Hi,
While working on FDW DML pushdown, I ran into a copy-pasto in the
ExecForeignDelete documentation in fdwhandler.sgml:
The data in the returned slot is used only if the <command>DELETE</>
query has a <literal>RETURNING</> clause or the foreign table has
an <literal>AFTER ROW</> trigger. Triggers require all columns,
but the
I don't think the data is referenced by the AFTER ROW DELETE triggers.
Attached is a patch to fix that. The patch also avoids adding an
unnecessary RETURNING clause to DELETE when deparsing a remote DELETE
statement in postgres_fdw.
I'll add this to the next CF.
Best regards,
Etsuro Fujita
*** a/contrib/postgres_fdw/deparse.c
--- b/contrib/postgres_fdw/deparse.c
***************
*** 1078,1085 **** deparseDeleteSql(StringInfo buf, PlannerInfo *root,
deparseRelation(buf, rel);
appendStringInfoString(buf, " WHERE ctid = $1");
! deparseReturningList(buf, root, rtindex, rel,
! rel->trigdesc && rel->trigdesc->trig_delete_after_row,
returningList, retrieved_attrs);
}
--- 1078,1085 ----
deparseRelation(buf, rel);
appendStringInfoString(buf, " WHERE ctid = $1");
! /* No need to retrieve columns for AFTER ROW DELETE triggers */
! deparseReturningList(buf, root, rtindex, rel, false,
returningList, retrieved_attrs);
}
*** a/doc/src/sgml/fdwhandler.sgml
--- b/doc/src/sgml/fdwhandler.sgml
***************
*** 606,613 **** ExecForeignDelete (EState *estate,
<para>
The data in the returned slot is used only if the <command>DELETE</>
! query has a <literal>RETURNING</> clause or the foreign table has
! an <literal>AFTER ROW</> trigger. Triggers require all columns, but the
FDW could choose to optimize away returning some or all columns depending
on the contents of the <literal>RETURNING</> clause. Regardless, some
slot must be returned to indicate success, or the query's reported row
--- 606,614 ----
<para>
The data in the returned slot is used only if the <command>DELETE</>
! query has a <literal>RETURNING</> clause. (Note that the data is not
! referenced by <literal>AFTER ROW</> triggers on the foreign table in
! the <command>DELETE</> case.) The
FDW could choose to optimize away returning some or all columns depending
on the contents of the <literal>RETURNING</> clause. Regardless, some
slot must be returned to indicate success, or the query's reported row
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