就地升级：存储
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存储
页面布局版本
| PostgreSQL 版本 | ||||||
|---|---|---|---|---|---|---|
| 7.4 | 8.0 | 8.1 | 8.2 | 8.3 | 8.4devel | |
| 布局版本 | 1 | 2 | 3 | 3 | 4 | 4 |
| 头大小 [B] | 20 | 20 | 20 | 20 | 24 | 24 |
| 元组头大小 [B] | 23 | 27 | 27 | 27 | 23 | 23 |
| 元组头对齐大小 [B] (MAX_ALIGN 4B/8B) |
24/24 | 28/32 | 28/32 | 28/32 | 24/24 | 24/24 |
| 元组头对齐大小 [B] 带有空位数组 (MAX_ALIGN=4B/8B) |
28/32 | 32/32 | 32/32 | 32/32 | 28/32 | 28/32 |
| 最大 TOAST 块大小 [B] (MAX_ALIGN=4B/8B) |
?/? | ?? | 1994/1986 | 1994/1986 | 2000/1996 | 2000/1996 |
页面头
版本 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) | +--------+--------+--------+--------+-------->
版本 2 和 3
注意：页面头对于页面布局 2 和 3 都是相同的。
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) | +--------+--------+--------+--------+-------->
版本 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) | | +--------+--------+--------+--------+--------+--------+--------+--------+-------->
元组头
版本 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[] +--------+--------+--------+--------+--------+--------+--------+-------->
版本 2 和 3
注意：元组头结构对于版本 2 和 3 来说是相同的，但 infomask 内容略有不同。
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[] +--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+-------->
版本 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[] +--------+--------+--------+--------+--------+--------+--------+-------->
元组信息掩码
注意：页面布局 4 引入了第二个 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 编码
- 图例
- e ... 外部存储
- c ... 压缩
- s ... 大小
8.3 之前
- 大端字节序
ecss ssss :: ssss ssss :: ssss ssss :: ssss ssss d2 34 56 78 is external compressed datum, size is 12345678B
- 小端字节序
ssss ssss :: ssss ssss :: ssss ssss :: ecss ssss 78 56 34 d2 is external compressed datum, size is 12345678B
8.3 及更高版本
- 大端字节序
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
- 小端字节序
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
