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Make the world very nearly safe for composite-type columns in tables.
1. Solve the problem of not having TOAST references hiding inside composite values by establishing the rule that toasting only goes one level deep: a tuple can contain toasted fields, but a composite-type datum that is to be inserted into a tuple cannot. Enforcing this in heap_formtuple is relatively cheap and it avoids a large increase in the cost of running the tuptoaster during final storage of a row. 2. Fix some interesting problems in expansion of inherited queries that reference whole-row variables. We never really did this correctly before, but it's now relatively painless to solve by expanding the parent's whole-row Var into a RowExpr() selecting the proper columns from the child. If you dike out the preventive check in CheckAttributeType(), composite-type columns now seem to actually work. However, we surely cannot ship them like this --- without I/O for composite types, you can't get pg_dump to dump tables containing them. So a little more work still to do.
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12 files changed

+376
-67
lines changed

12 files changed

+376
-67
lines changed

‎src/backend/access/common/heaptuple.c

Lines changed: 29 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@
99
*
1010
*
1111
* IDENTIFICATION
12-
* $PostgreSQL: pgsql/src/backend/access/common/heaptuple.c,v 1.91 2004/06/04 20:35:21 tgl Exp $
12+
* $PostgreSQL: pgsql/src/backend/access/common/heaptuple.c,v 1.92 2004/06/05 01:55:04 tgl Exp $
1313
*
1414
* NOTES
1515
* The old interface functions have been converted to macros
@@ -21,6 +21,7 @@
2121
#include "postgres.h"
2222

2323
#include "access/heapam.h"
24+
#include "access/tuptoaster.h"
2425
#include "catalog/pg_type.h"
2526

2627

@@ -567,8 +568,9 @@ heap_formtuple(TupleDesc tupleDescriptor,
567568
unsigned long len;
568569
int hoff;
569570
bool hasnull = false;
570-
int i;
571+
Form_pg_attribute *att = tupleDescriptor->attrs;
571572
int numberOfAttributes = tupleDescriptor->natts;
573+
int i;
572574

573575
if (numberOfAttributes > MaxTupleAttributeNumber)
574576
ereport(ERROR,
@@ -577,17 +579,34 @@ heap_formtuple(TupleDesc tupleDescriptor,
577579
numberOfAttributes, MaxTupleAttributeNumber)));
578580

579581
/*
580-
* Determine total space needed
582+
* Check for nulls and embedded tuples; expand any toasted attributes
583+
* in embedded tuples. This preserves the invariant that toasting can
584+
* only go one level deep.
585+
*
586+
* We can skip calling toast_flatten_tuple_attribute() if the attribute
587+
* couldn't possibly be of composite type. All composite datums are
588+
* varlena and have alignment 'd'; furthermore they aren't arrays.
589+
* Also, if an attribute is already toasted, it must have been sent to
590+
* disk already and so cannot contain toasted attributes.
581591
*/
582592
for (i = 0; i < numberOfAttributes; i++)
583593
{
584594
if (nulls[i] != ' ')
585-
{
586595
hasnull = true;
587-
break;
596+
else if (att[i]->attlen == -1 &&
597+
att[i]->attalign == 'd' &&
598+
att[i]->attndims == 0 &&
599+
!VARATT_IS_EXTENDED(values[i]))
600+
{
601+
values[i] = toast_flatten_tuple_attribute(values[i],
602+
att[i]->atttypid,
603+
att[i]->atttypmod);
588604
}
589605
}
590606

607+
/*
608+
* Determine total space needed
609+
*/
591610
len = offsetof(HeapTupleHeaderData, t_bits);
592611

593612
if (hasnull)
@@ -744,7 +763,11 @@ heap_deformtuple(HeapTuple tuple,
744763
bool slow = false; /* can we use/set attcacheoff? */
745764

746765
natts = tup->t_natts;
747-
/* This min() operation is pure paranoia */
766+
/*
767+
* In inheritance situations, it is possible that the given tuple actually
768+
* has more fields than the caller is expecting. Don't run off the end
769+
* of the caller's arrays.
770+
*/
748771
natts = Min(natts, tdesc_natts);
749772

750773
tp = (char *) tup + tup->t_hoff;

‎src/backend/access/heap/tuptoaster.c

Lines changed: 128 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.42 2004/06/04 20:35:21 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.43 2004/06/05 01:55:04 tgl Exp $
1212
*
1313
*
1414
* INTERFACE ROUTINES
@@ -35,6 +35,7 @@
3535
#include "utils/builtins.h"
3636
#include "utils/fmgroids.h"
3737
#include "utils/pg_lzcompress.h"
38+
#include "utils/typcache.h"
3839

