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1

according to mysql reference, 6-byte transaction ID field will be added in the cluster index record and will be set to the value the transaction which create/modifed it.
my question is:
let say transaction 1, 2 are active in mysql and 2 modified a record, meanwhile set its transaction ID to 2. release the lock and exit. then transaction 1 entered in and modified the same record again, will transaction ID be modified smaller than 2 to 1?

mysql innodb

share|improve this question

edited Mar 24 at 22:04

Keyang Ma

asked Mar 24 at 18:54

Keyang MaKeyang Ma

186

add a comment | 

1

according to mysql reference, 6-byte transaction ID field will be added in the cluster index record and will be set to the value the transaction which create/modifed it.
my question is:
let say transaction 1, 2 are active in mysql and 2 modified a record, meanwhile set its transaction ID to 2. release the lock and exit. then transaction 1 entered in and modified the same record again, will transaction ID be modified smaller than 2 to 1?

mysql innodb

share|improve this question

edited Mar 24 at 22:04

Keyang Ma

asked Mar 24 at 18:54

Keyang MaKeyang Ma

186

add a comment | 

according to mysql reference, 6-byte transaction ID field will be added in the cluster index record and will be set to the value the transaction which create/modifed it.
my question is:
let say transaction 1, 2 are active in mysql and 2 modified a record, meanwhile set its transaction ID to 2. release the lock and exit. then transaction 1 entered in and modified the same record again, will transaction ID be modified smaller than 2 to 1?

mysql innodb

share|improve this question

edited Mar 24 at 22:04

Keyang Ma

asked Mar 24 at 18:54

Keyang MaKeyang Ma

186

share|improve this question

edited Mar 24 at 22:04

Keyang Ma

asked Mar 24 at 18:54

Keyang MaKeyang Ma

186

share|improve this question

edited Mar 24 at 22:04

Keyang Ma

asked Mar 24 at 18:54

Keyang MaKeyang Ma

186

asked Mar 24 at 18:54

Keyang MaKeyang Ma

186

asked Mar 24 at 18:54

Keyang MaKeyang Ma

186

1 Answer
1

active

oldest

votes

0

If you're interested in InnoDB internal storage formats, you might like to get Jeremy Cole's Innodb_ruby tool.

I tried creating a table test.foo with 1 row, and updated the row with a series of transactions. I can then use Jeremy Cole's script to dump the page:

innodb_space -s ibdata1 -T test/foo -p 3 page-dump

...

records:
:format=>:compact,
 :offset=>125,
 :header=>
 :next=>112,
 :type=>:conventional,
 :heap_number=>2,
 :n_owned=>0,
 :min_rec=>false,
 :deleted=>false,
 :nulls=>[],
 :lengths=>,
 :externs=>[],
 :length=>5,
 :next=>112,
 :type=>:clustered,
 :key=>[:name=>"id", :type=>"BIGINT UNSIGNED", :value=>7],
 :row=>[],
 :sys=>
 [:name=>"DB_TRX_ID", :type=>"TRX_ID", :value=>2843,
 :name=>"DB_ROLL_PTR",
 :type=>"ROLL_PTR",
 :value=>
 :is_insert=>true, :rseg_id=>20, :undo_log=>:page=>335, :offset=>272],
 :length=>21,
 :transaction_id=>2843,
 :roll_pointer=>
 :is_insert=>true, :rseg_id=>20, :undo_log=>:page=>335, :offset=>272

You can see under the :sys key there's the DB_TRX_ID. As I make further updates to the row, this value is changed. You can try it yourself and see how the value changes.

Read Jeremy's series of blog posts to understand more about the InnoDB format:

Here's a list of his blog posts: https://blog.jcole.us/innodb/

share|improve this answer

answered Mar 24 at 22:21

Bill KarwinBill Karwin

391k65526682

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  My pleasure. Remember it is traditional on Stack Overflow to upvote an answer that helps you, or mark as "accepted" the answer that really answers your question fully. See stackoverflow.com/help/someone-answers
  
  – Bill Karwin
  Mar 25 at 12:23
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  my bad. I first vote the answer and it turns out that I'm the new comer for the stack overflow and my vote can't be used to influence the rank. so I just give up other actions like accepted the answer.
  
