Class: Innodb::UndoRecord
- Inherits:
-
Object
- Object
- Innodb::UndoRecord
- Defined in:
- lib/innodb/undo_record.rb
Overview
A single undo log record.
Constant Summary collapse
- TYPE =
Possible undo record types.
{ 11 => :insert, 12 => :update_existing, 13 => :update_deleted, 14 => :delete, }
- TYPE_MASK =
0x0f
- COMPILATION_INFO_MASK =
0x70
- COMPILATION_INFO_SHIFT =
4
- COMPILATION_INFO_NO_ORDER_CHANGE_BV =
1
- COMPILATION_INFO_NO_SIZE_CHANGE_BV =
2
- EXTERN_FLAG =
0x80
Instance Attribute Summary collapse
-
#index_page ⇒ Object
Returns the value of attribute index_page.
-
#position ⇒ Object
readonly
Returns the value of attribute position.
-
#undo_log ⇒ Object
Returns the value of attribute undo_log.
-
#undo_page ⇒ Object
readonly
Returns the value of attribute undo_page.
Instance Method Summary collapse
-
#cursor(position) ⇒ Object
Return a BufferCursor starting before the header.
- #get(prev_or_next) ⇒ Object
- #has_previous_version? ⇒ Boolean
- #header ⇒ Object
-
#initialize(undo_page, position) ⇒ UndoRecord
constructor
A new instance of UndoRecord.
- #key ⇒ Object
- #key_string ⇒ Object
- #new_subordinate(undo_page, position) ⇒ Object
- #next ⇒ Object
-
#pos_header ⇒ Object
The header really starts 2 bytes before the undo record position, as the pointer to the previous record is written there.
- #pos_record ⇒ Object
- #prev ⇒ Object
-
#prev_by_history ⇒ Object
Find the previous row version by following the roll_ptr from one undo record to the next (backwards through the record version history).
- #read_record ⇒ Object
- #read_record_fields(this_record, c) ⇒ Object
- #record_size ⇒ Object
- #roll_ptr ⇒ Object
- #row ⇒ Object
- #row_string ⇒ Object
-
#size_header ⇒ Object
The size of the header.
- #string ⇒ Object
- #table_id ⇒ Object
- #trx_id ⇒ Object
- #type ⇒ Object
- #undo_no ⇒ Object
- #undo_record ⇒ Object
Constructor Details
#initialize(undo_page, position) ⇒ UndoRecord
Returns a new instance of UndoRecord.
11 12 13 14 15 16 17 |
# File 'lib/innodb/undo_record.rb', line 11 def initialize(undo_page, position) @undo_page = undo_page @position = position @undo_log = nil @index_page = nil end |
Instance Attribute Details
#index_page ⇒ Object
Returns the value of attribute index_page.
9 10 11 |
# File 'lib/innodb/undo_record.rb', line 9 def index_page @index_page end |
#position ⇒ Object (readonly)
Returns the value of attribute position.
6 7 8 |
# File 'lib/innodb/undo_record.rb', line 6 def position @position end |
#undo_log ⇒ Object
Returns the value of attribute undo_log.
8 9 10 |
# File 'lib/innodb/undo_record.rb', line 8 def undo_log @undo_log end |
#undo_page ⇒ Object (readonly)
Returns the value of attribute undo_page.
5 6 7 |
# File 'lib/innodb/undo_record.rb', line 5 def undo_page @undo_page end |
Instance Method Details
#cursor(position) ⇒ Object
Return a BufferCursor starting before the header.
43 44 45 46 47 48 49 50 |
# File 'lib/innodb/undo_record.rb', line 43 def cursor(position) new_cursor = @undo_page.cursor(position) if @undo_log new_cursor.push_name("undo_log[#{@undo_log.position}]") end new_cursor.push_name("undo_record[#{@position}]") new_cursor end |
#get(prev_or_next) ⇒ Object
95 96 97 98 99 100 101 102 |
# File 'lib/innodb/undo_record.rb', line 95 def get(prev_or_next) if header[prev_or_next] != 0 new_undo_record = new_subordinate(@undo_page, header[prev_or_next]) if new_undo_record.type new_undo_record end end end |
#has_previous_version? ⇒ Boolean
91 92 93 |
# File 'lib/innodb/undo_record.rb', line 91 def has_previous_version? [:update_existing, :update_deleted, :delete].include?(type) end |
#header ⇒ Object
67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 |
# File 'lib/innodb/undo_record.rb', line 67 def header @header ||= cursor(pos_header).name("header") do |c| header = { :prev => c.name("prev") { c.get_uint16 }, :next => c.name("next") { c.get_uint16 }, } info = c.name("info") { c.get_uint8 } cmpl = (info & COMPILATION_INFO_MASK) >> COMPILATION_INFO_SHIFT header[:type] = TYPE[info & TYPE_MASK] header[:extern_flag] = (info & EXTERN_FLAG) != 0 header[:info] = { :order_may_change => (cmpl & COMPILATION_INFO_NO_ORDER_CHANGE_BV) == 0, :size_may_change => (cmpl & COMPILATION_INFO_NO_SIZE_CHANGE_BV) == 0, } header end end |
#key ⇒ Object
204 205 206 |
# File 'lib/innodb/undo_record.rb', line 204 def key undo_record[:key] end |
#key_string ⇒ Object
208 209 210 |
# File 'lib/innodb/undo_record.rb', line 208 def key_string key && key.map { |r| "%s=%s" % [r[:name], r[:value].inspect] }.join(", ") end |
#new_subordinate(undo_page, position) ⇒ Object
19 20 21 22 23 24 25 |
# File 'lib/innodb/undo_record.rb', line 19 def new_subordinate(undo_page, position) new_undo_record = self.class.new(undo_page, position) new_undo_record.undo_log = undo_log new_undo_record.index_page = index_page new_undo_record end |
#next ⇒ Object
108 109 110 |
# File 'lib/innodb/undo_record.rb', line 108 def next get(:next) end |
#pos_header ⇒ Object
The header really starts 2 bytes before the undo record position, as the pointer to the previous record is written there.
