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author | Tom Lane <tgl@sss.pgh.pa.us> | 2015-07-31 19:26:33 -0400 |
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committer | Tom Lane <tgl@sss.pgh.pa.us> | 2015-07-31 19:26:33 -0400 |
commit | a6492ff8970b06b9e27cc314c7d1aa574fcc7b04 (patch) | |
tree | e7e3b9b388c0b1f65c565f135a79ac17114a47be /src/backend/access/transam/xlog.c | |
parent | 16c4e6d8dc8fb98cd32d9af473fb06a730fb40d3 (diff) | |
download | postgresql-a6492ff8970b06b9e27cc314c7d1aa574fcc7b04.tar.gz postgresql-a6492ff8970b06b9e27cc314c7d1aa574fcc7b04.zip |
Fix an oversight in checking whether a join with LATERAL refs is legal.
In many cases, we can implement a semijoin as a plain innerjoin by first
passing the righthand-side relation through a unique-ification step.
However, one of the cases where this does NOT work is where the RHS has
a LATERAL reference to the LHS; that makes the RHS dependent on the LHS
so that unique-ification is meaningless. joinpath.c understood this,
and so would not generate any join paths of this kind ... but join_is_legal
neglected to check for the case, so it would think that we could do it.
The upshot would be a "could not devise a query plan for the given query"
failure once we had failed to generate any join paths at all for the bogus
join pair.
Back-patch to 9.3 where LATERAL was added.
Diffstat (limited to 'src/backend/access/transam/xlog.c')
0 files changed, 0 insertions, 0 deletions