Avoid unnecessary single-child Append nodes.
Before commit d3cc37f1d801a6b5cad9bf179274a8, an inheritance parent
whose only children were temp tables of other sessions would end up
as a simple scan of the parent; but with that commit, we end up with
an Append node, per a report from Ashutosh Bapat. Tweak the logic
so that we go back to the old way, and update the function header
comment for partitioning while we're at it.
Ashutosh Bapat, reviewed by Amit Langote and adjusted by me.
Discussion: http://postgr.es/m/CAFjFpReWJr1yTkHU=OqiMBmcYCMoSW3VPR39RBuQ_ovwDFBT5Q@mail.gmail.com
Branch
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REL_10_STABLE
Details
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https://git.postgresql.org/pg/commitdiff/17a2a27b49ae19a1002b8230a6ceeef53082211e
Modified Files
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src/backend/optimizer/prep/prepunion.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)