In-place upgrade:Storage
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This page contains historical information or deprecated articles.
Storage
Page Layout Versions
| PostgreSQL Version | ||||||
|---|---|---|---|---|---|---|
| 7.4 | 8.0 | 8.1 | 8.2 | 8.3 | 8.4devel | |
| Layout version | 1 | 2 | 3 | 3 | 4 | 4 |
| Header Size [B] | 20 | 20 | 20 | 20 | 24 | 24 |
| Tuple Header Size [B] | 23 | 27 | 27 | 27 | 23 | 23 |
| Tuple Header Aligned Size [B]
(MAX_ALIGN 4B/8B) |
24/24 | 28/32 | 28/32 | 28/32 | 24/24 | 24/24 |
| Tuple Header Aligned Size [B]
with null bit array (MAX_ALIGN=4B/8B) |
28/32 | 32/32 | 32/32 | 32/32 | 28/32 | 28/32 |
| Max TOAST Chunk Size [B]
(MAX_ALIGN=4B/8B) |
?/? | ?? | 1994/1986 | 1994/1986 | 2000/1996 | 2000/1996 |
Page Header
Version 1
00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ | (XLogPtr) pd_lsn | (uint32)pd_sui |(uint16)pd_lower |(uint16)pd_upper | | (uint32)XLogPtr.xlogid | (uint32)XLogPtr.xrecoff | | | | +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ 16 17 18 19 20 +--------+--------+--------+--------+--------> | (uint16) |pd_pagesize_\ | pd_linp[] | pd_special |version(uint16) | +--------+--------+--------+--------+-------->
Verison 2 & 3
Note: Page header is same for page layout 2 and 3.
00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ | (XLogPtr) pd_lsn | (uint32)pd_tli |(uint16)pd_lower |(uint16)pd_upper | | (uint32)XLogPtr.xlogid | (uint32)XLogPtr.xrecoff | | | | +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ 16 17 18 19 20 +--------+--------+--------+--------+--------> | (uint16) |pd_pagesize_\ | pd_linp[] | pd_special |version(uint16) | +--------+--------+--------+--------+-------->
Version 4
00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ | (XLogPtr) pd_lsn | (uint16)pd_tli |(uint16)pd_flags |(uint16)pd_lower |(uint16)pd_upper | | (uint32)XLogPtr.xlogid | (uint32)XLogPtr.xrecoff | | | | | +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ 16 17 18 19 20 21 22 23 24 +--------+--------+--------+--------+--------+--------+--------+--------+--------> | (uint16) |pd_pagesize_\ | (uint32)pd_prune_xid | pd_linp[] | pd_special |version(uint16) | | +--------+--------+--------+--------+--------+--------+--------+--------+-------->
Tuple Header
Version 1
00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ | (uint32)t_xmin | (union)t_field2 | (union)t_field3 | (ItemPointerData)t_ctid | | (uint32)t_cmin/(uint32)t_xmax | (uint32)t_cmax/(uint32)t_xvac | (uint32)ip_blkid | +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ 16 17 18 19 20 21 22 23 +--------+--------+--------+--------+--------+--------+--------+--------> ... t_ctid | (int16)t_natts | (uint16) |(uint8) | |(uint16)ip_posid | | t_infomask | t_hoff |t_bits[] +--------+--------+--------+--------+--------+--------+--------+-------->
Version 2 & 3
Note: Tuple header structure is same for version 2 and 3, but infomask content is little bit different.
00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ | (uint32)t_xmin | (uint32)t_cmin | (uint32)t_xmax | (union)t_field4 | | | | | (uint32)t_cmax/(uint32)t_xvac | +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ 16 17 18 19 20 21 22 23 24 25 26 27 +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------> | (ItemPointerData)t_ctid | (int16)t_natts | (uint16) |(uint8) | | (uint32)ip_blkid |(uint16)ip_posid | | t_infomask | t_hoff |t_bits[] +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+-------->
Version 4
00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ | (uint32)t_xmin | (uint32)t_xmax | (union)t_field3 | (ItemPointerData)t_ctid | | | (uint32)t_cid/(uint32)t_xvac | (uint32)ip_blkid | +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ 16 17 18 19 20 21 22 23 +--------+--------+--------+--------+--------+--------+--------+--------> ... t_ctid | (int16) | (uint16) |(uint8) | |(uint16)ip_posid | t_infomask2 | t_infomask | t_hoff |t_bits[] +--------+--------+--------+--------+--------+--------+--------+-------->
Tuple info mask
Note: Page layout 4 introduces second infomask.
