_rtable;
RangeTblEntry *jrte;
int tllen;
qry->commandType = CMD_SELECT;
/*
* Find leftmost leaf SelectStmt; extract the one-time-only items from it
* and from the top-level node.
*/
leftmostSelect = stmt->larg;
while (leftmostSelect && leftmostSelect->op != SETOP_NONE)
leftmostSelect = leftmostSelect->larg;
Assert(leftmostSelect && IsA(leftmostSelect, SelectStmt) &&
leftmostSelect->larg == NULL);
if (leftmostSelect->intoClause)
{
qry->intoClause = leftmostSelect->intoClause;
intoColNames = leftmostSelect->intoClause->colNames;
}
/* clear this to prevent complaints in transformSetOperationTree() */
leftmostSelect->intoClause = NULL;
/*
* These are not one-time, exactly, but we want to process them here and
* not let transformSetOperationTree() see them --- else it'll just
* recurse right back here!
*/
sortClause = stmt->sortClause;
limitOffset = stmt->limitOffset;
limitCount = stmt->limitCount;
lockingClause = stmt->lockingClause;
stmt->sortClause = NIL;
stmt->limitOffset = NULL;
stmt->limitCount = NULL;
stmt->lockingClause = NIL;
/* We don't support FOR UPDATE/SHARE with set ops at the moment. */
if (lockingClause)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE is not allowed with UNION/INTERSECT/EXCEPT")));
/*
* Recursively transform the components of the tree.
*/
sostmt = (SetOperationStmt *) transformSetOperationTree(pstate, stmt);
Assert(sostmt && IsA(sostmt, SetOperationStmt));
qry->setOperations = (Node *) sostmt;
/*
* Re-find leftmost SELECT (now it's a sub-query in rangetable)
*/
node = sostmt->larg;
while (node && IsA(node, SetOperationStmt))
node = ((SetOperationStmt *) node)->larg;
Assert(node && IsA(node, RangeTblRef));
leftmostRTI = ((RangeTblRef *) node)->rtindex;
leftmostQuery = rt_fetch(leftmostRTI, pstate->p_rtable)->subquery;
Assert(leftmostQuery != NULL);
/*
* Generate dummy targetlist for outer query using column names of
* leftmost select and common datatypes of topmost set operation. Also
* make lists of the dummy vars and their names for use in parsing ORDER
* BY.
*
* Note: we use leftmostRTI as the varno of the dummy variables. It
* shouldn't matter too much which RT index they have, as long as they
* have one that corresponds to a real RT entry; else funny things may
* happen when the tree is mashed by rule rewriting.
*/
qry->targetList = NIL;
targetvars = NIL;
targetnames = NIL;
left_tlist = list_head(leftmostQuery->targetList);
forboth(lct, sostmt->colTypes, lcm, sostmt->colTypmods)
{
Oid colType = lfirst_oid(lct);
int32 colTypmod = lfirst_int(lcm);
TargetEntry *lefttle = (TargetEntry *) lfirst(left_tlist);
char *colName;
TargetEntry *tle;
Expr *expr;
Assert(!lefttle->resjunk);
colName = pstrdup(lefttle->resname);
expr = (Expr *) makeVar(leftmostRTI,
lefttle->resno,
colType,
colTypmod,
0);
tle = makeTargetEntry(expr,
(AttrNumber) pstate->p_next_resno++,
colName,
false);
qry->targetList = lappend(qry->targetList, tle);
targetvars = lappend(targetvars, expr);
targetnames = lappend(targetnames, makeString(colName));
left_tlist = lnext(left_tlist);
}
/*
* As a first step towards supporting sort clauses that are expressions
* using the output columns, generate a varnamespace entry that makes the
* output columns visible. A Join RTE node is handy for this, since we
* can easily control the Vars generated upon matches.
*
* Note: we don't yet do anything useful with such cases, but at least
* "ORDER BY upper(foo)" will draw the right error message rather than
* "foo not found".
