diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/event-trigger.sgml | 150 | ||||
| -rw-r--r-- | doc/src/sgml/func.sgml | 85 |
2 files changed, 227 insertions, 8 deletions
diff --git a/doc/src/sgml/event-trigger.sgml b/doc/src/sgml/event-trigger.sgml index 6f71a27855e..02199727720 100644 --- a/doc/src/sgml/event-trigger.sgml +++ b/doc/src/sgml/event-trigger.sgml @@ -65,6 +65,16 @@ </para> <para> + The <literal>table_rewrite</> event occurs just before a table is + rewritten by the command <literal>ALTER TABLE</literal>. While other + control statements are available to rewrite a table, + like <literal>CLUSTER</literal> and <literal>VACUUM</literal>, + the <literal>table_rewrite</> event is currently only triggered by + the <literal>ALTER TABLE</literal> command, and only when that command + attempts to rewrite the table. + </para> + + <para> Event triggers (like other functions) cannot be executed in an aborted transaction. Thus, if a DDL command fails with an error, any associated <literal>ddl_command_end</> triggers will not be executed. Conversely, @@ -120,6 +130,7 @@ <entry><literal>ddl_command_start</literal></entry> <entry><literal>ddl_command_end</literal></entry> <entry><literal>sql_drop</literal></entry> + <entry><literal>table_rewrite</literal></entry> </row> </thead> <tbody> @@ -128,510 +139,595 @@ <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER COLLATION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER CONVERSION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER DOMAIN</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER EXTENSION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER FOREIGN DATA WRAPPER</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER FOREIGN TABLE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER FUNCTION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER LANGUAGE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER OPERATOR</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER OPERATOR CLASS</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER OPERATOR FAMILY</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER POLICY</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER SCHEMA</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER SEQUENCE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER SERVER</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER TABLE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>X</literal></entry> </row> <row> <entry align="left"><literal>ALTER TEXT SEARCH CONFIGURATION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER TEXT SEARCH DICTIONARY</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER TEXT SEARCH PARSER</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER TEXT SEARCH TEMPLATE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER TRIGGER</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER TYPE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER USER MAPPING</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>ALTER VIEW</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE AGGREGATE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE CAST</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE COLLATION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE CONVERSION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE DOMAIN</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE EXTENSION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE FOREIGN DATA WRAPPER</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE FOREIGN TABLE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE FUNCTION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE INDEX</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE LANGUAGE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE OPERATOR</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE OPERATOR CLASS</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE OPERATOR FAMILY</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE POLICY</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE RULE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE SCHEMA</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE SEQUENCE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE SERVER</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE TABLE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE TABLE AS</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE TEXT SEARCH CONFIGURATION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE TEXT SEARCH DICTIONARY</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE TEXT SEARCH PARSER</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE TEXT SEARCH TEMPLATE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE TRIGGER</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE TYPE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE USER MAPPING</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>CREATE VIEW</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP AGGREGATE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP CAST</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP COLLATION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP CONVERSION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP DOMAIN</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP EXTENSION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP FOREIGN DATA WRAPPER</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP FOREIGN TABLE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP FUNCTION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP INDEX</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP LANGUAGE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP OPERATOR</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP OPERATOR CLASS</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP OPERATOR FAMILY</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP OWNED</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP POLICY</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP