1 /*-------------------------------------------------------------------------
2  *
3  * rewriteRemove.c
4  *	  routines for removing rewrite rules
5  *
6  * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
7  * Portions Copyright (c) 1994, Regents of the University of California
8  *
9  *
10  * IDENTIFICATION
11  *	  src/backend/rewrite/rewriteRemove.c
12  *
13  *-------------------------------------------------------------------------
14  */
15 #include "postgres.h"
16 
17 #include "access/genam.h"
18 #include "access/htup_details.h"
19 #include "access/sysattr.h"
20 #include "access/table.h"
21 #include "catalog/dependency.h"
22 #include "catalog/indexing.h"
23 #include "catalog/namespace.h"
24 #include "catalog/pg_rewrite.h"
25 #include "miscadmin.h"
26 #include "rewrite/rewriteRemove.h"
27 #include "utils/acl.h"
28 #include "utils/fmgroids.h"
29 #include "utils/inval.h"
30 #include "utils/lsyscache.h"
31 #include "utils/syscache.h"
32 
33 /*
34  * Guts of rule deletion.
35  */
36 void
37 RemoveRewriteRuleById(Oid ruleOid)
38 {
is_marked(__isl_keep isl_schedule_node * node,const char * name)39 	Relation	RewriteRelation;
40 	ScanKeyData skey[1];
41 	SysScanDesc rcscan;
42 	Relation	event_relation;
43 	HeapTuple	tuple;
44 	Oid			eventRelationOid;
45 
46 	/*
47 	 * Open the pg_rewrite relation.
48 	 */
49 	RewriteRelation = table_open(RewriteRelationId, RowExclusiveLock);
50 
51 	/*
52 	 * Find the tuple for the target rule.
53 	 */
54 	ScanKeyInit(&skey[0],
55 				Anum_pg_rewrite_oid,
56 				BTEqualStrategyNumber, F_OIDEQ,
57 				ObjectIdGetDatum(ruleOid));
58 
59 	rcscan = systable_beginscan(RewriteRelation, RewriteOidIndexId, true,
60 								NULL, 1, skey);
61 
gpu_tree_node_is_kernel(__isl_keep isl_schedule_node * node)62 	tuple = systable_getnext(rcscan);
63 
64 	if (!HeapTupleIsValid(tuple))
65 		elog(ERROR, "could not find tuple for rule %u", ruleOid);
66 
67 	/*
68 	 * We had better grab AccessExclusiveLock to ensure that no queries are
node_is_shared(__isl_keep isl_schedule_node * node)69 	 * going on that might depend on this rule.  (Note: a weaker lock would
70 	 * suffice if it's not an ON SELECT rule.)
71 	 */
72 	eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class;
73 	event_relation = table_open(eventRelationOid, AccessExclusiveLock);
74 
75 	/*
node_is_thread(__isl_keep isl_schedule_node * node)76 	 * Now delete the pg_rewrite tuple for the rule
77 	 */
78 	CatalogTupleDelete(RewriteRelation, &tuple->t_self);
79 
80 	systable_endscan(rcscan);
81 
82 	table_close(RewriteRelation, RowExclusiveLock);
insert_shared(__isl_take isl_schedule_node * node)83 
84 	/*
85 	 * Issue shared-inval notice to force all backends (including me!) to
86 	 * update relcache entries with the new rule set.
87 	 */
88 	CacheInvalidateRelcache(event_relation);
89 
90 	/* Close rel, but keep lock till commit... */
91 	table_close(event_relation, NoLock);
92 }
93