沧州住房和城乡建设部网站,深夜十大亏app软件,中铁建设集团登陆,被称为网站开发神器前言
最近看到了 何登成 大佬的 深入MySQL源码 -- Step By Step 的 pdf 呵呵 似乎是找到了一些 方向
之前对于 mysql 方面的东西, 更多的仅仅是简单的使用[业务中的各种增删改查], 以及一些面试题的背诵
这里会参照 MySQL Internals Manual 来大致的看一下 i…前言
最近看到了 何登成 大佬的 深入MySQL源码 -- Step By Step 的 pdf 呵呵 似乎是找到了一些 方向
之前对于 mysql 方面的东西, 更多的仅仅是简单的使用[业务中的各种增删改查], 以及一些面试题的背诵
这里会参照 MySQL Internals Manual 来大致的看一下 innodb 里面的 record 的存储相关, 这些是深入了解 mysql 的基础
我们这里主要是会了解一下两种 RowFormat : Redundant 和 Compact
本文内容对应的是 mysql调试的一些基础方法 里面的 查看一下 rec 的数据信息 MySQL Internals Manual - 22.1 InnoDB Record Structure
以下截图参照自 MySQL Internals Manual
这里的说明是基于 RowFormat - Redundant
总的来说一个 record 分成了三个部分 : 各个字段的偏移(Field Start Offsets), 元数据信息(Extra Bytes), 记录信息(Field Contents)
Field Start Offsets : 描述的是 record 中的各个字段在 Field Contents 中的偏移, 以此偏移可以确认各个字段的数据信息
Extra Bytes : 描述的是 record 的元数据, 包括了 删除标记, minRecord标记, 字段数量, Field Start Offsets 的单位, 记录编号, 下一个记录的偏移 等等信息
Field Contents : 里面存储的是具体的数据信息
22.1.1.3 FIELD CONTENTS 里面介绍了一个实例的案例, 剖析一个实际的记录在内存中的数据分布情况, 以及拆解每一个字节的逻辑意义, 可以移步文档看一下, 这里就不截图了, 请自行查阅文档 源码中的说明 remOrec.cc | remOrec.ic | remOrec.h
我们再来根据源码中的注释结合 来看一下
里面注释写的相当详尽, 因此 建议多读注释, 以方便理解
深入MySQL源码 -- Step By Step 里面也提到了 不放过源码中的每一处注释 RowFormat - Redundant
注释里面描述的内容 和 上面 MySQL Internals Manual - 22.1 InnoDB Record Structure 一致 Extra Bytes 的结构信息 RowFormat - Compact
注释里面描述的内容 就是 Compact 的 RowFormat 的格式了, MySQL Internals Manual 上面我没有找到
总的来说一个 record 分成了三个部分 : 各个字段的偏移(Field Start Offsets), 元数据信息(Extra Bytes), 记录信息(Field Contents)
Field Start Offsets : 描述的是 record 中的各个长度可变字段在 Field Contents 中的偏移, table元数据中固定字段偏移 结合 此偏移 可以确认所有字段的偏移, 进而可以确认各个字段的数据信息
Extra Bytes : 描述的是 record 的元数据, 包括了 null字段标记, 删除标记, minRecord标记, 记录编号, 下一个记录的偏移 等等信息
Field Contents : 里面存储的是具体的数据信息 Extra Bytes 的结构信息 RowFormat - Redundant 实际案例剖析
# ROW_FORMAT Redundant 的内存情况
(lldb) x 0x12c694000 -c 0x100
0x12c694000: 1c 18 8c aa 00 00 00 03 ff ff ff ff ff ff ff ff .......
0x12c694010: 00 00 00 00 00 1a b2 d5 45 bf 00 00 00 00 00 00 ......E......
0x12c694020: 00 00 00 00 00 07 00 02 00 c6 00 04 00 00 00 00 ...............
0x12c694030: 00 ad 00 02 00 01 00 02 00 00 00 00 00 00 00 00 ...............
0x12c694040: 00 00 00 00 00 00 00 00 00 17 00 00 00 07 00 00 ................
0x12c694050: 00 02 00 f2 00 00 00 07 00 00 00 02 00 32 08 01 ............2..
