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Arrange to squeeze out the MINIMAL_TUPLE_PADDING in the tuple representation

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written to temp files by tuplesort.c and tuplestore.c.  This saves 2 bytes per
row for 32-bit machines, and 6 bytes per row for 64-bit machines, which seems
worth the slight additional uglification of the tuple read/write routines.
This commit is contained in:
Tom Lane
2008-10-28 15:51:03 +00:00
parent 8ecd535169
commit d26bf23f34
3 changed files with 41 additions and 21 deletions
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8
src/include/access/htup.h
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@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/htup.h,v 1.101 2008/08/11 11:05:11 heikki Exp $
* $PostgreSQL: pgsql/src/include/access/htup.h,v 1.102 2008/10/28 15:51:03 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -420,11 +420,17 @@ do { \
*
* Note that t_hoff is computed the same as in a full tuple, hence it includes
* the MINIMAL_TUPLE_OFFSET distance. t_len does not include that, however.
*
* MINIMAL_TUPLE_DATA_OFFSET is the offset to the first useful (non-pad) data
* other than the length word. tuplesort.c and tuplestore.c use this to avoid
* writing the padding to disk.
*/
#define MINIMAL_TUPLE_OFFSET \
((offsetof(HeapTupleHeaderData, t_infomask2) - sizeof(uint32)) / MAXIMUM_ALIGNOF * MAXIMUM_ALIGNOF)
#define MINIMAL_TUPLE_PADDING \
((offsetof(HeapTupleHeaderData, t_infomask2) - sizeof(uint32)) % MAXIMUM_ALIGNOF)
#define MINIMAL_TUPLE_DATA_OFFSET \
offsetof(MinimalTupleData, t_infomask2)
typedef struct MinimalTupleData
{