Advantages of Fragmenting Across DBSpaces
Is there any advantage to spreading table fragments across distinct dbspaces if bulk storage is managed via SAN?
Simply? Yes. More parallelism within the engine and most queries are processed against memory anyway. ALso improved flush times up to the limits of the array. Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Fri, Jul 22, 2011 at 2:03 PM, red_valsen <red_valsen@yahoo.com> wrote: > Is there any advantage to spreading table fragments across distinct > dbspaces if bulk storage is managed via SAN? > _______________________________________________ > Informix-list mailing list > Informix-list@iiug.org > http://www.iiug.org/mailman/listinfo/informix-list >
On Jul 22, 3:02 pm, Art Kagel <art.ka...@gmail.com> wrote: > Simply? Yes. More parallelism within the engine and most queries are > processed against memory anyway. ALso improved flush times up to the limits > of the array. > > Art > > Art S. Kagel > Advanced DataTools (www.advancedatatools.com) > Blog:http://informix-myview.blogspot.com/ > > Disclaimer: Please keep in mind that my own opinions are my own opinions and > do not reflect on my employer, Advanced DataTools, the IIUG, nor any other > organization with which I am associated either explicitly, implicitly, or by > inference. Neither do those opinions reflect those of other individuals > affiliated with any entity with which I am affiliated nor those of the > entities themselves. > But can't I get the same performance gains simply by fragmenting within the same dbspace? > > > > > > > On Fri, Jul 22, 2011 at 2:03 PM, red_valsen <red_val...@yahoo.com> wrote: > > Is there any advantage to spreading table fragments across distinct > > dbspaces if bulk storage is managed via SAN? > > _______________________________________________ > > Informix-list mailing list > > Informix-l...@iiug.org > >http://www.iiug.org/mailman/listinfo/informix-list
Oh, yes. As far as parallelism is concerned, no difference. Note, however, that dirty page flushes at checkpoint time happen with one thread per chunk, so you have to balance the ease of a single dbspace with a single huge chunk versus many chunks in one or more dbspaces. The main downside to ganging all of the fragments of a large table in to a single large dbspace is that as extents are added to the fragments they will be interleaved between all of the fragments. Dedicating a dbspace to each fragment will ensure that each new extent is contiguous with the existing extent in that chunk and will be coalesced into a single larger extent which means less head movement - potentially. Of course the uncertainlty of a SAN environment limit how much this will actually improve overall performance, but we can try. Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Fri, Jul 22, 2011 at 4:13 PM, red_valsen <red_valsen@yahoo.com> wrote: > On Jul 22, 3:02 pm, Art Kagel <art.ka...@gmail.com> wrote: > > Simply? Yes. More parallelism within the engine and most queries are > > processed against memory anyway. ALso improved flush times up to the > limits > > of the array. > > > > Art > > > > Art S. Kagel > > Advanced DataTools (www.advancedatatools.com) > > Blog:http://informix-myview.blogspot.com/ > > > > Disclaimer: Please keep in mind that my own opinions are my own opinions > and > > do not reflect on my employer, Advanced DataTools, the IIUG, nor any > other > > organization with which I am associated either explicitly, implicitly, or > by > > inference. Neither do those opinions reflect those of other individuals > > affiliated with any entity with which I am affiliated nor those of the > > entities themselves. > > But can't I get the same performance gains simply by fragmenting within > the same dbspace? > > > > > > > > > > > > > > On Fri, Jul 22, 2011 at 2:03 PM, red_valsen <red_val...@yahoo.com> > wrote: > > > Is there any advantage to spreading table fragments across distinct > > > dbspaces if bulk storage is managed via SAN? > > > _______________________________________________ > > > Informix-list mailing list > > > Informix-l...@iiug.org > > >http://www.iiug.org/mailman/listinfo/informix-list > > _______________________________________________ > Informix-list mailing list > Informix-list@iiug.org > http://www.iiug.org/mailman/listinfo/informix-list >