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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
View File

@@ -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;

133
src/backend/access/heap/tuptoaster.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.42 2004/06/04 20:35:21 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.43 2004/06/05 01:55:04 tgl Exp $
*
*
* INTERFACE ROUTINES
@@ -35,6 +35,7 @@
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/pg_lzcompress.h"
#include "utils/typcache.h"
#undef TOAST_DEBUG
@@ -458,10 +459,10 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
* still in the tuple must be someone else's we cannot reuse.
* Expand it to plain (and, probably, toast it again below).
*/
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i])))
if (VARATT_IS_EXTERNAL(new_value))
{
toast_values[i] = PointerGetDatum(heap_tuple_untoast_attr(
(varattrib *) DatumGetPointer(toast_values[i])));
new_value = heap_tuple_untoast_attr(new_value);
toast_values[i] = PointerGetDatum(new_value);
toast_free[i] = true;
need_change = true;
need_free = true;
@@ -470,7 +471,7 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
/*
* Remember the size of this attribute
*/
toast_sizes[i] = VARATT_SIZE(DatumGetPointer(toast_values[i]));
toast_sizes[i] = VARATT_SIZE(new_value);
}
else
{
@@ -785,6 +786,128 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
}
/* ----------
* toast_flatten_tuple_attribute -
*
* If a Datum is of composite type, "flatten" it to contain no toasted fields.
* This must be invoked on any potentially-composite field that is to be
* inserted into a tuple. Doing this preserves the invariant that toasting
* goes only one level deep in a tuple.
* ----------
*/
Datum
toast_flatten_tuple_attribute(Datum value,
Oid typeId, int32 typeMod)
{
TupleDesc tupleDesc;
HeapTupleHeader olddata;
HeapTupleHeader new_data;
int32 new_len;
HeapTupleData tmptup;
Form_pg_attribute *att;
int numAttrs;
int i;
bool need_change = false;
bool has_nulls = false;
Datum toast_values[MaxTupleAttributeNumber];
char toast_nulls[MaxTupleAttributeNumber];
bool toast_free[MaxTupleAttributeNumber];
/*
* See if it's a composite type, and get the tupdesc if so.
*/
tupleDesc = lookup_rowtype_tupdesc_noerror(typeId, typeMod, true);
if (tupleDesc == NULL)
return value; /* not a composite type */
att = tupleDesc->attrs;
numAttrs = tupleDesc->natts;
/*
* Break down the tuple into fields.
*/
olddata = DatumGetHeapTupleHeader(value);
Assert(typeId == HeapTupleHeaderGetTypeId(olddata));
Assert(typeMod == HeapTupleHeaderGetTypMod(olddata));
/* Build a temporary HeapTuple control structure */
tmptup.t_len = HeapTupleHeaderGetDatumLength(olddata);
ItemPointerSetInvalid(&(tmptup.t_self));
tmptup.t_tableOid = InvalidOid;
tmptup.t_data = olddata;
Assert(numAttrs <= MaxTupleAttributeNumber);
heap_deformtuple(&tmptup, tupleDesc, toast_values, toast_nulls);
memset(toast_free, 0, numAttrs * sizeof(bool));
for (i = 0; i < numAttrs; i++)
{
/*
* Look at non-null varlena attributes
*/
if (toast_nulls[i] == 'n')
has_nulls = true;
else if (att[i]->attlen == -1)
{
varattrib *new_value;
new_value = (varattrib *) DatumGetPointer(toast_values[i]);
if (VARATT_IS_EXTENDED(new_value))
{
new_value = heap_tuple_untoast_attr(new_value);
toast_values[i] = PointerGetDatum(new_value);
toast_free[i] = true;
need_change = true;
}
}
}
/*
* If nothing to untoast, just return the original tuple.
*/
if (!need_change)
return value;
/*
* Calculate the new size of the tuple. Header size should not
* change, but data size might.
*/
new_len = offsetof(HeapTupleHeaderData, t_bits);
if (has_nulls)
new_len += BITMAPLEN(numAttrs);
if (olddata->t_infomask & HEAP_HASOID)
new_len += sizeof(Oid);
new_len = MAXALIGN(new_len);
Assert(new_len == olddata->t_hoff);
new_len += ComputeDataSize(tupleDesc, toast_values, toast_nulls);
new_data = (HeapTupleHeader) palloc0(new_len);
/*
* Put the tuple header and the changed values into place
*/
memcpy(new_data, olddata, olddata->t_hoff);
HeapTupleHeaderSetDatumLength(new_data, new_len);
DataFill((char *) new_data + olddata->t_hoff,
tupleDesc,
toast_values,
toast_nulls,
&(new_data->t_infomask),
has_nulls ? new_data->t_bits : NULL);
/*
* Free allocated temp values
*/
for (i = 0; i < numAttrs; i++)
if (toast_free[i])
pfree(DatumGetPointer(toast_values[i]));
return PointerGetDatum(new_data);
}
/* ----------
* toast_compress_datum -
*