3ca4abd60c
To import attribute statistics, postgres_fdw sent a query wity COLLATE
"C" to remote servers without checking their version. Since COLLATE is
only supported since v9.1, this could break the import against older
servers; fix by modifying postgres_fdw to check their version and if
older, fall back to sampling. (This commit still allows importing only
relation statistics from such an older server.)
Also, expand the documentation to mention that attribute statistics are
stored into the local server without applying the foreign table columns'
n_distinct option.
Oversight in commit 28972b6fc.
Reported-by: Fujii Masao <masao.fujii@gmail.com>
Reported-by: Osama Abdul Qader <osamaabdulqader.cs@gmail.com>
Author: Etsuro Fujita <etsuro.fujita@gmail.com>
Reviewed-by: Corey Huinker <corey.huinker@gmail.com>
Discussion: https://postgr.es/m/CAHGQGwH8%2BuDTwfohpck9v_9L3nwSWACbmC36JYRyqHd5xQN_OA%40mail.gmail.com
Backpatch-through: 19
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.