From dd3bab5fd74db009c946278bb314c8458a2fef11 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 27 Nov 2011 22:27:24 -0500 Subject: Ensure that whole-row junk Vars are always of composite type. The EvalPlanQual machinery assumes that whole-row Vars generated for the outputs of non-table RTEs will be of composite types. However, for the case where the RTE is a function call returning a scalar type, we were doing the wrong thing, as a result of sharing code with a parser case where the function's scalar output is wanted. (Or at least, that's what that 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 execution of UPDATEs involving joins to the result of UNNEST() --- in READ COMMITTED mode, we'd run the EvalPlanQual machinery after a conflicting row update commits, and it was expecting to get a HeapTuple not a scalar datum from the "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 correct collation 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 --- src/backend/parser/parse_expr.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'src/backend/parser/parse_expr.c') diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index 79328c99797..75236c76a1f 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -2059,8 +2059,15 @@ transformWholeRowRef(ParseState *pstate, RangeTblEntry *rte, int location) /* Find the RTE's rangetable location */ vnum = RTERangeTablePosn(pstate, rte, &sublevels_up); - /* Build the appropriate referencing node */ - result = makeWholeRowVar(rte, vnum, sublevels_up); + /* + * Build the appropriate referencing node. Note that if the RTE is a + * function returning scalar, we create just a plain reference to the + * function value, not a composite containing a single column. This is + * pretty inconsistent at first sight, but it's what we've done + * historically. One argument for it is that "rel" and "rel.*" mean the + * same thing for composite relations, so why not for scalar functions... + */ + result = makeWholeRowVar(rte, vnum, sublevels_up, true); /* location is not filled in by makeWholeRowVar */ result->location = location; -- cgit v1.2.3