Hi,
I've been having some issues with LMDB on i686/s390x when building
python-zarr and its dependants. I filed a bug report [1], but the
maintainer suggested asking here to get more reach. I have replicated
my original message from the report below:
The documentation for LMDB [2] states that the map size should be
"chosen as large as possible". Consequently, the zarr developers have
chosen a map size of 2**40 on 64-bit systems and 2**28 on 32-bit
systems [3]. When the package is built on a 64-bit system [4],
everything works fine. However, if the build is run on a 32-bit system
[5], it fails with a MemoryError.
I have narrowed this down to the mmap call at [6] which attempts to
map the backing file into memory. AFAICT, the mapped size is far below
the RAM on the build machine as well as far below the normal 32-bit VM
limit. So I don't know why the call is failing.
I can reproduce this in mock with the fedora-rawhide-i386 config, but
what's weird is it also fails in the fedora-rawhide-s390x config. This
machine has 16G of RAM, so it's enough for 2**28, but not 2**40. So it
fails on 32-bit x86 with more than enough RAM, works on 64-bit x86
with nowhere near enough RAM, yet fails with 64-bit s390x.
[1]
https://bugzilla.redhat.com/show_bug.cgi?id=1695525
[2]
http://www.lmdb.tech/doc/group__mdb.html#gaa2506ec8dab3d969b0e609cd82e619e5
[3]
https://github.com/zarr-developers/zarr/blob/f6ced1e31b919065f8834d813ec0...
[4]
https://koji.fedoraproject.org/koji/taskinfo?taskID=33910305
[5]
https://koji.fedoraproject.org/koji/taskinfo?taskID=33881973
[6]
http://www.openldap.org/devel/gitweb.cgi?p=openldap.git;a=blob;f=librarie...
--
Elliott