Win32 processCancelRequest/waitpid (was fork/exec patch : pre-CreateProcess finalization)

Claudio Natoli wrote:

I wrote:

But I'll happily concede the point, and prove it by knocking
up a patch for it over the weekend (unless anyone else
particularly wants to).

Occurs to me I could kill 2 birds with one stone, and also implement another
Win32 sticking point, namely the waitpid changes for the Postmaster, by
having win32_forkexec do one of the following:

a) - when a backend startup is indicated, add a pid/cancel_key struct
(Backend) to this new array in shared mem
- when any child of the postmaster is started, also add a pid/HANDLE
struct to a postmaster local array (or perhaps a dlllist)

b) - when any child of the postmaster is started, add a
pid/cancel_key/HANDLE/isBackend struct to this new array in shared mem

(HANDLE for waiting on to determine child death; isBackend to separate
BackendList backends from other children)

Choosing a over b:
PRO: as we've already been through, keeps the postmaster-only data
local to the postmaster, stopping tampering from rouge backends
CON: yet more redundancy

Given recent conversations, I'm guessing (a), but any comments before going
ahead and doing it?

As I understand it, the postmaster shared memory idea is good because
only the postmaster writes to it, and only the backends read from it.
If the HANDLE works the same way, I think you should put it into the
shared memory too, hence (b).

[ FYI, I haven't seen you on IM lately.]

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

Bruce Momjian <pgman@candle.pha.pa.us> writes:

As I understand it, the postmaster shared memory idea is good because
only the postmaster writes to it, and only the backends read from it.
If the HANDLE works the same way, I think you should put it into the
shared memory too, hence (b).

But the postmaster needs to use the HANDLE, hence not (b).

regards, tom lane

Tom Lane wrote:

Bruce Momjian <pgman@candle.pha.pa.us> writes:

As I understand it, the postmaster shared memory idea is good because
only the postmaster writes to it, and only the backends read from it.
If the HANDLE works the same way, I think you should put it into the
shared memory too, hence (b).

But the postmaster needs to use the HANDLE, hence not (b).

That's where I was unclear. If the postmaster has to read the HANDLE,
we are better with keeping it in local memory (a).

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073