diff options
| -rw-r--r-- | doc/src/sgml/postgres-fdw.sgml | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml index 1fa394ba1d9..4d5adf1f1b1 100644 --- a/doc/src/sgml/postgres-fdw.sgml +++ b/doc/src/sgml/postgres-fdw.sgml @@ -82,8 +82,8 @@ referenced columns of the remote table. Although <filename>postgres_fdw</> is currently rather forgiving about performing data type conversions at need, surprising semantic anomalies may arise when types or collations do - not match, due to the remote server interpreting <literal>WHERE</> clauses - slightly differently from the local server. + not match, due to the remote server interpreting query conditions + differently from the local server. </para> <para> @@ -382,6 +382,17 @@ need to turn this off if the remote server has a different set of collation names than the local server does, which is likely to be the case if it's running on a different operating system. + If you do so, however, there is a very severe risk that the imported + table columns' collations will not match the underlying data, resulting + in anomalous query behavior. + </para> + + <para> + Even when this parameter is set to <literal>true</literal>, importing + columns whose collation is the remote server's default can be risky. + They will be imported with <literal>COLLATE "default"</literal>, which + will select the local server's default collation, which could be + different. </para> </listitem> </varlistentry> |