*/
jrte = addRangeTableEntryForJoin(NULL,
targetnames,
JOIN_INNER,
targetvars,
NULL,
false);
sv_rtable = pstate->p_rtable;
pstate->p_rtable = list_make1(jrte);
sv_relnamespace = pstate->p_relnamespace;
pstate->p_relnamespace = NIL; /* no qualified names allowed */
sv_varnamespace = pstate->p_varnamespace;
pstate->p_varnamespace = list_make1(jrte);
/*
* For now, we don't support resjunk sort clauses on the output of a
* setOperation tree --- you can only use the SQL92-spec options of
* selecting an output column by name or number. Enforce by checking that
* transformSortClause doesn't add any items to tlist.
*/
tllen = list_length(qry->targetList);
qry->sortClause = transformSortClause(pstate,
sortClause,
&qry->targetList,
false /* no unknowns expected */ );
pstate->p_rtable = sv_rtable;
pstate->p_relnamespace = sv_relnamespace;
pstate->p_varnamespace = sv_varnamespace;
if (tllen != list_length(qry->targetList))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("invalid UNION/INTERSECT/EXCEPT ORDER BY clause"),
errdetail("Only result column names can be used, not expressions or functions."),
errhint("Add the expression/function to every SELECT, or move the UNION into a FROM clause.")));
qry->limitOffset = transformLimitClause(pstate, limitOffset,
"OFFSET");
qry->limitCount = transformLimitClause(pstate, limitCount,
"LIMIT");
/*
* Handle SELECT INTO/CREATE TABLE AS.
*
* Any column names from CREATE TABLE AS need to be attached to both the
* top level and the leftmost subquery. We do not do this earlier because
* we do *not* want sortClause processing to be affected.
*/
if (intoColNames)
{
applyColumnNames(qry->targetList, intoColNames);
applyColumnNames(leftmostQuery->targetList, intoColNames);
}
qry->rtable = pstate->p_rtable;
qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);
qry->hasSubLinks = pstate->p_hasSubLinks;
qry->hasAggs = pstate->p_hasAggs;
if (pstate->p_hasAggs || qry->groupClause || qry->havingQual)
parseCheckAggregates(pstate, qry);
foreach(l, lockingClause)
{
transformLockingClause(qry, (LockingClause *) lfirst(l));
}
return qry;
}
/*
* transformSetOperationTree
* Recursively transform leaves and internal nodes of a set-op tree
*/
static Node *
transformSetOperationTree(ParseState *pstate, SelectStmt *stmt)
{
bool isLeaf;
Assert(stmt && IsA(stmt, SelectStmt));
/*
* Validity-check both leaf and internal SELECTs for disallowed ops.
*/
if (stmt->intoClause)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("INTO is only allowed on first SELECT of UNION/INTERSECT/EXCEPT")));
/* We don't support FOR UPDATE/SHARE with set ops at the moment. */
if (stmt->lockingClause)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE is not allowed with UNION/INTERSECT/EXCEPT")));
/*
* If an internal node of a set-op tree has ORDER BY, UPDATE, or LIMIT
* clauses attached, we need to treat it like a leaf node to generate an
* independent sub-Query tree. Otherwise, it can be represented by a
* SetOperationStmt node underneath the parent Query.
*/
if (stmt->op == SETOP_NONE)
{
Assert(stmt->larg == NULL && stmt->rarg == NULL);
isLeaf = true;
}
else
{
Assert(stmt->larg != NULL && stmt->rarg != NULL);
if (stmt->sortClause || stmt->limitOffset || stmt->limitCount ||
stmt->lockingClause)
isLeaf = true;
else
isLeaf = false;
}
if (isLeaf)
{
/* Process leaf SELECT */
Query *selectQuery;
char selectName[32];
RangeTblEntry *rte;
RangeTblRef *rtr;
/*
* Transform SelectStmt into a Query.
