Fix an Assert that turns out to be reachable after all.
estimate_num_groups() gets unhappy with
create table empty();
select * from empty except select * from empty e2;
I can't see any actual use-case for such a query (and the table is illegal
per SQL spec), but it seems like a good idea that it not cause an assert
failure.
Branch
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REL8_3_STABLE
Details
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http://git.postgresql.org/pg/commitdiff/454c7fb3a372ef8970a3896dcec94efb6db41382
Modified Files
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src/backend/utils/adt/selfuncs.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)