Merge branch 'main' of https://github.com/sraoss/pg_ivm into main

README.md

@@ -101,6 +101,12 @@ refresh_immv(immv_name text, with_data bool) RETURNS bigint
 
 The with_data flag is corresponding to `WITH [NO] DATA` option of REFRESH MATERIALIZED VIEW` command. If with_data is true, the backing query is executed to provide the new data, and if the IMMV is unpopulated, triggers for maintaining the view are created. Also, a unique index is created for IMMV if it is possible and the view doesn't have that yet. If with_data is false, no new data is generated and the IMMV become unpopulated, and the triggers are dropped from the IMMV. Note that unpopulated IMMV is still scannable although the result is empty. This behaviour may be changed in future to raise an error when an unpopulated IMMV is scanned.
 
+#### get_immv_def
+
+`get_immv_def` reconstructs the underlying SELECT command for an IMMV. (This is a decompiled reconstruction, not the original text of the command.)
+```
+get_immv_def(immv regclass) RETURNS text
+```
 
 ### IMMV metadata catalog
 

pg_ivm--1.2--1.3.sql

@@ -11,3 +11,8 @@ RETURNS text
 STRICT
 AS 'MODULE_PATHNAME', 'get_immv_def'
 LANGUAGE C;
+
+-- event trigger
+
+DROP EVENT TRIGGER pg_ivm_sql_drop_trigger;
+DROP FUNCTION pg_ivm_sql_drop_trigger_func;

pg_ivm.c

@@ -11,10 +11,13 @@
  */
 #include "postgres.h"
 
+#include "access/genam.h"
 #include "access/table.h"
 #include "access/xact.h"
 #include "catalog/dependency.h"
+#include "catalog/indexing.h"
 #include "catalog/namespace.h"
+#include "catalog/objectaccess.h"
 #include "catalog/pg_namespace_d.h"
 #include "catalog/pg_trigger_d.h"
 #include "commands/trigger.h"
@@ -23,6 +26,7 @@
 #include "parser/scansup.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"
+#include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
 #include "utils/regproc.h"
 #include "utils/rel.h"
@@ -35,6 +39,8 @@ PG_MODULE_MAGIC;
 static Oid pg_ivm_immv_id = InvalidOid;
 static Oid pg_ivm_immv_pkey_id = InvalidOid;
 
+static object_access_hook_type PrevObjectAccessHook = NULL;
+
 void		_PG_init(void);
 
 static void IvmXactCallback(XactEvent event, void *arg);
@@ -42,6 +48,9 @@ static void IvmSubXactCallback(SubXactEvent event, SubTransactionId mySubid,
 							   SubTransactionId parentSubid, void *arg);
 static void parseNameAndColumns(const char *string, List **names, List **colNames);
 
+static void PgIvmObjectAccessHook(ObjectAccessType access, Oid classId,
+								  Oid objectId, int subId, void *arg);
+
 /* SQL callable functions */
 PG_FUNCTION_INFO_V1(create_immv);
 PG_FUNCTION_INFO_V1(refresh_immv);
@@ -75,6 +84,9 @@ _PG_init(void)
 {
 	RegisterXactCallback(IvmXactCallback, NULL);
 	RegisterSubXactCallback(IvmSubXactCallback, NULL);
+
+	PrevObjectAccessHook = object_access_hook;
+	object_access_hook = PgIvmObjectAccessHook;
 }
 
 /*
@@ -350,3 +362,37 @@ get_immv_def(PG_FUNCTION_ARGS)
 	table_close(matviewRel, NoLock);
 	PG_RETURN_TEXT_P(cstring_to_text(querystring));
 }
+
+/*
+ * object_access_hook function for dropping an IMMV
+ */
+static void
+PgIvmObjectAccessHook(ObjectAccessType access, Oid classId,
+					  Oid objectId, int subId, void *arg)
+{
+	if (PrevObjectAccessHook)
+		PrevObjectAccessHook(access, classId, objectId, subId, arg);
+
+	if (access == OAT_DROP && classId == RelationRelationId && !OidIsValid(subId))
+	{
+		Relation pgIvmImmv = table_open(PgIvmImmvRelationId(), AccessShareLock);
+		SysScanDesc scan;
+		ScanKeyData key;
+		HeapTuple tup;
+
+		ScanKeyInit(&key,
+					Anum_pg_ivm_immv_immvrelid,
+					BTEqualStrategyNumber, F_OIDEQ,
+					ObjectIdGetDatum(objectId));
+		scan = systable_beginscan(pgIvmImmv, PgIvmImmvPrimaryKeyIndexId(),
+								  true, NULL, 1, &key);
+
+		tup = systable_getnext(scan);
+
+		if (HeapTupleIsValid(tup))
+			CatalogTupleDelete(pgIvmImmv, &tup->t_self);
+
+		systable_endscan(scan);
+		table_close(pgIvmImmv, NoLock);
+	}
+}