1. 15-415 Fall 2009 B+ Tree Recitation
Leman Akoglu 9/30/2009

2. Schedule Overview of the provided B+ tree package
Assignment 5 – the what’s
Assignment 5 – the how’s
11/13/2018
B+ Tree Recitation

3. B+ Tree Package – Compile&Run
make main  compiles the source code
./main
This starts you with an “empty” B+ tree
11/13/2018
B+ Tree Recitation

4. B+ Tree Package – Existing Func.s
"P” to scan and print all the keys in the tree
"i" to insert
"p" to print a B+ tree page (p 1 prints the root)
"s" to search and print the key
"S" to search and print the key as well as its posting list
"T" to print the B+ tree in in-order format
"x" to exit
11/13/2018
B+ Tree Recitation

5. B+ Tree Package – Main SRC files
main.c parses the input
scanTree.c scans the keys in the tree
How leaf pages are accessed
insert.c inserts a given key
Looks for the insert position for a given key
search.c to search and print the key
How to traverse child nodes
strdist.c returns distance between two keys
11/13/2018
B+ Tree Recitation

6. B+ Tree Package – Preloaded
make loaddb compiles the source code and inserts keys from several example text files
./main starts you with a B+ tree to play with
11/13/2018
B+ Tree Recitation

7. Assignment 5 – the what’s
WHAT TO IMPLEMENT:  2 new functions
Medium difficulty: range queries
R <key1> <key2> print keys in-between
r <key1> <key2> print count of keys in-between
More difficult: all-pairs queries
A < ε > print pairs of keys within ε distance
a < ε > print count of pairs of keys within ε
Show the given code and point to functions
Say that they print Please implement me right now
11/13/2018
B+ Tree Recitation

8. Assignment 5 – the how’s HOW TO START: All source files are in SRC
Implement:
1) R  keysInRange.c 2) r  countKeysInRange.c
3) A  allPairsWithin.c 4) a  countAllPairsWithin.c
Note: If you include .c files of your own, do not forget to update SRC/makefile
Show the makefile in SRC and how the .c files are included there
11/13/2018
B+ Tree Recitation

9. Assignment 5 – the how’s HOW TO TEST: Run ‘make hw5’
no errors/warnings
diff’s should be empty
Sample test files in Tests
generate test files for yourself if necessary
Note: We will use other tests for grading
Show the sample tests and their outputs
Show what make hw does
11/13/2018
B+ Tree Recitation

10. Reminders
Start EARLY!
Your implementation should be correct AND efficient.
No hard-copy this time.
Tar your source code and send it to with subject ‘submission homework 5’.
Talk about efficiency
11/13/2018
B+ Tree Recitation

11. Questions? Provided B+ tree package Assignment 5 – the what’s
Assignment 5 – the how’s
11/13/2018
B+ Tree Recitation