*
* Note: previously transformed sub-queries don't affect the parsing
* of this sub-query, because they are not in the toplevel pstate's
* namespace list.
*/
selectQuery = parse_sub_analyze((Node *) stmt, pstate);
/*
* Check for bogus references to Vars on the current query level (but
* upper-level references are okay). Normally this can't happen
* because the namespace will be empty, but it could happen if we are
* inside a rule.
*/
if (pstate->p_relnamespace || pstate->p_varnamespace)
{
if (contain_vars_of_level((Node *) selectQuery, 1))
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("UNION/INTERSECT/EXCEPT member statement cannot refer to other relations of same query level")));
}
/*
* Make the leaf query be a subquery in the top-level rangetable.
*/
snprintf(selectName, sizeof(selectName), "*SELECT* %d",
list_length(pstate->p_rtable) + 1);
rte = addRangeTableEntryForSubquery(pstate,
selectQuery,
makeAlias(selectName, NIL),
false);
/*
* Return a RangeTblRef to replace the SelectStmt in the set-op tree.
*/
rtr = makeNode(RangeTblRef);
/* assume new rte is at end */
rtr->rtindex = list_length(pstate->p_rtable);
Assert(rte == rt_fetch(rtr->rtindex, pstate->p_rtable));
return (Node *) rtr;
}
else
{
/* Process an internal node (set operation node) */
SetOperationStmt *op = makeNode(SetOperationStmt);
List *lcoltypes;
List *rcoltypes;
List *lcoltypmods;
List *rcoltypmods;
ListCell *lct;
ListCell *rct;
ListCell *lcm;
ListCell *rcm;
const char *context;
context = (stmt->op == SETOP_UNION ? "UNION" :
(stmt->op == SETOP_INTERSECT ? "INTERSECT" :
"EXCEPT"));
op->op = stmt->op;
op->all = stmt->all;
/*
* Recursively transform the child nodes.
*/
op->larg = transformSetOperationTree(pstate, stmt->larg);
op->rarg = transformSetOperationTree(pstate, stmt->rarg);
/*
* Verify that the two children have the same number of non-junk
* columns, and determine the types of the merged output columns.
*/
getSetColTypes(pstate, op->larg, &lcoltypes, &lcoltypmods);
getSetColTypes(pstate, op->rarg, &rcoltypes, &rcoltypmods);
if (list_length(lcoltypes) != list_length(rcoltypes))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("each %s query must have the same number of columns",
context)));
Assert(list_length(lcoltypes) == list_length(lcoltypmods));
Assert(list_length(rcoltypes) == list_length(rcoltypmods));
op->colTypes = NIL;
op->colTypmods = NIL;
/* don't have a "foreach4", so chase two of the lists by hand */
lcm = list_head(lcoltypmods);
rcm = list_head(rcoltypmods);
forboth(lct, lcoltypes, rct, rcoltypes)
{
Oid lcoltype = lfirst_oid(lct);
Oid rcoltype = lfirst_oid(rct);
int32 lcoltypmod = lfirst_int(lcm);
int32 rcoltypmod = lfirst_int(rcm);
Oid rescoltype;
int32 rescoltypmod;
/* select common type, same as CASE et al */
rescoltype = select_common_type(list_make2_oid(lcoltype, rcoltype),
context);
/* if same type and same typmod, use typmod; else default */
if (lcoltype == rcoltype && lcoltypmod == rcoltypmod)
rescoltypmod = lcoltypmod;
else
rescoltypmod = -1;
op->colTypes = lappend_oid(op->colTypes, rescoltype);
op->colTypmods = lappend_int(op->colTypmods, rescoltypmod);
lcm = lnext(lcm);
rcm = lnext(rcm);
}
return (Node *) op;
}
}
/*
* getSetColTypes
* Get output column types/typmods of an (already transformed) set-op node
*/
static void
getSetColTypes(ParseState *pstate, Node *node,
List **colTypes, List **colTypmods)
{
*colTypes = NIL;
*colTypmods = NIL;
if (IsA(node, RangeTblRef))
{
RangeTblRef *rtr = (RangeTblRef *) node;
