Remove duplicated comment block in event_trigger.c

The reasons why event triggers are disabled in standalone mode are
documented in the code path of ddl_command_start, and other places
checking if standalone mode is enabled or not mention to refer to the
comment for ddl_command_start, except for table_rewrite that duplicated
the same explanation.

Reported-by: David G. Johnston
Discussion: https://postgr.es/m/CAKFQuwYqHtXpvr2mBJRwH9f+Y5y1GXw3rhbaAu0Dk2MoNevsmA@mail.gmail.com
This commit is contained in:
Michael Paquier 2020-05-15 08:19:30 +09:00
parent 2e619f86a9
commit ff87fabef2

View file

@ -833,20 +833,8 @@ EventTriggerTableRewrite(Node *parsetree, Oid tableOid, int reason)
EventTriggerData trigdata;
/*
* Event Triggers are completely disabled in standalone mode. There are
* (at least) two reasons for this:
*
* 1. A sufficiently broken event trigger might not only render the
* database unusable, but prevent disabling itself to fix the situation.
* In this scenario, restarting in standalone mode provides an escape
* hatch.
*
* 2. BuildEventTriggerCache relies on systable_beginscan_ordered, and
* therefore will malfunction if pg_event_trigger's indexes are damaged.
* To allow recovery from a damaged index, we need some operating mode
* wherein event triggers are disabled. (Or we could implement
* heapscan-and-sort logic for that case, but having disaster recovery
* scenarios depend on code that's otherwise untested isn't appetizing.)
* See EventTriggerDDLCommandStart for a discussion about why event
* triggers are disabled in single user mode.
*/
if (!IsUnderPostmaster)
return;