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Commitdd3bab5

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Ensure that whole-row junk Vars are always of composite type.
The EvalPlanQual machinery assumes that whole-row Vars generated for theoutputs of non-table RTEs will be of composite types. However, for thecase where the RTE is a function call returning a scalar type, we weredoing the wrong thing, as a result of sharing code with a parser casewhere the function's scalar output is wanted. (Or at least, that's whatthat case has done historically; it does seem a bit inconsistent.)To fix, extend makeWholeRowVar's API so that it can support both use-cases.This fixes Belinda Cussen's report of crashes during concurrent executionof UPDATEs involving joins to the result of UNNEST() --- in READ COMMITTEDmode, we'd run the EvalPlanQual machinery after a conflicting row updatecommits, and it was expecting to get a HeapTuple not a scalar datum fromthe "wholerowN" variable referencing the function RTE.Back-patch to 9.0 where the current EvalPlanQual implementation appeared.In 9.1 and up, this patch also fixes failure to attach the correctcollation to the Var generated for a scalar-result case. An example:regression=# select upper(x.*) from textcat('ab', 'cd') x;ERROR: could not determine which collation to use for upper() function
1 parent91572ee commitdd3bab5

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5 files changed

+38
-27
lines changed

5 files changed

+38
-27
lines changed

‎src/backend/nodes/makefuncs.c

Lines changed: 23 additions & 22 deletions
Original file line numberDiff line numberDiff line change
@@ -121,11 +121,17 @@ makeVarFromTargetEntry(Index varno,
121121
* with error cases, but it's not worth changing now.) The vartype indicates
122122
* a rowtype; either a named composite type, or RECORD. This function
123123
* encapsulates the logic for determining the correct rowtype OID to use.
124+
*
125+
* If allowScalar is true, then for the case where the RTE is a function
126+
* returning a non-composite result type, we produce a normal Var referencing
127+
* the function's result directly, instead of the single-column composite
128+
* value that the whole-row notation might otherwise suggest.
124129
*/
125130
Var*
126131
makeWholeRowVar(RangeTblEntry*rte,
127132
Indexvarno,
128-
Indexvarlevelsup)
133+
Indexvarlevelsup,
134+
boolallowScalar)
129135
{
130136
Var*result;
131137
Oidtoid;
@@ -157,39 +163,34 @@ makeWholeRowVar(RangeTblEntry *rte,
157163
InvalidOid,
158164
varlevelsup);
159165
}
160-
else
166+
elseif (allowScalar)
161167
{
162-
/*
163-
* func returns scalar; instead of making a whole-row Var,
164-
* just reference the function's scalar output. (XXX this
165-
* seems a tad inconsistent, especially if "f.*" was
166-
* explicitly written ...)
167-
*/
168+
/* func returns scalar; just return its output as-is */
168169
result=makeVar(varno,
169170
1,
170171
toid,
171172
-1,
173+
exprCollation(rte->funcexpr),
174+
varlevelsup);
175+
}
176+
else
177+
{
178+
/* func returns scalar, but we want a composite result */
179+
result=makeVar(varno,
180+
InvalidAttrNumber,
181+
RECORDOID,
182+
-1,
172183
InvalidOid,
173184
varlevelsup);
174185
}
175186
break;
176-
caseRTE_VALUES:
177-
toid=RECORDOID;
178-
/* returns composite; same as relation case */
179-
result=makeVar(varno,
180-
InvalidAttrNumber,
181-
toid,
182-
-1,
183-
InvalidOid,
184-
varlevelsup);
185-
break;
186187
default:
187188

188189
/*
189-
* RTE is a joinorsubselect.We represent this as a whole-row
190-
* Var of RECORD type.(Note that in most cases the Var will be
191-
* expanded to a RowExpr during planning, but that is not our
192-
* concern here.)
190+
* RTE is a join, subselect,orVALUES.We represent this as a
191+
*whole-rowVar of RECORD type.(Note that in most cases the Var
192+
*will beexpanded to a RowExpr during planning, but that is not
193+
*ourconcern here.)
193194
*/
194195
result=makeVar(varno,
195196
InvalidAttrNumber,

‎src/backend/optimizer/prep/preptlist.c

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -129,7 +129,8 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
129129
/* Not a table, so we need the whole row as a junk var */
130130
var=makeWholeRowVar(rt_fetch(rc->rti,range_table),
131131
rc->rti,
132-
0);
132+
0,
133+
false);
133134
snprintf(resname,sizeof(resname),"wholerow%u",rc->rowmarkId);
134135
tle=makeTargetEntry((Expr*)var,
135136
list_length(tlist)+1,

‎src/backend/parser/parse_expr.c

Lines changed: 9 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -2059,8 +2059,15 @@ transformWholeRowRef(ParseState *pstate, RangeTblEntry *rte, int location)
20592059
/* Find the RTE's rangetable location */
20602060
vnum=RTERangeTablePosn(pstate,rte,&sublevels_up);
20612061

2062-
/* Build the appropriate referencing node */
2063-
result=makeWholeRowVar(rte,vnum,sublevels_up);
2062+
/*
2063+
* Build the appropriate referencing node. Note that if the RTE is a
2064+
* function returning scalar, we create just a plain reference to the
2065+
* function value, not a composite containing a single column. This is
2066+
* pretty inconsistent at first sight, but it's what we've done
2067+
* historically. One argument for it is that "rel" and "rel.*" mean the
2068+
* same thing for composite relations, so why not for scalar functions...
2069+
*/
2070+
result=makeWholeRowVar(rte,vnum,sublevels_up, true);
20642071

20652072
/* location is not filled in by makeWholeRowVar */
20662073
result->location=location;

‎src/backend/rewrite/rewriteHandler.c

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1188,7 +1188,8 @@ rewriteTargetListUD(Query *parsetree, RangeTblEntry *target_rte,
11881188
*/
11891189
var=makeWholeRowVar(target_rte,
11901190
parsetree->resultRelation,
1191-
0);
1191+
0,
1192+
false);
11921193

11931194
attrname="wholerow";
11941195
}

‎src/include/nodes/makefuncs.h

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -35,7 +35,8 @@ extern Var *makeVarFromTargetEntry(Index varno,
3535

3636
externVar*makeWholeRowVar(RangeTblEntry*rte,
3737
Indexvarno,
38-
Indexvarlevelsup);
38+
Indexvarlevelsup,
39+
boolallowScalar);
3940

4041
externTargetEntry*makeTargetEntry(Expr*expr,
4142
AttrNumberresno,

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