Thanks. This is helpful. Below is the result when I add a column to public.accounts.
obj.classid, -- 1259 obj.objid, -- 16409 obj.objsubid, -- 0 obj.command_tag, -- ALTER TABLE obj.object_type, -- table obj.schema_name, -- public obj.object_identity, -- public.accounts obj.in_extension; -- f The info useful for me is command_tag, object_type, object_identity. classid, objid is not useful since object_identity is more explicit. objsubid is not useful because I don't need comment <https://www.postgresql.org/message-id/pine.lnx.4.33.0212091822050.15095-100...@leary.csoft.net> information for schema change. Besides table name, I still need: * which columns are added and their types. * which columns have type change, the old and new types. * which columns are dropped. Will command field provide this info? I don't have an example and decoding it needs C code <https://www.postgresql.org/message-id/20190712222343.GA26924%40alvherre.pgsql> . If I cannot get such info from pg_event_trigger_ddl_commands, I may need to maintain schema snapshots myself and diff the old and new snapshots upon an alter table/view event. Which way should I go? Thanks a lot. On Tue, May 30, 2023 at 2:42 PM Erik Wienhold <e...@ewie.name> wrote: > > On 30/05/2023 22:23 CEST Lian Jiang <jiangok2...@gmail.com> wrote: > > > > I plan to create an event trigger to detect schema change (e.g. > add/remove > > a column, change column type), and write it into a separate table (e.g. > > EVENTS). Then a process periodically reads this table to send schema > change > > notification. However, the event trigger ( > https://www.postgresql.org/docs/current/plpgsql-trigger.html) > > (43.10.2. Triggers on Events) does not provide me info such as which > table > > is altered, old and new schema. Am I missing something? Thanks very much > for > > any hints. > > You must use ddl_command_end event triggers[0] and call function > pg_event_trigger_ddl_commands[1] to get info such as altered table and > column. > > [0] https://www.postgresql.org/docs/current/event-trigger-definition.html > [1] https://www.postgresql.org/docs/current/functions-event-triggers.html > > -- > Erik > > > -- Create your own email signature <https://www.wisestamp.com/signature-in-email/?utm_source=promotion&utm_medium=signature&utm_campaign=create_your_own&srcid=5234462839406592>