3940

4041
#undef TOAST_DEBUG
@@ -458,10 +459,10 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
458459
* still in the tuple must be someone else's we cannot reuse.
459460
* Expand it to plain (and, probably, toast it again below).
460461
*/
461-
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i])))
462+
if (VARATT_IS_EXTERNAL(new_value))
462463
{
463-
toast_values[i] = PointerGetDatum(heap_tuple_untoast_attr(
464-
(varattrib *) DatumGetPointer(toast_values[i])));
464+
new_value = heap_tuple_untoast_attr(new_value);
465+
toast_values[i] = PointerGetDatum(new_value);
465466
toast_free[i] = true;
466467
need_change = true;
467468
need_free = true;
@@ -470,7 +471,7 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
470471
/*
471472
* Remember the size of this attribute
472473
*/
473-
toast_sizes[i] = VARATT_SIZE(DatumGetPointer(toast_values[i]));
474+
toast_sizes[i] = VARATT_SIZE(new_value);
474475
}
475476
else
476477
{
@@ -785,6 +786,128 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
785786
}
786787

787788

789+
/* ----------
790+
* toast_flatten_tuple_attribute -
791+
*
792+
* If a Datum is of composite type, "flatten" it to contain no toasted fields.
793+
* This must be invoked on any potentially-composite field that is to be
794+
* inserted into a tuple. Doing this preserves the invariant that toasting
795+
* goes only one level deep in a tuple.
796+
* ----------
797+
*/
798+
Datum
799+
toast_flatten_tuple_attribute(Datum value,
800+
Oid typeId, int32 typeMod)
801+
{
802+
TupleDesc tupleDesc;
803+
HeapTupleHeader olddata;
804+
HeapTupleHeader new_data;
805+
int32 new_len;
806+
HeapTupleData tmptup;
807+
Form_pg_attribute *att;
808+
int numAttrs;
809+
int i;
810+
bool need_change = false;
811+
bool has_nulls = false;
812+
Datum toast_values[MaxTupleAttributeNumber];
813+
char toast_nulls[MaxTupleAttributeNumber];
814+
bool toast_free[MaxTupleAttributeNumber];
815+
816+
/*
817+
* See if it's a composite type, and get the tupdesc if so.
818+
*/
819+
tupleDesc = lookup_rowtype_tupdesc_noerror(typeId, typeMod, true);
820+
if (tupleDesc == NULL)
821+
return value; /* not a composite type */
822+
823+
att = tupleDesc->attrs;
824+
numAttrs = tupleDesc->natts;
825+
826+
/*
827+
* Break down the tuple into fields.
828+
*/
829+
olddata = DatumGetHeapTupleHeader(value);
830+
Assert(typeId == HeapTupleHeaderGetTypeId(olddata));
831+
Assert(typeMod == HeapTupleHeaderGetTypMod(olddata));
832+
/* Build a temporary HeapTuple control structure */
833+
tmptup.t_len = HeapTupleHeaderGetDatumLength(olddata);
834+
ItemPointerSetInvalid(&(tmptup.t_self));
835+
tmptup.t_tableOid = InvalidOid;
836+
tmptup.t_data = olddata;
837+
838+
Assert(numAttrs <= MaxTupleAttributeNumber);
839+
heap_deformtuple(&tmptup, tupleDesc, toast_values, toast_nulls);
840+
841+
memset(toast_free, 0, numAttrs * sizeof(bool));
842+
843+
for (i = 0; i < numAttrs; i++)
844+
{
845+
/*
846+
* Look at non-null varlena attributes
847+
*/
848+
if (toast_nulls[i] == 'n')
849+
has_nulls = true;
850+
else if (att[i]->attlen == -1)
851+
{
852+
varattrib *new_value;
853+
854+
new_value = (varattrib *) DatumGetPointer(toast_values[i]);
855+
if (VARATT_IS_EXTENDED(new_value))
856+
{
857+
new_value = heap_tuple_untoast_attr(new_value);
858+
toast_values[i] = PointerGetDatum(new_value);
859+
toast_free[i] = true;
860+
need_change = true;
861+
}
862+
}
863+
}
864+
865+
/*
866+
* If nothing to untoast, just return the original tuple.
867+
*/
868+
if (!need_change)
869+
return value;
870+
871+
/*
872+
* Calculate the new size of the tuple. Header size should not
873+
* change, but data size might.
874+
*/
875+
new_len = offsetof(HeapTupleHeaderData, t_bits);
876+
if (has_nulls)
877+
new_len += BITMAPLEN(numAttrs);
878+
if (olddata->t_infomask & HEAP_HASOID)
879+
new_len += sizeof(Oid);
880+
new_len = MAXALIGN(new_len);
881+
Assert(new_len == olddata->t_hoff);
882+
new_len += ComputeDataSize(tupleDesc, toast_values, toast_nulls);
883+
884+
new_data = (HeapTupleHeader) palloc0(new_len);
885+
886+
/*
887+
* Put the tuple header and the changed values into place
888+
*/
889+
memcpy(new_data, olddata, olddata->t_hoff);
890+
891+
HeapTupleHeaderSetDatumLength(new_data, new_len);
892+
893+
DataFill((char *) new_data + olddata->t_hoff,
894+
tupleDesc,
895+
toast_values,
896+
toast_nulls,
897+
&(new_data->t_infomask),
898+
has_nulls ? new_data->t_bits : NULL);
899+
900+
/*
901+
* Free allocated temp values
902+
*/
903+
for (i = 0; i < numAttrs; i++)
904+
if (toast_free[i])
905+
pfree(DatumGetPointer(toast_values[i]));
906+
907+
return PointerGetDatum(new_data);
908+
}
909+
910+
788911
/* ----------
789912
* toast_compress_datum -
790913
*

