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postgres/src/backend/parser/parse_relation.c
Tom Lane 0b78106cd4 Fix reporting of column typmods for multi-row VALUES constructs. 
expandRTE() and get_rte_attribute_type() reported the exprType() and
exprTypmod() values of the expressions in the first row of the VALUES as
being the column type/typmod returned by the VALUES RTE.  That's fine for
the data type, since we coerce all expressions in a column to have the same
common type.  But we don't coerce them to have a common typmod, so it was
possible for rows after the first one to return values that violate the
claimed column typmod.  This leads to the incorrect result seen in bug
#14448 from Hassan Mahmood, as well as some other corner-case misbehaviors.

The desired behavior is the same as we use in other type-unification
cases: report the common typmod if there is one, but otherwise return -1
indicating no particular constraint.  It's cheap for transformValuesClause
to determine the common typmod while transforming a multi-row VALUES, but
it'd be less cheap for expandRTE() and get_rte_attribute_type() to
re-determine that info every time they're asked --- possibly a lot less
cheap, if the VALUES has many rows.  Therefore, the best fix is to record
the common typmods explicitly in a list in the VALUES RTE, as we were
already doing for column collations.  This looks quite a bit like what
we're doing for CTE RTEs, so we can save a little bit of space and code by
unifying the representation for those two RTE types.  They both now share
coltypes/coltypmods/colcollations fields.  (At some point it might seem
desirable to populate those fields for all RTE types; but right now it
looks like constructing them for other RTE types would add more code and
cycles than it would save.)

The RTE change requires a catversion bump, so this fix is only usable
in HEAD.  If we fix this at all in the back branches, the patch will
need to look quite different.

Report: https://postgr.es/m/20161205143037.4377.60754@wrigleys.postgresql.org
Discussion: https://postgr.es/m/27429.1480968538@sss.pgh.pa.us
2016-12-08 11:40:02 -05:00

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/*-------------------------------------------------------------------------
*
* parse_relation.c
* parser support routines dealing with relations
*
* Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/parser/parse_relation.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <ctype.h>
#include "access/htup_details.h"
#include "access/sysattr.h"
#include "catalog/heap.h"
#include "catalog/namespace.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "parser/parsetree.h"
#include "parser/parse_relation.h"
#include "parser/parse_type.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/syscache.h"
#define MAX_FUZZY_DISTANCE 3
static RangeTblEntry *scanNameSpaceForRefname(ParseState *pstate,
const char *refname, int location);
static RangeTblEntry *scanNameSpaceForRelid(ParseState *pstate, Oid relid,
int location);
static void check_lateral_ref_ok(ParseState *pstate, ParseNamespaceItem *nsitem,
int location);
static void markRTEForSelectPriv(ParseState *pstate, RangeTblEntry *rte,
int rtindex, AttrNumber col);
static void expandRelation(Oid relid, Alias *eref,
int rtindex, int sublevels_up,
int location, bool include_dropped,
List **colnames, List **colvars);
static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
int count, int offset,
int rtindex, int sublevels_up,
int location, bool include_dropped,
List **colnames, List **colvars);
static int specialAttNum(const char *attname);
static bool isQueryUsingTempRelation_walker(Node *node, void *context);
/*
* refnameRangeTblEntry
* Given a possibly-qualified refname, look to see if it matches any RTE.
* If so, return a pointer to the RangeTblEntry; else return NULL.
*
* Optionally get RTE's nesting depth (0 = current) into *sublevels_up.
* If sublevels_up is NULL, only consider items at the current nesting
* level.
*
* An unqualified refname (schemaname == NULL) can match any RTE with matching
* alias, or matching unqualified relname in the case of alias-less relation
* RTEs. It is possible that such a refname matches multiple RTEs in the
* nearest nesting level that has a match; if so, we report an error via
* ereport().
*
* A qualified refname (schemaname != NULL) can only match a relation RTE
* that (a) has no alias and (b) is for the same relation identified by
* schemaname.refname. In this case we convert schemaname.refname to a
* relation OID and search by relid, rather than by alias name. This is
* peculiar, but it's what SQL says to do.
*/
RangeTblEntry *
refnameRangeTblEntry(ParseState *pstate,
const char *schemaname,
const char *refname,
int location,
int *sublevels_up)
{
Oid relId = InvalidOid;
if (sublevels_up)
*sublevels_up = 0;
if (schemaname != NULL)
{
Oid namespaceId;
/*
* We can use LookupNamespaceNoError() here because we are only
* interested in finding existing RTEs. Checking USAGE permission on
* the schema is unnecessary since it would have already been checked
* when the RTE was made. Furthermore, we want to report "RTE not
* found", not "no permissions for schema", if the name happens to
* match a schema name the user hasn't got access to.
*/
namespaceId = LookupNamespaceNoError(schemaname);
if (!OidIsValid(namespaceId))
return NULL;
relId = get_relname_relid(refname, namespaceId);
if (!OidIsValid(relId))
return NULL;
}
while (pstate != NULL)
{
RangeTblEntry *result;
if (OidIsValid(relId))
result = scanNameSpaceForRelid(pstate, relId, location);
else
result = scanNameSpaceForRefname(pstate, refname, location);
if (result)
return result;
if (sublevels_up)
(*sublevels_up)++;
else
break;
pstate = pstate->parentParseState;
}
return NULL;
}
/*
* Search the query's table namespace for an RTE matching the
* given unqualified refname. Return the RTE if a unique match, or NULL
* if no match. Raise error if multiple matches.
*
* Note: it might seem that we shouldn't have to worry about the possibility
* of multiple matches; after all, the SQL standard disallows duplicate table
* aliases within a given SELECT level. Historically, however, Postgres has
* been laxer than that. For example, we allow
* SELECT ... FROM tab1 x CROSS JOIN (tab2 x CROSS JOIN tab3 y) z
* on the grounds that the aliased join (z) hides the aliases within it,
* therefore there is no conflict between the two RTEs named "x". However,
* if tab3 is a LATERAL subquery, then from within the subquery both "x"es
* are visible. Rather than rejecting queries that used to work, we allow
* this situation, and complain only if there's actually an ambiguous
* reference to "x".
*/
static RangeTblEntry *
scanNameSpaceForRefname(ParseState *pstate, const char *refname, int location)
{
RangeTblEntry *result = NULL;
ListCell *l;
foreach(l, pstate->p_namespace)
{
ParseNamespaceItem *nsitem = (ParseNamespaceItem *) lfirst(l);
RangeTblEntry *rte = nsitem->p_rte;
/* Ignore columns-only items */
if (!nsitem->p_rel_visible)
continue;
/* If not inside LATERAL, ignore lateral-only items */
if (nsitem->p_lateral_only && !pstate->p_lateral_active)
continue;
if (strcmp(rte->eref->aliasname, refname) == 0)
{
if (result)
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_ALIAS),
errmsg("table reference \"%s\" is ambiguous",
refname),
parser_errposition(pstate, location)));
check_lateral_ref_ok(pstate, nsitem, location);
result = rte;
}
}
return result;
}
/*
* Search the query's table namespace for a relation RTE matching the
* given relation OID. Return the RTE if a unique match, or NULL
* if no match. Raise error if multiple matches.
*
* See the comments for refnameRangeTblEntry to understand why this
* acts the way it does.
*/
static RangeTblEntry *
scanNameSpaceForRelid(ParseState *pstate, Oid relid, int location)
{
RangeTblEntry *result = NULL;
ListCell *l;
foreach(l, pstate->p_namespace)
{
ParseNamespaceItem *nsitem = (ParseNamespaceItem *) lfirst(l);
RangeTblEntry *rte = nsitem->p_rte;
/* Ignore columns-only items */
if (!nsitem->p_rel_visible)
continue;
/* If not inside LATERAL, ignore lateral-only items */
if (nsitem->p_lateral_only && !pstate->p_lateral_active)
continue;
/* yes, the test for alias == NULL should be there... */
if (rte->rtekind == RTE_RELATION &&
rte->relid == relid &&
rte->alias == NULL)
{
if (result)
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_ALIAS),
errmsg("table reference %u is ambiguous",
relid),
parser_errposition(pstate, location)));
check_lateral_ref_ok(pstate, nsitem, location);
result = rte;
}
}
return result;
}
/*
* Search the query's CTE namespace for a CTE matching the given unqualified
* refname. Return the CTE (and its levelsup count) if a match, or NULL
* if no match. We need not worry about multiple matches, since parse_cte.c
* rejects WITH lists containing duplicate CTE names.
*/
CommonTableExpr *
scanNameSpaceForCTE(ParseState *pstate, const char *refname,
Index *ctelevelsup)
{
Index levelsup;
for (levelsup = 0;
pstate != NULL;
pstate = pstate->parentParseState, levelsup++)
{
ListCell *lc;
foreach(lc, pstate->p_ctenamespace)
{
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
if (strcmp(cte->ctename, refname) == 0)
{
*ctelevelsup = levelsup;
return cte;
}
}
}
return NULL;
}
/*
* Search for a possible "future CTE", that is one that is not yet in scope
* according to the WITH scoping rules. This has nothing to do with valid
* SQL semantics, but it's important for error reporting purposes.
*/
static bool
isFutureCTE(ParseState *pstate, const char *refname)
{
for (; pstate != NULL; pstate = pstate->parentParseState)
{
ListCell *lc;
foreach(lc, pstate->p_future_ctes)
{
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
if (strcmp(cte->ctename, refname) == 0)
return true;
}
}
return false;
}
/*
* searchRangeTableForRel
* See if any RangeTblEntry could possibly match the RangeVar.
* If so, return a pointer to the RangeTblEntry; else return NULL.
*
* This is different from refnameRangeTblEntry in that it considers every
* entry in the ParseState's rangetable(s), not only those that are currently
* visible in the p_namespace list(s). This behavior is invalid per the SQL
* spec, and it may give ambiguous results (there might be multiple equally
* valid matches, but only one will be returned). This must be used ONLY
* as a heuristic in giving suitable error messages. See errorMissingRTE.
*
* Notice that we consider both matches on actual relation (or CTE) name
* and matches on alias.
*/
static RangeTblEntry *
searchRangeTableForRel(ParseState *pstate, RangeVar *relation)
{
const char *refname = relation->relname;
Oid relId = InvalidOid;
CommonTableExpr *cte = NULL;
Index ctelevelsup = 0;
Index levelsup;
/*
* If it's an unqualified name, check for possible CTE matches. A CTE
* hides any real relation matches. If no CTE, look for a matching
* relation.
*
* NB: It's not critical that RangeVarGetRelid return the correct answer
* here in the face of concurrent DDL. If it doesn't, the worst case
* scenario is a less-clear error message. Also, the tables involved in
* the query are already locked, which reduces the number of cases in
* which surprising behavior can occur. So we do the name lookup
* unlocked.
