That is strange, because the majority of the comments are new. Much of the code and comments are reused from the SysV code because, you know, this is an enhancement. The comments that are left serve a purpose. In PGSharedMemoryCreate, this implementation avoids the need to tell if live backends are attached to an existing segment, since exisiting segments are not reattached to--the old segments are cleared when the live orphan backends die. I would love to hear some specific, less sweeping, comments about how the code is actually written and functions. Otherwise, I'll try to refactor this and return once again.

Thank you,
Chris Marcellino

On Feb 9, 2007, at 6:40 AM, Tom Lane wrote:

Chris Marcellino <[EMAIL PROTECTED]> writes:
Here is a new patch that uses the POSIX api's. It encodes the
canonical path (see 'man realpath') of the database's data directory
into the shared memory segment name using an strong hash function to
make it fit in the shared memory segment name under all cases,
without risk of key collision.

I find this patch utterly unreadable, because of your cavalier disregard for making the comments match the truth. You have copied-and- pasted the original SysV code and fixed some small fraction of the comments, and I
cannot tell which ones still reflect reality --- but I can tell that a
lot of them don't.

Also, I don't see where this implements any sort of detection of live
backends attached to an existing segment, so I don't think you have
responded to that objection.  Magnus' idea for Windows was to use a
segment set up to automatically go away as soon as the last attacher
died, but AFAICT that isn't how this works.

                        regards, tom lane

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