Re: Why Doesn't Buffer Pagesize match System Pagesize?

We run Informix OnLine 7.12UC5 on a Sun Ultra 6000. >Solaris reports a pagesize of 8k (for the sun4u Ultra SPARC, >- - type "pagesize" on your Solaris system if you have a >different chip) > >Informix seems to be dealing with a pagesize of 2k. >("onstat -b" says ".... 2048 buffer size"). > >Does this mean that every time the engine reads a buffer >page, the system delivers 8k, and Informix ignores all but >the first 2k? So that to read 200k, Informix performs 100 >IO operations, instead of 25? No. The kernel page size that the OS is reporting refers to the page size that is used in reads/writes to and from the swap file. The informix pagesize refers to the "block size" that is done to/from the database chunks. The only thing that they have in common is the word "pagesize". There is bound to be some "reshuffeling" with the actual IO becaues the prep factors of the actual disk drives that are used on any system are the only "real physical" IO that ever occurs. Also, there will be some because of any volume managers involved. Madison Pruet