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Commit97bfffe

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This patch, which is built upon the "HeapTupleHeader accessor macros"
patch from 2002-06-10, is supposed to reduce the heap tuple header sizeby four bytes on most architectures. Of course it changes the on-disktuple format and therefore requires initdb.This overlays cmin/cmax/xmax fields into only two fields.Manfred Koizar
1 parent8661039 commit97bfffe

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3 files changed

+90
-31
lines changed

3 files changed

+90
-31
lines changed

‎src/backend/access/heap/heapam.c‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.139 2002/06/20 20:29:24 momjian Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.140 2002/07/02 05:46:14 momjian Exp $
1212
*
1313
*
1414
* INTERFACE ROUTINES
@@ -2204,7 +2204,7 @@ heap_xlog_insert(bool redo, XLogRecPtr lsn, XLogRecord *record)
22042204
htup->t_infomask=HEAP_XMAX_INVALID |xlhdr.mask;
22052205
HeapTupleHeaderSetXmin(htup,record->xl_xid);
22062206
HeapTupleHeaderSetCmin(htup,FirstCommandId);
2207-
HeapTupleHeaderSetXmax(htup,InvalidTransactionId);
2207+
HeapTupleHeaderSetXmaxInvalid(htup);
22082208
HeapTupleHeaderSetCmax(htup,FirstCommandId);
22092209

22102210
offnum=PageAddItem(page, (Item)htup,newlen,offnum,

‎src/include/access/htup.h‎

Lines changed: 86 additions & 27 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $Id: htup.h,v 1.54 2002/06/20 20:29:43 momjian Exp $
10+
* $Id: htup.h,v 1.55 2002/07/02 05:46:14 momjian Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -57,15 +57,24 @@
5757
* Also note that we omit the nulls bitmap if t_infomask shows that there
5858
* are no nulls in the tuple.
5959
*/
60+
/*
61+
** We store five "virtual" fields Xmin, Cmin, Xmax, Cmax, and Xvac
62+
** in three physical fields t_xmin, t_cid, t_xmax:
63+
** CommandId Cmin;insert CID stamp
64+
** CommandId Cmax;delete CommandId stamp
65+
** TransactionId Xmin;insert XID stamp
66+
** TransactionId Xmax;delete XID stamp
67+
** TransactionId Xvac;used by VACCUUM
68+
**
69+
** This assumes, that a CommandId can be stored in a TransactionId.
70+
*/
6071
typedefstructHeapTupleHeaderData
6172
{
6273
Oidt_oid;/* OID of this tuple -- 4 bytes */
6374

64-
CommandIdt_cmin;/* insert CID stamp -- 4 bytes each */
65-
CommandIdt_cmax;/* delete CommandId stamp */
66-
67-
TransactionIdt_xmin;/* insert XID stamp -- 4 bytes each */
68-
TransactionIdt_xmax;/* delete XID stamp */
75+
TransactionIdt_xmin;/* Xmin -- 4 bytes each */
76+
TransactionIdt_cid;/* Cmin, Cmax, Xvac */
77+
TransactionIdt_xmax;/* Xmax, Cmax */
6978

7079
ItemPointerDatat_ctid;/* current TID of this or newer tuple */
7180

@@ -75,7 +84,7 @@ typedef struct HeapTupleHeaderData
7584

7685
uint8t_hoff;/* sizeof header incl. bitmap, padding */
7786

78-
/* ^ -31 bytes - ^ */
87+
/* ^ -27 bytes - ^ */
7988

8089
bits8t_bits[1];/* bitmap of NULLs -- VARIABLE LENGTH */
8190

@@ -96,6 +105,8 @@ typedef HeapTupleHeaderData *HeapTupleHeader;
96105
* attribute(s) */
97106
#defineHEAP_HASEXTENDED0x000C/* the two above combined */
98107

108+
#defineHEAP_XMIN_IS_XMAX0x0040/* created and deleted in the */
109+
/* same transaction */
99110
#defineHEAP_XMAX_UNLOGGED0x0080/* to lock tuple for update */
100111
/* without logging */
101112
#defineHEAP_XMIN_COMMITTED0x0100/* t_xmin committed */
@@ -108,6 +119,7 @@ typedef HeapTupleHeaderData *HeapTupleHeader;
108119
* vacuum */
109120
#defineHEAP_MOVED_IN0x8000/* moved from another place by
110121
* vacuum */
122+
#defineHEAP_MOVED (HEAP_MOVED_OFF | HEAP_MOVED_IN)
111123

112124
#defineHEAP_XACT_MASK0xFFF0/* visibility-related bits */
113125

@@ -116,53 +128,100 @@ typedef HeapTupleHeaderData *HeapTupleHeader;
116128
/* HeapTupleHeader accessor macros */
117129

118130
#defineHeapTupleHeaderGetXmin(tup) \
119-
((tup)->t_xmin)
131+
( \
132+
(tup)->t_xmin \
133+
)
120134

121135
#defineHeapTupleHeaderGetXmax(tup) \
122-
((tup)->t_xmax)
136+
( \
137+
((tup)->t_infomask & HEAP_XMIN_IS_XMAX) ? \
138+
(tup)->t_xmin \
139+
: \
140+
(tup)->t_xmax \
141+
)
123142