*/
if (!relation->schemaname)
cte = scanNameSpaceForCTE(pstate, refname, &ctelevelsup);
if (!cte)
relId = RangeVarGetRelid(relation, NoLock, true);
/* Now look for RTEs matching either the relation/CTE or the alias */
for (levelsup = 0;
pstate != NULL;
pstate = pstate->parentParseState, levelsup++)
{
ListCell *l;
foreach(l, pstate->p_rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
if (rte->rtekind == RTE_RELATION &&
OidIsValid(relId) &&
rte->relid == relId)
return rte;
if (rte->rtekind == RTE_CTE &&
cte != NULL &&
rte->ctelevelsup + levelsup == ctelevelsup &&
strcmp(rte->ctename, refname) == 0)
return rte;
if (strcmp(rte->eref->aliasname, refname) == 0)
return rte;
}
}
return NULL;
}
/*
* Check for relation-name conflicts between two namespace lists.
* Raise an error if any is found.
*
* Note: we assume that each given argument does not contain conflicts
* itself; we just want to know if the two can be merged together.
*
* Per SQL, two alias-less plain relation RTEs do not conflict even if
* they have the same eref->aliasname (ie, same relation name), if they
* are for different relation OIDs (implying they are in different schemas).
*
* We ignore the lateral-only flags in the namespace items: the lists must
* not conflict, even when all items are considered visible. However,
* columns-only items should be ignored.
*/
void
checkNameSpaceConflicts(ParseState *pstate, List *namespace1,
List *namespace2)
{
ListCell *l1;
foreach(l1, namespace1)
{
ParseNamespaceItem *nsitem1 = (ParseNamespaceItem *) lfirst(l1);
RangeTblEntry *rte1 = nsitem1->p_rte;
const char *aliasname1 = rte1->eref->aliasname;
ListCell *l2;
if (!nsitem1->p_rel_visible)
continue;
foreach(l2, namespace2)
{
ParseNamespaceItem *nsitem2 = (ParseNamespaceItem *) lfirst(l2);
RangeTblEntry *rte2 = nsitem2->p_rte;
if (!nsitem2->p_rel_visible)
continue;
if (strcmp(rte2->eref->aliasname, aliasname1) != 0)
continue; /* definitely no conflict */
if (rte1->rtekind == RTE_RELATION && rte1->alias == NULL &&
rte2->rtekind == RTE_RELATION && rte2->alias == NULL &&
rte1->relid != rte2->relid)
continue; /* no conflict per SQL rule */
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_ALIAS),
errmsg("table name \"%s\" specified more than once",
aliasname1)));
}
}
}
/*
* Complain if a namespace item is currently disallowed as a LATERAL reference.
* This enforces both SQL:2008's rather odd idea of what to do with a LATERAL
* reference to the wrong side of an outer join, and our own prohibition on
* referencing the target table of an UPDATE or DELETE as a lateral reference
* in a FROM/USING clause.
*
* Convenience subroutine to avoid multiple copies of a rather ugly ereport.
*/
static void
check_lateral_ref_ok(ParseState *pstate, ParseNamespaceItem *nsitem,
int location)
{
if (nsitem->p_lateral_only && !nsitem->p_lateral_ok)
{
/* SQL:2008 demands this be an error, not an invisible item */
RangeTblEntry *rte = nsitem->p_rte;
char *refname = rte->eref->aliasname;
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("invalid reference to FROM-clause entry for table \"%s\"",
refname),
(rte == pstate->p_target_rangetblentry) ?
errhint("There is an entry for table \"%s\", but it cannot be referenced from this part of the query.",
refname) :
errdetail("The combining JOIN type must be INNER or LEFT for a LATERAL reference."),
parser_errposition(pstate, location)));
}
}
/*
* given an RTE, return RT index (starting with 1) of the entry,
* and optionally get its nesting depth (0 = current). If sublevels_up
* is NULL, only consider rels at the current nesting level.
* Raises error if RTE not found.
*/
int
RTERangeTablePosn(ParseState *pstate, RangeTblEntry *rte, int *sublevels_up)
{
int index;
ListCell *l;
if (sublevels_up)
*sublevels_up = 0;
while (pstate != NULL)
{
index = 1;
foreach(l, pstate->p_rtable)
{
if (rte == (RangeTblEntry *) lfirst(l))
return index;
index++;
}
pstate = pstate->parentParseState;
if (sublevels_up)
(*sublevels_up)++;
else
break;
}
elog(ERROR, "RTE not found (internal error)");
return 0; /* keep compiler quiet */
}
/*
* Given an RT index and nesting depth, find the corresponding RTE.
* This is the inverse of RTERangeTablePosn.
*/
RangeTblEntry *
GetRTEByRangeTablePosn(ParseState *pstate,
int varno,
int sublevels_up)
{
while (sublevels_up-- > 0)
{
pstate = pstate->parentParseState;
Assert(pstate != NULL);
}
Assert(varno > 0 && varno <= list_length(pstate->p_rtable));
return rt_fetch(varno, pstate->p_rtable);
}
/*
* Fetch the CTE for a CTE-reference RTE.
*
* rtelevelsup is the number of query levels above the given pstate that the
* RTE came from. Callers that don't have this information readily available
* may pass -1 instead.
*/
CommonTableExpr *
GetCTEForRTE(ParseState *pstate, RangeTblEntry *rte, int rtelevelsup)
{
Index levelsup;
ListCell *lc;
/* Determine RTE's levelsup if caller didn't know it */
if (rtelevelsup < 0)
(void) RTERangeTablePosn(pstate, rte, &rtelevelsup);
Assert(rte->rtekind == RTE_CTE);
levelsup = rte->ctelevelsup + rtelevelsup;
while (levelsup-- > 0)
{
pstate = pstate->parentParseState;
if (!pstate) /* shouldn't happen */
elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
}
foreach(lc, pstate->p_ctenamespace)
{
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
if (strcmp(cte->ctename, rte->ctename) == 0)
return cte;
}
/* shouldn't happen */
elog(ERROR, "could not find CTE \"%s\"", rte->ctename);
return NULL; /* keep compiler quiet */
}
/*
* updateFuzzyAttrMatchState
* Using Levenshtein distance, consider if column is best fuzzy match.
*/
static void
updateFuzzyAttrMatchState(int fuzzy_rte_penalty,
FuzzyAttrMatchState *fuzzystate, RangeTblEntry *rte,
const char *actual, const char *match, int attnum)
{
int columndistance;
int matchlen;
/* Bail before computing the Levenshtein distance if there's no hope. */
if (fuzzy_rte_penalty > fuzzystate->distance)
return;
/*
* Outright reject dropped columns, which can appear here with apparent
* empty actual names, per remarks within scanRTEForColumn().
*/
if (actual[0] == '\0')
return;
/* Use Levenshtein to compute match distance. */
matchlen = strlen(match);
columndistance =
varstr_levenshtein_less_equal(actual, strlen(actual), match, matchlen,
1, 1, 1,
fuzzystate->distance + 1
- fuzzy_rte_penalty,
true);
/*
* If more than half the characters are different, don't treat it as a
* match, to avoid making ridiculous suggestions.
*/
if (columndistance > matchlen / 2)
return;
/*
* From this point on, we can ignore the distinction between the RTE-name
* distance and the column-name distance.
*/
columndistance += fuzzy_rte_penalty;
/*
* If the new distance is less than or equal to that of the best match
* found so far, update fuzzystate.
*/
if (columndistance < fuzzystate->distance)
{
/* Store new lowest observed distance for RTE */
fuzzystate->distance = columndistance;
fuzzystate->rfirst = rte;
fuzzystate->first = attnum;
fuzzystate->rsecond = NULL;
fuzzystate->second = InvalidAttrNumber;
}
else if (columndistance == fuzzystate->distance)
{
/*
* This match distance may equal a prior match within this same range
* table. When that happens, the prior match may also be given, but
* only if there is no more than two equally distant matches from the
* RTE (in turn, our caller will only accept two equally distant
* matches overall).
*/
if (AttributeNumberIsValid(fuzzystate->second))
{
/* Too many RTE-level matches */
fuzzystate->rfirst = NULL;
fuzzystate->first = InvalidAttrNumber;
fuzzystate->rsecond = NULL;
fuzzystate->second = InvalidAttrNumber;
/* Clearly, distance is too low a bar (for *any* RTE) */
fuzzystate->distance = columndistance - 1;
}
else if (AttributeNumberIsValid(fuzzystate->first))
{
/* Record as provisional second match for RTE */
fuzzystate->rsecond = rte;
fuzzystate->second = attnum;
}
else if (fuzzystate->distance <= MAX_FUZZY_DISTANCE)
{
/*
* Record as provisional first match (this can occasionally occur
* because previous lowest distance was "too low a bar", rather
* than being associated with a real match)
*/
fuzzystate->rfirst = rte;
fuzzystate->first = attnum;
}
}
}
/*
* scanRTEForColumn
* Search the column names of a single RTE for the given name.
* If found, return an appropriate Var node, else return NULL.
* If the name proves ambiguous within this RTE, raise error.
*
* Side effect: if we find a match, mark the RTE as requiring read access
* for the column.
*
* Additional side effect: if fuzzystate is non-NULL, check non-system columns
* for an approximate match and update fuzzystate accordingly.
*/
Node *
scanRTEForColumn(ParseState *pstate, RangeTblEntry *rte, char *colname,
int location, int fuzzy_rte_penalty,
FuzzyAttrMatchState *fuzzystate)
{
Node *result = NULL;
int attnum = 0;
Var *var;
ListCell *c;
/*
* Scan the user column names (or aliases) for a match. Complain if
* multiple matches.
*
* Note: eref->colnames may include entries for dropped columns, but those
* will be empty strings that cannot match any legal SQL identifier, so we
* don't bother to test for that case here.
*
* Should this somehow go wrong and we try to access a dropped column,
* we'll still catch it by virtue of the checks in
* get_rte_attribute_type(), which is called by make_var(). That routine
* has to do a cache lookup anyway, so the check there is cheap. Callers
* interested in finding match with shortest distance need to defend
* against this directly, though.
*/
foreach(c, rte->eref->colnames)
{
const char *attcolname = strVal(lfirst(c));
attnum++;
if (strcmp(attcolname, colname) == 0)
{
if (result)
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_COLUMN),
errmsg("column reference \"%s\" is ambiguous",
colname),
parser_errposition(pstate, location)));
var = make_var(pstate, rte, attnum, location);
/* Require read access to the column */
markVarForSelectPriv(pstate, var, rte);
result = (Node *) var;
}
/* Updating fuzzy match state, if provided. */
if (fuzzystate != NULL)
updateFuzzyAttrMatchState(fuzzy_rte_penalty, fuzzystate,
rte, attcolname, colname, attnum);
}
/*
* If we have a unique match, return it. Note that this allows a user
* alias to override a system column name (such as OID) without error.
*/
if (result)
return result;
/*
* If the RTE represents a real relation, consider system column names.
* Composites are only used for pseudo-relations like ON CONFLICT's
* excluded.
