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Add p_names field to ParseNamespaceItem

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ParseNamespaceItem had a wired-in assumption that p_rte->eref
describes the table and column aliases exposed by the nsitem.  This
relaxes this by creating a separate p_names field in an nsitem.  This
is mainly preparation for a patch for JOIN USING aliases, but it saves
one indirection in common code paths, so it's possibly a win on its
own.

Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/785329.1616455091@sss.pgh.pa.us
This commit is contained in:
Peter Eisentraut 2021-03-31 10:52:37 +02:00
parent 91c5a8caaa
commit 66392d3965
3 changed files with 28 additions and 17 deletions
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6
src/backend/parser/parse_clause.c
View File

@ -1217,9 +1217,9 @@ transformFromClauseItem(ParseState *pstate, Node *n,
* input column numbers more easily.
*/
l_nscolumns = l_nsitem->p_nscolumns;
l_colnames = l_nsitem->p_rte->eref->colnames;
l_colnames = l_nsitem->p_names->colnames;
r_nscolumns = r_nsitem->p_nscolumns;
r_colnames = r_nsitem->p_rte->eref->colnames;
r_colnames = r_nsitem->p_names->colnames;
/*
* Natural join does not explicitly specify columns; must generate
@ -1469,7 +1469,7 @@ transformFromClauseItem(ParseState *pstate, Node *n,
* Now that we know the join RTE's rangetable index, we can fix up the
* res_nscolumns data in places where it should contain that.
*/
Assert(res_colindex == list_length(nsitem->p_rte->eref->colnames));
Assert(res_colindex == list_length(nsitem->p_names->colnames));
for (k = 0; k < res_colindex; k++)
{
ParseNamespaceColumn *nscol = res_nscolumns + k;