124-
/* no AssertMacro, because this is read as a system-defined attributealso*/
143+
/* no AssertMacro, because this is read as a system-defined attribute */
125144
#defineHeapTupleHeaderGetCmin(tup) \
126145
( \
127-
(tup)->t_cmin \
146+
((tup)->t_infomask & HEAP_MOVED) ? \
147+
FirstCommandId \
148+
: \
149+
( \
150+
((tup)->t_infomask & (HEAP_XMIN_IS_XMAX | HEAP_XMAX_INVALID)) ? \
151+
(CommandId) (tup)->t_cid \
152+
: \
153+
FirstCommandId \
154+
) \
128155
)
129156

130157
#defineHeapTupleHeaderGetCmax(tup) \
131-
((tup)->t_cmax)
158+
( \
159+
((tup)->t_infomask & HEAP_MOVED) ? \
160+
FirstCommandId \
161+
: \
162+
( \
163+
((tup)->t_infomask & (HEAP_XMIN_IS_XMAX | HEAP_XMAX_INVALID)) ? \
164+
(CommandId) (tup)->t_xmax \
165+
: \
166+
(CommandId) (tup)->t_cid \
167+
) \
168+
)
132169

133170
#defineHeapTupleHeaderGetXvac(tup) \
134171
( \
135-
AssertMacro((tup)->t_infomask &(HEAP_MOVED_IN | HEAP_MOVED_OFF)), \
136-
(TransactionId) (tup)->t_cmin \
172+
AssertMacro((tup)->t_infomask &HEAP_MOVED), \
173+
(tup)->t_cid \
137174
)
138175

139176

140177
#defineHeapTupleHeaderSetXmin(tup,xid) \
141-
(TransactionIdStore((xid), &(tup)->t_xmin))
178+
( \
179+
TransactionIdStore((xid), &(tup)->t_xmin) \
180+
)
142181

143182
#defineHeapTupleHeaderSetXminInvalid(tup) \
144-
(StoreInvalidTransactionId(&(tup)->t_xmin))
183+
do { \
184+
(tup)->t_infomask &= ~HEAP_XMIN_IS_XMAX; \
185+
StoreInvalidTransactionId(&(tup)->t_xmin); \
186+
} while (0)
145187

146188
#defineHeapTupleHeaderSetXmax(tup,xid) \
147-
(TransactionIdStore((xid), &(tup)->t_xmax))
189+
do { \
190+
if (TransactionIdEquals((tup)->t_xmin, (xid))) \
191+
(tup)->t_infomask |= HEAP_XMIN_IS_XMAX; \
192+
else \
193+
{ \
194+
(tup)->t_infomask &= ~HEAP_XMIN_IS_XMAX; \
195+
TransactionIdStore((xid), &(tup)->t_xmax); \
196+
} \
197+
} while (0)
148198

149199
#defineHeapTupleHeaderSetXmaxInvalid(tup) \
150-
(StoreInvalidTransactionId(&(tup)->t_xmax))
200+
do { \
201+
(tup)->t_infomask &= ~HEAP_XMIN_IS_XMAX; \
202+
StoreInvalidTransactionId(&(tup)->t_xmax); \
203+
} while (0)
151204

152205
#defineHeapTupleHeaderSetCmin(tup,cid) \
153-
( \
154-
AssertMacro(!((tup)->t_infomask &(HEAP_MOVED_IN | HEAP_MOVED_OFF))), \
155-
(tup)->t_cmin =(cid) \
156-
)
206+
do { \
207+
Assert(!((tup)->t_infomask &HEAP_MOVED)); \
208+
TransactionIdStore((TransactionId)(cid), &(tup)->t_cid); \
209+
} while (0)
157210

158211
#defineHeapTupleHeaderSetCmax(tup,cid) \
159-
((tup)->t_cmax = (cid))
212+
do { \
213+
Assert(!((tup)->t_infomask & HEAP_MOVED)); \
214+
if ((tup)->t_infomask & HEAP_XMIN_IS_XMAX) \
215+
TransactionIdStore((TransactionId) (cid), &(tup)->t_xmax); \
216+
else \
217+
TransactionIdStore((TransactionId) (cid), &(tup)->t_cid); \
218+
} while (0)
160219

161220
#defineHeapTupleHeaderSetXvac(tup,xid) \
162-
( \
163-
AssertMacro((tup)->t_infomask &(HEAP_MOVED_IN | HEAP_MOVED_OFF)), \
164-
TransactionIdStore((xid),(TransactionId *) &((tup)->t_cmin)) \
165-
)
221+
do { \
222+
Assert((tup)->t_infomask &HEAP_MOVED); \
223+
TransactionIdStore((xid),&(tup)->t_cid); \
224+
} while (0)
166225

167226

168227
/*

‎src/include/catalog/catversion.h‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -37,7 +37,7 @@
3737
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
3838
* Portions Copyright (c) 1994, Regents of the University of California
3939
*
40-
* $Id: catversion.h,v 1.136 2002/06/20 20:29:43 momjian Exp $
40+
* $Id: catversion.h,v 1.137 2002/07/02 05:46:14 momjian Exp $
4141
*
4242
*-------------------------------------------------------------------------
4343
*/
@@ -53,6 +53,6 @@
5353
*/
5454

5555
/*yyyymmddN */
56-
#defineCATALOG_VERSION_NO200206151
56+
#defineCATALOG_VERSION_NO200207021
5757

5858
#endif

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