*/
if (rte->rtekind == RTE_RELATION &&
rte->relkind != RELKIND_COMPOSITE_TYPE)
{
/* quick check to see if name could be a system column */
attnum = specialAttNum(colname);
/* In constraint check, no system column is allowed except tableOid */
if (pstate->p_expr_kind == EXPR_KIND_CHECK_CONSTRAINT &&
attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("system column \"%s\" reference in check constraint is invalid",
colname),
parser_errposition(pstate, location)));
if (attnum != InvalidAttrNumber)
{
/* now check to see if column actually is defined */
if (SearchSysCacheExists2(ATTNUM,
ObjectIdGetDatum(rte->relid),
Int16GetDatum(attnum)))
{
var = make_var(pstate, rte, attnum, location);
/* Require read access to the column */
markVarForSelectPriv(pstate, var, rte);
result = (Node *) var;
}
}
}
return result;
}
/*
* colNameToVar
* Search for an unqualified column name.
* If found, return the appropriate Var node (or expression).
* If not found, return NULL. If the name proves ambiguous, raise error.
* If localonly is true, only names in the innermost query are considered.
*/
Node *
colNameToVar(ParseState *pstate, char *colname, bool localonly,
int location)
{
Node *result = NULL;
ParseState *orig_pstate = pstate;
while (pstate != NULL)
{
ListCell *l;
foreach(l, pstate->p_namespace)
{
ParseNamespaceItem *nsitem = (ParseNamespaceItem *) lfirst(l);
RangeTblEntry *rte = nsitem->p_rte;
Node *newresult;
/* Ignore table-only items */
if (!nsitem->p_cols_visible)
continue;
/* If not inside LATERAL, ignore lateral-only items */
if (nsitem->p_lateral_only && !pstate->p_lateral_active)
continue;
/* use orig_pstate here to get the right sublevels_up */
newresult = scanRTEForColumn(orig_pstate, rte, colname, location,
0, NULL);
if (newresult)
{
if (result)
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_COLUMN),
errmsg("column reference \"%s\" is ambiguous",
colname),
parser_errposition(pstate, location)));
check_lateral_ref_ok(pstate, nsitem, location);
result = newresult;
}
}
if (result != NULL || localonly)
break; /* found, or don't want to look at parent */
pstate = pstate->parentParseState;
}
return result;
}
/*
* searchRangeTableForCol
* See if any RangeTblEntry could possibly provide the given column name (or
* find the best match available). Returns state with relevant details.
*
* This is different from colNameToVar in that it considers every entry in
* the ParseState's rangetable(s), not only those that are currently visible
* in the p_namespace list(s). This behavior is invalid per the SQL spec,
* and it may give ambiguous results (there might be multiple equally valid
* matches, but only one will be returned). This must be used ONLY as a
* heuristic in giving suitable error messages. See errorMissingColumn.
*
* This function is also different in that it will consider approximate
* matches -- if the user entered an alias/column pair that is only slightly
* different from a valid pair, we may be able to infer what they meant to
* type and provide a reasonable hint.
*
* The FuzzyAttrMatchState will have 'rfirst' pointing to the best RTE
* containing the most promising match for the alias and column name. If
* the alias and column names match exactly, 'first' will be InvalidAttrNumber;
* otherwise, it will be the attribute number for the match. In the latter
* case, 'rsecond' may point to a second, equally close approximate match,
* and 'second' will contain the attribute number for the second match.
*/
static FuzzyAttrMatchState *
searchRangeTableForCol(ParseState *pstate, const char *alias, char *colname,
int location)
{
ParseState *orig_pstate = pstate;
FuzzyAttrMatchState *fuzzystate = palloc(sizeof(FuzzyAttrMatchState));
fuzzystate->distance = MAX_FUZZY_DISTANCE + 1;
fuzzystate->rfirst = NULL;
fuzzystate->rsecond = NULL;
fuzzystate->first = InvalidAttrNumber;
fuzzystate->second = InvalidAttrNumber;
while (pstate != NULL)
{
ListCell *l;
foreach(l, pstate->p_rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
int fuzzy_rte_penalty = 0;
/*
* Typically, it is not useful to look for matches within join
* RTEs; they effectively duplicate other RTEs for our purposes,
* and if a match is chosen from a join RTE, an unhelpful alias is
* displayed in the final diagnostic message.
*/
if (rte->rtekind == RTE_JOIN)
continue;
/*
* If the user didn't specify an alias, then matches against one
* RTE are as good as another. But if the user did specify an
* alias, then we want at least a fuzzy - and preferably an exact
* - match for the range table entry.
*/
if (alias != NULL)
fuzzy_rte_penalty =
varstr_levenshtein_less_equal(alias, strlen(alias),
rte->eref->aliasname,
strlen(rte->eref->aliasname),
1, 1, 1,
MAX_FUZZY_DISTANCE + 1,
true);
/*
* Scan for a matching column; if we find an exact match, we're
* done. Otherwise, update fuzzystate.
*/
if (scanRTEForColumn(orig_pstate, rte, colname, location,
fuzzy_rte_penalty, fuzzystate)
&& fuzzy_rte_penalty == 0)
{
fuzzystate->rfirst = rte;
fuzzystate->first = InvalidAttrNumber;
fuzzystate->rsecond = NULL;
fuzzystate->second = InvalidAttrNumber;
return fuzzystate;
}
}
pstate = pstate->parentParseState;
}
return fuzzystate;
}
/*
* markRTEForSelectPriv
* Mark the specified column of an RTE as requiring SELECT privilege
*
* col == InvalidAttrNumber means a "whole row" reference
*
* The caller should pass the actual RTE if it has it handy; otherwise pass
* NULL, and we'll look it up here. (This uglification of the API is
* worthwhile because nearly all external callers have the RTE at hand.)
*/
static void
markRTEForSelectPriv(ParseState *pstate, RangeTblEntry *rte,
int rtindex, AttrNumber col)
{
if (rte == NULL)
rte = rt_fetch(rtindex, pstate->p_rtable);
if (rte->rtekind == RTE_RELATION)
{
/* Make sure the rel as a whole is marked for SELECT access */
rte->requiredPerms |= ACL_SELECT;
/* Must offset the attnum to fit in a bitmapset */
rte->selectedCols = bms_add_member(rte->selectedCols,
col - FirstLowInvalidHeapAttributeNumber);
}
else if (rte->rtekind == RTE_JOIN)
{
if (col == InvalidAttrNumber)
{
/*
* A whole-row reference to a join has to be treated as whole-row
* references to the two inputs.
*/
JoinExpr *j;
if (rtindex > 0 && rtindex <= list_length(pstate->p_joinexprs))
j = (JoinExpr *) list_nth(pstate->p_joinexprs, rtindex - 1);
else
j = NULL;
if (j == NULL)
elog(ERROR, "could not find JoinExpr for whole-row reference");
Assert(IsA(j, JoinExpr));
/* Note: we can't see FromExpr here */
if (IsA(j->larg, RangeTblRef))
{
int varno = ((RangeTblRef *) j->larg)->rtindex;
markRTEForSelectPriv(pstate, NULL, varno, InvalidAttrNumber);
}
else if (IsA(j->larg, JoinExpr))
{
int varno = ((JoinExpr *) j->larg)->rtindex;
markRTEForSelectPriv(pstate, NULL, varno, InvalidAttrNumber);
}
else
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(j->larg));
if (IsA(j->rarg, RangeTblRef))
{
int varno = ((RangeTblRef *) j->rarg)->rtindex;
markRTEForSelectPriv(pstate, NULL, varno, InvalidAttrNumber);
}
else if (IsA(j->rarg, JoinExpr))
{
int varno = ((JoinExpr *) j->rarg)->rtindex;
markRTEForSelectPriv(pstate, NULL, varno, InvalidAttrNumber);
}
else
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(j->rarg));
}
else
{
/*
* Regular join attribute, look at the alias-variable list.
*
* The aliasvar could be either a Var or a COALESCE expression,
* but in the latter case we should already have marked the two
* referent variables as being selected, due to their use in the
* JOIN clause. So we need only be concerned with the Var case.
* But we do need to drill down through implicit coercions.
*/
Var *aliasvar;
Assert(col > 0 && col <= list_length(rte->joinaliasvars));
aliasvar = (Var *) list_nth(rte->joinaliasvars, col - 1);
aliasvar = (Var *) strip_implicit_coercions((Node *) aliasvar);
if (aliasvar && IsA(aliasvar, Var))
markVarForSelectPriv(pstate, aliasvar, NULL);
}
}
/* other RTE types don't require privilege marking */
}
/*
* markVarForSelectPriv
* Mark the RTE referenced by a Var as requiring SELECT privilege
*
* The caller should pass the Var's referenced RTE if it has it handy
* (nearly all do); otherwise pass NULL.
*/
void
markVarForSelectPriv(ParseState *pstate, Var *var, RangeTblEntry *rte)
{
Index lv;
Assert(IsA(var, Var));
/* Find the appropriate pstate if it's an uplevel Var */
for (lv = 0; lv < var->varlevelsup; lv++)
pstate = pstate->parentParseState;
markRTEForSelectPriv(pstate, rte, var->varno, var->varattno);
}
/*
* buildRelationAliases
* Construct the eref column name list for a relation RTE.
* This code is also used for function RTEs.
*
* tupdesc: the physical column information
* alias: the user-supplied alias, or NULL if none
* eref: the eref Alias to store column names in
*
* eref->colnames is filled in. Also, alias->colnames is rebuilt to insert
* empty strings for any dropped columns, so that it will be one-to-one with
* physical column numbers.
*
* It is an error for there to be more aliases present than required.
*/
static void
buildRelationAliases(TupleDesc tupdesc, Alias *alias, Alias *eref)
{
int maxattrs = tupdesc->natts;
ListCell *aliaslc;
int numaliases;
int varattno;
int numdropped = 0;
Assert(eref->colnames == NIL);
if (alias)
{
aliaslc = list_head(alias->colnames);
numaliases = list_length(alias->colnames);
/* We'll rebuild the alias colname list */
alias->colnames = NIL;
}
else
{
aliaslc = NULL;
numaliases = 0;
}
for (varattno = 0; varattno < maxattrs; varattno++)
{
Form_pg_attribute attr = tupdesc->attrs[varattno];
Value *attrname;
if (attr->attisdropped)
{
/* Always insert an empty string for a dropped column */
attrname = makeString(pstrdup(""));
if (aliaslc)
alias->colnames = lappend(alias->colnames, attrname);
numdropped++;
}
else if (aliaslc)
{
/* Use the next user-supplied alias */
attrname = (Value *) lfirst(aliaslc);
aliaslc = lnext(aliaslc);
alias->colnames = lappend(alias->colnames, attrname);
}
else
{
attrname = makeString(pstrdup(NameStr(attr->attname)));
/* we're done with the alias if any */
}
eref->colnames = lappend(eref->colnames, attrname);
}
/* Too many user-supplied aliases? */
if (aliaslc)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("table \"%s\" has %d columns available but %d columns specified",
eref->aliasname, maxattrs - numdropped, numaliases)));
}
/*
* chooseScalarFunctionAlias
* Select the column alias for a function in a function RTE,
* when the function returns a scalar type (not composite or RECORD).
