Re: Too many logs are written on Windows (LOG: could not reserve shared memory region (addr=%p) for child %p:)

On Tue, Nov 20, 2018 at 1:21 AM Takahashi, Ryohei
<r(dot)takahashi_2(at)jp(dot)fujitsu(dot)com> wrote:
> My customer uses PostgreSQL on Windows and hits the problem that following log is written to the server logs too frequently (250 thousand times per day).
> "LOG: could not reserve shared memory region (addr=%p) for child %p:"
>
> This log is written when pgwin32_ReserveSharedMemoryRegion() in win32_shmem.c fails. If fails, internal_forkexec() in postmaster.c retries up to 100 times. In most of my customer cases, internal_forkexec() finally succeeded to pgwin32_ReserveSharedMemoryRegion() by retrying.
>
> According to the comment of internal_forkexec(), pgwin32_ReserveSharedMemoryRegion() sometimes fails if ASLR is active. If so, I think administrators are not interested in this log since it is a normal event.

You might be right, but maybe we should first try to understand why
this is happening so frequently. Maybe it's not that normal.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company