  – Keyang Ma
  Mar 25 at 20:46
  

  
  
  
  

add a comment | 

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0

If you're interested in InnoDB internal storage formats, you might like to get Jeremy Cole's Innodb_ruby tool.

I tried creating a table test.foo with 1 row, and updated the row with a series of transactions. I can then use Jeremy Cole's script to dump the page:

innodb_space -s ibdata1 -T test/foo -p 3 page-dump

...

records:
:format=>:compact,
 :offset=>125,
 :header=>
 :next=>112,
 :type=>:conventional,
 :heap_number=>2,
 :n_owned=>0,
 :min_rec=>false,
 :deleted=>false,
 :nulls=>[],
 :lengths=>,
 :externs=>[],
 :length=>5,
 :next=>112,
 :type=>:clustered,
 :key=>[:name=>"id", :type=>"BIGINT UNSIGNED", :value=>7],
 :row=>[],
 :sys=>
 [:name=>"DB_TRX_ID", :type=>"TRX_ID", :value=>2843,
 :name=>"DB_ROLL_PTR",
 :type=>"ROLL_PTR",
 :value=>
 :is_insert=>true, :rseg_id=>20, :undo_log=>:page=>335, :offset=>272],
 :length=>21,
 :transaction_id=>2843,
 :roll_pointer=>
 :is_insert=>true, :rseg_id=>20, :undo_log=>:page=>335, :offset=>272

You can see under the :sys key there's the DB_TRX_ID. As I make further updates to the row, this value is changed. You can try it yourself and see how the value changes.

Read Jeremy's series of blog posts to understand more about the InnoDB format:

Here's a list of his blog posts: https://blog.jcole.us/innodb/

share|improve this answer

answered Mar 24 at 22:21

Bill KarwinBill Karwin

391k65526682

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  My pleasure. Remember it is traditional on Stack Overflow to upvote an answer that helps you, or mark as "accepted" the answer that really answers your question fully. See stackoverflow.com/help/someone-answers
  
  – Bill Karwin
  Mar 25 at 12:23
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  my bad. I first vote the answer and it turns out that I'm the new comer for the stack overflow and my vote can't be used to influence the rank. so I just give up other actions like accepted the answer.
  
  – Keyang Ma
  Mar 25 at 20:46
  

  
  
  
  

add a comment | 

0

If you're interested in InnoDB internal storage formats, you might like to get Jeremy Cole's Innodb_ruby tool.

I tried creating a table test.foo with 1 row, and updated the row with a series of transactions. I can then use Jeremy Cole's script to dump the page:

innodb_space -s ibdata1 -T test/foo -p 3 page-dump

...

records:
:format=>:compact,
 :offset=>125,
 :header=>
 :next=>112,
 :type=>:conventional,
 :heap_number=>2,
 :n_owned=>0,
 :min_rec=>false,
 :deleted=>false,
 :nulls=>[],
 :lengths=>,
 :externs=>[],
 :length=>5,
 :next=>112,
 :type=>:clustered,
 :key=>[:name=>"id", :type=>"BIGINT UNSIGNED", :value=>7],
 :row=>[],
 :sys=>
 [:name=>"DB_TRX_ID", :type=>"TRX_ID", :value=>2843,
 :name=>"DB_ROLL_PTR",
 :type=>"ROLL_PTR",
 :value=>
 :is_insert=>true, :rseg_id=>20, :undo_log=>:page=>335, :offset=>272],
 :length=>21,
 :transaction_id=>2843,
 :roll_pointer=>
 :is_insert=>true, :rseg_id=>20, :undo_log=>:page=>335, :offset=>272

You can see under the :sys key there's the DB_TRX_ID. As I make further updates to the row, this value is changed. You can try it yourself and see how the value changes.

