OK, John, I think I have an answer for you. It is not pretty. You
actually got pretty close.
First, increase SHMMAXPGS by 1024 for every additional 4MB of shared
memory:
/sys/sys/shm.h:69:#define SHMMAXPGS 1024 /* max hardware pages...
The default setting of 1024 is for a maximum of 4MB of shared memory.
Second, use bpatch to find the sysptsize value for the current kernel.
This is computed dynamically at bootup.
$ bpatch -r sysptsize
0x9 = 9
Next, change SYSPTSIZE to a hard-coded value. Use the bpatch value,
plus add 1 for every additional 4MB of shared memory you desire.
/sys/i386/i386/i386_param.c:28:#define SYSPTSIZE 0 /* dynamically...
sysptsize can not be changed by sysctl on the fly.
This should clearly be easier to do on BSDI. I will add a BSDI FAQ for
PostgreSQL to cover this. One downside is that shared memory is not
pageable. It is locked in RAM.
Sorry I am getting to this so late. I just finished my book.
--
Bruce Momjian | http://www.op.net/~candle
pgman@candle.pha.pa.us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026
