Обсуждение: pgsql: Handle lack of DSM slots in parallel btree build, take 2.

Handle lack of DSM slots in parallel btree build, take 2.

Commit 74618e77 added a new check intended to fix a bug, but put
it in the wrong place so that parallel btree build was always
disabled.  Do the check after we've actually tried to create
a DSM segment.  Back-patch to 11, like the earlier commit.

Reviewed-by: Peter Geoghegan
Discussion: https://postgr.es/m/CAH2-WzmDABkJzrNnvf%2BOULK-_A_j9gkYg_Dz-H62jzNv4eKQTw%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/d9fe702a2c9843af71419ad0df069859e5581694

Modified Files
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src/backend/access/nbtree/nbtsort.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)