I haven't taken the time to really grok why the limitation exists (e.g. i'd be interested in to know if it's fundamental). There is a comment here: https://github.com/ceph/ceph/blob/master/src/osd/PrimaryLogPG.cc#L3221 - Noah On Sat, Jun 3, 2017 at 8:18 PM, Zheyuan Chen <zchen137@xxxxxxxx> wrote: >> Unfortunately, this isn't a bug. Rados clears any returned data from >> an object class method if the operation also writes to the object. > > Do you have any idea why RADOS behaves like this? > > > > On Sat, Jun 3, 2017 at 9:30 AM, Noah Watkins <noahwatkins@xxxxxxxxx> wrote: >> >> Comments inline >> >> > ---------- Forwarded message ---------- >> > From: Zheyuan Chen <zchen137@xxxxxxxx> >> > Date: Sat, Jun 3, 2017 at 1:45 PM >> > Subject: Bug report: unexpected behavior when executing >> > Lua object class >> > To: ceph-users@xxxxxxxxxxxxxx >> > >> > Bug 1: I can not get returned output in the first script. "data" is >> > always empty. >> > >> >> import rados, json >> >> cluster = rados.Rados(conffile='') >> >> cluster.connect() >> >> ioctx = cluster.open_ioctx('data') >> >> cmd = { >> >> "script": """ >> >> function test(input, output) >> >> data = bufferlist.new() >> >> data:append("test") >> >> objclass.write_full(data, #data) >> >> output:append("Here is the return value") >> >> end >> >> objclass.register(test) >> >> """, >> >> "handler": "test", >> >> "input": "", >> >> } >> >> # I can not get returned data >> >> ret, data = ioctx.execute('test', 'lua', 'eval_json', json.dumps(cmd)) >> >> print ret, data >> >> Unfortunately, this isn't a bug. Rados clears any returned data from >> an object class method if the operation also writes to the object. >> >> > Bug 2: >> > The returned mtime is always 0. >> >> This might be a bug, but there are a few things to rule out. Did you >> write to the object before running stat? There is also a test case >> here: can you try to run them? >> >> >> https://github.com/ceph/ceph/blob/master/src/test/cls_lua/test_cls_lua.cc#L679 >> >> - Noah > > _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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