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Remove VARLENA_FIXED_SIZE hack, which is irreversibly broken now that

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both MULTIBYTE and TOAST prevent char(n) from being truly fixed-size.
Simplify and speed up fastgetattr() and index_getattr() macros by
eliminating special cases for attnum=1.  It's just as fast to handle
the first attribute by presetting its attcacheoff to zero; so do that
instead when loading the tupledesc in relcache.c.
This commit is contained in:
Tom Lane
2000-11-30 18:38:47 +00:00
parent 59a9735fc8
commit 1f5cc8c78a
7 changed files with 123 additions and 152 deletions
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43
src/backend/access/common/heaptuple.c
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@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/common/heaptuple.c,v 1.66 2000/11/14 21:04:32 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/access/common/heaptuple.c,v 1.67 2000/11/30 18:38:45 tgl Exp $
*
* NOTES
* The old interface functions have been converted to macros
@ -300,11 +300,11 @@ nocachegetattr(HeapTuple tuple,
TupleDesc tupleDesc,
bool *isnull)
{
char *tp; /* ptr to att in tuple */
HeapTupleHeader tup = tuple->t_data;
bits8 *bp = tup->t_bits; /* ptr to att in tuple */
Form_pg_attribute *att = tupleDesc->attrs;
int slow = 0; /* do we have to walk nulls? */
char *tp; /* ptr to att in tuple */
bits8 *bp = tup->t_bits; /* ptr to null bitmask in tuple */
bool slow = false; /* do we have to walk nulls? */
(void) isnull; /* not used */
#ifdef IN_MACRO
@ -336,14 +336,6 @@ nocachegetattr(HeapTuple tuple,
fetchatt(&(att[attnum]),
(char *) tup + tup->t_hoff + att[attnum]->attcacheoff);
}
else if (attnum == 0)
{
/*
* first attribute is always at position zero
*/
return (Datum) fetchatt(&(att[0]), (char *) tup + tup->t_hoff);
}
#endif
}
else
@ -378,7 +370,7 @@ nocachegetattr(HeapTuple tuple,
/* check for nulls "before" final bit of last byte */
if ((~bp[byte]) & ((1 << finalbit) - 1))
slow = 1;
slow = true;
else
{
/* check for nulls in any "earlier" bytes */
@ -388,7 +380,7 @@ nocachegetattr(HeapTuple tuple,
{
if (bp[i] != 0xFF)
{
slow = 1;
slow = true;
break;
}
}
@ -408,21 +400,19 @@ nocachegetattr(HeapTuple tuple,
return (Datum) fetchatt(&(att[attnum]),
tp + att[attnum]->attcacheoff);
}
else if (attnum == 0)
return (Datum) fetchatt(&(att[0]), tp);
else if (!HeapTupleAllFixed(tuple))
{
int j;
/*
* In for(), we make this <= and not < because we want to test
* In for(), we test <= and not < because we want to see
* if we can go past it in initializing offsets.
*/
for (j = 0; j <= attnum; j++)
{
if (att[j]->attlen < 1 && !VARLENA_FIXED_SIZE(att[j]))
if (att[j]->attlen <= 0)
{
slow = 1;
slow = true;
break;
}
}
@ -430,7 +420,7 @@ nocachegetattr(HeapTuple tuple,
}
/*
* If slow is zero, and we got here, we know that we have a tuple with
* If slow is false, and we got here, we know that we have a tuple with
* no nulls or varlenas before the target attribute. If possible, we
* also want to initialize the remainder of the attribute cached
* offset values.
@ -446,21 +436,17 @@ nocachegetattr(HeapTuple tuple,
att[0]->attcacheoff = 0;
while (att[j]->attcacheoff > 0)
while (j < attnum && att[j]->attcacheoff > 0)
j++;
if (!VARLENA_FIXED_SIZE(att[j - 1]))
off = att[j - 1]->attcacheoff + att[j - 1]->attlen;
else
off = att[j - 1]->attcacheoff + att[j - 1]->atttypmod;
off = att[j - 1]->attcacheoff + att[j - 1]->attlen;
for (; j <= attnum ||
/* Can we compute more? We will probably need them */
(j < tup->t_natts &&
att[j]->attcacheoff == -1 &&
(HeapTupleNoNulls(tuple) || !att_isnull(j, bp)) &&
(HeapTupleAllFixed(tuple) ||
att[j]->attlen > 0 || VARLENA_FIXED_SIZE(att[j]))); j++)
(HeapTupleAllFixed(tuple) || att[j]->attlen > 0)); j++)
{
/*
@ -516,8 +502,7 @@ nocachegetattr(HeapTuple tuple,
off = att_addlength(off, att[i]->attlen, tp + off);
if (usecache &&
att[i]->attlen == -1 && !VARLENA_FIXED_SIZE(att[i]))
if (usecache && att[i]->attlen == -1)
usecache = false;
}