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 ------ master Details ------- https://git.postgresql.org/pg/commitdiff/3ca4abd60ce3661c6ccd3d83a13986ef9541bf40 Modified Files -------------- contrib/postgres_fdw/postgres_fdw.c | 35 +++++++++++++++++++++++------------ doc/src/sgml/postgres-fdw.sgml | 11 ++++++----- 2 files changed, 29 insertions(+), 17 deletions(-)
