Fix a bug in the event trigger function that checks table rewrites. W…

…hen 1) an application table has been removed from a logging tables group and then 2) an ALTER TABLE leads to a table rewrite, the event trigger erroneously blocked the statement, with a message telling that the application table belongs to a tables group. Aside the fix, a dedicated test case has been added to the regression test scenarios. As a workaround, event triggers can be disabled before and enabled after the faulting ALTER TABLE statement, using the emaj_disable_protection_by_event_triggers() and emaj_enable_protection_by_event_triggers() functions. Reported by Djamel Haddadi.
dalibo · Jun 29, 2019 · 5e9c380 · 5e9c380
1 parent 576b216
commit 5e9c380
Show file tree

Hide file tree

Showing 16 changed files with 79 additions and 13 deletions.
diff --git a/CHANGES.md b/CHANGES.md
@@ -6,8 +6,10 @@ E-Maj - Change log
 
 
 ###Bug fixes:###
-
-
+  * Fix a bug in the event trigger function that checks table rewrites. When
+    an application table has been removed from a logging tables group and an
+    ALTER TABLE leads then to a table rewrite, the event trigger erroneously
+    blocked the statement.
 
 3.1.0 (2019-Jun-20)
 ------

diff --git a/sql/emaj--3.1.0--devel.sql b/sql/emaj--3.1.0--devel.sql
@@ -98,6 +98,45 @@ SELECT emaj._disable_event_triggers();
 ------------------------------------------------------------------
 -- create new or modified functions                             --
 ------------------------------------------------------------------
+CREATE OR REPLACE FUNCTION emaj._event_trigger_table_rewrite_fnct()
+RETURNS EVENT_TRIGGER LANGUAGE plpgsql
+SECURITY DEFINER SET search_path = pg_catalog, pg_temp AS
+$_event_trigger_table_rewrite_fnct$
+-- This function is called by the emaj_table_rewrite_trg event trigger.
+-- The function blocks any ddl operation that leads to a table rewrite for:
+--   - an application table registered into an active (not stopped) E-Maj group,
+--   - an E-Maj log table.
+-- The function is declared SECURITY DEFINER so that non emaj roles can access the emaj internal tables when altering their tables.
+  DECLARE
+    v_tableSchema            TEXT;
+    v_tableName              TEXT;
+    v_groupName              TEXT;
+  BEGIN
+-- get the schema and table names of the altered table
+    SELECT nspname, relname INTO v_tableSchema, v_tableName FROM pg_catalog.pg_class, pg_catalog.pg_namespace
+      WHERE relnamespace = pg_namespace.oid AND pg_class.oid = pg_event_trigger_table_rewrite_oid();
+-- look at the emaj_relation table to verify that the table being rewritten does not belong to any active (not stopped) group
+    SELECT rel_group INTO v_groupName FROM emaj.emaj_relation, emaj.emaj_group
+      WHERE rel_schema = v_tableSchema AND rel_tblseq = v_tableName AND upper_inf(rel_time_range)
+        AND group_name = rel_group AND group_is_logging;
+    IF FOUND THEN
+-- the table is an application table that belongs to a group, so raise an exception
+      RAISE EXCEPTION 'E-Maj event trigger: Attempting to change the application table "%.%" structure. But the table belongs to the'
+                      ' active tables group "%".', v_tableSchema, v_tableName , v_groupName;
+    END IF;
+-- look at the emaj_relation table to verify that the table being rewritten is not a known log table
+    SELECT rel_group INTO v_groupName FROM emaj.emaj_relation
+      WHERE rel_log_schema = v_tableSchema AND rel_log_table = v_tableName;
+    IF FOUND THEN
+-- the table is an E-Maj log table, so raise an exception
+      RAISE EXCEPTION 'E-Maj event trigger: Attempting to change the log table "%.%" structure. But the table belongs to the tables'
+                      ' group "%".', v_tableSchema, v_tableName , v_groupName;
+    END IF;
+  END;
+$_event_trigger_table_rewrite_fnct$;
+COMMENT ON FUNCTION emaj._event_trigger_table_rewrite_fnct() IS
+$$E-Maj extension: support of the emaj_table_rewrite_trg event trigger.$$;
+
 --<end_functions>                                pattern used by the tool that extracts and insert the functions definition
 ------------------------------------------
 --                                      --

