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Commit 924d85bb authored by Bruce Momjian's avatar Bruce Momjian
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Update faq's.

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This outlines how to increase the number of shared memory buffers
supported by BSD/OS. By default, only 4MB of shared memory is supported
by BSDI.
Bruce Momjian (pgman@candle.pha.pa.us)
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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.
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