I am seeing Postgres 8.3.7 running as a service on Windows Server 2003
repeatedly fail to restart after a backend crash because of the
following code in port/win32_shmem.c:
/* * If the segment already existed, CreateFileMapping() will return a * handle to the existing one. */
if(GetLastError() == ERROR_ALREADY_EXISTS) { /* * When recycling a shared memory segment, it may take a
shortwhile * before it gets dropped from the global namespace. So re-try after * sleeping for a second.
*/ CloseHandle(hmap); /* Close the old handle, since we got a
valid * one to the previous segment. */
Sleep(1000);
hmap = CreateFileMapping((HANDLE) 0xFFFFFFFF, NULL,
PAGE_READWRITE, 0L, (DWORD) size, szShareMem); if (!hmap) ereport(FATAL,
(errmsg("couldnot create shared memory segment:
%lu", GetLastError()), errdetail("Failed system call was
CreateFileMapping(size=%lu, name=%s).", (unsigned long) size, szShareMem)));
if (GetLastError() == ERROR_ALREADY_EXISTS) ereport(FATAL, (errmsg("pre-existing shared
memoryblock is still in
use"), errhint("Check if there are any old server processes
still running, and terminate them."))); }
It strikes me that we really need to try reconnecting to the shared
memory here several times, and maybe the backoff need to increase each
time. On a loaded server this cause postgres to fail to restart fairly
reliably.
thoughts?
cheers
andrew
