Re: (ITS#8335) MDB_MULTIPLE issues

[h.b.furuseth@usit.uio.no]

On 07/12/15 10:14, h.b.furuseth@usit.uio.no wrote:
> Put(0 data items, MDB_MULTIPLE) stores 1 item.  The doc does
> not warn against 0 items.  I suggest supporting 0 items, it
> is a commonly supported convenience elsewhere (e.g. memcpy).

I.e. supporting it as a no-op.  But on second thought I think
that's misleading and EINVAL is better: If the key doesn't exist,
this is an attempt to create a key with no data.  Unsupported.
Bryan Matsuo just posted a test case to openldap-technical.

datacount > UINT_MAX is truncated to unsigned int:
data[1].mv_size = 0x100000002 puts 2 items.

datacount * datasize can exceed UINT_MAX, which mdb_page_spill()
truncates to unsigned int.  Such a massive put() will likely
fail anyway, but it should at least try to spill properly first.

> Why does MDB_MULTIPLE require a cursor? mdb_put() rejects it.