Hello,
according to my mentor's suggestion, I send first PoC patch of
"RETURNING AFTER/BEFORE" statement. Some info:
- it is early version - more hack PoC than RC patch
- AFTER in this version works as decribed before but it returns row
after update but before post-update before (to be fixed or switch with
current "*" behaviour - I don't know yet)
- patch passes all regression tests
- the code is uncommented already, to be fixed
I'm not sure what may fail so you use it on your risk ;)
Regards,
Karol
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index b2183f4..2698535 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2351,6 +2351,7 @@ _outRangeTblEntry(StringInfo str, const RangeTblEntry *node)
switch (node->rtekind)
{
case RTE_RELATION:
+ case RTE_BEFORE:
WRITE_OID_FIELD(relid);
WRITE_CHAR_FIELD(relkind);
break;
diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index 3a16e9d..04931ee 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -1189,6 +1189,7 @@ _readRangeTblEntry(void)
switch (local_node->rtekind)
{
case RTE_RELATION:
+ case RTE_BEFORE:
READ_OID_FIELD(relid);
READ_CHAR_FIELD(relkind);
break;
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 839ed9d..7fc6ea1 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -174,9 +174,16 @@ add_vars_to_targetlist(PlannerInfo *root, List *vars,
if (IsA(node, Var))
{
Var *var = (Var *) node;
- RelOptInfo *rel = find_base_rel(root, var->varno);
+ RelOptInfo *rel;
int attno = var->varattno;
+ RangeTblEntry *rte;
+ if (root->parse->commandType == CMD_UPDATE){
+ rte = ((RangeTblEntry *) list_nth(root->parse->rtable, (var->varno)-1));
+ if(rte->rtekind == RTE_BEFORE)
+ continue;
+ }
+ rel = find_base_rel(root, var->varno);
Assert(attno >= rel->min_attr && attno <= rel->max_attr);
attno -= rel->min_attr;
if (rel->attr_needed[attno] == NULL)
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index d80c264..77b0c38 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -1989,6 +1989,9 @@ preprocess_rowmarks(PlannerInfo *root)
if (rte->relkind == RELKIND_FOREIGN_TABLE)
continue;
+ if (rte->relkind == RELKIND_BEFORE)
+ continue;
+
rels = bms_del_member(rels, rc->rti);
newrc = makeNode(PlanRowMark);
@@ -2028,6 +2031,9 @@ preprocess_rowmarks(PlannerInfo *root)
if (!bms_is_member(i, rels))
continue;
+ if (rte->relkind == RELKIND_BEFORE)
+ continue;
+
newrc = makeNode(PlanRowMark);
newrc->rti = newrc->prti = i;
newrc->rowmarkId = ++(root->glob->lastRowMarkId);
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index b78d727..6828a7d 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -1691,6 +1691,12 @@ fix_join_expr_mutator(Node *node, fix_join_expr_context *context)
if (IsA(node, Var))
{
Var *var = (Var *) node;
+ if (var->varno<=list_length(context->root->parse->rtable) && var->varno>1 && context->root->parse->commandType == CMD_UPDATE){
+ RangeTblEntry *rte_a,*rte_b;
+ rte_a = (RangeTblEntry *)list_nth(context->root->parse->rtable,var->varno-1);
+ rte_b = (RangeTblEntry *)list_nth(context->root->parse->rtable,var->varno-2);
+ if (rte_a->rtekind == RTE_BEFORE && rte_b->rtekind == RTE_BEFORE) var->varno-=1;
+ }
/* First look for the var in the input tlists */
newvar = search_indexed_tlist_for_var(var,
@@ -1892,6 +1898,37 @@ fix_upper_expr_mutator(Node *node, fix_upper_expr_context *context)
*
* Note: resultRelation is not yet adjusted by rtoffset.
