diff options
| -rw-r--r-- | doc/src/sgml/ddl.sgml | 14 | ||||
| -rw-r--r-- | doc/src/sgml/fdwhandler.sgml | 4 |
2 files changed, 15 insertions, 3 deletions
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml index ca6b8637934..c624fc2d9a2 100644 --- a/doc/src/sgml/ddl.sgml +++ b/doc/src/sgml/ddl.sgml @@ -3008,6 +3008,9 @@ ANALYZE measurement; <indexterm> <primary>foreign table</primary> </indexterm> + <indexterm> + <primary>user mapping</primary> + </indexterm> <para> <productname>PostgreSQL</productname> implements portions of the SQL/MED @@ -3037,8 +3040,15 @@ ANALYZE measurement; tables</firstterm>, which define the structure of the remote data. A foreign table can be used in queries just like a normal table, but a foreign table has no storage in the PostgreSQL server. Whenever it is - used, PostgreSQL asks the foreign data wrapper to fetch the data from the - external source. + used, <productname>PostgreSQL</productname> asks the foreign data wrapper + to fetch the data from the external source. + </para> + + <para> + Accessing remote data may require authentication at the external + data source. This information can be provided by a + <firstterm>user mapping</>, which can provide additional options based + on the current <productname>PostgreSQL</productname> role. </para> <para> diff --git a/doc/src/sgml/fdwhandler.sgml b/doc/src/sgml/fdwhandler.sgml index 9ab712f6d18..76ff243f5d3 100644 --- a/doc/src/sgml/fdwhandler.sgml +++ b/doc/src/sgml/fdwhandler.sgml @@ -152,7 +152,9 @@ BeginForeignScan (ForeignScanState *node, </programlisting> Begin executing a foreign scan. This is called during executor startup. - It should perform any initialization needed before the scan can start. + It should perform any initialization needed before the scan can start, + but not start executing the actual scan (that should be done upon the + first call to <function>IterateForeignScan</>). The <structname>ForeignScanState</> node has already been created, but its <structfield>fdw_state</> field is still NULL. Information about the table to scan is accessible through the |