29 30 31 |
# File 'lib/innodb/undo_record.rb', line 29 def pos_header @position - 2 end |
#pos_record ⇒ Object
38 39 40 |
# File 'lib/innodb/undo_record.rb', line 38 def pos_record pos_header + size_header end |
#prev ⇒ Object
104 105 106 |
# File 'lib/innodb/undo_record.rb', line 104 def prev get(:prev) end |
#prev_by_history ⇒ Object
Find the previous row version by following the roll_ptr from one undo record to the next (backwards through the record version history). Since we are operating without the benefit of knowing about active transactions and without protection from purge, check that everything looks sane before returning it.
229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 |
# File 'lib/innodb/undo_record.rb', line 229 def prev_by_history unless has_previous_version? # This undo record type has no previous version information. return nil end undo_log = roll_ptr[:undo_log] older_undo_page = @undo_page.space.page(undo_log[:page]) unless older_undo_page and older_undo_page.is_a?(Innodb::Page::UndoLog) # The page was probably re-used for something else. return nil end older_undo_record = new_subordinate(older_undo_page, undo_log[:offset]) unless older_undo_record and table_id == older_undo_record.table_id # The record space was probably re-used for something else. return nil end unless older_undo_record.trx_id.nil? or trx_id >= older_undo_record.trx_id # The trx_id should not be newer; but may be absent (for insert). return nil end older_undo_record end |
#read_record ⇒ Object
116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 |
# File 'lib/innodb/undo_record.rb', line 116 def read_record cursor(pos_record).name("record") do |c| this_record = { :page => undo_page.offset, :offset => position, :header => header, :undo_no => c.name("undo_no") { c.get_imc_uint64 }, :table_id => c.name("table_id") { c.get_imc_uint64 }, } if has_previous_version? this_record[:info_bits] = c.name("info_bits") { c.get_uint8 } this_record[:trx_id] = c.name("trx_id") { c.get_ic_uint64 } this_record[:roll_ptr] = c.name("roll_ptr") { Innodb::DataType::RollPointerType.parse_roll_pointer(c.get_ic_uint64) } end if index_page read_record_fields(this_record, c) else # Slurp up the remaining data as a string. this_record[:data] = c.get_bytes(header[:next] - c.position - 2) end this_record end end |
#read_record_fields(this_record, c) ⇒ Object
145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 |
# File 'lib/innodb/undo_record.rb', line 145 def read_record_fields(this_record, c) this_record[:key] = [] index_page.record_format[:key].each do |field| this_record[:key][field.position] = { :name => field.name, :type => field.data_type.name, :value => c.name(field.name) { field_length = c.name("field_length") { c.get_ic_uint32 } field.value_by_length(c, field_length) } } end if has_previous_version? field_count = c.name("field_count") { c.get_ic_uint32 } this_record[:row] = Array.new(index_page.record_format[:row].size) field_count.times do field_number = c.name("field_number[#{field_count}]") { c.get_ic_uint32 } field = nil field_index = nil index_page.record_format[:row].each_with_index do |candidate_field, index| if candidate_field.position == field_number field = candidate_field field_index = index end end raise "Unknown field #{field_number}" unless field this_record[:row][field_index] = { :name => field.name, :type => field.data_type.name, :value => c.name(field.name) { field_length = c.name("field_length") { c.get_ic_uint32 } field.value_by_length(c, field_length) } } end end end |
#record_size ⇒ Object
112 113 114 |
# File 'lib/innodb/undo_record.rb', line 112 def record_size header[:next] - @position - size_header end |
#roll_ptr ⇒ Object
200 201 202 |
# File 'lib/innodb/undo_record.rb', line 200 def roll_ptr undo_record[:roll_ptr] end |
#row ⇒ Object
212 213 214 |
# File 'lib/innodb/undo_record.rb', line 212 def row undo_record[:row] end |
#row_string ⇒ Object
216 217 218 |
# File 'lib/innodb/undo_record.rb', line 216 def row_string row && row.select { |r| !r.nil? }.map { |r| r && "%s=%s" % [r[:name], r[:value].inspect] }.join(", ") end |
#size_header ⇒ Object
The size of the header.
34 35 36 |
# File 'lib/innodb/undo_record.rb', line 34 def size_header 2 + 2 + 1 end |
#string ⇒ Object
220 221 222 |
# File 'lib/innodb/undo_record.rb', line 220 def string "(%s) → (%s)" % [key_string, row_string] end |
#table_id ⇒ Object
192 193 194 |
# File 'lib/innodb/undo_record.rb', line 192 def table_id undo_record[:table_id] end |
#trx_id ⇒ Object
196 197 198 |
# File 'lib/innodb/undo_record.rb', line 196 def trx_id undo_record[:trx_id] end |
#type ⇒ Object
87 88 89 |
# File 'lib/innodb/undo_record.rb', line 87 def type header[:type] end |
#undo_no ⇒ Object
188 189 190 |
# File 'lib/innodb/undo_record.rb', line 188 def undo_no undo_record[:undo_no] end |
#undo_record ⇒ Object
184 185 186 |
# File 'lib/innodb/undo_record.rb', line 184 def undo_record @undo_record ||= read_record end |