pgsql: Don't truncate away non-key attributes for leftmost downlinks.

Don't truncate away non-key attributes for leftmost downlinks.

nbtsort.c does not need to truncate away non-key attributes for the
minimum key of the leftmost page on a level, since this is only used to
build a minus infinity downlink for the level's leftmost page.
Truncating away non-key attributes in advance of truncating away all
attributes in _bt_sortaddtup() does not affect the correctness of CREATE
INDEX, but it is misleading.

Author: Peter Geoghegan
Discussion: https://www.postgresql.org/message-id/CAH2-WzkAS2M3ussHG-s_Av=Zo6dPjOxyu5fNRkYnxQV+YzGQ4w@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/2a9e04f0a8ada12d4af4f095e4dbe164e2983bce

Modified Files
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src/backend/access/nbtree/nbtsort.c | 30 ++++++++++++++----------------
1 file changed, 14 insertions(+), 16 deletions(-)