On 4/6/22 17:03, Peter Geoghegan wrote:
> On Wed, Apr 6, 2022 at 7:49 AM Frédéric Yhuel <frederic(dot)yhuel(at)dalibo(dot)com> wrote:
>> From the documentation
>> (https://www.postgresql.org/docs/current/sql-reindex.html#id-1.9.3.162.7)
>> it sounds like REINDEX won't block read queries that don't need the
>> index. But it seems like the planner wants to take an ACCESS SHARE lock
>> on every indexes, regardless of the query, and so REINDEX actually
>> blocks any queries but some prepared queries whose plan have been cached.
>>
>> I wonder if it is a bug, or if the documentation should be updated. What
>> do you think?
>
> I've always thought that the docs for REINDEX, while technically
> accurate, are very misleading in practice.
>
Maybe something along this line? (patch attached)