*
* funcexpr: transformed expression tree for the function call
* funcname: function name (as determined by FigureColname)
* alias: the user-supplied alias for the RTE, or NULL if none
* nfuncs: the number of functions appearing in the function RTE
*
* Note that the name we choose might be overridden later, if the user-given
* alias includes column alias names. That's of no concern here.
*/
static char *
chooseScalarFunctionAlias(Node *funcexpr, char *funcname,
Alias *alias, int nfuncs)
{
char *pname;
/*
* If the expression is a simple function call, and the function has a
* single OUT parameter that is named, use the parameter's name.
*/
if (funcexpr && IsA(funcexpr, FuncExpr))
{
pname = get_func_result_name(((FuncExpr *) funcexpr)->funcid);
if (pname)
return pname;
}
/*
* If there's just one function in the RTE, and the user gave an RTE alias
* name, use that name. (This makes FROM func() AS foo use "foo" as the
* column name as well as the table alias.)
*/
if (nfuncs == 1 && alias)
return alias->aliasname;
/*
* Otherwise use the function name.
*/
return funcname;
}
/*
* Open a table during parse analysis
*
* This is essentially just the same as heap_openrv(), except that it caters
* to some parser-specific error reporting needs, notably that it arranges
* to include the RangeVar's parse location in any resulting error.
*
* Note: properly, lockmode should be declared LOCKMODE not int, but that
* would require importing storage/lock.h into parse_relation.h. Since
* LOCKMODE is typedef'd as int anyway, that seems like overkill.
*/
Relation
parserOpenTable(ParseState *pstate, const RangeVar *relation, int lockmode)
{
Relation rel;
ParseCallbackState pcbstate;
setup_parser_errposition_callback(&pcbstate, pstate, relation->location);
rel = heap_openrv_extended(relation, lockmode, true);
if (rel == NULL)
{
if (relation->schemaname)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s.%s\" does not exist",
relation->schemaname, relation->relname)));
else
{
/*
* An unqualified name might have been meant as a reference to
* some not-yet-in-scope CTE. The bare "does not exist" message
* has proven remarkably unhelpful for figuring out such problems,
* so we take pains to offer a specific hint.
*/
if (isFutureCTE(pstate, relation->relname))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
relation->relname),
errdetail("There is a WITH item named \"%s\", but it cannot be referenced from this part of the query.",
relation->relname),
errhint("Use WITH RECURSIVE, or re-order the WITH items to remove forward references.")));
else
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" does not exist",
relation->relname)));
}
}
cancel_parser_errposition_callback(&pcbstate);
return rel;
}
/*
* Add an entry for a relation to the pstate's range table (p_rtable).
*
* Note: formerly this checked for refname conflicts, but that's wrong.
* Caller is responsible for checking for conflicts in the appropriate scope.
*/
RangeTblEntry *
addRangeTableEntry(ParseState *pstate,
RangeVar *relation,
Alias *alias,
bool inh,
bool inFromCl)
{
RangeTblEntry *rte = makeNode(RangeTblEntry);
char *refname = alias ? alias->aliasname : relation->relname;
LOCKMODE lockmode;
Relation rel;
Assert(pstate != NULL);
rte->rtekind = RTE_RELATION;
rte->alias = alias;
/*
* Get the rel's OID. This access also ensures that we have an up-to-date
* relcache entry for the rel. Since this is typically the first access
* to a rel in a statement, be careful to get the right access level
* depending on whether we're doing SELECT FOR UPDATE/SHARE.
*/
lockmode = isLockedRefname(pstate, refname) ? RowShareLock : AccessShareLock;
rel = parserOpenTable(pstate, relation, lockmode);
rte->relid = RelationGetRelid(rel);
rte->relkind = rel->rd_rel->relkind;
/*
* Build the list of effective column names using user-supplied aliases
* and/or actual column names.
*/
rte->eref = makeAlias(refname, NIL);
buildRelationAliases(rel->rd_att, alias, rte->eref);
/*
* Drop the rel refcount, but keep the access lock till end of transaction
* so that the table can't be deleted or have its schema modified
* underneath us.
*/
heap_close(rel, NoLock);
/*
* Set flags and access permissions.
*
* The initial default on access checks is always check-for-READ-access,
* which is the right thing for all except target tables.
*/
rte->lateral = false;
rte->inh = inh;
rte->inFromCl = inFromCl;
rte->requiredPerms = ACL_SELECT;
rte->checkAsUser = InvalidOid; /* not set-uid by default, either */
rte->selectedCols = NULL;
rte->insertedCols = NULL;
rte->updatedCols = NULL;
/*
* Add completed RTE to pstate's range table list, but not to join list
* nor namespace --- caller must do that if appropriate.
*/
pstate->p_rtable = lappend(pstate->p_rtable, rte);
return rte;
}
/*
* Add an entry for a relation to the pstate's range table (p_rtable).
*
* This is just like addRangeTableEntry() except that it makes an RTE
* given an already-open relation instead of a RangeVar reference.
*/
RangeTblEntry *
addRangeTableEntryForRelation(ParseState *pstate,
Relation rel,
Alias *alias,
bool inh,
bool inFromCl)
{
RangeTblEntry *rte = makeNode(RangeTblEntry);
char *refname = alias ? alias->aliasname : RelationGetRelationName(rel);
Assert(pstate != NULL);
rte->rtekind = RTE_RELATION;
rte->alias = alias;
rte->relid = RelationGetRelid(rel);
rte->relkind = rel->rd_rel->relkind;
/*
* Build the list of effective column names using user-supplied aliases
* and/or actual column names.
*/
rte->eref = makeAlias(refname, NIL);
buildRelationAliases(rel->rd_att, alias, rte->eref);
/*
* Set flags and access permissions.
*
* The initial default on access checks is always check-for-READ-access,
* which is the right thing for all except target tables.
*/
rte->lateral = false;
rte->inh = inh;
rte->inFromCl = inFromCl;
rte->requiredPerms = ACL_SELECT;
rte->checkAsUser = InvalidOid; /* not set-uid by default, either */
rte->selectedCols = NULL;
rte->insertedCols = NULL;
rte->updatedCols = NULL;
/*
* Add completed RTE to pstate's range table list, but not to join list
* nor namespace --- caller must do that if appropriate.
*/
pstate->p_rtable = lappend(pstate->p_rtable, rte);
return rte;
}
/*
* Add an entry for a subquery to the pstate's range table (p_rtable).
*
* This is just like addRangeTableEntry() except that it makes a subquery RTE.
* Note that an alias clause *must* be supplied.
*/
RangeTblEntry *
addRangeTableEntryForSubquery(ParseState *pstate,
Query *subquery,
Alias *alias,
bool lateral,
bool inFromCl)
{
RangeTblEntry *rte = makeNode(RangeTblEntry);
char *refname = alias->aliasname;
Alias *eref;
int numaliases;
int varattno;
ListCell *tlistitem;
Assert(pstate != NULL);
rte->rtekind = RTE_SUBQUERY;
rte->relid = InvalidOid;
rte->subquery = subquery;
rte->alias = alias;
eref = copyObject(alias);
numaliases = list_length(eref->colnames);
/* fill in any unspecified alias columns */
varattno = 0;
foreach(tlistitem, subquery->targetList)
{
TargetEntry *te = (TargetEntry *) lfirst(tlistitem);
if (te->resjunk)
continue;
varattno++;
Assert(varattno == te->resno);
if (varattno > numaliases)
{
char *attrname;
attrname = pstrdup(te->resname);
eref->colnames = lappend(eref->colnames, makeString(attrname));
}
}
if (varattno < numaliases)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("table \"%s\" has %d columns available but %d columns specified",
refname, varattno, numaliases)));
rte->eref = eref;
/*
* Set flags and access permissions.
*
* Subqueries are never checked for access rights.
*/
rte->lateral = lateral;
rte->inh = false; /* never true for subqueries */
rte->inFromCl = inFromCl;
rte->requiredPerms = 0;
rte->checkAsUser = InvalidOid;
rte->selectedCols = NULL;
rte->insertedCols = NULL;
rte->updatedCols = NULL;
/*
* Add completed RTE to pstate's range table list, but not to join list
* nor namespace --- caller must do that if appropriate.
*/
pstate->p_rtable = lappend(pstate->p_rtable, rte);
return rte;
}
/*
* Add an entry for a function (or functions) to the pstate's range table
* (p_rtable).
*
* This is just like addRangeTableEntry() except that it makes a function RTE.
*/
RangeTblEntry *
addRangeTableEntryForFunction(ParseState *pstate,
List *funcnames,
List *funcexprs,
List *coldeflists,
RangeFunction *rangefunc,
bool lateral,
bool inFromCl)
{
RangeTblEntry *rte = makeNode(RangeTblEntry);
Alias *alias = rangefunc->alias;
Alias *eref;
char *aliasname;
int nfuncs = list_length(funcexprs);
TupleDesc *functupdescs;
TupleDesc tupdesc;
ListCell *lc1,
*lc2,
*lc3;
int i;
int j;
int funcno;
int natts,
totalatts;
Assert(pstate != NULL);
rte->rtekind = RTE_FUNCTION;
rte->relid = InvalidOid;
rte->subquery = NULL;
rte->functions = NIL; /* we'll fill this list below */
rte->funcordinality = rangefunc->ordinality;
rte->alias = alias;
/*
* Choose the RTE alias name. We default to using the first function's
* name even when there's more than one; which is maybe arguable but beats
* using something constant like "table".
*/
if (alias)
aliasname = alias->aliasname;
else
aliasname = linitial(funcnames);
eref = makeAlias(aliasname, NIL);
rte->eref = eref;
/* Process each function ... */
functupdescs = (TupleDesc *) palloc(nfuncs * sizeof(TupleDesc));
totalatts = 0;
funcno = 0;
forthree(lc1, funcexprs, lc2, funcnames, lc3, coldeflists)
{
Node *funcexpr = (Node *) lfirst(lc1);
char *funcname = (char *) lfirst(lc2);
List *coldeflist = (List *) lfirst(lc3);
RangeTblFunction *rtfunc = makeNode(RangeTblFunction);
TypeFuncClass functypclass;
Oid funcrettype;
/* Initialize RangeTblFunction node */
rtfunc->funcexpr = funcexpr;
rtfunc->funccolnames = NIL;
rtfunc->funccoltypes = NIL;
rtfunc->funccoltypmods = NIL;
rtfunc->funccolcollations = NIL;
rtfunc->funcparams = NULL; /* not set until planning */
/*
* Now determine if the function returns a simple or composite type.