‎src/backend/optimizer/path/allpaths.c

Lines changed: 9 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.117 2004/06/01 03:02:51 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.118 2004/06/05 01:55:04 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -302,11 +302,15 @@ set_inherited_rel_pathlist(Query *root, RelOptInfo *rel,
302302
{
303303
Var *parentvar = (Var *) lfirst(parentvars);
304304
Var *childvar = (Var *) lfirst(childvars);
305-
int parentndx = parentvar->varattno - rel->min_attr;
306-
int childndx = childvar->varattno - childrel->min_attr;
307305

308-
if (childrel->attr_widths[childndx] > rel->attr_widths[parentndx])
309-
rel->attr_widths[parentndx] = childrel->attr_widths[childndx];
306+
if (IsA(parentvar, Var) && IsA(childvar, Var))
307+
{
308+
int pndx = parentvar->varattno - rel->min_attr;
309+
int cndx = childvar->varattno - childrel->min_attr;
310+
311+
if (childrel->attr_widths[cndx] > rel->attr_widths[pndx])
312+
rel->attr_widths[pndx] = childrel->attr_widths[cndx];
313+
}
310314
}
311315
}
312316

‎src/backend/optimizer/path/costsize.c

Lines changed: 10 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -49,7 +49,7 @@
4949
* Portions Copyright (c) 1994, Regents of the University of California
5050
*
5151
* IDENTIFICATION
52-
* $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.129 2004/06/01 03:02:52 tgl Exp $
52+
* $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.130 2004/06/05 01:55:04 tgl Exp $
5353
*
5454
*-------------------------------------------------------------------------
5555
*/
@@ -1704,11 +1704,18 @@ set_rel_width(Query *root, RelOptInfo *rel)
17041704
foreach(tllist, rel->reltargetlist)
17051705
{
17061706
Var *var = (Var *) lfirst(tllist);
1707-
int ndx = var->varattno - rel->min_attr;
1707+
int ndx;
17081708
Oid relid;
17091709
int32 item_width;
17101710

1711-
Assert(IsA(var, Var));
1711+
/* For now, punt on whole-row child Vars */
1712+
if (!IsA(var, Var))
1713+
{
1714+
tuple_width += 32; /* arbitrary */
1715+
continue;
1716+
}
1717+
1718+
ndx = var->varattno - rel->min_attr;
17121719

17131720
/*
17141721
* The width probably hasn't been cached yet, but may as well

‎src/backend/optimizer/path/pathkeys.c

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
1111
* Portions Copyright (c) 1994, Regents of the University of California
1212
*
1313
* IDENTIFICATION
14-
* $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.59 2004/06/01 03:02:52 tgl Exp $
14+
* $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.60 2004/06/05 01:55:04 tgl Exp $
1515
*
1616
*-------------------------------------------------------------------------
1717
*/
@@ -725,7 +725,8 @@ find_indexkey_var(Query *root, RelOptInfo *rel, AttrNumber varattno)
725725
{
726726
Var *var = (Var *) lfirst(temp);
727727

728-
if (var->varattno == varattno)
728+
if (IsA(var, Var) &&
729+
var->varattno == varattno)
729730
return var;
730731
}
731732

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