diff --git a/sql/emaj--devel.sql b/sql/emaj--devel.sql
@@ -8008,8 +8008,8 @@ $_event_trigger_table_rewrite_fnct$
       WHERE relnamespace = pg_namespace.oid AND pg_class.oid = pg_event_trigger_table_rewrite_oid();
 -- look at the emaj_relation table to verify that the table being rewritten does not belong to any active (not stopped) group
     SELECT rel_group INTO v_groupName FROM emaj.emaj_relation, emaj.emaj_group
-      WHERE rel_schema = v_tableSchema AND rel_tblseq = v_tableName
-              AND group_name = rel_group AND group_is_logging;
+      WHERE rel_schema = v_tableSchema AND rel_tblseq = v_tableName AND upper_inf(rel_time_range)
+        AND group_name = rel_group AND group_is_logging;
     IF FOUND THEN
 -- the table is an application table that belongs to a group, so raise an exception
       RAISE EXCEPTION 'E-Maj event trigger: Attempting to change the application table "%.%" structure. But the table belongs to the'

diff --git a/sql/emaj-devel.sql b/sql/emaj-devel.sql
@@ -8015,8 +8015,8 @@ $_event_trigger_table_rewrite_fnct$
       WHERE relnamespace = pg_namespace.oid AND pg_class.oid = pg_event_trigger_table_rewrite_oid();
 -- look at the emaj_relation table to verify that the table being rewritten does not belong to any active (not stopped) group
     SELECT rel_group INTO v_groupName FROM emaj.emaj_relation, emaj.emaj_group
-      WHERE rel_schema = v_tableSchema AND rel_tblseq = v_tableName
-              AND group_name = rel_group AND group_is_logging;
+      WHERE rel_schema = v_tableSchema AND rel_tblseq = v_tableName AND upper_inf(rel_time_range)
+        AND group_name = rel_group AND group_is_logging;
     IF FOUND THEN
 -- the table is an application table that belongs to a group, so raise an exception
       RAISE EXCEPTION 'E-Maj event trigger: Attempting to change the application table "%.%" structure. But the table belongs to the'

diff --git a/test/10/expected/alter_logging.out b/test/10/expected/alter_logging.out
@@ -1541,6 +1541,10 @@ WARNING:  _check_fk_groups: The foreign key "mytbl4_col44_fkey" on the table "my
 
   drop table mySchema1."myTbl3";
 rollback;
+-- testing an ALTER TABLE leading to a table rewrite
+begin;
+  alter table mySchema1."myTbl3" alter column col33 type decimal (10,1);
+rollback;
 -- re-add all removed tables
 update emaj.emaj_group_def set grpdef_group = 'myGroup1' where grpdef_group = 'temporarily_removed';
 select emaj.emaj_alter_group('myGroup1', 'tables re-added to myGroup1');

diff --git a/test/10/expected/check.out b/test/10/expected/check.out
@@ -126,7 +126,7 @@ select funcname, calls from pg_stat_user_functions
  _enable_event_triggers                    |   288
  _estimate_rollback_groups                 |    13
  _event_trigger_sql_drop_fnct              |   113
- _event_trigger_table_rewrite_fnct         |   138
+ _event_trigger_table_rewrite_fnct         |   139
  _gen_sql_groups                           |    23
  _gen_sql_tbl                              |    43
  _get_current_sequence_state               |  2308

diff --git a/test/11/expected/alter_logging.out b/test/11/expected/alter_logging.out
@@ -1541,6 +1541,10 @@ WARNING:  _check_fk_groups: The foreign key "mytbl4_col44_fkey" on the table "my
 
   drop table mySchema1."myTbl3";
 rollback;
+-- testing an ALTER TABLE leading to a table rewrite
+begin;
+  alter table mySchema1."myTbl3" alter column col33 type decimal (10,1);
+rollback;
 -- re-add all removed tables
 update emaj.emaj_group_def set grpdef_group = 'myGroup1' where grpdef_group = 'temporarily_removed';
 select emaj.emaj_alter_group('myGroup1', 'tables re-added to myGroup1');

diff --git a/test/11/expected/check.out b/test/11/expected/check.out
@@ -126,7 +126,7 @@ select funcname, calls from pg_stat_user_functions
  _enable_event_triggers                    |   288
  _estimate_rollback_groups                 |    13
  _event_trigger_sql_drop_fnct              |   115
- _event_trigger_table_rewrite_fnct         |   108
+ _event_trigger_table_rewrite_fnct         |   109
  _gen_sql_groups                           |    23
  _gen_sql_tbl                              |    43
  _get_current_sequence_state               |  2308

diff --git a/test/11/expected/install_psql.out b/test/11/expected/install_psql.out
@@ -7853,8 +7853,8 @@ $_event_trigger_table_rewrite_fnct$
       WHERE relnamespace = pg_namespace.oid AND pg_class.oid = pg_event_trigger_table_rewrite_oid();
 -- look at the emaj_relation table to verify that the table being rewritten does not belong to any active (not stopped) group
     SELECT rel_group INTO v_groupName FROM emaj.emaj_relation, emaj.emaj_group
-      WHERE rel_schema = v_tableSchema AND rel_tblseq = v_tableName
-              AND group_name = rel_group AND group_is_logging;
+      WHERE rel_schema = v_tableSchema AND rel_tblseq = v_tableName AND upper_inf(rel_time_range)
+        AND group_name = rel_group AND group_is_logging;
     IF FOUND THEN
 -- the table is an application table that belongs to a group, so raise an exception
       RAISE EXCEPTION 'E-Maj event trigger: Attempting to change the application table "%.%" structure. But the table belongs to the'

