Avoid an Assert failure in deconstruct_array() by making get_attstatsslot()

use the actual element type of the array it's disassembling, rather than
trusting the type OID passed in by its caller.  This is needed because
sometimes the planner passes in a type OID that's only binary-compatible
with the target column's type, rather than being an exact match.  Per an
example from Bernd Helmle.

Possibly we should refactor get_attstatsslot/free_attstatsslot to not expect
the caller to supply type ID data at all, but for now I'll just do the
minimum-change fix.

Back-patch to 7.4.  Bernd's test case only crashes back to 8.0, but since
these subroutines are the same in 7.4, I suspect there may be variant
cases that would crash 7.4 as well.
This commit is contained in:
Tom Lane 2010-07-09 22:57:47 +00:00
parent e5b8e868cd
commit 8e60c2423a

View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.170 2010/04/24 16:20:32 sriggs Exp $
* $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.170.2.1 2010/07/09 22:57:47 tgl Exp $
*
* NOTES
* Eventually, the index information should go through here, too.
@ -2463,6 +2463,10 @@ get_attavgwidth(Oid relid, AttrNumber attnum)
* If the attribute type is pass-by-reference, the values referenced by
* the values array are themselves palloc'd. The palloc'd stuff can be
* freed by calling free_attstatsslot.
*
* Note: at present, atttype/atttypmod aren't actually used here at all.
* But the caller must have the correct (or at least binary-compatible)
* type ID to pass to free_attstatsslot later.
*/
bool
get_attstatsslot(HeapTuple statstuple,
@ -2478,6 +2482,7 @@ get_attstatsslot(HeapTuple statstuple,
Datum val;
bool isnull;
ArrayType *statarray;
Oid arrayelemtype;
int narrayelem;
HeapTuple typeTuple;
Form_pg_type typeForm;
@ -2503,15 +2508,22 @@ get_attstatsslot(HeapTuple statstuple,
elog(ERROR, "stavalues is null");
statarray = DatumGetArrayTypeP(val);
/* Need to get info about the array element type */
typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(atttype));
/*
* Need to get info about the array element type. We look at the
* actual element type embedded in the array, which might be only
* binary-compatible with the passed-in atttype. The info we
* extract here should be the same either way, but deconstruct_array
* is picky about having an exact type OID match.
*/
arrayelemtype = ARR_ELEMTYPE(statarray);
typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(arrayelemtype));
if (!HeapTupleIsValid(typeTuple))
elog(ERROR, "cache lookup failed for type %u", atttype);
elog(ERROR, "cache lookup failed for type %u", arrayelemtype);
typeForm = (Form_pg_type) GETSTRUCT(typeTuple);
/* Deconstruct array into Datum elements; NULLs not expected */
deconstruct_array(statarray,
atttype,
arrayelemtype,
typeForm->typlen,
typeForm->typbyval,
typeForm->typalign,