RULE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP SCHEMA</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP SEQUENCE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP SERVER</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP TABLE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP TEXT SEARCH CONFIGURATION</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP TEXT SEARCH DICTIONARY</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP TEXT SEARCH PARSER</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP TEXT SEARCH TEMPLATE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP TRIGGER</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP TYPE</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP USER MAPPING</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>DROP VIEW</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>IMPORT FOREIGN SCHEMA</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> <row> <entry align="left"><literal>SELECT INTO</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>X</literal></entry> <entry align="center"><literal>-</literal></entry> + <entry align="center"><literal>-</literal></entry> </row> </tbody> </tgroup> @@ -843,4 +939,58 @@ COMMIT; event triggers.) </para> </sect1> + + <sect1 id="event-trigger-table-rewrite-example"> + <title>A Table Rewrite Event Trigger Example</title> + + <para> + Thanks to the <literal>table_rewrite</> event, it is possible to implement + a table rewriting policy only allowing the rewrite in maintenance windows. + </para> + + <para> + Here's an example implementing such a policy. +<programlisting> +CREATE OR REPLACE FUNCTION no_rewrite() + RETURNS event_trigger + LANGUAGE plpgsql AS +$$ +--- +--- Implement local Table Rewriting policy: +--- public.foo is not allowed rewriting, ever +--- other tables are only allowed rewriting between 1am and 6am +--- unless they have more than 100 blocks +--- +DECLARE + table_oid oid := pg_event_trigger_table_rewrite_oid(); + current_hour integer := extract('hour' from current_time); + pages integer; + max_pages integer := 100; +BEGIN + IF pg_event_trigger_table_rewrite_oid() = 'public.foo'::regclass + THEN + RAISE EXCEPTION 'you''re not allowed to rewrite the table %', + table_oid::regclass; + END IF; + + SELECT INTO pages relpages FROM pg_class WHERE oid = table_oid; + IF pages > max_pages + THEN + RAISE EXCEPTION 'rewrites only allowed for table with less than % pages', + max_pages; + END IF; + + IF current_hour NOT BETWEEN 1 AND 6 + THEN + RAISE EXCEPTION 'rewrites only allowed between 1am and 6am'; + END IF; +END; +$$; + +CREATE EVENT TRIGGER no_rewrite_allowed + ON table_rewrite + EXECUTE PROCEDURE no_rewrite(); +</programlisting> + </para> + </sect1> </chapter> diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 62ec275a9e5..c3b61269438 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -17607,15 +17607,23 @@ FOR EACH ROW EXECUTE PROCEDURE suppress_redundant_updates_trigger(); <sect1 id="functions-event-triggers"> <title>Event Trigger Functions</title> - <indexterm> - <primary>pg_event_trigger_dropped_objects</primary> - </indexterm> + <para> + <productname>PostgreSQL</> provides these helper functions + to retrieve information from event triggers. + </para> <para> - Currently <productname>PostgreSQL</> provides one built-in event trigger - helper function, <function>pg_event_trigger_dropped_objects</>. + For more information about event triggers, + see <xref linkend="event-triggers">. </para> + <sect2 id="pg-event-trigger-sql-drop-functions"> + <title>Processing objects dropped by a DDL command.</title> + + <indexterm> + <primary>pg_event_trigger_dropped_objects</primary> + </indexterm> + <para> <function>pg_event_trigger_dropped_objects</> returns a list of all objects dropped by the command in whose <literal>sql_drop</> event it is called. @@ -17709,11 +17717,72 @@ CREATE EVENT TRIGGER test_event_trigger_for_drops EXECUTE PROCEDURE test_event_trigger_for_drops(); </programlisting> </para> + </sect2> - <para> - For more information about event triggers, - see <xref linkend="event-triggers">. + <sect2 id="pg-event-trigger-table-rewrite-functions"> + <title>Handling a Table Rewrite Event</title> + + <para> + The functions shown in + <xref linkend="functions-event-trigger-table-rewrite"> + provide information about a table for which a + <literal>table_rewrite</> event has just been called. + If called in any other context, an error is raised. + </para> + + <table id="functions-event-trigger-table-rewrite"> + <title>Table Rewrite information</title> + <tgroup cols="3"> + <thead> + <row><entry>Name</entry> <entry>Return Type</entry> <entry>Description</entry></row> + </thead> + + <tbody> + <row> + <entry> + <indexterm><primary>pg_event_trigger_table_rewrite_oid</primary></indexterm> + <literal><function>pg_event_trigger_table_rewrite_oid()</function></literal> + </entry> + <entry><type>Oid</type></entry> + <entry>The Oid of the table about to be rewritten.</entry> + </row> + + <row> + <entry> + <indexterm><primary>pg_event_trigger_table_rewrite_reason</primary></indexterm> + <literal><function>pg_event_trigger_table_rewrite_reason()</function></literal> + </entry> + <entry><type>int</type></entry> + <entry> + The reason code(s) explaining the reason for rewriting. The exact + meaning of the codes is release dependent. + </entry> + </row> + </tbody> + </tgroup> + </table> + + <para> + The <function>pg_event_trigger_table_rewrite_oid</> function can be used + in an event trigger like this: +<programlisting> +CREATE FUNCTION test_event_trigger_table_rewrite_oid() + RETURNS event_trigger + LANGUAGE plpgsql AS +$$ +BEGIN + RAISE NOTICE 'rewriting table % for reason %', + pg_event_trigger_table_rewrite_oid()::regclass, + pg_event_trigger_table_rewrite_reason(); +END; +$$; + +CREATE EVENT TRIGGER test_table_rewrite_oid + ON table_rewrite + EXECUTE PROCEDURE test_event_trigger_table_rewrite_oid(); +</programlisting> </para> + </sect2> </sect1> </chapter> |