diff --git a/test/12/expected/alter_logging.out b/test/12/expected/alter_logging.out
@@ -1541,6 +1541,10 @@ WARNING:  _check_fk_groups: The foreign key "mytbl4_col44_fkey" on the table "my
 
   drop table mySchema1."myTbl3";
 rollback;
+-- testing an ALTER TABLE leading to a table rewrite
+begin;
+  alter table mySchema1."myTbl3" alter column col33 type decimal (10,1);
+rollback;
 -- re-add all removed tables
 update emaj.emaj_group_def set grpdef_group = 'myGroup1' where grpdef_group = 'temporarily_removed';
 select emaj.emaj_alter_group('myGroup1', 'tables re-added to myGroup1');

diff --git a/test/12/expected/check.out b/test/12/expected/check.out
@@ -126,7 +126,7 @@ select funcname, calls from pg_stat_user_functions
  _enable_event_triggers                    |   288
  _estimate_rollback_groups                 |    13
  _event_trigger_sql_drop_fnct              |   115
- _event_trigger_table_rewrite_fnct         |   108
+ _event_trigger_table_rewrite_fnct         |   109
  _gen_sql_groups                           |    23
  _gen_sql_tbl                              |    43
  _get_current_sequence_state               |  2308

diff --git a/test/95/expected/alter_logging.out b/test/95/expected/alter_logging.out
@@ -1757,6 +1757,10 @@ PL/pgSQL function emaj.emaj_alter_group(text,text) line 6 at RETURN
 
   drop table mySchema1."myTbl3";
 rollback;
+-- testing an ALTER TABLE leading to a table rewrite
+begin;
+  alter table mySchema1."myTbl3" alter column col33 type decimal (10,1);
+rollback;
 -- re-add all removed tables
 update emaj.emaj_group_def set grpdef_group = 'myGroup1' where grpdef_group = 'temporarily_removed';
 select emaj.emaj_alter_group('myGroup1', 'tables re-added to myGroup1');

diff --git a/test/95/expected/check.out b/test/95/expected/check.out
@@ -126,7 +126,7 @@ select funcname, calls from pg_stat_user_functions
  _enable_event_triggers                    |   288
  _estimate_rollback_groups                 |    13
  _event_trigger_sql_drop_fnct              |   111
- _event_trigger_table_rewrite_fnct         |   138
+ _event_trigger_table_rewrite_fnct         |   139
  _gen_sql_groups                           |    23
  _gen_sql_tbl                              |    43
  _get_current_sequence_state               |  2308

diff --git a/test/96/expected/alter_logging.out b/test/96/expected/alter_logging.out
@@ -1541,6 +1541,10 @@ WARNING:  _check_fk_groups: The foreign key "mytbl4_col44_fkey" on the table "my
 
   drop table mySchema1."myTbl3";
 rollback;
+-- testing an ALTER TABLE leading to a table rewrite
+begin;
+  alter table mySchema1."myTbl3" alter column col33 type decimal (10,1);
+rollback;
 -- re-add all removed tables
 update emaj.emaj_group_def set grpdef_group = 'myGroup1' where grpdef_group = 'temporarily_removed';
 select emaj.emaj_alter_group('myGroup1', 'tables re-added to myGroup1');

diff --git a/test/96/expected/check.out b/test/96/expected/check.out
@@ -126,7 +126,7 @@ select funcname, calls from pg_stat_user_functions
  _enable_event_triggers                    |   288
  _estimate_rollback_groups                 |    13
  _event_trigger_sql_drop_fnct              |   111
- _event_trigger_table_rewrite_fnct         |   138
+ _event_trigger_table_rewrite_fnct         |   139
  _gen_sql_groups                           |    23
  _gen_sql_tbl                              |    43
  _get_current_sequence_state               |  2308

diff --git a/test/sql/alter_logging.sql b/test/sql/alter_logging.sql
@@ -495,6 +495,11 @@ begin;
   drop table mySchema1."myTbl3";
 rollback;
 
+-- testing an ALTER TABLE leading to a table rewrite
+begin;
+  alter table mySchema1."myTbl3" alter column col33 type decimal (10,1);
+rollback;
+
 -- re-add all removed tables
 update emaj.emaj_group_def set grpdef_group = 'myGroup1' where grpdef_group = 'temporarily_removed';
 select emaj.emaj_alter_group('myGroup1', 'tables re-added to myGroup1');