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a1feb90ef3
outer join clauses. Given, say, ... from a left join b on a.a1 = b.b1 where a.a1 = 42; we'll deduce a clause b.b1 = 42 and then mark the original join clause redundant (we can't remove it completely for reasons I don't feel like squeezing into this log entry). However the original implementation of that wasn't bulletproof, because clause_selectivity() wouldn't honor this_selec if given nonzero varRelid --- which in practice meant that it worked as desired *except* when considering index scan quals. Which resulted in bogus underestimation of the size of the indexscan result for an inner indexscan in an outer join, and consequently a possibly bad choice of indexscan vs. bitmap scan. Fix by introducing an explicit test into clause_selectivity(). Also, to make sure we don't trigger that test in corner cases, change the convention to be that this_selec > 1, not this_selec = 1, means it's been marked redundant. Per trouble report from Scara Maccai. Back-patch to 8.2, where the problem was introduced. |
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| .. | ||
| bitmapset.h | ||
| execnodes.h | ||
| makefuncs.h | ||
| memnodes.h | ||
| nodeFuncs.h | ||
| nodes.h | ||
| params.h | ||
| parsenodes.h | ||
| pg_list.h | ||
| plannodes.h | ||
| primnodes.h | ||
| print.h | ||
| readfuncs.h | ||
| relation.h | ||
| tidbitmap.h | ||
| value.h | ||