Characteristics
DB2 tables
MyISAM 
InnoDB 
BDB tables
tables
tables
Commitment 
Yes
No Yes
Yes
Control
Isolation level
UR, CS, RS, 
No
RU, RC, RR, 
RR
Serializable
Rollback on DDL
Yes
No
No
No
Consider using table level locking for:
Applications that use mostly reads such as Data Warehouse and Business 
Intelligence applications
Applications reading and updating through key positioning such as 
UPDATE... WHERE Custno = ?
Applications using INSERTs with subselects and only a small number of 
UPDATE and DELETEs
Consider to use for row level locking for:
Applications requiring a high level of concurrency and OLTP capabilities
Many SELECTs with only small result sets
Applications with high UPDATE/INSERT/DELETE frequency
However, let us attempt to summarize the concurrency issues that may arise 
when migrating a MySQL application to DB2 based on the two MySQL table 
types, which we consider significant:
MyISAM tables provide a high level of concurrency since SQL processing 
occurs in autocommit mode and no row level locks are maintained. When 
migrating to DB2 ensure your application operates in autocommit mode, 
which is by default not the case. Verify the lowest isolation level required for 
your application and MyISAM tables.
InnoDB tables provide concurrency control very similar to DB2. Please be 
aware that default transaction isolation for InnoDB is 
repeatable read 
while 
DB2 operates by default with 
cursor stability
.
7.3.5  Specifying the isolation level in DB2
Because the isolation level determines how data is locked and isolated from 
other processes while the data is being accessed, you should select an isolation 
level that balances the requirements of concurrency and data integrity. The 
isolation level that you specify is in effect for the duration of the 
unit of work.
230 
MySQL to DB2 UDB Conversion Guide






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