RangeTblEntry *rte = rt_fetch(rtr->rtindex, pstate->p_rtable);
Query *selectQuery = rte->subquery;
ListCell *tl;
Assert(selectQuery != NULL);
/* Get types of non-junk columns */
foreach(tl, selectQuery->targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(tl);
if (tle->resjunk)
continue;
*colTypes = lappend_oid(*colTypes,
exprType((Node *) tle->expr));
*colTypmods = lappend_int(*colTypmods,
exprTypmod((Node *) tle->expr));
}
}
else if (IsA(node, SetOperationStmt))
{
SetOperationStmt *op = (SetOperationStmt *) node;
/* Result already computed during transformation of node */
Assert(op->colTypes != NIL);
*colTypes = op->colTypes;
*colTypmods = op->colTypmods;
}
else
elog(ERROR, "unrecognized node type: %d", (int) nodeTag(node));
}
/*
* Attach column names from a ColumnDef list to a TargetEntry list
* (for CREATE TABLE AS)
*/
static void
applyColumnNames(List *dst, List *src)
{
ListCell *dst_item;
ListCell *src_item;
src_item = list_head(src);
foreach(dst_item, dst)
{
TargetEntry *d = (TargetEntry *) lfirst(dst_item);
ColumnDef *s;
/* junk targets don't count */
if (d->resjunk)
continue;
/* fewer ColumnDefs than target entries is OK */
if (src_item == NULL)
break;
s = (ColumnDef *) lfirst(src_item);
src_item = lnext(src_item);
d->resname = pstrdup(s->colname);
}
/* more ColumnDefs than target entries is not OK */
if (src_item != NULL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("CREATE TABLE AS specifies too many column names")));
}
/*
* transformUpdateStmt -
* transforms an update statement
*/
static Query *
transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
{
Query *qry = makeNode(Query);
Node *qual;
ListCell *origTargetList;
ListCell *tl;
qry->commandType = CMD_UPDATE;
pstate->p_is_update = true;
qry->resultRelation = setTargetTable(pstate, stmt->relation,
interpretInhOption(stmt->relation->inhOpt),
true,
ACL_UPDATE);
/*
* the FROM clause is non-standard SQL syntax. We used to be able to do
* this with REPLACE in POSTQUEL so we keep the feature.
*/
transformFromClause(pstate, stmt->fromClause);
qry->targetList = transformTargetList(pstate, stmt->targetList);
qual = transformWhereClause(pstate, stmt->whereClause, "WHERE");
qry->returningList = transformReturningList(pstate, stmt->returningList);
qry->rtable = pstate->p_rtable;
qry->jointree = makeFromExpr(pstate->p_joinlist, qual);
qry->hasSubLinks = pstate->p_hasSubLinks;
/*
* Top-level aggregates are simply disallowed in UPDATE, per spec. (From
* an implementation point of view, this is forced because the implicit
* ctid reference would otherwise be an ungrouped variable.)
*/
if (pstate->p_hasAggs)
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in UPDATE")));
/*
* Now we are done with SELECT-like processing, and can get on with
* transforming the target list to match the UPDATE target columns.
*/
/* Prepare to assign non-conflicting resnos to resjunk attributes */
if (pstate->p_next_resno <= pstate->p_target_relation->rd_rel->relnatts)
pstate->p_next_resno = pstate->p_target_relation->rd_rel->relnatts + 1;
/* Prepare non-junk columns for assignment to target table */
origTargetList = list_head(stmt->targetList);
foreach(tl, qry->targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(tl);
ResTarget *origTarget;
int attrno;
if (tle->resjunk)
{
/*
* Resjunk nodes need no additional processing, but be sure they
* have resnos that do not match any target columns; else rewriter
* or planner might get confused. They don't need a resname
* either.
