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Apply fixes for problems with dropped columns whose types have also been

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dropped.  The simplest fix for INSERT/UPDATE cases turns out to be for
preptlist.c to insert NULLs of a known-good type (I used INT4) rather
than making them match the deleted column's type.  Since the representation
of NULL is actually datatype-independent, this should work fine.
I also re-reverted the patch to disable the use_physical_tlist optimization
in the presence of dropped columns.  It still doesn't look worth the
trouble to be smarter, if there are no other bugs to fix.
Added a regression test to catch future problems in this area.
This commit is contained in:
Tom Lane
2003-05-12 00:17:03 +00:00
parent a7c50cd92b
commit d97c9b3662
6 changed files with 167 additions and 27 deletions
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8
src/backend/optimizer/plan/createplan.c
View File

@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.141 2003/05/11 20:25:50 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.142 2003/05/12 00:17:03 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -295,6 +295,12 @@ use_physical_tlist(RelOptInfo *rel)
*/
if (rel->reloptkind != RELOPT_BASEREL)
return false;
/*
* Can't do it if relation contains dropped columns. This is detected
* in plancat.c, see notes there.
*/
if (rel->varlist == NIL)
return false;
/*
* Can't do it if any system columns are requested, either. (This could
* possibly be fixed but would take some fragile assumptions in setrefs.c,

58
src/backend/optimizer/prep/preptlist.c
View File

@ -15,7 +15,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/prep/preptlist.c,v 1.60 2003/02/03 21:15:44 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/prep/preptlist.c,v 1.61 2003/05/12 00:17:03 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -171,6 +171,15 @@ expand_targetlist(List *tlist, int command_type,
* the attribute, so that it gets copied to the new tuple. But
* generate a NULL for dropped columns (we want to drop any
* old values).
*
* When generating a NULL constant for a dropped column, we label
* it INT4 (any other guaranteed-to-exist datatype would do as
* well). We can't label it with the dropped column's datatype
* since that might not exist anymore. It does not really
* matter what we claim the type is, since NULL is NULL --- its
* representation is datatype-independent. This could perhaps
* confuse code comparing the finished plan to the target
* relation, however.
*/
Oid atttype = att_tup->atttypid;
int32 atttypmod = att_tup->atttypmod;
@ -179,31 +188,52 @@ expand_targetlist(List *tlist, int command_type,
switch (command_type)
{
case CMD_INSERT:
new_expr = (Node *) makeConst(atttype,
att_tup->attlen,
(Datum) 0,
true, /* isnull */
att_tup->attbyval);
if (!att_tup->attisdropped)
{
new_expr = (Node *) makeConst(atttype,
att_tup->attlen,
(Datum) 0,
true, /* isnull */
att_tup->attbyval);
new_expr = coerce_to_domain(new_expr,
InvalidOid,
atttype,
COERCE_IMPLICIT_CAST);
}
else
{
/* Insert NULL for dropped column */
new_expr = (Node *) makeConst(INT4OID,
sizeof(int32),
(Datum) 0,
true, /* isnull */
true /* byval */);
/* label resdom with INT4, too */
atttype = INT4OID;
atttypmod = -1;
}
break;
case CMD_UPDATE:
/* Insert NULLs for dropped columns */
if (att_tup->attisdropped)
new_expr = (Node *) makeConst(atttype,
att_tup->attlen,
(Datum) 0,
true, /* isnull */
att_tup->attbyval);
else
if (!att_tup->attisdropped)
{
new_expr = (Node *) makeVar(result_relation,
attrno,
atttype,
atttypmod,
0);
}
else
{
/* Insert NULL for dropped column */
new_expr = (Node *) makeConst(INT4OID,
sizeof(int32),
(Datum) 0,
true, /* isnull */
true /* byval */);
/* label resdom with INT4, too */
atttype = INT4OID;
atttypmod = -1;
}
break;
default:
elog(ERROR, "expand_targetlist: unexpected command_type");

20
src/backend/optimizer/util/plancat.c
View File

@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.81 2003/05/11 20:25:50 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.82 2003/05/12 00:17:03 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -62,8 +62,15 @@ get_relation_info(Oid relationObjectId, RelOptInfo *rel)
relation = heap_open(relationObjectId, AccessShareLock);
/*
* Make list of physical Vars. Note we do NOT ignore dropped columns;
* the intent is to model the physical tuples of the relation.
* Make list of physical Vars. But if there are any dropped columns,
* punt and set varlist to NIL. (XXX Ideally we would like to include
* dropped columns so that the varlist models the physical tuples
* of the relation. However this creates problems for ExecTypeFromTL,
* which may be asked to build a tupdesc for a tlist that includes vars
* of no-longer-existent types. In theory we could dig out the required
* info from the pg_attribute entries of the relation, but that data is
* not readily available to ExecTypeFromTL. For now, punt and don't
* apply the physical-tlist optimization when there are dropped cols.)
*/
numattrs = RelationGetNumberOfAttributes(relation);
@ -71,6 +78,13 @@ get_relation_info(Oid relationObjectId, RelOptInfo *rel)
{
Form_pg_attribute att_tup = relation->rd_att->attrs[attrno - 1];
if (att_tup->attisdropped)
{
/* found a dropped col, so punt */
varlist = NIL;
break;
}
varlist = lappend(varlist,
makeVar(varno,
attrno,