*/
functypclass = get_expr_result_type(funcexpr,
&funcrettype,
&tupdesc);
/*
* A coldeflist is required if the function returns RECORD and hasn't
* got a predetermined record type, and is prohibited otherwise.
*/
if (coldeflist != NIL)
{
if (functypclass != TYPEFUNC_RECORD)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("a column definition list is only allowed for functions returning \"record\""),
parser_errposition(pstate,
exprLocation((Node *) coldeflist))));
}
else
{
if (functypclass == TYPEFUNC_RECORD)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("a column definition list is required for functions returning \"record\""),
parser_errposition(pstate, exprLocation(funcexpr))));
}
if (functypclass == TYPEFUNC_COMPOSITE)
{
/* Composite data type, e.g. a table's row type */
Assert(tupdesc);
}
else if (functypclass == TYPEFUNC_SCALAR)
{
/* Base data type, i.e. scalar */
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc,
(AttrNumber) 1,
chooseScalarFunctionAlias(funcexpr, funcname,
alias, nfuncs),
funcrettype,
-1,
0);
}
else if (functypclass == TYPEFUNC_RECORD)
{
ListCell *col;
/*
* Use the column definition list to construct a tupdesc and fill
* in the RangeTblFunction's lists.
*/
tupdesc = CreateTemplateTupleDesc(list_length(coldeflist), false);
i = 1;
foreach(col, coldeflist)
{
ColumnDef *n = (ColumnDef *) lfirst(col);
char *attrname;
Oid attrtype;
int32 attrtypmod;
Oid attrcollation;
attrname = n->colname;
if (n->typeName->setof)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("column \"%s\" cannot be declared SETOF",
attrname),
parser_errposition(pstate, n->location)));
typenameTypeIdAndMod(pstate, n->typeName,
&attrtype, &attrtypmod);
attrcollation = GetColumnDefCollation(pstate, n, attrtype);
TupleDescInitEntry(tupdesc,
(AttrNumber) i,
attrname,
attrtype,
attrtypmod,
0);
TupleDescInitEntryCollation(tupdesc,
(AttrNumber) i,
attrcollation);
rtfunc->funccolnames = lappend(rtfunc->funccolnames,
makeString(pstrdup(attrname)));
rtfunc->funccoltypes = lappend_oid(rtfunc->funccoltypes,
attrtype);
rtfunc->funccoltypmods = lappend_int(rtfunc->funccoltypmods,
attrtypmod);
rtfunc->funccolcollations = lappend_oid(rtfunc->funccolcollations,
attrcollation);
i++;
}
/*
* Ensure that the coldeflist defines a legal set of names (no
* duplicates) and datatypes (no pseudo-types, for instance).
*/
CheckAttributeNamesTypes(tupdesc, RELKIND_COMPOSITE_TYPE, false);
}
else
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("function \"%s\" in FROM has unsupported return type %s",
funcname, format_type_be(funcrettype)),
parser_errposition(pstate, exprLocation(funcexpr))));
/* Finish off the RangeTblFunction and add it to the RTE's list */
rtfunc->funccolcount = tupdesc->natts;
rte->functions = lappend(rte->functions, rtfunc);
/* Save the tupdesc for use below */
functupdescs[funcno] = tupdesc;
totalatts += tupdesc->natts;
funcno++;
}
/*
* If there's more than one function, or we want an ordinality column, we
* have to produce a merged tupdesc.
*/
if (nfuncs > 1 || rangefunc->ordinality)
{
if (rangefunc->ordinality)
totalatts++;
/* Merge the tuple descs of each function into a composite one */
tupdesc = CreateTemplateTupleDesc(totalatts, false);
natts = 0;
for (i = 0; i < nfuncs; i++)
{
for (j = 1; j <= functupdescs[i]->natts; j++)
TupleDescCopyEntry(tupdesc, ++natts, functupdescs[i], j);
}
/* Add the ordinality column if needed */
if (rangefunc->ordinality)
TupleDescInitEntry(tupdesc,
(AttrNumber) ++natts,
"ordinality",
INT8OID,
-1,
0);
Assert(natts == totalatts);
}
else
{
/* We can just use the single function's tupdesc as-is */
tupdesc = functupdescs[0];
}
/* Use the tupdesc while assigning column aliases for the RTE */
buildRelationAliases(tupdesc, alias, eref);
/*
* Set flags and access permissions.
*
* Functions are never checked for access rights (at least, not by the RTE
* permissions mechanism).
*/
rte->lateral = lateral;
rte->inh = false; /* never true for functions */
rte->inFromCl = inFromCl;
rte->requiredPerms = 0;
rte->checkAsUser = InvalidOid;
rte->selectedCols = NULL;
rte->insertedCols = NULL;
rte->updatedCols = NULL;
/*
* Add completed RTE to pstate's range table list, but not to join list
* nor namespace --- caller must do that if appropriate.
*/
pstate->p_rtable = lappend(pstate->p_rtable, rte);
return rte;
}
/*
* Add an entry for a VALUES list to the pstate's range table (p_rtable).
*
* This is much like addRangeTableEntry() except that it makes a values RTE.
*/
RangeTblEntry *
addRangeTableEntryForValues(ParseState *pstate,
List *exprs,
List *coltypes,
List *coltypmods,
List *colcollations,
Alias *alias,
bool lateral,
bool inFromCl)
{
RangeTblEntry *rte = makeNode(RangeTblEntry);
char *refname = alias ? alias->aliasname : pstrdup("*VALUES*");
Alias *eref;
int numaliases;
int numcolumns;
Assert(pstate != NULL);
rte->rtekind = RTE_VALUES;
rte->relid = InvalidOid;
rte->subquery = NULL;
rte->values_lists = exprs;
rte->coltypes = coltypes;
rte->coltypmods = coltypmods;
rte->colcollations = colcollations;
rte->alias = alias;
eref = alias ? copyObject(alias) : makeAlias(refname, NIL);
/* fill in any unspecified alias columns */
numcolumns = list_length((List *) linitial(exprs));
numaliases = list_length(eref->colnames);
while (numaliases < numcolumns)
{
char attrname[64];
numaliases++;
snprintf(attrname, sizeof(attrname), "column%d", numaliases);
eref->colnames = lappend(eref->colnames,
makeString(pstrdup(attrname)));
}
if (numcolumns < numaliases)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("VALUES lists \"%s\" have %d columns available but %d columns specified",
refname, numcolumns, numaliases)));
rte->eref = eref;
/*
* Set flags and access permissions.
*
* Subqueries are never checked for access rights.
*/
rte->lateral = lateral;
rte->inh = false; /* never true for values RTEs */
rte->inFromCl = inFromCl;
rte->requiredPerms = 0;
rte->checkAsUser = InvalidOid;
rte->selectedCols = NULL;
rte->insertedCols = NULL;
rte->updatedCols = NULL;
/*
* Add completed RTE to pstate's range table list, but not to join list
* nor namespace --- caller must do that if appropriate.
*/
pstate->p_rtable = lappend(pstate->p_rtable, rte);
return rte;
}
/*
* Add an entry for a join to the pstate's range table (p_rtable).
*
* This is much like addRangeTableEntry() except that it makes a join RTE.
*/
RangeTblEntry *
addRangeTableEntryForJoin(ParseState *pstate,
List *colnames,
JoinType jointype,
List *aliasvars,
Alias *alias,
bool inFromCl)
{
RangeTblEntry *rte = makeNode(RangeTblEntry);
Alias *eref;
int numaliases;
Assert(pstate != NULL);
/*
* Fail if join has too many columns --- we must be able to reference any
* of the columns with an AttrNumber.
*/
if (list_length(aliasvars) > MaxAttrNumber)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("joins can have at most %d columns",
MaxAttrNumber)));
rte->rtekind = RTE_JOIN;
rte->relid = InvalidOid;
rte->subquery = NULL;
rte->jointype = jointype;
rte->joinaliasvars = aliasvars;
rte->alias = alias;
eref = alias ? (Alias *) copyObject(alias) : makeAlias("unnamed_join", NIL);
numaliases = list_length(eref->colnames);
/* fill in any unspecified alias columns */
if (numaliases < list_length(colnames))
eref->colnames = list_concat(eref->colnames,
list_copy_tail(colnames, numaliases));
rte->eref = eref;
/*
* Set flags and access permissions.
*
* Joins are never checked for access rights.
*/
rte->lateral = false;
rte->inh = false; /* never true for joins */
rte->inFromCl = inFromCl;
rte->requiredPerms = 0;
rte->checkAsUser = InvalidOid;
rte->selectedCols = NULL;
rte->insertedCols = NULL;
rte->updatedCols = NULL;
/*
* Add completed RTE to pstate's range table list, but not to join list
* nor namespace --- caller must do that if appropriate.
*/
pstate->p_rtable = lappend(pstate->p_rtable, rte);
return rte;
}
/*
* Add an entry for a CTE reference to the pstate's range table (p_rtable).
*
* This is much like addRangeTableEntry() except that it makes a CTE RTE.
*/
RangeTblEntry *
addRangeTableEntryForCTE(ParseState *pstate,
CommonTableExpr *cte,
Index levelsup,
RangeVar *rv,
bool inFromCl)
{
RangeTblEntry *rte = makeNode(RangeTblEntry);
Alias *alias = rv->alias;
char *refname = alias ? alias->aliasname : cte->ctename;
Alias *eref;
int numaliases;
int varattno;
ListCell *lc;
Assert(pstate != NULL);
rte->rtekind = RTE_CTE;
rte->ctename = cte->ctename;
rte->ctelevelsup = levelsup;
/* Self-reference if and only if CTE's parse analysis isn't completed */
rte->self_reference = !IsA(cte->ctequery, Query);
Assert(cte->cterecursive || !rte->self_reference);
/* Bump the CTE's refcount if this isn't a self-reference */
if (!rte->self_reference)
cte->cterefcount++;
/*
* We throw error if the CTE is INSERT/UPDATE/DELETE without RETURNING.
* This won't get checked in case of a self-reference, but that's OK
* because data-modifying CTEs aren't allowed to be recursive anyhow.
*/
if (IsA(cte->ctequery, Query))
{
Query *ctequery = (Query *) cte->ctequery;
if (ctequery->commandType != CMD_SELECT &&
ctequery->returningList == NIL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("WITH query \"%s\" does not have a RETURNING clause",
cte->ctename),
parser_errposition(pstate, rv->location)));
}
rte->coltypes = cte->ctecoltypes;
rte->coltypmods = cte->ctecoltypmods;
rte->colcollations = cte->ctecolcollations;
rte->alias = alias;
if (alias)
eref = copyObject(alias);
else
eref = makeAlias(refname, NIL);
numaliases = list_length(eref->colnames);
/* fill in any unspecified alias columns */
varattno = 0;
foreach(lc, cte->ctecolnames)
{
varattno++;
if (varattno > numaliases)
eref->colnames = lappend(eref->colnames, lfirst(lc));
}
if (varattno < numaliases)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("table \"%s\" has %d columns available but %d columns specified",
refname, varattno, numaliases)));
rte->eref = eref;
/*
* Set flags and access permissions.
