pgsql: doc: Clarify behavior of query planner locking with REINDEX

doc: Clarify behavior of query planner locking with REINDEX

The documentation of REINDEX has never mentioned that the query planner
may take an ACCESS SHARE lock on the indexes depending on the query
used.  This adds also a note about prepared queries not impacted when
they do not use the index(es) rebuilt.

Author: Frédéric Yhuel
Reviewed-by: Guillaume Lelarge, Justin Pryzby
Discussion: https://postgr.es/m/65d08718-6f11-978a-4b5a-72b807d4c663@dalibo.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/8ac700acffc7b17d88414be47b8dff44fb1ea681

Modified Files
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doc/src/sgml/ref/reindex.sgml | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)