*/
tle->resno = (AttrNumber) pstate->p_next_resno++;
tle->resname = NULL;
continue;
}
if (origTargetList == NULL)
elog(ERROR, "UPDATE target count mismatch --- internal error");
origTarget = (ResTarget *) lfirst(origTargetList);
Assert(IsA(origTarget, ResTarget));
attrno = attnameAttNum(pstate->p_target_relation,
origTarget->name, true);
if (attrno == InvalidAttrNumber)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
origTarget->name,
RelationGetRelationName(pstate->p_target_relation)),
parser_errposition(pstate, origTarget->location)));
updateTargetListEntry(pstate, tle, origTarget->name,
attrno,
origTarget->indirection,
origTarget->location);
origTargetList = lnext(origTargetList);
}
if (origTargetList != NULL)
elog(ERROR, "UPDATE target count mismatch --- internal error");
return qry;
}
/*
* transformReturningList -
* handle a RETURNING clause in INSERT/UPDATE/DELETE
*/
static List *
transformReturningList(ParseState *pstate, List *returningList)
{
List *rlist;
int save_next_resno;
bool save_hasAggs;
int length_rtable;
if (returningList == NIL)
return NIL; /* nothing to do */
/*
* We need to assign resnos starting at one in the RETURNING list. Save
* and restore the main tlist's value of p_next_resno, just in case
* someone looks at it later (probably won't happen).
*/
save_next_resno = pstate->p_next_resno;
pstate->p_next_resno = 1;
/* save other state so that we can detect disallowed stuff */
save_hasAggs = pstate->p_hasAggs;
pstate->p_hasAggs = false;
length_rtable = list_length(pstate->p_rtable);
/* transform RETURNING identically to a SELECT targetlist */
rlist = transformTargetList(pstate, returningList);
/* check for disallowed stuff */
/* aggregates not allowed (but subselects are okay) */
if (pstate->p_hasAggs)
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in RETURNING")));
/* no new relation references please */
if (list_length(pstate->p_rtable) != length_rtable)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("RETURNING cannot contain references to other relations")));
/* mark column origins */
markTargetListOrigins(pstate, rlist);
/* restore state */
pstate->p_next_resno = save_next_resno;
pstate->p_hasAggs = save_hasAggs;
return rlist;
}
/*
* transformDeclareCursorStmt -
* transform a DECLARE CURSOR Statement
*
* DECLARE CURSOR is a hybrid case: it's an optimizable statement (in fact not
* significantly different from a SELECT) as far as parsing/rewriting/planning
* are concerned, but it's not passed to the executor and so in that sense is
* a utility statement. We transform it into a Query exactly as if it were
* a SELECT, then stick the original DeclareCursorStmt into the utilityStmt
* field to carry the cursor name and options.