*
* Subqueries are never checked for access rights.
*/
rte->lateral = false;
rte->inh = false; /* never true for subqueries */
rte->inFromCl = inFromCl;
rte->requiredPerms = 0;
rte->checkAsUser = InvalidOid;
rte->selectedCols = NULL;
rte->insertedCols = NULL;
rte->updatedCols = NULL;
/*
* Add completed RTE to pstate's range table list, but not to join list
* nor namespace --- caller must do that if appropriate.
*/
pstate->p_rtable = lappend(pstate->p_rtable, rte);
return rte;
}
/*
* Has the specified refname been selected FOR UPDATE/FOR SHARE?
*
* This is used when we have not yet done transformLockingClause, but need
* to know the correct lock to take during initial opening of relations.
*
* Note: we pay no attention to whether it's FOR UPDATE vs FOR SHARE,
* since the table-level lock is the same either way.
*/
bool
isLockedRefname(ParseState *pstate, const char *refname)
{
ListCell *l;
/*
* If we are in a subquery specified as locked FOR UPDATE/SHARE from
* parent level, then act as though there's a generic FOR UPDATE here.
*/
if (pstate->p_locked_from_parent)
return true;
foreach(l, pstate->p_locking_clause)
{
LockingClause *lc = (LockingClause *) lfirst(l);
if (lc->lockedRels == NIL)
{
/* all tables used in query */
return true;
}
else
{
/* just the named tables */
ListCell *l2;
foreach(l2, lc->lockedRels)
{
RangeVar *thisrel = (RangeVar *) lfirst(l2);
if (strcmp(refname, thisrel->relname) == 0)
return true;
}
}
}
return false;
}
/*
* Add the given RTE as a top-level entry in the pstate's join list
* and/or namespace list. (We assume caller has checked for any
* namespace conflicts.) The RTE is always marked as unconditionally
* visible, that is, not LATERAL-only.
*
* Note: some callers know that they can find the new ParseNamespaceItem
* at the end of the pstate->p_namespace list. This is a bit ugly but not
* worth complicating this function's signature for.
*/
void
addRTEtoQuery(ParseState *pstate, RangeTblEntry *rte,
bool addToJoinList,
bool addToRelNameSpace, bool addToVarNameSpace)
{
if (addToJoinList)
{
int rtindex = RTERangeTablePosn(pstate, rte, NULL);
RangeTblRef *rtr = makeNode(RangeTblRef);
rtr->rtindex = rtindex;
pstate->p_joinlist = lappend(pstate->p_joinlist, rtr);
}
if (addToRelNameSpace || addToVarNameSpace)
{
ParseNamespaceItem *nsitem;
nsitem = (ParseNamespaceItem *) palloc(sizeof(ParseNamespaceItem));
nsitem->p_rte = rte;
nsitem->p_rel_visible = addToRelNameSpace;
nsitem->p_cols_visible = addToVarNameSpace;
nsitem->p_lateral_only = false;
nsitem->p_lateral_ok = true;
pstate->p_namespace = lappend(pstate->p_namespace, nsitem);
}
}
/*
* expandRTE -- expand the columns of a rangetable entry
*
* This creates lists of an RTE's column names (aliases if provided, else
* real names) and Vars for each column. Only user columns are considered.
* If include_dropped is FALSE then dropped columns are omitted from the
* results. If include_dropped is TRUE then empty strings and NULL constants
* (not Vars!) are returned for dropped columns.
*
* rtindex, sublevels_up, and location are the varno, varlevelsup, and location
* values to use in the created Vars. Ordinarily rtindex should match the
* actual position of the RTE in its rangetable.
*
* The output lists go into *colnames and *colvars.
* If only one of the two kinds of output list is needed, pass NULL for the
* output pointer for the unwanted one.
*/
void
expandRTE(RangeTblEntry *rte, int rtindex, int sublevels_up,
int location, bool include_dropped,
List **colnames, List **colvars)
{
int varattno;
if (colnames)
*colnames = NIL;
if (colvars)
*colvars = NIL;
switch (rte->rtekind)
{
case RTE_RELATION:
/* Ordinary relation RTE */
expandRelation(rte->relid, rte->eref,
rtindex, sublevels_up, location,
include_dropped, colnames, colvars);
break;
case RTE_SUBQUERY:
{
/* Subquery RTE */
ListCell *aliasp_item = list_head(rte->eref->colnames);
ListCell *tlistitem;
varattno = 0;
foreach(tlistitem, rte->subquery->targetList)
{
TargetEntry *te = (TargetEntry *) lfirst(tlistitem);
if (te->resjunk)
continue;
varattno++;
Assert(varattno == te->resno);
if (colnames)
{
/* Assume there is one alias per target item */
char *label = strVal(lfirst(aliasp_item));
*colnames = lappend(*colnames, makeString(pstrdup(label)));
aliasp_item = lnext(aliasp_item);
}
if (colvars)
{
Var *varnode;
varnode = makeVar(rtindex, varattno,
exprType((Node *) te->expr),
exprTypmod((Node *) te->expr),
exprCollation((Node *) te->expr),
sublevels_up);
varnode->location = location;
*colvars = lappend(*colvars, varnode);
}
}
}
break;
case RTE_FUNCTION:
{
/* Function RTE */
int atts_done = 0;
ListCell *lc;
foreach(lc, rte->functions)
{
RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
TypeFuncClass functypclass;
Oid funcrettype;
TupleDesc tupdesc;
functypclass = get_expr_result_type(rtfunc->funcexpr,
&funcrettype,
&tupdesc);
if (functypclass == TYPEFUNC_COMPOSITE)
{
/* Composite data type, e.g. a table's row type */
Assert(tupdesc);
expandTupleDesc(tupdesc, rte->eref,
rtfunc->funccolcount, atts_done,
rtindex, sublevels_up, location,
include_dropped, colnames, colvars);
}
else if (functypclass == TYPEFUNC_SCALAR)
{
/* Base data type, i.e. scalar */
if (colnames)
*colnames = lappend(*colnames,
list_nth(rte->eref->colnames,
atts_done));
if (colvars)
{
Var *varnode;
varnode = makeVar(rtindex, atts_done + 1,
funcrettype, -1,
exprCollation(rtfunc->funcexpr),
sublevels_up);
varnode->location = location;
*colvars = lappend(*colvars, varnode);
}
}
else if (functypclass == TYPEFUNC_RECORD)
{
if (colnames)
{
List *namelist;
/* extract appropriate subset of column list */
namelist = list_copy_tail(rte->eref->colnames,
atts_done);
namelist = list_truncate(namelist,
rtfunc->funccolcount);
*colnames = list_concat(*colnames, namelist);
}
if (colvars)
{
ListCell *l1;
ListCell *l2;
ListCell *l3;
int attnum = atts_done;
forthree(l1, rtfunc->funccoltypes,
l2, rtfunc->funccoltypmods,
l3, rtfunc->funccolcollations)
{
Oid attrtype = lfirst_oid(l1);
int32 attrtypmod = lfirst_int(l2);
Oid attrcollation = lfirst_oid(l3);
Var *varnode;
attnum++;
varnode = makeVar(rtindex,
attnum,
attrtype,
attrtypmod,
attrcollation,
sublevels_up);
varnode->location = location;
*colvars = lappend(*colvars, varnode);
}
}
}
else
{
/* addRangeTableEntryForFunction should've caught this */
elog(ERROR, "function in FROM has unsupported return type");
}
atts_done += rtfunc->funccolcount;
}
/* Append the ordinality column if any */
if (rte->funcordinality)
{
if (colnames)
*colnames = lappend(*colnames,
llast(rte->eref->colnames));
if (colvars)
{
Var *varnode = makeVar(rtindex,
atts_done + 1,
INT8OID,
-1,
InvalidOid,
sublevels_up);
*colvars = lappend(*colvars, varnode);
}
}
}
break;
case RTE_JOIN:
{
/* Join RTE */
ListCell *colname;
ListCell *aliasvar;
Assert(list_length(rte->eref->colnames) == list_length(rte->joinaliasvars));
varattno = 0;
forboth(colname, rte->eref->colnames, aliasvar, rte->joinaliasvars)
{
Node *avar = (Node *) lfirst(aliasvar);
varattno++;
/*
* During ordinary parsing, there will never be any
* deleted columns in the join; but we have to check since
* this routine is also used by the rewriter, and joins
* found in stored rules might have join columns for
* since-deleted columns. This will be signaled by a null
* pointer in the alias-vars list.
*/
if (avar == NULL)
{
if (include_dropped)
{
if (colnames)
*colnames = lappend(*colnames,
makeString(pstrdup("")));
if (colvars)
{
/*
* Can't use join's column type here (it might
* be dropped!); but it doesn't really matter
* what type the Const claims to be.
*/
*colvars = lappend(*colvars,
makeNullConst(INT4OID, -1,
InvalidOid));
}
}
continue;
}
if (colnames)
{
char *label = strVal(lfirst(colname));
*colnames = lappend(*colnames,
makeString(pstrdup(label)));
}
if (colvars)
{
Var *varnode;
varnode = makeVar(rtindex, varattno,
exprType(avar),
exprTypmod(avar),
exprCollation(avar),
sublevels_up);
varnode->location = location;
*colvars = lappend(*colvars, varnode);
}
}
}
break;
case RTE_VALUES:
case RTE_CTE:
{
/* Values or CTE RTE */
ListCell *aliasp_item = list_head(rte->eref->colnames);
ListCell *lct;
ListCell *lcm;
ListCell *lcc;
varattno = 0;
forthree(lct, rte->coltypes,
lcm, rte->coltypmods,
lcc, rte->colcollations)
{
Oid coltype = lfirst_oid(lct);
int32 coltypmod = lfirst_int(lcm);
Oid colcoll = lfirst_oid(lcc);
varattno++;
if (colnames)
{
/* Assume there is one alias per output column */
char *label = strVal(lfirst(aliasp_item));
*colnames = lappend(*colnames,
makeString(pstrdup(label)));
aliasp_item = lnext(aliasp_item);
}
if (colvars)
{
Var *varnode;
varnode = makeVar(rtindex, varattno,
coltype, coltypmod, colcoll,
sublevels_up);
varnode->location = location;
*colvars = lappend(*colvars, varnode);
}
}
}
break;
default:
elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
}
}
/*
* expandRelation -- expandRTE subroutine
*/
static void
expandRelation(Oid relid, Alias *eref, int rtindex, int sublevels_up,
int location, bool include_dropped,
List **colnames, List **colvars)
{
Relation rel;
/* Get the tupledesc and turn it over to expandTupleDesc */
rel = relation_open(relid, AccessShareLock);
expandTupleDesc(rel->rd_att, eref, rel->rd_att->natts, 0,
rtindex, sublevels_up,
location, include_dropped,
colnames, colvars);
relation_close(rel, AccessShareLock);
}
/*
* expandTupleDesc -- expandRTE subroutine
*
* Generate names and/or Vars for the first "count" attributes of the tupdesc,
* and append them to colnames/colvars. "offset" is added to the varattno
* that each Var would otherwise have, and we also skip the first "offset"
* entries in eref->colnames. (These provisions allow use of this code for
* an individual composite-returning function in an RTE_FUNCTION RTE.)
