(mysql.info.gz) InnoDB consistent read

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(mysql.info.gz) InnoDB transaction isolation

(mysql.info.gz) InnoDB transaction model

(mysql.info.gz) InnoDB locking reads

 
 15.11.3 Consistent Non-Locking Read
 -----------------------------------
 
 A consistent read means that `InnoDB' uses its multi-versioning to
 present to a query a snapshot of the database at a point in time.  The
 query will see the changes made by exactly those transactions that
 committed before that point of time, and no changes made by later or
 uncommitted transactions. The exception to this rule is that the query
 will see the changes made by the transaction itself that issues the
 query.
 
 If you are running with the default `REPEATABLE READ' isolation level,
 then all consistent reads within the same transaction read the snapshot
 established by the first such read in that transaction. You can get a
 fresher snapshot for your queries by committing the current transaction
 and after that issuing new queries.
 
 Consistent read is the default mode in which `InnoDB' processes
 `SELECT' statements in `READ COMMITTED' and `REPEATABLE READ' isolation
 levels. A consistent read does not set any locks on the tables it
 accesses, and therefore other users are free to modify those tables at
 the same time a consistent read is being performed on the table.
 

Info Catalog

(mysql.info.gz) InnoDB transaction isolation

(mysql.info.gz) InnoDB transaction model

(mysql.info.gz) InnoDB locking reads