diff options
Diffstat (limited to 'src/include/access/htup.h')
| -rw-r--r-- | src/include/access/htup.h | 20 |
1 files changed, 9 insertions, 11 deletions
diff --git a/src/include/access/htup.h b/src/include/access/htup.h index ddde6a466d1..eecc6959e89 100644 --- a/src/include/access/htup.h +++ b/src/include/access/htup.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/access/htup.h,v 1.89 2007/01/09 22:01:00 momjian Exp $ + * $PostgreSQL: pgsql/src/include/access/htup.h,v 1.90 2007/02/05 04:22:18 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -314,19 +314,17 @@ do { \ #define BITMAPLEN(NATTS) (((int)(NATTS) + 7) / 8) /* - * MaxTupleSize is the maximum allowed size of a tuple, including header and - * MAXALIGN alignment padding. Basically it's BLCKSZ minus the other stuff - * that has to be on a disk page. The "other stuff" includes access-method- - * dependent "special space", which we assume will be no more than - * MaxSpecialSpace bytes (currently, on heap pages it's actually zero). + * MaxHeapTupleSize is the maximum allowed size of a heap tuple, including + * header and MAXALIGN alignment padding. Basically it's BLCKSZ minus the + * other stuff that has to be on a disk page. Since heap pages use no + * "special space", there's no deduction for that. * * NOTE: we do not need to count an ItemId for the tuple because - * sizeof(PageHeaderData) includes the first ItemId on the page. + * sizeof(PageHeaderData) includes the first ItemId on the page. But beware + * of assuming that, say, you can fit 2 tuples of size MaxHeapTupleSize/2 + * on the same page. */ -#define MaxSpecialSpace 32 - -#define MaxTupleSize \ - (BLCKSZ - MAXALIGN(sizeof(PageHeaderData) + MaxSpecialSpace)) +#define MaxHeapTupleSize (BLCKSZ - MAXALIGN(sizeof(PageHeaderData))) /* * MaxHeapTuplesPerPage is an upper bound on the number of tuples that can |