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The "LucyBookClub" page has been changed by MarvinHumphrey: http://wiki.apache.org/lucy/LucyBookClub?action=diff&rev1=32&rev2=33 Comment: Add Jan 15 2003 meeting on PFOR-DELTA paper. == Upcoming Meetings == - '''NOTICE: Lucy book club will not be meeting during the holiday season, next meeting is January 3rd, 2013''' - === Tuesday January 15, 7:00 pm PDT: === + + The Lucy Book Club is taking a break from our book-in-progress this week to read a paper on integer compression techniques. One of the algorithms described in the paper is PFOR-DELTA (Patched Frame-Of-Reference with delta encoding), which is particularly suitable for inverted lists. + + [[http://oai.cwi.nl/oai/asset/15564/15564B.pdf|Super-Scalar RAM-CPU Cache Compression]] by Marcin Zukowski, Sándor Héman, Niels Nes, Peter Boncz + + We'll go over the following questions: + + 1. Why is PFOR-DELTA interesting to Lucy? + 2. What is a ''segment'' in PFOR-DELTA? + 3. What are the 4 major parts of a segment? What is in them? + 4. What are the tradeoffs for choosing different sizes of `b` (bit width)? + 5. What type of data structure is used to keep track of exceptions? + 6. What is a ''compulsory exception''? How does it influence your choice of `b`? + 7. PFOR-DELTA is a very interesting compression technique, but why is it really faster? What is PFOR-DELTA really optimizing for? + 8. In their testing, was RAM-RAM or RAM-Cache faster and why? + 9. Fine-grained access has some extra cost -- what is it? == Community Notes ==
