Обсуждение: pgsql: Further harden nbtree posting split code.

Further harden nbtree posting split code.

Add more defensive checks around posting list split code.  These should
detect corruption involving duplicate table TIDs earlier and more
reliably than any existing check.

Follow up to commit 8f72bbac.

Discussion: https://postgr.es/m/CAH2-WzkrSY_kjyd1_M5xJK1uM0govJXMxPn8JUSvwcUOiHuWVw@mail.gmail.com
Backpatch: 13-, where nbtree deduplication was introduced.

Branch
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REL_14_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/d078fe83d592618d9137e50306566c5a34ceb8aa

Modified Files
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src/backend/access/nbtree/nbtinsert.c | 23 +++++++++++++++++++++--
src/backend/access/nbtree/nbtsearch.c | 17 +++++++++++++++++
2 files changed, 38 insertions(+), 2 deletions(-)