Hi Mark, > lineitem has 1535724 pages (11997 MB) > > Shared Buffers Elapsed IO rate (from vmstat) > -------------- ------- --------------------- > 400MB 101 s 122 MB/s > > 2MB 100 s > 1MB 97 s > 768KB 93 s > 512KB 86 s > 256KB 77 s > 128KB 74 s 166 MB/s > > I've added the observed IO rate for the two extreme cases > (the rest can be pretty much deduced via interpolation). > > Note that the system will do about 220 MB/s with the now > (in)famous dd test, so we have a bit of headroom (not too bad > for a PIII).
What's really interesting: try this with a table that fits into I/O cache (say half your system memory), and run VACUUM on the table. That way the effect will stand out more dramatically. - Luke ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
