database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-29 10:41:53 +03:00
Code Activity

Refactor parser's generation of Var nodes.

Browse Source 
Instead of passing around a pointer to the RangeTblEntry that
provides the desired column, pass a pointer to the associated
ParseNamespaceItem.  The RTE is trivially reachable from the nsitem,
and having the ParseNamespaceItem allows access to additional
information.  As proof of concept for that, add the rangetable index
to ParseNamespaceItem, and use that to get rid of RTERangeTablePosn
searches.

(I have in mind to teach the parser to generate some different
representation for Vars that are nullable by outer joins, and
keeping the necessary information in ParseNamespaceItems seems
like a reasonable approach to that.  But whether that ever
happens or not, this seems like good cleanup.)

Also refactor the code around scanRTEForColumn so that the
"fuzzy match" stuff does not leak out of parse_relation.c.

Discussion: https://postgr.es/m/26144.1576858373@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2019-12-26 11:16:42 -05:00
parent 044b319cd7
commit b541e9accb
9 changed files with 335 additions and 292 deletions
Download Patch File Download Diff File Expand all files Collapse all files

23
src/backend/parser/parse_clause.c
View File

@ -52,7 +52,8 @@
#include "utils/syscache.h"
/* Convenience macro for the most common makeNamespaceItem() case */
#define makeDefaultNSItem(rte) makeNamespaceItem(rte, true, true, false, true)
#define makeDefaultNSItem(rte, rti) \
makeNamespaceItem(rte, rti, true, true, false, true)
static void extractRemainingColumns(List *common_colnames,
List *src_colnames, List *src_colvars,
@ -78,7 +79,7 @@ static Node *transformFromClauseItem(ParseState *pstate, Node *n,
List **namespace);
static Node *buildMergedJoinVar(ParseState *pstate, JoinType jointype,
Var *l_colvar, Var *r_colvar);
static ParseNamespaceItem *makeNamespaceItem(RangeTblEntry *rte,
static ParseNamespaceItem *makeNamespaceItem(RangeTblEntry *rte, int rtindex,
bool rel_visible, bool cols_visible,
bool lateral_only, bool lateral_ok);
static void setNamespaceColumnVisibility(List *namespace, bool cols_visible);
@ -216,12 +217,15 @@ setTargetTable(ParseState *pstate, RangeVar *relation,
rte = addRangeTableEntryForRelation(pstate, pstate->p_target_relation,
RowExclusiveLock,
relation->alias, inh, false);
pstate->p_target_rangetblentry = rte;
/* assume new rte is at end */
rtindex = list_length(pstate->p_rtable);
Assert(rte == rt_fetch(rtindex, pstate->p_rtable));
/* remember the RTE as being the query target */
pstate->p_target_rangetblentry = rte;
pstate->p_target_rtindex = rtindex;
/*
* Override addRangeTableEntry's default ACL_SELECT permissions check, and
* instead mark target table as requiring exactly the specified
@ -1084,7 +1088,7 @@ transformFromClauseItem(ParseState *pstate, Node *n,
Assert(rte == rt_fetch(rtindex, pstate->p_rtable));
*top_rte = rte;
*top_rti = rtindex;
*namespace = list_make1(makeDefaultNSItem(rte));
*namespace = list_make1(makeDefaultNSItem(rte, rtindex));
rtr = makeNode(RangeTblRef);
rtr->rtindex = rtindex;
return (Node *) rtr;
@ -1102,7 +1106,7 @@ transformFromClauseItem(ParseState *pstate, Node *n,
Assert(rte == rt_fetch(rtindex, pstate->p_rtable));
*top_rte = rte;
*top_rti = rtindex;
*namespace = list_make1(makeDefaultNSItem(rte));
*namespace = list_make1(makeDefaultNSItem(rte, rtindex));
rtr = makeNode(RangeTblRef);
rtr->rtindex = rtindex;
return (Node *) rtr;
@ -1120,7 +1124,7 @@ transformFromClauseItem(ParseState *pstate, Node *n,
Assert(rte == rt_fetch(rtindex, pstate->p_rtable));
*top_rte = rte;
*top_rti = rtindex;
*namespace = list_make1(makeDefaultNSItem(rte));
*namespace = list_make1(makeDefaultNSItem(rte, rtindex));
rtr = makeNode(RangeTblRef);
rtr->rtindex = rtindex;
return (Node *) rtr;
@ -1138,7 +1142,7 @@ transformFromClauseItem(ParseState *pstate, Node *n,
Assert(rte == rt_fetch(rtindex, pstate->p_rtable));
*top_rte = rte;
*top_rti = rtindex;
*namespace = list_make1(makeDefaultNSItem(rte));
*namespace = list_make1(makeDefaultNSItem(rte, rtindex));
rtr = makeNode(RangeTblRef);
rtr->rtindex = rtindex;
return (Node *) rtr;
@ -1481,6 +1485,7 @@ transformFromClauseItem(ParseState *pstate, Node *n,
*/
*namespace = lappend(my_namespace,
makeNamespaceItem(rte,
j->rtindex,
(j->alias != NULL),
true,
false,
@ -1617,13 +1622,15 @@ buildMergedJoinVar(ParseState *pstate, JoinType jointype,
* Convenience subroutine to construct a ParseNamespaceItem.
*/
static ParseNamespaceItem *
makeNamespaceItem(RangeTblEntry *rte, bool rel_visible, bool cols_visible,
makeNamespaceItem(RangeTblEntry *rte, int rtindex,
bool rel_visible, bool cols_visible,
bool lateral_only, bool lateral_ok)
{
ParseNamespaceItem *nsitem;
nsitem = (ParseNamespaceItem *) palloc(sizeof(ParseNamespaceItem));
nsitem->p_rte = rte;
nsitem->p_rtindex = rtindex;
nsitem->p_rel_visible = rel_visible;
nsitem->p_cols_visible = cols_visible;
nsitem->p_lateral_only = lateral_only;