Re: shmem_seq may be a bad idea - Mailing list pgsql-hackers

From Tom Lane
Subject Re: shmem_seq may be a bad idea
Date
Msg-id 4046.957282753@sss.pgh.pa.us
Whole thread Raw
In response to Re: shmem_seq may be a bad idea  (Thomas Lockhart <lockhart@alumni.caltech.edu>)
List 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


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