Join

Multicolumn Join

Changes from the previous project

1. Modify the declaration of the API function from "int delete (int table_id, keynum_t key)" to "int remove (int table_id, keynum_t key)"
2. Change the file extensions of all source files in the source folder(project4/bpt/src/) into ".cpp".
3. Enhance the code readability by introducing OOP concepts in C++.
4. Modify the current record format for supporting multiple columns.
5. Support simple command parsing
6. Support join features
7. Parallel Execution

1. Modify the declaration of the API function

• Modification of the signatures of 'delete' API call from "int delete (int table_id, keynum_t key)" to "int remove (int table_id, keynum_t key)"

2. Change the file extensions of all source files into ".cpp"

• Change the current file extensions into cpp(C++).

3. Enhance the code readability

• Using object oriented architectures, the readability and productivity of codes get better.

4. Modify the current record format for supporting multiple columns.

• Supply the multi-column feature by replacing previously used data space.
• Add a column copying function into "class Page" for utilization of convenient access.

5. Support simple command parsing

• Add a simple command parser on the join query module. (ParseTree)
• This feature is supported by C++ String.

6. Support join operation feature

• Use just Naive Hash Join.
  • In detail, first read the entire table from the disk.
  • Second, hash the data into the an in-memory hash table.
  • Third, for each key, join the two distinct tables.
  • If there are other tables to join, proceed the same procedure to the other tables.
  • Otherwise, get the summation of all join keys.

7. Parallel Execution

• The hashing procedure is implemented in a parallel way (using two threads hashing its own table).
• The joining two distinct tables is also implemented in a parallel way.
• Calculating the sum of all keys derived from the result of the final join operation is being calculated by atomic operations with multiple threads.