dan 6fde1799f8 Fix another problem in lead()/lag(). And some errors that could occur
following OOM faults.

FossilOrigin-Name: fadd4dc119d8df0d871f4d839b7a11070e2ffb8927e84b3e7a94f34196db3de3
2018-06-15 19:01:35 +00:00
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2018-06-08 20:58:27 +00:00
2018-03-28 15:06:39 +00:00
2018-05-30 00:59:09 +00:00