*/
static Query *
transformDeclareCursorStmt(ParseState *pstate, DeclareCursorStmt *stmt)
{
Query *result;
/*
* Don't allow both SCROLL and NO SCROLL to be specified
*/
if ((stmt->options & CURSOR_OPT_SCROLL) &&
(stmt->options & CURSOR_OPT_NO_SCROLL))
ereport(ERROR,
(errcode(ERRCODE_INVALID_CURSOR_DEFINITION),
errmsg("cannot specify both SCROLL and NO SCROLL")));
result = transformStmt(pstate, stmt->query);
if (!IsA(result, Query) ||
result->commandType != CMD_SELECT ||
result->utilityStmt != NULL)
elog(ERROR, "unexpected non-SELECT command in cursor statement");
/* But we must explicitly disallow DECLARE CURSOR ... SELECT INTO */
if (result->intoClause)
ereport(ERROR,
(errcode(ERRCODE_INVALID_CURSOR_DEFINITION),
errmsg("DECLARE CURSOR cannot specify INTO")));
/* FOR UPDATE and WITH HOLD are not compatible */
if (result->rowMarks != NIL && (stmt->options & CURSOR_OPT_HOLD))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("DECLARE CURSOR WITH HOLD ... FOR UPDATE/SHARE is not supported"),
errdetail("Holdable cursors must be READ ONLY.")));
/* FOR UPDATE and SCROLL are not compatible */
if (result->rowMarks != NIL && (stmt->options & CURSOR_OPT_SCROLL))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("DECLARE SCROLL CURSOR ... FOR UPDATE/SHARE is not supported"),
errdetail("Scrollable cursors must be READ ONLY.")));
/* FOR UPDATE and INSENSITIVE are not compatible */
if (result->rowMarks != NIL && (stmt->options & CURSOR_OPT_INSENSITIVE))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("DECLARE INSENSITIVE CURSOR ... FOR UPDATE/SHARE is not supported"),
errdetail("Insensitive cursors must be READ ONLY.")));
/* We won't need the raw querytree any more */
stmt->query = NULL;
result->utilityStmt = (Node *) stmt;
return result;
}
/*
* transformExplainStmt -
* transform an EXPLAIN Statement
*
* EXPLAIN is just like other utility statements in that we emit it as a
* CMD_UTILITY Query node with no transformation of the raw parse tree.
* However, if p_variableparams is set, it could be that the client is
* expecting us to resolve parameter types in something like
* EXPLAIN SELECT * FROM tab WHERE col = $1
* To deal with such cases, we run parse analysis and throw away the result;
* this is a bit grotty but not worth contorting the rest of the system for.
* (The approach we use for DECLARE CURSOR won't work because the statement
* being explained isn't necessarily a SELECT, and in particular might rewrite
* to multiple parsetrees.)
*/
static Query *
transformExplainStmt(ParseState *pstate, ExplainStmt *stmt)
{
Query *result;
if (pstate->p_variableparams)
{
/* Since parse analysis scribbles on its input, copy the tree first! */
(void) transformStmt(pstate, copyObject(stmt->query));
}
/* Now return the untransformed command as a utility Query */
result = makeNode(Query);
result->commandType = CMD_UTILITY;
result->utilityStmt = (Node *) stmt;
return result;
}
/* exported so planner can check again after rewriting, query pullup, etc */
void
CheckSelectLocking(Query *qry)
{
if (qry->setOperations)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE is not allowed with UNION/INTERSECT/EXCEPT")));
if (qry->distinctClause != NIL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE is not allowed with DISTINCT clause")));
if (qry->groupClause != NIL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE is not allowed with GROUP BY clause")));
if (qry->havingQual != NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE is not allowed with HAVING clause")));
if (qry->hasAggs)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE is not allowed with aggregate functions")));
}
/*
* Transform a FOR UPDATE/SHARE clause
*
* This basically involves replacing names by integer relids.
*
* NB: if you need to change this, see also markQueryForLocking()
* in rewriteHandler.c.
