Event Trigger for table_rewrite

Generate a table_rewrite event when ALTER TABLE
attempts to rewrite a table. Provide helper
functions to identify table and reason.

Intended use case is to help assess or to react
to schema changes that might hold exclusive locks
for long periods.

Dimitri Fontaine, triggering an edit by Simon Riggs

Reviewed in detail by Michael Paquier

1 files changed, 6 insertions, 0 deletions

diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index 0233f4c4832..bcd656b72dd 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -26,6 +26,11 @@ typedef struct EventTriggerData
 	const char *tag;			/* command tag */
 } EventTriggerData;
 
+#define AT_REWRITE_ALTER_PERSISTENCE	0x01
+#define AT_REWRITE_DEFAULT_VAL			0x02
+#define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_OID			0x08
+
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
  * when a function is called by the event trigger manager.
@@ -46,6 +51,7 @@ extern bool EventTriggerSupportsObjectClass(ObjectClass objclass);
 extern void EventTriggerDDLCommandStart(Node *parsetree);
 extern void EventTriggerDDLCommandEnd(Node *parsetree);
 extern void EventTriggerSQLDrop(Node *parsetree);
+extern void EventTriggerTableRewrite(Node *parsetree, Oid tableOid, int reason);
 
 extern bool EventTriggerBeginCompleteQuery(void);
 extern void EventTriggerEndCompleteQuery(void);