Re: blobspaces

Mike Segel wrote: > > Sujit Pal wrote: > > > > Chao/Art > > > > Here is my $ 0.02. > > > Also, as both Art and I have stated, BLOBs of 1-2 pages (which are > not = > > exactly large :-)) would perform better if stored in tablespaces > since = > > they can take advantage of the buffer cache. However Chao's > application = > > has BLOBs of sizes 25-40 pages (assuming 1 page =3D 2K). In that > case, = > > as Chao rightly says the benefits of buffering may be offset by high > = > > page swapping. > > > > And thanks Art and Chao for lots of well thought out practical > advice. > > > Hmmm, > Considering that a page is either 2 or 4K and if you are storing > blobs in table space, are they being stored with the row? Or > does the row have a pointer to an offset in a different chunk? All the pages will be stored in the table extent. But remember that each page stores homogenous data, that is, some pages will store data, some index, and some BLOB info, etc. The type of storage is never mixed in the same page. > I mean this may be a totally brain dead question, but, > how does Informix store a blob in "table" space? > Also, what happens when the data grows? What happens to the > organization of extents? Same as NOT storing BLOB data in the tablespace. BLOB data is just another page type in the tablespace. > It's been a while since I have looked at blobs so my alzhimers > is kicking in. Alzheimer's! Is THAT what they're calling it these days? ;-) I suppose your doctor said; "you have Alcohol poisoning and Alzheimer's", and you said, "at least I don't have Alcohol poisoning!" :-) Cheers, -- Mark. +----------------------------------------------------------+-----------+ |Mark D. Stock - Informix SA http://www.informix.com |//////// /| |mailto:mdstock@informix.com FAQ http://www.iiug.org |///// / //| | +-----------------------------------+//// / ///| | Tel: +27 11 807 0313 |If it's slow, the users complain. |/// / ////| | Fax: +27 11 807 2594 |If it's fast, the users keep quiet.|// / /////| |Cell: +27 83 250 2325 |Therefore, "No news: travels fast"!|/ ////////| +----------------------+-----------------------------------+-----------+