diff --git a/src/backend/access/common/heaptuple.c b/src/backend/access/common/heaptuple.c index 3d0b684306..4cf0098f5e 100644 --- a/src/backend/access/common/heaptuple.c +++ b/src/backend/access/common/heaptuple.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/access/common/heaptuple.c,v 1.46 1998/11/27 19:51:27 vadim Exp $ + * $Header: /cvsroot/pgsql/src/backend/access/common/heaptuple.c,v 1.47 1999/01/24 22:53:25 tgl Exp $ * * NOTES * The old interface functions have been converted to macros @@ -311,13 +311,13 @@ heap_getsysattr(HeapTuple tup, Buffer b, int attnum) * * This caches attribute offsets in the attribute descriptor. * - * an alternate way to speed things up would be to cache offsets + * An alternate way to speed things up would be to cache offsets * with the tuple, but that seems more difficult unless you take * the storage hit of actually putting those offsets into the * tuple you send to disk. Yuck. * * This scheme will be slightly slower than that, but should - * preform well for queries which hit large #'s of tuples. After + * perform well for queries which hit large #'s of tuples. After * you cache the offsets once, examining all the other tuples using * the same attribute descriptor will go much quicker. -cim 5/4/91 * ---------------- @@ -331,8 +331,8 @@ nocachegetattr(HeapTuple tuple, char *tp; /* ptr to att in tuple */ HeapTupleHeader tup = tuple->t_data; bits8 *bp = tup->t_bits; /* ptr to att in tuple */ - int slow; /* do we have to walk nulls? */ Form_pg_attribute *att = tupleDesc->attrs; + int slow = 0; /* do we have to walk nulls? */ #if IN_MACRO @@ -343,6 +343,8 @@ nocachegetattr(HeapTuple tuple, *isnull = false; #endif + attnum--; + /* ---------------- * Three cases: * @@ -354,8 +356,6 @@ nocachegetattr(HeapTuple tuple, if (HeapTupleNoNulls(tuple)) { - attnum--; - #if IN_MACRO /* This is handled in the macro */ if (att[attnum]->attcacheoff != -1) @@ -373,20 +373,13 @@ nocachegetattr(HeapTuple tuple, return (Datum) fetchatt(&(att[0]), (char *) tup + tup->t_hoff); } #endif - - slow = 0; } else { - /* * there's a null somewhere in the tuple */ - tp = (char *) tup + tup->t_hoff; - slow = 0; - attnum--; - /* ---------------- * check to see if desired att is null * ---------------- @@ -403,34 +396,27 @@ nocachegetattr(HeapTuple tuple, #endif /* ---------------- - * Now check to see if any preceeding bits are null... + * Now check to see if any preceding bits are null... * ---------------- */ { - int i = 0; /* current offset in bp */ - int mask; /* bit in byte we're looking at */ - char n; /* current byte in bp */ - int byte, - finalbit; + int byte = attnum >> 3; + int finalbit = attnum & 0x07; - byte = attnum >> 3; - finalbit = attnum & 0x07; - - for (; i <= byte && !slow; i++) + /* check for nulls "before" final bit of last byte */ + if ((~ bp[byte]) & ((1 << finalbit) - 1)) + slow = 1; + else { - n = bp[i]; - if (i < byte) + /* check for nulls in any "earlier" bytes */ + int i; + for (i = 0; i < byte; i++) { - /* check for nulls in any "earlier" bytes */ - if ((~n) != 0) - slow = 1; - } - else - { - /* check for nulls "before" final bit of last byte */ - mask = (1 << finalbit) - 1; - if ((~n) & mask) + if (bp[i] != 0xFF) + { slow = 1; + break; + } } } } @@ -449,24 +435,29 @@ nocachegetattr(HeapTuple tuple, tp + att[attnum]->attcacheoff); } else if (attnum == 0) - return (Datum) fetchatt(&(att[0]), (char *) tp); + return (Datum) fetchatt(&(att[0]), tp); else if (!HeapTupleAllFixed(tuple)) { - int j = 0; - + int j; /* * In for(), we make this <= and not < because we want to test * if we can go past it in initializing offsets. */ - for (j = 0; j <= attnum && !slow; j++) + for (j = 0; j <= attnum; j++) + { if (att[j]->attlen < 1 && !VARLENA_FIXED_SIZE(att[j])) + { slow = 1; + break; + } + } } } /* - * if slow is zero, and we got here, we know that we have a tuple with - * no nulls. We also have to initialize the remainder of the + * If slow is zero, 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. */ if (!slow) @@ -550,7 +541,8 @@ nocachegetattr(HeapTuple tuple, off = att_addlength(off, att[i]->attlen, tp + off); - if (att[i]->attlen == -1 && !VARLENA_FIXED_SIZE(att[i])) + if (usecache && + att[i]->attlen == -1 && !VARLENA_FIXED_SIZE(att[i])) usecache = false; }