Re: shmem_seq may be a bad idea

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Lockhart <lockhart@alumni.caltech.edu>
Cc: Peter Eisentraut <peter_e@gmx.net>, pgsql-hackers@postgreSQL.org, Michael Blakeley <mike@blakeley.com>
Date: 2000-05-02T15:52:33Z
Lists: pgsql-hackers
Thomas Lockhart <lockhart@alumni.caltech.edu> writes:
>> A while ago while thinking about a way to make ipcclean better I thunk
>> that perhaps the postmaster should write the keys of the segments it gets
>> to a flat-text file.

> Hmm. Could we write this to a separate shared memory segment? Much
> more likely to be of fixed length and compatible between versions, and
> more likely to exist or not exist with the same behavior as the large
> shared memory segment under discussion??

What happens if you get a key collision with some other application
for that segment?  Seems to me that using shmem to remember where you
put your shmem segments is dangerously circular ;-)

The flat text file is not a bad idea, but I think the logic I suggested
yesterday makes it unnecessary...

			regards, tom lane