tests/overview/xref.t failing

[Wim Lewis]

Running 'make test', I find that xref.t is failing (tests 20-27 and 
29-32). Looking at the code, I think the problem is that the overview IDX
files aren't being re-read after an article is written to them--- the 
failing tests are the places where a stored overview line is read back to 
check that it was stored correctly, except for the first time each group 
is read (tests 2-5, 11-18) and when the high water mark is advanced 
(7-10), which work correctly.

I don't see a mechanism in the code for the files to be refreshed except 
in the case that the high water mark has been advanced, so I'm not sure 
what the proper fix is. On systems which don't have MMAP_MISSES_WRITES, 
perhaps the underlying write shows up automatically? Are there other 
systems which have MMAP_MISSES_WRITES but on which this test doesn't fail?

I tried turning off tradindexedmmap in fake_innconf(), to see if the bug 
is specific to mmap semantics, but index_map() refuses to open an index 
for writing without it.


Wim.