Re: REINDEX blocks virtually any queries but some prepared queries. - Mailing list pgsql-hackers

From Frédéric Yhuel
Subject Re: REINDEX blocks virtually any queries but some prepared queries.
Date
Msg-id 449f275c-eeb9-3292-86c9-00aa6bda7609@dalibo.com
Whole thread Raw
In response to Re: REINDEX blocks virtually any queries but some prepared queries.  (Peter Geoghegan <pg@bowt.ie>)
Responses Re: REINDEX blocks virtually any queries but some prepared queries.  (Justin Pryzby <pryzby@telsasoft.com>)
List pgsql-hackers

On 4/6/22 17:03, Peter Geoghegan wrote:
> On Wed, Apr 6, 2022 at 7:49 AM Frédéric Yhuel <frederic.yhuel@dalibo.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)
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