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Make the world very nearly safe for composite-type columns in tables.

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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.
This commit is contained in:
Tom Lane
2004-06-05 01:55:05 +00:00
parent 8f2ea8b7b5
commit ae93e5fd6e
12 changed files with 376 additions and 67 deletions
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35
src/backend/access/common/heaptuple.c
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@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/common/heaptuple.c,v 1.91 2004/06/04 20:35:21 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/common/heaptuple.c,v 1.92 2004/06/05 01:55:04 tgl Exp $
*
* NOTES
* The old interface functions have been converted to macros
@ -21,6 +21,7 @@
#include "postgres.h"
#include "access/heapam.h"
#include "access/tuptoaster.h"
#include "catalog/pg_type.h"
@ -567,8 +568,9 @@ heap_formtuple(TupleDesc tupleDescriptor,
unsigned long len;
int hoff;
bool hasnull = false;
int i;
Form_pg_attribute *att = tupleDescriptor->attrs;
int numberOfAttributes = tupleDescriptor->natts;
int i;
if (numberOfAttributes > MaxTupleAttributeNumber)
ereport(ERROR,
@ -577,17 +579,34 @@ heap_formtuple(TupleDesc tupleDescriptor,
numberOfAttributes, MaxTupleAttributeNumber)));
/*
* Determine total space needed
* Check for nulls and embedded tuples; expand any toasted attributes
* in embedded tuples. This preserves the invariant that toasting can
* only go one level deep.
*
* We can skip calling toast_flatten_tuple_attribute() if the attribute
* couldn't possibly be of composite type. All composite datums are
* varlena and have alignment 'd'; furthermore they aren't arrays.
* Also, if an attribute is already toasted, it must have been sent to
* disk already and so cannot contain toasted attributes.
*/
for (i = 0; i < numberOfAttributes; i++)
{
if (nulls[i] != ' ')
{
hasnull = true;
break;
else if (att[i]->attlen == -1 &&
att[i]->attalign == 'd' &&
att[i]->attndims == 0 &&
!VARATT_IS_EXTENDED(values[i]))
{
values[i] = toast_flatten_tuple_attribute(values[i],
att[i]->atttypid,
att[i]->atttypmod);
}
}
/*
* Determine total space needed
*/
len = offsetof(HeapTupleHeaderData, t_bits);
if (hasnull)
@ -744,7 +763,11 @@ heap_deformtuple(HeapTuple tuple,
bool slow = false; /* can we use/set attcacheoff? */
natts = tup->t_natts;
/* This min() operation is pure paranoia */
/*
* In inheritance situations, it is possible that the given tuple actually
* has more fields than the caller is expecting. Don't run off the end
* of the caller's arrays.
*/
natts = Min(natts, tdesc_natts);
tp = (char *) tup + tup->t_hoff;