29
src/backend/parser/parse_relation.c
View File

@ -65,6 +65,7 @@ static ParseNamespaceItem *scanNameSpaceForRelid(ParseState *pstate, Oid relid,
static void check_lateral_ref_ok(ParseState *pstate, ParseNamespaceItem *nsitem,
int location);
static int scanRTEForColumn(ParseState *pstate, RangeTblEntry *rte,
Alias *eref,
const char *colname, int location,
int fuzzy_rte_penalty,
FuzzyAttrMatchState *fuzzystate);
@ -184,7 +185,6 @@ scanNameSpaceForRefname(ParseState *pstate, const char *refname, int location)
foreach(l, pstate->p_namespace)
{
ParseNamespaceItem *nsitem = (ParseNamespaceItem *) lfirst(l);
RangeTblEntry *rte = nsitem->p_rte;
/* Ignore columns-only items */
if (!nsitem->p_rel_visible)
@ -193,7 +193,7 @@ scanNameSpaceForRefname(ParseState *pstate, const char *refname, int location)
if (nsitem->p_lateral_only && !pstate->p_lateral_active)
continue;
if (strcmp(rte->eref->aliasname, refname) == 0)
if (strcmp(nsitem->p_names->aliasname, refname) == 0)
{
if (result)
ereport(ERROR,
@ -420,7 +420,7 @@ checkNameSpaceConflicts(ParseState *pstate, List *namespace1,
{
ParseNamespaceItem *nsitem1 = (ParseNamespaceItem *) lfirst(l1);
RangeTblEntry *rte1 = nsitem1->p_rte;
const char *aliasname1 = rte1->eref->aliasname;
const char *aliasname1 = nsitem1->p_names->aliasname;
ListCell *l2;
if (!nsitem1->p_rel_visible)
@ -430,10 +430,11 @@ checkNameSpaceConflicts(ParseState *pstate, List *namespace1,
{
ParseNamespaceItem *nsitem2 = (ParseNamespaceItem *) lfirst(l2);
RangeTblEntry *rte2 = nsitem2->p_rte;
const char *aliasname2 = nsitem2->p_names->aliasname;
if (!nsitem2->p_rel_visible)
continue;
if (strcmp(rte2->eref->aliasname, aliasname1) != 0)
if (strcmp(aliasname2, aliasname1) != 0)
continue; /* definitely no conflict */
if (rte1->rtekind == RTE_RELATION && rte1->alias == NULL &&
rte2->rtekind == RTE_RELATION && rte2->alias == NULL &&
@ -466,7 +467,7 @@ check_lateral_ref_ok(ParseState *pstate, ParseNamespaceItem *nsitem,
{
/* SQL:2008 demands this be an error, not an invisible item */
RangeTblEntry *rte = nsitem->p_rte;
char *refname = rte->eref->aliasname;
char *refname = nsitem->p_names->aliasname;
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
@ -672,10 +673,10 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
Var *var;
/*
* Scan the RTE's column names (or aliases) for a match. Complain if
* Scan the nsitem's column names (or aliases) for a match. Complain if
* multiple matches.
*/
attnum = scanRTEForColumn(pstate, rte,
attnum = scanRTEForColumn(pstate, rte, nsitem->p_names,
colname, location,
0, NULL);
@ -712,7 +713,7 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colname,
rte->eref->aliasname)));
nsitem->p_names->aliasname)));
var = makeVar(nscol->p_varno,
nscol->p_varattno,
@ -765,6 +766,7 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
*/
static int
scanRTEForColumn(ParseState *pstate, RangeTblEntry *rte,
Alias *eref,
const char *colname, int location,
int fuzzy_rte_penalty,
FuzzyAttrMatchState *fuzzystate)
@ -786,7 +788,7 @@ scanRTEForColumn(ParseState *pstate, RangeTblEntry *rte,
* Callers interested in finding match with shortest distance need to
* defend against this directly, though.
*/
foreach(c, rte->eref->colnames)
foreach(c, eref->colnames)
{
const char *attcolname = strVal(lfirst(c));
@ -970,7 +972,7 @@ searchRangeTableForCol(ParseState *pstate, const char *alias, const char *colnam
* Scan for a matching column; if we find an exact match, we're
* done. Otherwise, update fuzzystate.
*/
if (scanRTEForColumn(orig_pstate, rte, colname, location,
if (scanRTEForColumn(orig_pstate, rte, rte->eref, colname, location,
fuzzy_rte_penalty, fuzzystate)
&& fuzzy_rte_penalty == 0)
{
@ -1252,6 +1254,7 @@ buildNSItemFromTupleDesc(RangeTblEntry *rte, Index rtindex, TupleDesc tupdesc)
/* ... and build the nsitem */
nsitem = (ParseNamespaceItem *) palloc(sizeof(ParseNamespaceItem));
nsitem->p_names = rte->eref;
nsitem->p_rte = rte;
nsitem->p_rtindex = rtindex;
nsitem->p_nscolumns = nscolumns;
@ -1313,6 +1316,7 @@ buildNSItemFromLists(RangeTblEntry *rte, Index rtindex,
/* ... and build the nsitem */
nsitem = (ParseNamespaceItem *) palloc(sizeof(ParseNamespaceItem));
nsitem->p_names = rte->eref;
nsitem->p_rte = rte;
nsitem->p_rtindex = rtindex;
nsitem->p_nscolumns = nscolumns;
@ -2198,6 +2202,7 @@ addRangeTableEntryForJoin(ParseState *pstate,
* list --- caller must do that if appropriate.
*/
nsitem = (ParseNamespaceItem *) palloc(sizeof(ParseNamespaceItem));
nsitem->p_names = rte->eref;
nsitem->p_rte = rte;
nsitem->p_rtindex = list_length(pstate->p_rtable);
nsitem->p_nscolumns = nscolumns;
@ -2356,7 +2361,7 @@ addRangeTableEntryForCTE(ParseState *pstate,
*/
if (rte->ctelevelsup > 0)
for (int i = 0; i < n_dontexpand_columns; i++)
psi->p_nscolumns[list_length(psi->p_rte->eref->colnames) - 1 - i].p_dontexpand = true;
psi->p_nscolumns[list_length(psi->p_names->colnames) - 1 - i].p_dontexpand = true;
return psi;
}
@ -3037,7 +3042,7 @@ expandNSItemVars(ParseNamespaceItem *nsitem,
if (colnames)
*colnames = NIL;
colindex = 0;
foreach(lc, nsitem->p_rte->eref->colnames)
foreach(lc, nsitem->p_names->colnames)
{
Value *colnameval = (Value *) lfirst(lc);
const char *colname = strVal(colnameval);

10
src/include/parser/parse_node.h
View File

@ -227,8 +227,13 @@ struct ParseState
/*
* An element of a namespace list.
*
* p_names contains the table name and column names exposed by this nsitem.
* (Currently, it's always equal to p_rte->eref.)
*
* p_rte and p_rtindex link to the underlying rangetable entry.
*
* The p_nscolumns array contains info showing how to construct Vars
* referencing corresponding elements of the RTE's colnames list.
* referencing the names appearing in the p_names->colnames list.
*
* Namespace items with p_rel_visible set define which RTEs are accessible by
* qualified names, while those with p_cols_visible set define which RTEs are
@ -256,9 +261,10 @@ struct ParseState
*/
struct ParseNamespaceItem
{
Alias *p_names; /* Table and column names */
RangeTblEntry *p_rte; /* The relation's rangetable entry */
int p_rtindex; /* The relation's index in the rangetable */
/* array of same length as p_rte->eref->colnames: */
/* array of same length as p_names->colnames: */
ParseNamespaceColumn *p_nscolumns; /* per-column data */
bool p_rel_visible; /* Relation name is visible? */
bool p_cols_visible; /* Column names visible as unqualified refs? */