0x12c694060: 00 00 03 00 88 69 6e 66 69 6d 75 6d 00 09 03 00 .....infimum....
0x12c694070: 08 03 00 00 73 75 70 72 65 6d 75 6d 00 1a 15 11 ....supremum....
0x12c694080: 0a 04 00 00 10 0b 00 ad 80 00 00 01 00 00 00 00 ...............
0x12c694090: 3b 07 87 00 00 01 3a 01 10 80 00 00 1c 6a 65 72 ;.....:......jer
0x12c6940a0: 72 79 19 15 11 0a 04 00 00 18 0b 00 74 80 00 00 ry..........t...
0x12c6940b0: 02 00 00 00 00 3b 08 88 00 00 01 3e 01 10 80 00 .....;.........
0x12c6940c0: 00 16 6c 75 63 79 00 00 00 00 00 00 00 00 00 00 ..lucy..........
0x12c6940d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x12c6940e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x12c6940f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................# 0x12c694050
0x12c694050: 00 02 00 f2 00 00 00 07 00 00 00 02 00 32 08 01 ............2..
0x12c694060: 00 00 03 00 88 69 6e 66 69 6d 75 6d 00 09 03 00 .....infimum....
0x12c694070: 08 03 00 00 73 75 70 72 65 6d 75 6d 00 1a 15 11 ....supremum....
0x12c694080: 0a 04 00 00 10 0b 00 ad 80 00 00 01 00 00 00 00 ...............
0x12c694090: 3b 07 87 00 00 01 3a 01 10 80 00 00 1c 6a 65 72 ;.....:......jer
0x12c6940a0: 72 79 19 15 11 0a 04 00 00 18 0b 00 74 80 00 00 ry..........t...
0x12c6940b0: 02 00 00 00 00 3b 08 88 00 00 01 3e 01 10 80 00 .....;.........
0x12c6940c0: 00 16 6c 75 63 79 00 00 00 00 00 00 00 00 00 00 ..lucy..........# infimum PAGE_OLD_INFIMUM 0x65
08 : offset of infimum
01 : deleted_flag 0, min_rec_flag 0, n_owned 1
00 00 03 : heap_no 0, n_fields 1, 1byte_offs_flag 1
00 88 : next record pointer - jerry
69 6e 66 69 6d 75 6d 00 : infimum# supremum PAGE_OLD_SUPREMUM 0x74
09 : offset of supremum
03 : deleted_flag 0, min_rec_flag 0, n_owned 3
00 08 03 : heap_no 1, n_fields 1, 1byte_offs_flag 1
00 00 : next record pointer - self
73 75 70 72 65 6d 75 6d 00 : supremum# record jerry : 0x12c694088 # 格式为 redundant row format
1a 15 11 0a 04 : field offset of id, trx_id, poll_ptr, age, name
00 : deleted_flag 0, min_rec_flag 0, n_owned 0
00 10 0b : heap_no 2, n_fields 5, 1byte_offs_flag 1
00 ad : next record offset - record lucyid 80 00 00 01 1
trx_id 00 00 00 00 3b 07 15111
poll_ptr 87 00 00 01 3a 01 10
age 80 00 00 1c 28
name 6a 65 72 72 79 jerry# record lucy : 0x12c6940ad # 格式为 redundant row format
19 15 11 0a 04 : field offset of id, trx_id, poll_ptr, age, name
00 : deleted_flag 0, min_rec_flag 0, n_owned 0
00 18 0b : heap_no 3, n_fields 5, 1byte_offs_flag 1
00 74 : next record offset - supremumid 80 00 00 02 2
trx_id 00 00 00 00 3b 08 15112
poll_ptr 88 00 00 01 3e 01 10
age 80 00 00 16 22
name 6c 75 63 79 lucyRowFormat - Compact 实际案例剖析
# user 对应的数据 当前页的数据信息, 拆解
(lldb) x 0x1286cc000 -c 0x120
0x1286cc000: 10 aa fb 30 00 00 00 03 ff ff ff ff ff ff ff ff .0....
0x1286cc010: 00 00 00 00 00 1a a2 7d 45 bf 00 00 00 00 00 00 ......}E......
