Do You Use blobspaces?
natebsi asked whether people always put large BYTE columns in blobspaces, since a recent move showed no visible performance gain and caused headaches. Ian Michael Gumby answered that it depends: blobspaces avoid filling logical logs and shared memory, but gains depend on tuning, column size and load, and may not show under light load. No further answer.
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I'm curious if, when you have a byte column (in a table that will contain a significant amount of data), lets say, that you always create that column in a blobspace? We have recently begun moving over just such a column to a blobspace, and I've read all about the alleged performance benefits (data not passing through shared memory and logical logs), but it also creates some headaches for us. And, most importantly, the performance enhancements are not readily visible. I'm just curious if blobspaces for large tables are standard for everyone or not?
I'm not sure what you mean. It sounds like that you have a very large column in a table and you want to store it as a blob in an effort to shrink the table size. Is this column ever used in a query's condition statement? The answer is that "it depends". > From: natebsi@gmail.com > Subject: Do You Use blobspaces? > Date: Wed, 11 Jun 2008 11:19:47 -0700 > To: informix-list@iiug.org > > I'm curious if, when you have a byte column (in a table that will > contain a significant amount of data), lets say, that you always > create that column in a blobspace? > > We have recently begun moving over just such a column to a blobspace, > and I've read all about the alleged performance benefits (data not > passing through shared memory and logical logs), but it also creates > some headaches for us. And, most importantly, the performance > enhancements are not readily visible. > > I'm just curious if blobspaces for large tables are standard for > everyone or not? > _______________________________________________ > Informix-list mailing list > Informix-list@iiug.org > http://www.iiug.org/mailman/listinfo/informix-list _________________________________________________________________ It’s easy to add contacts from Facebook and other social sites through Windows Live™ Messenger. Learn how. https://www.invite2messenger.net/im/?source=TXT_EML_WLH_LearnHow
> It sounds like that you have a very large column in a table and you want to store it as a blob in an effort to shrink the table size. Yes, that part of it. But according to the doc, there are benefits to storing a text/byte column in a blobspace as opposed to a normal dbspace such as not having the data pass through the logical logs or shared memory. This would seem to suggest that that blobspaces, from a performance standpoint, are always better. Is that untrue? > Is this column ever used in a query's condition statement? No.
The answer again... it depends. In general, yes, you can expect to see some gains in performance. But it will depend on a couple of things. How well you tuned your system and how large is the column.... You don't fill up your logical logs as fast which is a good thing. The smaller row, the more rows to a page ... yada yada yada... you know the drill. But you may not see any gains if you're not under a heavy load. Does that make sense? > From: natebsi@gmail.com > Subject: Re: Do You Use blobspaces? > Date: Wed, 11 Jun 2008 11:59:50 -0700 > To: informix-list@iiug.org > > > > It sounds like that you have a very large column in a table and you want to store it as a blob in an effort to shrink the table size. > > Yes, that part of it. But according to the doc, there are benefits to > storing a text/byte column in a blobspace as opposed to a normal > dbspace such as not having the data pass through the logical logs or > shared memory. This would seem to suggest that that blobspaces, from a > performance standpoint, are always better. Is that untrue? > > > Is this column ever used in a query's condition statement? > > No. > _______________________________________________ > Informix-list mailing list > Informix-list@iiug.org > http://www.iiug.org/mailman/listinfo/informix-list _________________________________________________________________ Now you can invite friends from Facebook and other groups to join you on Windows Live™ Messenger. Add now. https://www.invite2messenger.net/im/?source=TXT_EML_WLH_AddNow_Now