postgres_fdw: Disable attribute statistics import from pre-9.1 servers. 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 <[email protected]> Reported-by: Osama Abdul Qader <[email protected]> Author: Etsuro Fujita <[email protected]> Reviewed-by: Corey Huinker <[email protected]> Discussion: https://postgr.es/m/CAHGQGwH8%2BuDTwfohpck9v_9L3nwSWACbmC36JYRyqHd5xQN_OA%40mail.gmail.com Backpatch-through: 19 Branch ------ REL_19_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/3e44c8a441f34117b3e6369fadfcbc94c7ae537d Modified Files -------------- contrib/postgres_fdw/postgres_fdw.c | 35 +++++++++++++++++++++++------------ doc/src/sgml/postgres-fdw.sgml | 11 ++++++----- 2 files changed, 29 insertions(+), 17 deletions(-)