0x1286cc020: 00 00 00 00 00 06 00 02 00 b9 80 04 00 00 00 00 ...............
0x1286cc030: 00 a0 00 02 00 01 00 02 00 00 00 00 00 00 00 00 ...............
0x1286cc040: 00 00 00 00 00 00 00 00 00 16 00 00 00 06 00 00 ................
0x1286cc050: 00 02 00 f2 00 00 00 06 00 00 00 02 00 32 01 00 ............2..
0x1286cc060: 02 00 1c 69 6e 66 69 6d 75 6d 00 03 00 0b 00 00 ...infimum......
0x1286cc070: 73 75 70 72 65 6d 75 6d 05 00 00 00 10 00 21 80 supremum......!.
0x1286cc080: 00 00 01 00 00 00 00 2b 07 04 00 00 01 56 04 7b ............V.{
0x1286cc090: 80 00 00 1c 6a 65 72 72 79 04 00 00 00 18 ff d0 ....jerry.....
0x1286cc0a0: 80 00 00 02 00 00 00 00 35 04 83 00 00 01 36 01 ........5.....6.
0x1286cc0b0: 10 80 00 00 16 6c 75 63 79 00 00 00 00 00 00 00 .....lucy.......
0x1286cc0c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x1286cc0d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x1286cc0e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x1286cc0f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x1286cc100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
0x1286cc110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................# 0x1286cc050
0x1286cc050: 00 02 00 f2 00 00 00 06 00 00 00 02 00 32 01 00 ............2..
0x1286cc060: 02 00 1c 69 6e 66 69 6d 75 6d 00 03 00 0b 00 00 ...infimum......
0x1286cc070: 73 75 70 72 65 6d 75 6d 05 00 00 00 10 00 21 80 supremum......!.
0x1286cc080: 00 00 01 00 00 00 00 2b 07 04 00 00 01 56 04 7b ............V.{
0x1286cc090: 80 00 00 1c 6a 65 72 72 79 04 00 00 00 18 ff d0 ....jerry.....
0x1286cc0a0: 80 00 00 02 00 00 00 00 35 04 83 00 00 01 36 01 ........5.....6.
0x1286cc0b0: 10 80 00 00 16 6c 75 63 79 00 00 00 00 00 00 00 .....lucy.......# infimum PAGE_NEW_INFIMUM 0x63
# infimum : 0x1286cc063
0x0 : delete_flag min_rec_flag
0x1 : number of records owned by the record
0b 0000 0000 0000 0 0 order number of this record
0b 010 infimum
0x 00 1c next record offset - jerry
69 6e 66 69 6d 75 6d 00 infimum# supremum PAGE_NEW_SUPREMUM 0x70
# supremum : 0x1286cc070
0x0 : delete_flag min_rec_flag
0x3 : number of records owned by the record
0b 0000 0000 0000 1 1 order number of this record
0b 011 supremum
0x 00 00 next record offset - self
73 75 70 72 65 6d 75 6d supremum# record jerry : 0x1286cc07f # 格式为 compact row format
0x05 : lengthOf(jerry)
0x00 nulls
0x0 : delete flag
0x0 : number of records owned by the record
0b 0000 0000 0001 0 2 order number of this record
0b 000 conventional
0x 00 21 : next record offset - record lucyrec 0x80
id 0x 80 00 00 01 1
trx_id 0x 00 00 00 00 2b 07 11015
poll_ptr 0x 04 00 00 01 56 04 7b
age 0x 80 00 00 1c 28
name 6a 65 72 72 79 jerry# record lucy : 0x1286cc0a0 # 格式为 compact row format
0x04 : lengthOf(lucy)
0x00 nulls
0x0 : delete flag
0x0 : number of records owned by the record
0b 0000 0000 0001 1 3 order number of this record
0b 000 conventional
0x ff d0 : next record offset - supremumrec 0x80
id 0x 80 00 00 02 2
trx_id 0x 00 00 00 00 35 04 13572
poll_ptr 0x 83 00 00 01 36 01 10
age 0x 80 00 00 16 22
name 6c 75 63 79 lucy 完 参考
MySQL Internals Manual
深入MySQL源码 -- Step By Step
mysql调试的一些基础方法