Read Jeremy's series of blog posts to understand more about the InnoDB format:

Here's a list of his blog posts: https://blog.jcole.us/innodb/

share|improve this answer

answered Mar 24 at 22:21

Bill KarwinBill Karwin

391k65526682

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  My pleasure. Remember it is traditional on Stack Overflow to upvote an answer that helps you, or mark as "accepted" the answer that really answers your question fully. See stackoverflow.com/help/someone-answers
  
  – Bill Karwin
  Mar 25 at 12:23
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  my bad. I first vote the answer and it turns out that I'm the new comer for the stack overflow and my vote can't be used to influence the rank. so I just give up other actions like accepted the answer.
  
  – Keyang Ma
  Mar 25 at 20:46
  

  
  
  
  

add a comment | 

If you're interested in InnoDB internal storage formats, you might like to get Jeremy Cole's Innodb_ruby tool.

I tried creating a table test.foo with 1 row, and updated the row with a series of transactions. I can then use Jeremy Cole's script to dump the page:

innodb_space -s ibdata1 -T test/foo -p 3 page-dump

...

records:
:format=>:compact,
 :offset=>125,
 :header=>
 :next=>112,
 :type=>:conventional,
 :heap_number=>2,
 :n_owned=>0,
 :min_rec=>false,
 :deleted=>false,
 :nulls=>[],
 :lengths=>,
 :externs=>[],
 :length=>5,
 :next=>112,
 :type=>:clustered,
 :key=>[:name=>"id", :type=>"BIGINT UNSIGNED", :value=>7],
 :row=>[],
 :sys=>
 [:name=>"DB_TRX_ID", :type=>"TRX_ID", :value=>2843,
 :name=>"DB_ROLL_PTR",
 :type=>"ROLL_PTR",
 :value=>
 :is_insert=>true, :rseg_id=>20, :undo_log=>:page=>335, :offset=>272],
 :length=>21,
 :transaction_id=>2843,
 :roll_pointer=>
 :is_insert=>true, :rseg_id=>20, :undo_log=>:page=>335, :offset=>272

You can see under the :sys key there's the DB_TRX_ID. As I make further updates to the row, this value is changed. You can try it yourself and see how the value changes.

Read Jeremy's series of blog posts to understand more about the InnoDB format:

Here's a list of his blog posts: https://blog.jcole.us/innodb/

share|improve this answer

answered Mar 24 at 22:21

Bill KarwinBill Karwin

391k65526682

innodb_space -s ibdata1 -T test/foo -p 3 page-dump

...

records:
:format=>:compact,
 :offset=>125,
 :header=>
 :next=>112,
 :type=>:conventional,
 :heap_number=>2,
 :n_owned=>0,
 :min_rec=>false,
 :deleted=>false,
 :nulls=>[],
 :lengths=>,
 :externs=>[],
 :length=>5,
 :next=>112,
 :type=>:clustered,
 :key=>[:name=>"id", :type=>"BIGINT UNSIGNED", :value=>7],
 :row=>[],
 :sys=>
 [:name=>"DB_TRX_ID", :type=>"TRX_ID", :value=>2843,
 :name=>"DB_ROLL_PTR",
 :type=>"ROLL_PTR",
 :value=>
 :is_insert=>true, :rseg_id=>20, :undo_log=>:page=>335, :offset=>272],
 :length=>21,
 :transaction_id=>2843,
 :roll_pointer=>
 :is_insert=>true, :rseg_id=>20, :undo_log=>:page=>335, :offset=>272

share|improve this answer

answered Mar 24 at 22:21

Bill KarwinBill Karwin

391k65526682

answered Mar 24 at 22:21

Bill KarwinBill Karwin

391k65526682

answered Mar 24 at 22:21

Bill KarwinBill Karwin

391k65526682