Hi, I wrote > Finally the paper is mostly about column stores - nothing about persistence.
Regarding column store, Hadi wrote 2014-04-03 18:43 GMT+02:00 about the release of a PostgreSQL Columnar Store called "cstore_fdw" [1]! @Hadi: Can you say something about usage of cstore FDW in-memory? Regards, S. [1] http://citusdata.com/blog/76-postgresql-columnar-store-for-analytics 2014-04-02 0:32 GMT+02:00 Stefan Keller <sfkel...@gmail.com>: > Hi Yeb > > Thanks for the pointers. > > Of course disk access is not obsolete: As I said, I suppose changes are > streamed to disk. > > When I mentioned "no disk access" I meant the indices of RDBMS which > designed to handle disk access - which seems to me different in in-memory > dabases. > > The paper referred by you is coming from SAP's chief scientist and it > confirms actually my claim, that there's no need for a primary index since > the primary attribute (i.e. all attributes) is already kept sorted > in-memory. > > It also mentions an insert-only technique: "This approach has been adopted > before in POSTGRES [21] in 1987 and was called "time-travel". > I would be interested what "time-travel" is and if this is still used by > Postgres. > Finally the paper is mostly about column stores - nothing about > persistence. In mentions Disaster recovery" in the last section about > future work, though. > > -S. > > > > > 2014-04-01 21:57 GMT+02:00 Yeb Havinga <yebhavi...@gmail.com>: > > On 2014-04-01 04:20, Jeff Janes wrote: >> >> On Sunday, March 30, 2014, Stefan Keller <sfkel...@gmail.com> wrote: >> >>> Hi Jeff >>> >>> 2013/11/20 Jeff Janes <jeff.ja...@gmail.com> >>> >>>> >>>> I don't know what you mean about enhancements in the buffer pool. >>>> For an in-memory database, there shouldn't be a buffer pool in the first >>>> place, as it is *all* in memory. >>>> >>> >>> You are right: In-memory DBs are making buffer-pooling obsolete - >>> except for making data persistent (see below). >>> >> >> >> I would be very reluctant to use any database engine which considered >> disk access obsolete. >> >> >> The disk is not obsolete but something called 'anti-caching' is used: >> http://www.vldb.org/pvldb/vol6/p1942-debrabant.pdf >> >> >> >> >> Are there any show cases out there? >>> >> >> What did the HANA users have to say? Seems like they would be in the >> best position to provide the test cases. >> >> >> This paper provides some insights into the research behind HANA >> http://www.sigmod09.org/images/sigmod1ktp-plattner.pdf >> >> regards >> Yeb >> >> >