*/
static void
expandTupleDesc(TupleDesc tupdesc, Alias *eref, int count, int offset,
int rtindex, int sublevels_up,
int location, bool include_dropped,
List **colnames, List **colvars)
{
ListCell *aliascell = list_head(eref->colnames);
int varattno;
if (colnames)
{
int i;
for (i = 0; i < offset; i++)
{
if (aliascell)
aliascell = lnext(aliascell);
}
}
Assert(count <= tupdesc->natts);
for (varattno = 0; varattno < count; varattno++)
{
Form_pg_attribute attr = tupdesc->attrs[varattno];
if (attr->attisdropped)
{
if (include_dropped)
{
if (colnames)
*colnames = lappend(*colnames, makeString(pstrdup("")));
if (colvars)
{
/*
* can't use atttypid here, but it doesn't really matter
* what type the Const claims to be.
*/
*colvars = lappend(*colvars,
makeNullConst(INT4OID, -1, InvalidOid));
}
}
if (aliascell)
aliascell = lnext(aliascell);
continue;
}
if (colnames)
{
char *label;
if (aliascell)
{
label = strVal(lfirst(aliascell));
aliascell = lnext(aliascell);
}
else
{
/* If we run out of aliases, use the underlying name */
label = NameStr(attr->attname);
}
*colnames = lappend(*colnames, makeString(pstrdup(label)));
}
if (colvars)
{
Var *varnode;
varnode = makeVar(rtindex, varattno + offset + 1,
attr->atttypid, attr->atttypmod,
attr->attcollation,
sublevels_up);
varnode->location = location;
*colvars = lappend(*colvars, varnode);
}
}
}
/*
* expandRelAttrs -
* Workhorse for "*" expansion: produce a list of targetentries
* for the attributes of the RTE
*
* As with expandRTE, rtindex/sublevels_up determine the varno/varlevelsup
* fields of the Vars produced, and location sets their location.
* pstate->p_next_resno determines the resnos assigned to the TLEs.
* The referenced columns are marked as requiring SELECT access.
*/
List *
expandRelAttrs(ParseState *pstate, RangeTblEntry *rte,
int rtindex, int sublevels_up, int location)
{
List *names,
*vars;
ListCell *name,
*var;
List *te_list = NIL;
expandRTE(rte, rtindex, sublevels_up, location, false,
&names, &vars);
/*
* Require read access to the table. This is normally redundant with the
* markVarForSelectPriv calls below, but not if the table has zero
* columns.
*/
rte->requiredPerms |= ACL_SELECT;
forboth(name, names, var, vars)
{
char *label = strVal(lfirst(name));
Var *varnode = (Var *) lfirst(var);
TargetEntry *te;
te = makeTargetEntry((Expr *) varnode,
(AttrNumber) pstate->p_next_resno++,
label,
false);
te_list = lappend(te_list, te);
/* Require read access to each column */
markVarForSelectPriv(pstate, varnode, rte);
}
Assert(name == NULL && var == NULL); /* lists not the same length? */
return te_list;
}
/*
* get_rte_attribute_name
* Get an attribute name from a RangeTblEntry
*
* This is unlike get_attname() because we use aliases if available.
* In particular, it will work on an RTE for a subselect or join, whereas
* get_attname() only works on real relations.
*
* "*" is returned if the given attnum is InvalidAttrNumber --- this case
* occurs when a Var represents a whole tuple of a relation.
*/
char *
get_rte_attribute_name(RangeTblEntry *rte, AttrNumber attnum)
{
if (attnum == InvalidAttrNumber)
return "*";
/*
* If there is a user-written column alias, use it.
*/
if (rte->alias &&
attnum > 0 && attnum <= list_length(rte->alias->colnames))
return strVal(list_nth(rte->alias->colnames, attnum - 1));
/*
* If the RTE is a relation, go to the system catalogs not the
* eref->colnames list. This is a little slower but it will give the
* right answer if the column has been renamed since the eref list was
* built (which can easily happen for rules).
*/
if (rte->rtekind == RTE_RELATION)
return get_relid_attribute_name(rte->relid, attnum);
/*
* Otherwise use the column name from eref. There should always be one.
*/
if (attnum > 0 && attnum <= list_length(rte->eref->colnames))
return strVal(list_nth(rte->eref->colnames, attnum - 1));
/* else caller gave us a bogus attnum */
elog(ERROR, "invalid attnum %d for rangetable entry %s",
attnum, rte->eref->aliasname);
return NULL; /* keep compiler quiet */
}
/*
* get_rte_attribute_type
* Get attribute type/typmod/collation information from a RangeTblEntry
*/
void
get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,
Oid *vartype, int32 *vartypmod, Oid *varcollid)
{
switch (rte->rtekind)
{
case RTE_RELATION:
{
/* Plain relation RTE --- get the attribute's type info */
HeapTuple tp;
Form_pg_attribute att_tup;
tp = SearchSysCache2(ATTNUM,
ObjectIdGetDatum(rte->relid),
Int16GetDatum(attnum));
if (!HeapTupleIsValid(tp)) /* shouldn't happen */
elog(ERROR, "cache lookup failed for attribute %d of relation %u",
attnum, rte->relid);
att_tup = (Form_pg_attribute) GETSTRUCT(tp);
/*
* If dropped column, pretend it ain't there. See notes in
* scanRTEForColumn.
*/
if (att_tup->attisdropped)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
NameStr(att_tup->attname),
get_rel_name(rte->relid))));
*vartype = att_tup->atttypid;
*vartypmod = att_tup->atttypmod;
*varcollid = att_tup->attcollation;
ReleaseSysCache(tp);
}
break;
case RTE_SUBQUERY:
{
/* Subselect RTE --- get type info from subselect's tlist */
TargetEntry *te = get_tle_by_resno(rte->subquery->targetList,
attnum);
if (te == NULL || te->resjunk)
elog(ERROR, "subquery %s does not have attribute %d",
rte->eref->aliasname, attnum);
*vartype = exprType((Node *) te->expr);
*vartypmod = exprTypmod((Node *) te->expr);
*varcollid = exprCollation((Node *) te->expr);
}
break;
case RTE_FUNCTION:
{
/* Function RTE */
ListCell *lc;
int atts_done = 0;
/* Identify which function covers the requested column */
foreach(lc, rte->functions)
{
RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
if (attnum > atts_done &&
attnum <= atts_done + rtfunc->funccolcount)
{
TypeFuncClass functypclass;
Oid funcrettype;
TupleDesc tupdesc;
attnum -= atts_done; /* now relative to this func */
functypclass = get_expr_result_type(rtfunc->funcexpr,
&funcrettype,
&tupdesc);
if (functypclass == TYPEFUNC_COMPOSITE)
{
/* Composite data type, e.g. a table's row type */
Form_pg_attribute att_tup;
Assert(tupdesc);
Assert(attnum <= tupdesc->natts);
att_tup = tupdesc->attrs[attnum - 1];
/*
* If dropped column, pretend it ain't there. See
* notes in scanRTEForColumn.
*/
if (att_tup->attisdropped)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
NameStr(att_tup->attname),
rte->eref->aliasname)));
*vartype = att_tup->atttypid;
*vartypmod = att_tup->atttypmod;
*varcollid = att_tup->attcollation;
}
else if (functypclass == TYPEFUNC_SCALAR)
{
/* Base data type, i.e. scalar */
*vartype = funcrettype;
*vartypmod = -1;
*varcollid = exprCollation(rtfunc->funcexpr);
}
else if (functypclass == TYPEFUNC_RECORD)
{
*vartype = list_nth_oid(rtfunc->funccoltypes,
attnum - 1);
*vartypmod = list_nth_int(rtfunc->funccoltypmods,
attnum - 1);
*varcollid = list_nth_oid(rtfunc->funccolcollations,
attnum - 1);
}
else
{
/*
* addRangeTableEntryForFunction should've caught
* this
*/
elog(ERROR, "function in FROM has unsupported return type");
}
return;
}
atts_done += rtfunc->funccolcount;
}
/* If we get here, must be looking for the ordinality column */
if (rte->funcordinality && attnum == atts_done + 1)
{
*vartype = INT8OID;
*vartypmod = -1;
*varcollid = InvalidOid;
return;
}
/* this probably can't happen ... */
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column %d of relation \"%s\" does not exist",
attnum,
rte->eref->aliasname)));
}
break;
case RTE_JOIN:
{
/*
* Join RTE --- get type info from join RTE's alias variable
*/
Node *aliasvar;
Assert(attnum > 0 && attnum <= list_length(rte->joinaliasvars));
aliasvar = (Node *) list_nth(rte->joinaliasvars, attnum - 1);
Assert(aliasvar != NULL);
*vartype = exprType(aliasvar);
*vartypmod = exprTypmod(aliasvar);
*varcollid = exprCollation(aliasvar);
}
break;
case RTE_VALUES:
case RTE_CTE:
{
/* VALUES or CTE RTE --- get type info from lists in the RTE */
Assert(attnum > 0 && attnum <= list_length(rte->coltypes));
*vartype = list_nth_oid(rte->coltypes, attnum - 1);
*vartypmod = list_nth_int(rte->coltypmods, attnum - 1);
*varcollid = list_nth_oid(rte->colcollations, attnum - 1);
}
break;
default:
elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
}
}
/*
* get_rte_attribute_is_dropped
* Check whether attempted attribute ref is to a dropped column
*/
bool
get_rte_attribute_is_dropped(RangeTblEntry *rte, AttrNumber attnum)
{
bool result;
switch (rte->rtekind)
{
case RTE_RELATION:
{
/*
* Plain relation RTE --- get the attribute's catalog entry
*/
HeapTuple tp;
Form_pg_attribute att_tup;
tp = SearchSysCache2(ATTNUM,
ObjectIdGetDatum(rte->relid),
Int16GetDatum(attnum));
if (!HeapTupleIsValid(tp)) /* shouldn't happen */
elog(ERROR, "cache lookup failed for attribute %d of relation %u",
attnum, rte->relid);
att_tup = (Form_pg_attribute) GETSTRUCT(tp);
result = att_tup->attisdropped;
ReleaseSysCache(tp);
}
break;
case RTE_SUBQUERY:
case RTE_VALUES:
case RTE_CTE:
/* Subselect, Values, CTE RTEs never have dropped columns */
result = false;
break;
case RTE_JOIN:
{
/*
* A join RTE would not have dropped columns when constructed,
* but one in a stored rule might contain columns that were
* dropped from the underlying tables, if said columns are
* nowhere explicitly referenced in the rule. This will be
* signaled to us by a null pointer in the joinaliasvars list.
