In Alfresco Share, the data-list is a the type - dl:datalist, the record value is stored as the node properties, I am afraid the performance issue will occur if there are too many records. So I want to build a new kind of data-list which stores the value in RDBMS, for example, MySQL.
Are there any samples or document on how to implement it? Thanks!
the standard Alfresco data-list already store the values in RDBMS via the NodeService. If you wanted to change how (specific) data lists are maintained, you are very likely to end up re-writing all of the existing data-list service code to achieve this. There should definitely not be any samples or documentation on this anywhere public, as this is something I would expect no-one in the community to ever have attempted (internal / customer projects of other partners excluded).
Have you tested and verified your performance anxiety with tests? Before going overboard and throwing stuff away that Alfresco provides for free, make sure you validate your assumptions by real-world and extreme test scenarios.