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Resurrect heap_deformtuple(), this time implemented as a singly nested

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loop over the fields instead of a loop around heap_getattr.  This is
considerably faster (O(N) instead of O(N^2)) when there are nulls or
varlena fields, since those prevent use of attcacheoff.  Replace loops
over heap_getattr with heap_deformtuple in situations where all or most
of the fields have to be fetched, such as printtup and tuptoaster.
Profiling done more than a year ago shows that this should be a nice
win for situations involving many-column tables.
This commit is contained in:
Tom Lane
2004-06-04 20:35:21 +00:00
parent af44cac6ef
commit 8f2ea8b7b5
8 changed files with 313 additions and 207 deletions
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70
src/backend/access/heap/tuptoaster.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.41 2003/11/29 19:51:40 pgsql Exp $
* $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.42 2004/06/04 20:35:21 tgl Exp $
*
*
* INTERFACE ROUTINES
@ -281,15 +281,26 @@ toast_delete(Relation rel, HeapTuple oldtup)
Form_pg_attribute *att;
int numAttrs;
int i;
Datum value;
bool isnull;
Datum toast_values[MaxHeapAttributeNumber];
char toast_nulls[MaxHeapAttributeNumber];
/*
* Get the tuple descriptor, the number of and attribute descriptors.
* Get the tuple descriptor and break down the tuple into fields.
*
* NOTE: it's debatable whether to use heap_deformtuple() here or
* just heap_getattr() only the varlena columns. The latter could
* win if there are few varlena columns and many non-varlena ones.
* However, heap_deformtuple costs only O(N) while the heap_getattr
* way would cost O(N^2) if there are many varlena columns, so it
* seems better to err on the side of linear cost. (We won't even
* be here unless there's at least one varlena column, by the way.)
*/
tupleDesc = rel->rd_att;
numAttrs = tupleDesc->natts;
att = tupleDesc->attrs;
numAttrs = tupleDesc->natts;
Assert(numAttrs <= MaxHeapAttributeNumber);
heap_deformtuple(oldtup, tupleDesc, toast_values, toast_nulls);
/*
* Check for external stored attributes and delete them from the
@ -299,8 +310,9 @@ toast_delete(Relation rel, HeapTuple oldtup)
{
if (att[i]->attlen == -1)
{
value = heap_getattr(oldtup, i + 1, tupleDesc, &isnull);
if (!isnull && VARATT_IS_EXTERNAL(value))
Datum value = toast_values[i];
if (toast_nulls[i] != 'n' && VARATT_IS_EXTERNAL(value))
toast_delete_datum(rel, value);
}
}
@ -321,8 +333,6 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
Form_pg_attribute *att;
int numAttrs;
int i;
bool old_isnull;
bool new_isnull;
bool need_change = false;
bool need_free = false;
@ -333,18 +343,24 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
char toast_action[MaxHeapAttributeNumber];
char toast_nulls[MaxHeapAttributeNumber];
char toast_oldnulls[MaxHeapAttributeNumber];
Datum toast_values[MaxHeapAttributeNumber];
Datum toast_oldvalues[MaxHeapAttributeNumber];
int32 toast_sizes[MaxHeapAttributeNumber];
bool toast_free[MaxHeapAttributeNumber];
bool toast_delold[MaxHeapAttributeNumber];
/*
* Get the tuple descriptor, the number of and attribute descriptors
* and the location of the tuple values.
* Get the tuple descriptor and break down the tuple(s) into fields.
*/
tupleDesc = rel->rd_att;
numAttrs = tupleDesc->natts;
att = tupleDesc->attrs;
numAttrs = tupleDesc->natts;
Assert(numAttrs <= MaxHeapAttributeNumber);
heap_deformtuple(newtup, tupleDesc, toast_values, toast_nulls);
if (oldtup != NULL)
heap_deformtuple(oldtup, tupleDesc, toast_oldvalues, toast_oldnulls);
/* ----------
* Then collect information about the values given
@ -353,12 +369,15 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
* ' ' default handling
* 'p' already processed --- don't touch it
* 'x' incompressible, but OK to move off
*
* NOTE: toast_sizes[i] is only made valid for varlena attributes with
* toast_action[i] different from 'p'.
* ----------
*/
memset(toast_action, ' ', numAttrs * sizeof(char));
memset(toast_nulls, ' ', numAttrs * sizeof(char));
memset(toast_free, 0, numAttrs * sizeof(bool));
memset(toast_delold, 0, numAttrs * sizeof(bool));
for (i = 0; i < numAttrs; i++)
{
varattrib *old_value;
@ -369,27 +388,24 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
/*
* For UPDATE get the old and new values of this attribute
*/
old_value = (varattrib *) DatumGetPointer(
heap_getattr(oldtup, i + 1, tupleDesc, &old_isnull));
toast_values[i] =
heap_getattr(newtup, i + 1, tupleDesc, &new_isnull);
old_value = (varattrib *) DatumGetPointer(toast_oldvalues[i]);
new_value = (varattrib *) DatumGetPointer(toast_values[i]);
/*
* If the old value is an external stored one, check if it has
* changed so we have to delete it later.
*/
if (!old_isnull && att[i]->attlen == -1 &&
if (att[i]->attlen == -1 && toast_oldnulls[i] != 'n' &&
VARATT_IS_EXTERNAL(old_value))
{
if (new_isnull || !VARATT_IS_EXTERNAL(new_value) ||
if (toast_nulls[i] == 'n' || !VARATT_IS_EXTERNAL(new_value) ||
old_value->va_content.va_external.va_valueid !=
new_value->va_content.va_external.va_valueid ||
old_value->va_content.va_external.va_toastrelid !=
new_value->va_content.va_external.va_toastrelid)
{
/*
* The old external store value isn't needed any more
* The old external stored value isn't needed any more
* after the update
*/
toast_delold[i] = true;
@ -413,23 +429,21 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
/*
* For INSERT simply get the new value
*/
toast_values[i] =
heap_getattr(newtup, i + 1, tupleDesc, &new_isnull);
new_value = (varattrib *) DatumGetPointer(toast_values[i]);
}
/*
* Handle NULL attributes
*/
if (new_isnull)
if (toast_nulls[i] == 'n')
{
toast_action[i] = 'p';
toast_nulls[i] = 'n';
has_nulls = true;
continue;
}
/*
* Now look at varsize attributes
* Now look at varlena attributes
*/
if (att[i]->attlen == -1)
{
@ -461,10 +475,9 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
else
{
/*
* Not a variable size attribute, plain storage always
* Not a varlena attribute, plain storage always
*/
toast_action[i] = 'p';
toast_sizes[i] = att[i]->attlen;
}
}
@ -768,8 +781,7 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup)
if (need_delold)
for (i = 0; i < numAttrs; i++)
if (toast_delold[i])
toast_delete_datum(rel,
heap_getattr(oldtup, i + 1, tupleDesc, &old_isnull));
toast_delete_datum(rel, toast_oldvalues[i]);
}