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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2011-04-15 17:45:41 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2011-04-15 17:46:50 -0400 |
| commit | 72826fb362c4aada6d2431df0b706df448806c02 (patch) | |
| tree | 59805e2d8e32a9ef1f7a0091e08fed960fa2008c | |
| parent | d5a7bf8c11c8b66c822bbb1a6c90e1a14425bd6e (diff) | |
| download | postgresql-72826fb362c4aada6d2431df0b706df448806c02.tar.gz postgresql-72826fb362c4aada6d2431df0b706df448806c02.zip | |
Guard against incoming rowcount estimate of NaN in cost_mergejoin().
Although rowcount estimates really ought not be NaN, a bug elsewhere
could perhaps result in that, and that would cause Assert failure in
cost_mergejoin, which I believe to be the explanation for bug #5977 from
Anton Kuznetsov. Seems like a good idea to expend a couple more cycles
to prevent that, even though the real bug is elsewhere. Not back-patching,
though, because we don't encourage running production systems with
Asserts on.
| -rw-r--r-- | src/backend/optimizer/path/costsize.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c index e200dcf4728..d3455228660 100644 --- a/src/backend/optimizer/path/costsize.c +++ b/src/backend/optimizer/path/costsize.c @@ -1704,10 +1704,10 @@ cost_mergejoin(MergePath *path, PlannerInfo *root, SpecialJoinInfo *sjinfo) innerendsel; Path sort_path; /* dummy for result of cost_sort */ - /* Protect some assumptions below that rowcounts aren't zero */ - if (outer_path_rows <= 0) + /* Protect some assumptions below that rowcounts aren't zero or NaN */ + if (outer_path_rows <= 0 || isnan(outer_path_rows)) outer_path_rows = 1; - if (inner_path_rows <= 0) + if (inner_path_rows <= 0 || isnan(inner_path_rows)) inner_path_rows = 1; if (!enable_mergejoin) |