*/
static void
transformLockingClause(Query *qry, LockingClause *lc)
{
List *lockedRels = lc->lockedRels;
ListCell *l;
ListCell *rt;
Index i;
LockingClause *allrels;
CheckSelectLocking(qry);
/* make a clause we can pass down to subqueries to select all rels */
allrels = makeNode(LockingClause);
allrels->lockedRels = NIL; /* indicates all rels */
allrels->forUpdate = lc->forUpdate;
allrels->noWait = lc->noWait;
if (lockedRels == NIL)
{
/* all regular tables used in query */
i = 0;
foreach(rt, qry->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
++i;
switch (rte->rtekind)
{
case RTE_RELATION:
applyLockingClause(qry, i, lc->forUpdate, lc->noWait);
rte->requiredPerms |= ACL_SELECT_FOR_UPDATE;
break;
case RTE_SUBQUERY:
/*
* FOR UPDATE/SHARE of subquery is propagated to all of
* subquery's rels
*/
transformLockingClause(rte->subquery, allrels);
break;
default:
/* ignore JOIN, SPECIAL, FUNCTION RTEs */
break;
}
}
}
else
{
/* just the named tables */
foreach(l, lockedRels)
{
char *relname = strVal(lfirst(l));
i = 0;
foreach(rt, qry->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
++i;
if (strcmp(rte->eref->aliasname, relname) == 0)
{
switch (rte->rtekind)
{
case RTE_RELATION:
applyLockingClause(qry, i,
lc->forUpdate, lc->noWait);
rte->requiredPerms |= ACL_SELECT_FOR_UPDATE;
break;
case RTE_SUBQUERY:
/*
* FOR UPDATE/SHARE of subquery is propagated to
* all of subquery's rels
*/
transformLockingClause(rte->subquery, allrels);
break;
case RTE_JOIN:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE cannot be applied to a join")));
break;
case RTE_SPECIAL:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE cannot be applied to NEW or OLD")));
break;
case RTE_FUNCTION:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE cannot be applied to a function")));
break;
case RTE_VALUES:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE cannot be applied to VALUES")));
break;
default:
elog(ERROR, "unrecognized RTE type: %d",
(int) rte->rtekind);
break;
}
break; /* out of foreach loop */
}
}
if (rt == NULL)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" in FOR UPDATE/SHARE clause not found in FROM clause",
relname)));
}
}
}
/*
* Record locking info for a single rangetable item
*/
void
applyLockingClause(Query *qry, Index rtindex, bool forUpdate, bool noWait)
{
RowMarkClause *rc;
/* Check for pre-existing entry for same rtindex */
if ((rc = get_rowmark(qry, rtindex)) != NULL)
{
/*
* If the same RTE is specified both FOR UPDATE and FOR SHARE, treat
* it as FOR UPDATE. (Reasonable, since you can't take both a shared
* and exclusive lock at the same time; it'll end up being exclusive
* anyway.)
*
* We also consider that NOWAIT wins if it's specified both ways. This
* is a bit more debatable but raising an error doesn't seem helpful.
* (Consider for instance SELECT FOR UPDATE NOWAIT from a view that
* internally contains a plain FOR UPDATE spec.)
*/
rc->forUpdate |= forUpdate;
rc->noWait |= noWait;
return;
}
/* Make a new RowMarkClause */
rc = makeNode(RowMarkClause);
rc->rti = rtindex;
rc->forUpdate = forUpdate;
rc->noWait = noWait;
qry->rowMarks = lappend(qry->rowMarks, rc);
}
/*
* Traverse a fully-analyzed tree to verify that parameter symbols
* match their types. We need this because some Params might still
* be UNKNOWN, if there wasn't anything to force their coercion,
* and yet other instances seen later might have gotten coerced.
*/
static bool
check_parameter_resolution_walker(Node *node,
check_parameter_resolution_context *context)
{
if (node == NULL)
return false;
if (IsA(node, Param))
{
Param *param = (Param *) node;
if (param->paramkind == PARAM_EXTERN)
{
int paramno = param->paramid;
if (paramno <= 0 || /* shouldn't happen, but... */
paramno > context->numParams)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_PARAMETER),
errmsg("there is no parameter $%d", paramno)));
if (param->paramtype != context->paramTypes[paramno - 1])
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_PARAMETER),
errmsg("could not determine data type of parameter $%d",
paramno)));
}
return false;
}
if (IsA(node, Query))
{
/* Recurse into RTE subquery or not-yet-planned sublink subquery */
return query_tree_walker((Query *) node,
check_parameter_resolution_walker,
(void *) context, 0);
}
return expression_tree_walker(node, check_parameter_resolution_walker,
(void *) context);
}
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