*/
+
+void fix_varno_varattno(List *rlist, int begin, int bef, int aft){
+ ListCell *temp;
+ ListCell *temp2;
+ Var *var;
+ foreach(temp, rlist){
+ TargetEntry *tle = (TargetEntry *)lfirst(temp);
+
+ if(IsA(tle, TargetEntry)){
+ var = (Var*)tle->expr;
+ }else if(IsA(tle, Var)) var=(Var*)tle;
+ if( IsA(var, Var) ){
+ if(var->varnoold == bef){
+ var->varno = OUTER_VAR;
+ var->varattno = var->varoattno + begin;
+ }
+ else if(var->varnoold == aft)
+ {
+ var->varno = OUTER_VAR;
+ var->varattno = var->varoattno;
+ }
+ }
+ else if( IsA(var, OpExpr )){
+ fix_varno_varattno(((OpExpr*)var)->args, begin, bef, aft);
+ }
+ else if( IsA(var, FuncExpr )){
+ fix_varno_varattno(((FuncExpr*)var)->args, begin, bef, aft);
+ }
+ }
+}
+
static List *
set_returning_clause_references(PlannerInfo *root,
List *rlist,
@@ -1900,7 +1937,48 @@ set_returning_clause_references(PlannerInfo *root,
int rtoffset)
{
indexed_tlist *itlist;
+ int before_index=0, after_index=0, var_index=0;
+ Query *parse = root->parse;
+
+ ListCell *rt;
+ RangeTblEntry *bef;
+ TargetEntry *tr;
+
+ int index_rel=1;
+ int index_var=0;
+
+
+ foreach(rt,parse->rtable)
+ {
+ bef = (RangeTblEntry *)lfirst(rt);
+ if(strcmp(bef->eref->aliasname,"before") == 0 && bef->rtekind == RTE_BEFORE )
+ {
+ before_index = index_rel;
+ }
+ else if(strcmp(bef->eref->aliasname,"after") == 0 && bef->rtekind == RTE_BEFORE )
+ {
+ after_index = index_rel;
+ }
+ index_rel++;
+ }
+
+ foreach(rt, topplan->targetlist)
+ {
+ Var *var;
+ tr = (TargetEntry*)lfirst(rt);
+ var = tr->expr;
+ if(IsA(var,Var))
+ {
+ if(var->varnoold == before_index && var->varattno == 1)
+ {
+ var_index = index_var;
+ break;
+ }
+ }
+
+ index_var++;
+ }
/*
* We can perform the desired Var fixup by abusing the fix_join_expr
* machinery that formerly handled inner indexscan fixup. We search the
@@ -1924,6 +2002,9 @@ set_returning_clause_references(PlannerInfo *root,
resultRelation,
rtoffset);
+
+
+ fix_varno_varattno(rlist, var_index, before_index, after_index);
pfree(itlist);
return rlist;
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 5284293..5e3f06d 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -648,6 +648,9 @@ pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
int varno = ((RangeTblRef *) jtnode)->rtindex;
RangeTblEntry *rte = rt_fetch(varno, root->parse->rtable);
+ if (rte->rtekind == RTE_BEFORE)
+ return NULL;
+
/*
* Is this a subquery RTE, and if so, is the subquery simple enough to
* pull up?
@@ -753,6 +756,35 @@ pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
return jtnode;
}
+void prepare_returning_before(PlannerInfo *root, List *ret, int varno)
+{
+ ListCell *v;
+ Var *var;
+ List *rtable = root->parse->rtable;
+ RangeTblEntry *rte;
+ TargetEntry *target;
+ foreach(v,ret)
+ {
+ target = (TargetEntry*)lfirst(v);
+ if(IsA(target,TargetEntry))
+ {
+ var = (Var*)target->expr;
+ if(IsA(var,Var))
+ {
+ if (var->varno <= list_length(rtable))
+ {
+ rte = (RangeTblEntry*)list_nth(rtable,var->varno-1);
+ if(rte->rtekind == RTE_BEFORE)
+ {
+ var->varno=varno;
+ }
+ }
+
+ }
+ }
+ }
+}
+
/*
* pull_up_simple_subquery
* Attempt to pull up a single simple subquery.
