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authorBruce Momjian <bruce@momjian.us>2024-08-19 19:54:39 -0400
committerBruce Momjian <bruce@momjian.us>2024-08-19 19:54:39 -0400
commite28a2719beeab1e3decfbaa81ebe73335e6282b1 (patch)
tree2ed8d49287b3f4e7d3c9984f008f12d2c4b0b5b8 /doc/src
parentcf3bb262044a741a47ff40080b145fe432c54407 (diff)
downloadpostgresql-e28a2719beeab1e3decfbaa81ebe73335e6282b1.tar.gz
postgresql-e28a2719beeab1e3decfbaa81ebe73335e6282b1.zip
doc: mention of postpostgres_fdw INSERT ON CONFLICT limitation
Reported-by: Fujii Masao Discussion: https://postgr.es/m/47801526-d017-4c89-9f52-c02c449a139b@oss.nttdata.com Author: Fujii Masao Backpatch-through: master
Diffstat (limited to 'doc/src')
-rw-r--r--doc/src/sgml/postgres-fdw.sgml12
1 files changed, 11 insertions, 1 deletions
diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml
index 90969f63ca7..468724e94ef 100644
--- a/doc/src/sgml/postgres-fdw.sgml
+++ b/doc/src/sgml/postgres-fdw.sgml
@@ -1096,7 +1096,10 @@ postgres=# SELECT postgres_fdw_disconnect_all();
<para>
<filename>postgres_fdw</filename> can be used with remote servers dating back
to <productname>PostgreSQL</productname> 8.3. Read-only capability is available
- back to 8.1. A limitation however is that <filename>postgres_fdw</filename>
+ back to 8.1.
+ </para>
+ <para>
+ A limitation however is that <filename>postgres_fdw</filename>
generally assumes that immutable built-in functions and operators are
safe to send to the remote server for execution, if they appear in a
<literal>WHERE</literal> clause for a foreign table. Thus, a built-in
@@ -1108,6 +1111,13 @@ postgres=# SELECT postgres_fdw_disconnect_all();
optimization fence, and placing the problematic function or operator
outside the sub-<literal>SELECT</literal>.
</para>
+ <para>
+ Another limitation is that when executing <command>INSERT</command>
+ statements with an <literal>ON CONFLICT DO NOTHING</literal> clause on
+ a foreign table, the remote server must be running
+ <productname>PostgreSQL</productname> 9.5 or later,
+ as earlier versions do not support this feature.
+ </para>
</sect2>
<sect2 id="postgres-fdw-wait-events">