*/
Var *aliasvar;
if (attnum <= 0 ||
attnum > list_length(rte->joinaliasvars))
elog(ERROR, "invalid varattno %d", attnum);
aliasvar = (Var *) list_nth(rte->joinaliasvars, attnum - 1);
result = (aliasvar == NULL);
}
break;
case RTE_FUNCTION:
{
/* Function RTE */
ListCell *lc;
int atts_done = 0;
/*
* Dropped attributes are only possible with functions that
* return named composite types. In such a case we have to
* look up the result type to see if it currently has this
* column dropped. So first, loop over the funcs until we
* find the one that covers the requested column.
*/
foreach(lc, rte->functions)
{
RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
if (attnum > atts_done &&
attnum <= atts_done + rtfunc->funccolcount)
{
TypeFuncClass functypclass;
Oid funcrettype;
TupleDesc tupdesc;
functypclass = get_expr_result_type(rtfunc->funcexpr,
&funcrettype,
&tupdesc);
if (functypclass == TYPEFUNC_COMPOSITE)
{
/* Composite data type, e.g. a table's row type */
Form_pg_attribute att_tup;
Assert(tupdesc);
Assert(attnum - atts_done <= tupdesc->natts);
att_tup = tupdesc->attrs[attnum - atts_done - 1];
return att_tup->attisdropped;
}
/* Otherwise, it can't have any dropped columns */
return false;
}
atts_done += rtfunc->funccolcount;
}
/* If we get here, must be looking for the ordinality column */
if (rte->funcordinality && attnum == atts_done + 1)
return false;
/* this probably can't happen ... */
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column %d of relation \"%s\" does not exist",
attnum,
rte->eref->aliasname)));
result = false; /* keep compiler quiet */
}
break;
default:
elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
result = false; /* keep compiler quiet */
}
return result;
}
/*
* Given a targetlist and a resno, return the matching TargetEntry
*
* Returns NULL if resno is not present in list.
*
* Note: we need to search, rather than just indexing with list_nth(),
* because not all tlists are sorted by resno.
*/
TargetEntry *
get_tle_by_resno(List *tlist, AttrNumber resno)
{
ListCell *l;
foreach(l, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(l);
if (tle->resno == resno)
return tle;
}
return NULL;
}
/*
* Given a Query and rangetable index, return relation's RowMarkClause if any
*
* Returns NULL if relation is not selected FOR UPDATE/SHARE
*/
RowMarkClause *
get_parse_rowmark(Query *qry, Index rtindex)
{
ListCell *l;
foreach(l, qry->rowMarks)
{
RowMarkClause *rc = (RowMarkClause *) lfirst(l);
if (rc->rti == rtindex)
return rc;
}
return NULL;
}
/*
* given relation and att name, return attnum of variable
*
* Returns InvalidAttrNumber if the attr doesn't exist (or is dropped).
*
* This should only be used if the relation is already
* heap_open()'ed. Use the cache version get_attnum()
* for access to non-opened relations.
*/
int
attnameAttNum(Relation rd, const char *attname, bool sysColOK)
{
int i;
for (i = 0; i < rd->rd_rel->relnatts; i++)
{
Form_pg_attribute att = rd->rd_att->attrs[i];
if (namestrcmp(&(att->attname), attname) == 0 && !att->attisdropped)
return i + 1;
}
if (sysColOK)
{
if ((i = specialAttNum(attname)) != InvalidAttrNumber)
{
if (i != ObjectIdAttributeNumber || rd->rd_rel->relhasoids)
return i;
}
}
/* on failure */
return InvalidAttrNumber;
}
/* specialAttNum()
*
* Check attribute name to see if it is "special", e.g. "oid".
* - thomas 2000-02-07
*
* Note: this only discovers whether the name could be a system attribute.
* Caller needs to verify that it really is an attribute of the rel,
* at least in the case of "oid", which is now optional.
*/
static int
specialAttNum(const char *attname)
{
Form_pg_attribute sysatt;
sysatt = SystemAttributeByName(attname,
true /* "oid" will be accepted */ );
if (sysatt != NULL)
return sysatt->attnum;
return InvalidAttrNumber;
}
/*
* given attribute id, return name of that attribute
*
* This should only be used if the relation is already
* heap_open()'ed. Use the cache version get_atttype()
* for access to non-opened relations.
*/
Name
attnumAttName(Relation rd, int attid)
{
if (attid <= 0)
{
Form_pg_attribute sysatt;
sysatt = SystemAttributeDefinition(attid, rd->rd_rel->relhasoids);
return &sysatt->attname;
}
if (attid > rd->rd_att->natts)
elog(ERROR, "invalid attribute number %d", attid);
return &rd->rd_att->attrs[attid - 1]->attname;
}
/*
* given attribute id, return type of that attribute
*
* This should only be used if the relation is already
* heap_open()'ed. Use the cache version get_atttype()
* for access to non-opened relations.
*/
Oid
attnumTypeId(Relation rd, int attid)
{
if (attid <= 0)
{
Form_pg_attribute sysatt;
sysatt = SystemAttributeDefinition(attid, rd->rd_rel->relhasoids);
return sysatt->atttypid;
}
if (attid > rd->rd_att->natts)
elog(ERROR, "invalid attribute number %d", attid);
return rd->rd_att->attrs[attid - 1]->atttypid;
}
/*
* given attribute id, return collation of that attribute
*
* This should only be used if the relation is already heap_open()'ed.
*/
Oid
attnumCollationId(Relation rd, int attid)
{
if (attid <= 0)
{
/* All system attributes are of noncollatable types. */
return InvalidOid;
}
if (attid > rd->rd_att->natts)
elog(ERROR, "invalid attribute number %d", attid);
return rd->rd_att->attrs[attid - 1]->attcollation;
}
/*
* Generate a suitable error about a missing RTE.
*
* Since this is a very common type of error, we work rather hard to
* produce a helpful message.
*/
void
errorMissingRTE(ParseState *pstate, RangeVar *relation)
{
RangeTblEntry *rte;
int sublevels_up;
const char *badAlias = NULL;
/*
* Check to see if there are any potential matches in the query's
* rangetable. (Note: cases involving a bad schema name in the RangeVar
* will throw error immediately here. That seems OK.)
*/
rte = searchRangeTableForRel(pstate, relation);
/*
* If we found a match that has an alias and the alias is visible in the
* namespace, then the problem is probably use of the relation's real name
* instead of its alias, ie "SELECT foo.* FROM foo f". This mistake is
* common enough to justify a specific hint.
*
* If we found a match that doesn't meet those criteria, assume the
* problem is illegal use of a relation outside its scope, as in the
* MySQL-ism "SELECT ... FROM a, b LEFT JOIN c ON (a.x = c.y)".
*/
if (rte && rte->alias &&
strcmp(rte->eref->aliasname, relation->relname) != 0 &&
refnameRangeTblEntry(pstate, NULL, rte->eref->aliasname,
relation->location,
&sublevels_up) == rte)
badAlias = rte->eref->aliasname;
if (rte)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("invalid reference to FROM-clause entry for table \"%s\"",
relation->relname),
(badAlias ?
errhint("Perhaps you meant to reference the table alias \"%s\".",
badAlias) :
errhint("There is an entry for table \"%s\", but it cannot be referenced from this part of the query.",
rte->eref->aliasname)),
parser_errposition(pstate, relation->location)));
else
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("missing FROM-clause entry for table \"%s\"",
relation->relname),
parser_errposition(pstate, relation->location)));
}
/*
* Generate a suitable error about a missing column.
*
* Since this is a very common type of error, we work rather hard to
* produce a helpful message.
*/
void
errorMissingColumn(ParseState *pstate,
char *relname, char *colname, int location)
{
FuzzyAttrMatchState *state;
char *closestfirst = NULL;
/*
* Search the entire rtable looking for possible matches. If we find one,
* emit a hint about it.
*
* TODO: improve this code (and also errorMissingRTE) to mention using
* LATERAL if appropriate.
*/
state = searchRangeTableForCol(pstate, relname, colname, location);
/*
* Extract closest col string for best match, if any.
*
* Infer an exact match referenced despite not being visible from the fact
* that an attribute number was not present in state passed back -- this
* is what is reported when !closestfirst. There might also be an exact
* match that was qualified with an incorrect alias, in which case
* closestfirst will be set (so hint is the same as generic fuzzy case).
*/
if (state->rfirst && AttributeNumberIsValid(state->first))
closestfirst = strVal(list_nth(state->rfirst->eref->colnames,
state->first - 1));
if (!state->rsecond)
{
/*
* Handle case where there is zero or one column suggestions to hint,
* including exact matches referenced but not visible.
*/
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
relname ?
errmsg("column %s.%s does not exist", relname, colname) :
errmsg("column \"%s\" does not exist", colname),
state->rfirst ? closestfirst ?
errhint("Perhaps you meant to reference the column \"%s.%s\".",
state->rfirst->eref->aliasname, closestfirst) :
errhint("There is a column named \"%s\" in table \"%s\", but it cannot be referenced from this part of the query.",
colname, state->rfirst->eref->aliasname) : 0,
parser_errposition(pstate, location)));
}
else
{
/* Handle case where there are two equally useful column hints */
char *closestsecond;
closestsecond = strVal(list_nth(state->rsecond->eref->colnames,
state->second - 1));
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
relname ?
errmsg("column %s.%s does not exist", relname, colname) :
errmsg("column \"%s\" does not exist", colname),
errhint("Perhaps you meant to reference the column \"%s.%s\" or the column \"%s.%s\".",
state->rfirst->eref->aliasname, closestfirst,
state->rsecond->eref->aliasname, closestsecond),
parser_errposition(pstate, location)));
}
}
/*
* Examine a fully-parsed query, and return TRUE iff any relation underlying
* the query is a temporary relation (table, view, or materialized view).
*/
bool
isQueryUsingTempRelation(Query *query)
{
return isQueryUsingTempRelation_walker((Node *) query, NULL);
}
static bool
isQueryUsingTempRelation_walker(Node *node, void *context)
{
if (node == NULL)
return false;
if (IsA(node, Query))
{
Query *query = (Query *) node;
ListCell *rtable;
foreach(rtable, query->rtable)
{
RangeTblEntry *rte = lfirst(rtable);
if (rte->rtekind == RTE_RELATION)
{
Relation rel = heap_open(rte->relid, AccessShareLock);
char relpersistence = rel->rd_rel->relpersistence;
heap_close(rel, AccessShareLock);
if (relpersistence == RELPERSISTENCE_TEMP)
return true;
}
}
return query_tree_walker(query,
isQueryUsingTempRelation_walker,
context,
QTW_IGNORE_JOINALIASES);
}
return expression_tree_walker(node,
isQueryUsingTempRelation_walker,
context);
}
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