On 12/21/18 4:04 PM, Thomas Munro wrote:
> On Sat, Dec 22, 2018 at 7:32 AM David Fetter <david@fetter.org> wrote:
>> On Sat, Dec 22, 2018 at 07:03:32AM +1100, Thomas Munro wrote:
>>> That talks about using -D__ANDROID_API__=23 (or presumably higher) to
>>> make sure that sigtimedwait is exposed by signal.h. Something similar
>>> may be afoot here.
>> That worked perfectly...to expose the next issue, namely that at least
>> part of the System-V IPC mechanisms have been left out. Do we support
>> other systems where this is true?
> Interesting, they left that stuff out deliberately out basically
> because it all sucks:
>
>
https://android.googlesource.com/platform/ndk/+/4e159d95ebf23b5f72bb707b0cb1518ef96b3d03/docs/system/libc/SYSV-IPC.TXT
>
> PostgreSQL currently needs SysV shm just for the small segment that's
> used for preventing multiple copies running in the same pgdata. You'd
> need to find a new way to do that. We don't use SysV semaphores
> (though we can) or message queues.
That doc says:
Killing processes automatically to make room for new ones is an
important part of Android's application lifecycle implementation.
How's that going to play with Postgres? Sounds like the OOM killer on
steroids.
cheers
andrew
--
Andrew Dunstan https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
