Support TRUNCATE triggers on foreign tables.

Now some foreign data wrappers support TRUNCATE command.
So it's useful to support TRUNCATE triggers on foreign tables for
audit logging or for preventing undesired truncation.

Author: Yugo Nagata
Reviewed-by: Fujii Masao, Ian Lawrence Barwick
Discussion: https://postgr.es/m/20220630193848.5b02e0d6076b86617a915682@sraoss.co.jp

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 44457f930c26ca6958040164fa36d63312ebbbf8..5f2ef88cf38a212c95636706b690feeb988b4171 100644 (file)
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -6732,9 +6732,9 @@ BEGIN
        TG_ARGV[0], TG_OP, TG_WHEN, TG_LEVEL;
    RETURN NULL;
 END;$$;
-CREATE TRIGGER trig_stmt_before BEFORE DELETE OR INSERT OR UPDATE ON rem1
+CREATE TRIGGER trig_stmt_before BEFORE DELETE OR INSERT OR UPDATE OR TRUNCATE ON rem1
    FOR EACH STATEMENT EXECUTE PROCEDURE trigger_func();
-CREATE TRIGGER trig_stmt_after AFTER DELETE OR INSERT OR UPDATE ON rem1
+CREATE TRIGGER trig_stmt_after AFTER DELETE OR INSERT OR UPDATE OR TRUNCATE ON rem1
    FOR EACH STATEMENT EXECUTE PROCEDURE trigger_func();
 CREATE OR REPLACE FUNCTION trigger_data()  RETURNS trigger
 LANGUAGE plpgsql AS $$
@@ -6821,6 +6821,9 @@ NOTICE:  OLD: (1,update),NEW: (1,updateupdate)
 NOTICE:  trig_row_after(23, skidoo) AFTER ROW UPDATE ON rem1
 NOTICE:  OLD: (1,update),NEW: (1,updateupdate)
 NOTICE:  trigger_func(<NULL>) called: action = UPDATE, when = AFTER, level = STATEMENT
+truncate rem1;
+NOTICE:  trigger_func(<NULL>) called: action = TRUNCATE, when = BEFORE, level = STATEMENT
+NOTICE:  trigger_func(<NULL>) called: action = TRUNCATE, when = AFTER, level = STATEMENT
 -- cleanup
 DROP TRIGGER trig_row_before ON rem1;
 DROP TRIGGER trig_row_after ON rem1;
@@ -7087,7 +7090,7 @@ NOTICE:  trig_row_after(23, skidoo) AFTER ROW INSERT ON rem1
 NOTICE:  NEW: (13,"test triggered !")
   ctid  
 --------
- (0,32)
+ (0,25)
 (1 row)
 
 -- cleanup

diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 92d12120272b78f0d697855986c6dc82608a53fa..ae1fc8f58be53481fc4a963e21d50b5c0cee7714 100644 (file)
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1595,9 +1595,9 @@ BEGIN
    RETURN NULL;
 END;$$;
 
-CREATE TRIGGER trig_stmt_before BEFORE DELETE OR INSERT OR UPDATE ON rem1
+CREATE TRIGGER trig_stmt_before BEFORE DELETE OR INSERT OR UPDATE OR TRUNCATE ON rem1
    FOR EACH STATEMENT EXECUTE PROCEDURE trigger_func();
-CREATE TRIGGER trig_stmt_after AFTER DELETE OR INSERT OR UPDATE ON rem1
+CREATE TRIGGER trig_stmt_after AFTER DELETE OR INSERT OR UPDATE OR TRUNCATE ON rem1
    FOR EACH STATEMENT EXECUTE PROCEDURE trigger_func();
 
 CREATE OR REPLACE FUNCTION trigger_data()  RETURNS trigger
@@ -1652,6 +1652,7 @@ delete from rem1;
 insert into rem1 values(1,'insert');
 update rem1 set f2  = 'update' where f1 = 1;
 update rem1 set f2 = f2 || f2;
+truncate rem1;
 
 
 -- cleanup

diff --git a/doc/src/sgml/ref/create_trigger.sgml b/doc/src/sgml/ref/create_trigger.sgml
index ee42f413e9657799a9fffef2c8998cedc5fcda33..982ab6f3ee4509cc813021c734c32f20fb6b0810 100644 (file)
--- a/doc/src/sgml/ref/create_trigger.sgml
+++ b/doc/src/sgml/ref/create_trigger.sgml
@@ -131,7 +131,7 @@ CREATE [ OR REPLACE ] [ CONSTRAINT ] TRIGGER <replaceable class="parameter">name
      <row>
       <entry align="center"><command>TRUNCATE</command></entry>
       <entry align="center">&mdash;</entry>
-      <entry align="center">Tables</entry>
+      <entry align="center">Tables and foreign tables</entry>
      </row>
      <row>
       <entry align="center" morerows="1"><literal>AFTER</literal></entry>
@@ -142,7 +142,7 @@ CREATE [ OR REPLACE ] [ CONSTRAINT ] TRIGGER <replaceable class="parameter">name
      <row>
       <entry align="center"><command>TRUNCATE</command></entry>
       <entry align="center">&mdash;</entry>
-      <entry align="center">Tables</entry>
+      <entry align="center">Tables and foreign tables</entry>
      </row>
      <row>
       <entry align="center" morerows="1"><literal>INSTEAD OF</literal></entry>

diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 13cb516752b2bf88a73a40f7b9e24e3b5bd9a2fe..b8db53b66deffa600106375e8d167660773e0087 100644 (file)
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -295,13 +295,6 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
                            RelationGetRelationName(rel)),
                     errdetail("Foreign tables cannot have INSTEAD OF triggers.")));
 
-       if (TRIGGER_FOR_TRUNCATE(stmt->events))
-           ereport(ERROR,
-                   (errcode(ERRCODE_WRONG_OBJECT_TYPE),
-                    errmsg("\"%s\" is a foreign table",
-                           RelationGetRelationName(rel)),
-                    errdetail("Foreign tables cannot have TRUNCATE triggers.")));
-
        /*
         * We disallow constraint triggers to protect the assumption that
         * triggers on FKs can't be deferred.  See notes with AfterTriggers