Fix old oversight in const-simplification of COALESCE() expressions.
Once we have found a non-null constant argument, there is no need to
examine additional arguments of the COALESCE. The previous coding got it
right only if the constant was in the first argument position; otherwise
it tried to simplify following arguments too, leading to unexpected
behavior like this:
regression=# select coalesce(f1, 42, 1/0) from int4_tbl;
ERROR: division by zero
It's a minor corner case, but a bug is a bug, so back-patch all the way.
Branch
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REL8_1_STABLE
Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=faea08353120ed455df84ba30c07505248f5332b
Modified Files
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src/backend/optimizer/util/clauses.c | 6 +++++-
1 files changed, 5 insertions(+), 1 deletions(-)