@@ -912,6 +944,8 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
*/
parse->targetList = (List *)
pullup_replace_vars((Node *) parse->targetList, &rvcontext);
+
+ prepare_returning_before(root,parse->returningList,varno);
parse->returningList = (List *)
pullup_replace_vars((Node *) parse->returningList, &rvcontext);
replace_vars_in_jointree((Node *) parse->jointree, &rvcontext,
diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c
index 8ee5671..28c5ff7 100644
--- a/src/backend/optimizer/util/relnode.c
+++ b/src/backend/optimizer/util/relnode.c
@@ -135,6 +135,8 @@ build_simple_rel(PlannerInfo *root, int relid, RelOptKind reloptkind)
/* Table --- retrieve statistics from the system catalogs */
get_relation_info(root, rte->relid, rte->inh, rel);
break;
+ case RTE_BEFORE:
+ break;
case RTE_SUBQUERY:
case RTE_FUNCTION:
case RTE_VALUES:
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 16ff234..fd51a0e 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -2003,6 +2003,9 @@ transformReturningList(ParseState *pstate, List *returningList)
save_next_resno = pstate->p_next_resno;
pstate->p_next_resno = 1;
+ if (pstate->p_is_update)
+ addAliases(pstate);
+
/* transform RETURNING identically to a SELECT targetlist */
rlist = transformTargetList(pstate, returningList, EXPR_KIND_RETURNING);
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index cbfb431..bcc3f91 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -85,7 +85,54 @@ static WindowClause *findWindowClause(List *wclist, const char *name);
static Node *transformFrameOffset(ParseState *pstate, int frameOptions,
Node *clause);
+extern void addAliases(ParseState *pstate);
+void addAliases(ParseState *pstate){
+ const int noal = 2;
+ char *aliases[] = {"before","after"};
+ int i;
+ ListCell *l;
+ ParseNamespaceItem *nsitem;
+ RangeTblEntry *rte = NULL;
+
+ foreach(l, pstate->p_namespace)
+ {
+ nsitem = (ParseNamespaceItem *) lfirst(l);
+ 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;
+
+ for(i=0 ; i<noal; i++){
+ if (aliases[i])
+ if (strcmp(rte->eref->aliasname, aliases[i]) == 0)
+ {
+ aliases[i] = NULL;
+ }
+ }
+ }
+
+ l = pstate->p_namespace->head;
+ nsitem = (ParseNamespaceItem *) lfirst(l);
+
+ for(i=0 ; i<noal; i++){
+ if (aliases[i])
+ {
+ rte = makeNode(RangeTblEntry);
+ rte->eref = makeAlias(aliases[i], nsitem->p_rte->eref->colnames);
+ rte->inh = INH_NO;
+ rte->rtekind = RTE_BEFORE;
+ rte->relkind = RELKIND_BEFORE;
+ rte->relid = nsitem->p_rte->relid;
+ pstate->p_rtable = lappend(pstate->p_rtable, rte);
+ addRTEtoQuery(pstate, rte, true, true, false);
+ }
+ }
+}
/*
* transformFromClause -
* Process the FROM clause and add items to the query's range table,
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index a9254c8..e57fccf 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -1658,6 +1658,7 @@ expandRTE(RangeTblEntry *rte, int rtindex, int sublevels_up,
switch (rte->rtekind)
{
case RTE_RELATION:
+ case RTE_BEFORE:
/* Ordinary relation RTE */
expandRelation(rte->relid, rte->eref,
rtindex, sublevels_up, location,
@@ -2113,6 +2114,7 @@ get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,
switch (rte->rtekind)
{
case RTE_RELATION:
+ case RTE_BEFORE:
{
/* Plain relation RTE --- get the attribute's type info */
HeapTuple tp;
@@ -2273,6 +2275,7 @@ get_rte_attribute_is_dropped(RangeTblEntry *rte, AttrNumber attnum)
switch (rte->rtekind)
{
case RTE_RELATION:
+ case RTE_BEFORE:
{
/*
* Plain relation RTE --- get the attribute's catalog entry
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index 49c4f6f..1b09994 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -154,6 +154,7 @@ DESCR("");
#define RELKIND_COMPOSITE_TYPE 'c' /* composite type */
#define RELKIND_FOREIGN_TABLE 'f' /* foreign table */
#define RELKIND_MATVIEW 'm' /* materialized view */
+#define RELKIND_BEFORE 'b' /* virtual table for before/after statements */
#define RELPERSISTENCE_PERMANENT 'p' /* regular table */
#define RELPERSISTENCE_UNLOGGED 'u' /* unlogged permanent table */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index de22dff..fa5083c 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -698,7 +698,8 @@ typedef enum RTEKind
RTE_JOIN, /* join */
RTE_FUNCTION, /* function in FROM */
RTE_VALUES, /* VALUES (<exprlist>), (<exprlist>), ... */
- RTE_CTE /* common table expr (WITH list element) */
+ RTE_CTE, /* common table expr (WITH list element) */
+ RTE_BEFORE /* for before/after statements */
} RTEKind;
typedef struct RangeTblEntry
diff --git a/src/include/parser/parse_clause.h b/src/include/parser/parse_clause.h
index 9bdb033..67cbbb2 100644
--- a/src/include/parser/parse_clause.h
+++ b/src/include/parser/parse_clause.h
@@ -44,5 +44,6 @@ extern List *transformDistinctOnClause(ParseState *pstate, List *distinctlist,
extern Index assignSortGroupRef(TargetEntry *tle, List *tlist);
extern bool targetIsInSortList(TargetEntry *tle, Oid sortop, List *sortList);
+extern void addAliases(ParseState *pstate);
#endif /* PARSE_CLAUSE_H */
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