> [I prefer to keep the mailing list involved to share the discussion; > I hope you don't mind ... ;-) ]
Oops, I didn't notice... > http://repository.cwi.nl/search/searchrepository.php?stheme=INS1), > in particular > http://repository.cwi.nl/search/fullrecord.php?publnr=14290 > http://repository.cwi.nl/search/fullrecord.php?publnr=11117 > > and/or these PhD these: > http://repository.cwi.nl/search/fullrecord.php?publnr=14832 > http://repository.cwi.nl/search/fullrecord.php?publnr=14301 > http://repository.cwi.nl/search/fullrecord.php?publnr=16706 Wow, thank you. Especially "Self-organizing Tuple Reconstruction in Column-stores" seems to be very informative. I'm going to study ... > In the first case, tuple reconstruction is cheap (almost "for free"), as > columns are physically aligned, and hence, highly efficient in-order > positional lookup can be exploited for tuple reconstruction. > Obviously, with keeping the columns physically aligned does not allow to > order them individually according to their values. Thus without further > indeces, value-lookups using binary search are only possible for on sorted > column; for all other columns, some secondary index structure would be > required. MonetDB only used (automatically) hash-indeces for single-value > (point-)lookups, but resorts to (highly optimized) sequential scans for any > range lookups on non-sorted columns. > > In the second case, value-lookups can be done (reasonably) efficient using > binary search on each column, however tuple-reconstruction (i.e., OID > lookups) can no longer be done with simple highly efficient in-order > positional lookups. In that case, MonetDB would (automatically on-the-fly) > build a hash-index on the non-ordered (non-dense) OID columns. > > In general, there is no such thing as a "free lunch" ... ;-) > Again, thank you very much for your fast and illuminating answer. Gruß Tim ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2d-c2 _______________________________________________ Monetdb-developers mailing list Monetdb-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/monetdb-developers
