Issue #5106 has been reported by Kurt Stephens. ---------------------------------------- Feature #5106: Is MurmurHash overkill? http://redmine.ruby-lang.org/issues/5106 Author: Kurt Stephens Status: Open Priority: Normal Assignee: Category: Target version: st.c implements MurmurHash to compute hash table indexes (#hash). Simpler hash functions may be appropriate for hash tables, esp. small tables. Is there a particular reason this hash function was chosen? Is MurmurHash typically used for check-summing purposes? Anybody positively adverse to changing it? If so I won't bother. Otherwise I might take a crack at it. -- KAS
on 2011-07-27 05:55
on 2011-07-27 09:17
Issue #5106 has been updated by Yui NARUSE. Priority changed from Normal to Low ---------------------------------------- Feature #5106: Is MurmurHash overkill? http://redmine.ruby-lang.org/issues/5106 Author: Kurt Stephens Status: Open Priority: Low Assignee: Category: Target version: st.c implements MurmurHash to compute hash table indexes (#hash). Simpler hash functions may be appropriate for hash tables, esp. small tables. Is there a particular reason this hash function was chosen? Is MurmurHash typically used for check-summing purposes? Anybody positively adverse to changing it? If so I won't bother. Otherwise I might take a crack at it. -- KAS
on 2012-03-25 10:23
Issue #5106 has been updated by mame (Yusuke Endoh). Status changed from Open to Assigned Assignee set to mame (Yusuke Endoh) ---------------------------------------- Feature #5106: Is MurmurHash overkill? https://bugs.ruby-lang.org/issues/5106#change-25159 Author: kstephens (Kurt Stephens) Status: Assigned Priority: Low Assignee: mame (Yusuke Endoh) Category: Target version: st.c implements MurmurHash to compute hash table indexes (#hash). Simpler hash functions may be appropriate for hash tables, esp. small tables. Is there a particular reason this hash function was chosen? Is MurmurHash typically used for check-summing purposes? Anybody positively adverse to changing it? If so I won't bother. Otherwise I might take a crack at it. -- KAS
on 2012-03-26 18:45
Issue #5106 has been updated by mame (Yusuke Endoh). Status changed from Assigned to Feedback Hello, > Simpler hash functions may be appropriate for hash tables, esp. small > tables. Please make it quantitative when talking about performance. Please show a benchmark first. How slow is MurmurHash? How fast will st.c be if the algoritm is replaced with another one? And how much the drawback? That is, how many collision will increase in actual cases? > Anybody positively adverse to changing it? If so I won't bother. Otherwise > I might take a crack at it. Please make your move first. We cannot answer your question until you show a benchmark. Even after that, we cannot promise to import your patch before you create it. The chicken or the egg :-) Thanks, -- Yusuke Endoh <mame@tsg.ne.jp> ---------------------------------------- Feature #5106: Is MurmurHash overkill? https://bugs.ruby-lang.org/issues/5106#change-25195 Author: kstephens (Kurt Stephens) Status: Feedback Priority: Low Assignee: mame (Yusuke Endoh) Category: Target version: st.c implements MurmurHash to compute hash table indexes (#hash). Simpler hash functions may be appropriate for hash tables, esp. small tables. Is there a particular reason this hash function was chosen? Is MurmurHash typically used for check-summing purposes? Anybody positively adverse to changing it? If so I won't bother. Otherwise I might take a crack at it. -- KAS
on 2012-03-28 22:23
Issue #5106 has been updated by MartinBosslet (Martin Bosslet). With the recent changes since hashDoS I'm not sure whether we should really aim for simplicity. It's quite easy to become a target with a function that is algebraically as simple as for example DJB33X. But speed on the other hand couldn't hurt. We use Murmur 2, there is a version 3 by the same author who claims it is generally faster than 2. Maybe we should give that a try first? ---------------------------------------- Feature #5106: Is MurmurHash overkill? https://bugs.ruby-lang.org/issues/5106#change-25319 Author: kstephens (Kurt Stephens) Status: Feedback Priority: Low Assignee: mame (Yusuke Endoh) Category: Target version: st.c implements MurmurHash to compute hash table indexes (#hash). Simpler hash functions may be appropriate for hash tables, esp. small tables. Is there a particular reason this hash function was chosen? Is MurmurHash typically used for check-summing purposes? Anybody positively adverse to changing it? If so I won't bother. Otherwise I might take a crack at it. -- KAS
on 2012-11-19 18:33
Issue #5106 has been updated by mame (Yusuke Endoh). Status changed from Feedback to Rejected I'm closing this ticket. Feel free to reopen with benchmark. BTW: MurmurHash was replaced with SipHash which is a bit slower than MurmurHash. -- Yusuke Endoh <mame@tsg.ne.jp> ---------------------------------------- Feature #5106: Is MurmurHash overkill? https://bugs.ruby-lang.org/issues/5106#change-33104 Author: kstephens (Kurt Stephens) Status: Rejected Priority: Low Assignee: mame (Yusuke Endoh) Category: Target version: st.c implements MurmurHash to compute hash table indexes (#hash). Simpler hash functions may be appropriate for hash tables, esp. small tables. Is there a particular reason this hash function was chosen? Is MurmurHash typically used for check-summing purposes? Anybody positively adverse to changing it? If so I won't bother. Otherwise I might take a crack at it. -- KAS
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