01 02 03 04 +--------------------------+--------------------------+--------------------------+--------------------------+ 00 | HEAP_HASNULL | HEAP_HASNULL | HEAP_HASNULL | HEAP_HASNULL | +--------------------------+--------------------------+--------------------------+--------------------------+ 01 | HEAP_HASVARWIDTH | HEAP_HASVARWIDTH | HEAP_HASVARWIDTH | HEAP_HASVARWIDTH | +--------------------------+--------------------------+--------------------------+--------------------------+ 02 | HEAP_HASEXTERNAL | HEAP_HASEXTERNAL | HEAP_HASEXTERNAL | HEAP_HASEXTERNAL | +--------------------------+--------------------------+--------------------------+--------------------------+ 03 | HEAP_HASCOMPRESSED | HEAP_HASCOMPRESSED | HEAP_HASCOMPRESSED | HEAP_HASOID | +--------------------------+--------------------------+--------------------------+--------------------------+ 04 | HEAP_HASOID | HEAP_HASOID | HEAP_HASOID | (UNUSED) | +--------------------------+--------------------------+--------------------------+--------------------------+ 05 | (UNUSED) | (UNUSED) | (UNUSED) | HEAP_COMBOCID | +--------------------------+--------------------------+--------------------------+--------------------------+ 06 | HEAP_XMAX_IS_XMIN | (UNUSED) | HEAP_XMAX_EXCL_LOCK | HEAP_XMAX_EXCL_LOCK | +--------------------------+--------------------------+--------------------------+--------------------------+ 07 | HEAP_XMAX_UNLOGGED | HEAP_XMAX_UNLOGGED | HEAP_XMAX_SHARED_LOCK | HEAP_XMAX_SHARED_LOCK | +--------------------------+--------------------------+--------------------------+--------------------------+ 08 | HEAP_XMIN_COMMITTED | HEAP_XMIN_COMMITTED | HEAP_XMIN_COMMITTED | HEAP_XMIN_COMMITTED | +--------------------------+--------------------------+--------------------------+--------------------------+ 09 | HEAP_XMIN_INVALID | HEAP_XMIN_INVALID | HEAP_XMIN_INVALID | HEAP_XMIN_INVALID | +--------------------------+--------------------------+--------------------------+--------------------------+ 10 | HEAP_XMAX_COMMITTED | HEAP_XMAX_COMMITTED | HEAP_XMAX_COMMITTED | HEAP_XMAX_COMMITTED | +--------------------------+--------------------------+--------------------------+--------------------------+ 11 | HEAP_XMAX_INVALID | HEAP_XMAX_INVALID | HEAP_XMAX_INVALID | HEAP_XMAX_INVALID | +--------------------------+--------------------------+--------------------------+--------------------------+ 12 | HEAP_MARKED_FOR_UPDATE | HEAP_MARKED_FOR_UPDATE | HEAP_XMAX_IS_MULTI | HEAP_XMAX_IS_MULTI | +--------------------------+--------------------------+--------------------------+--------------------------+ 13 | HEAP_UPDATED | HEAP_UPDATED | HEAP_UPDATED | HEAP_UPDATED | +--------------------------+--------------------------+--------------------------+--------------------------+ 14 | HEAP_MOVED_OFF | HEAP_MOVED_OFF | HEAP_MOVED_OFF | HEAP_MOVED_OFF | +--------------------------+--------------------------+--------------------------+--------------------------+ 15 | HEAP_MOVED_IN | HEAP_MOVED_IN | HEAP_MOVED_IN | HEAP_MOVED_IN | +--------------------------+--------------------------+--------------------------+--------------------------+
Varlen encoding
- Legend
- e ... external storage
- c ... compressed
- s ... size
prior 8.3
- big endian
ecss ssss :: ssss ssss :: ssss ssss :: ssss ssss d2 34 56 78 is external compressed datum, size is 12345678B
- little endian
ssss ssss :: ssss ssss :: ssss ssss :: ecss ssss 78 56 34 d2 is external compressed datum, size is 12345678B
8.3 and later
- big endian
0sss ssss - uncompressed, unaligned data max 126 bytes long 1000 0000 - TOAST pointer 0css ssss :: ssss ssss :: ssss ssss :: ssss ssss - aligned data up to 1GB 7e is internal 126 bytes unaligned long data 12 34 56 78 is internal uncompressed datum, size is 12345678B 52 34 56 78 is internal compressed datum, size is 12345678B
- little endian
ssss sss0 - uncompressed, unaligned data max 126 bytes long 0000 0001 - TOAST pointer ssss ssc0 :: ssss ssss :: ssss ssss :: ssss ssss - aligned data up to 1GB FC is internal 126 bytes unaligned long data E0 59 D1 48 is internal uncompressed datum, size is 12345678B E2 59 D1 48 is internal compressed datum, size is 12345678B
