From 1da2feea83f43736c14732910d6af49dcae11b76 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Tue, 12 Sep 2000 04:33:18 +0000
Subject: [PATCH] Previous patch backed out.
Here is a patch against CVS (without my earlier patch)
to disallow
LOCK x
if x is a view.
It does not use the SPI interface.
--
Mark Hollomon
---
doc/TODO | 2 +-
src/backend/commands/command.c | 91 ++++++++++++++++++++++++----------
2 files changed, 66 insertions(+), 27 deletions(-)
diff --git a/doc/TODO b/doc/TODO
index f903ba053df..804d52a3a4b 100644
--- a/doc/TODO
+++ b/doc/TODO
@@ -35,7 +35,7 @@ VIEWS
* Views containing aggregates sometimes fail(Jan)
* Creating view and inheriting the view causes view* to show
duplicates(inherit)
-* Disallow LOCK on view
+* -Disallow LOCK on view(Mark Hollomon)
MISC
diff --git a/src/backend/commands/command.c b/src/backend/commands/command.c
index 668858d0772..d0de9e2e4de 100644
--- a/src/backend/commands/command.c
+++ b/src/backend/commands/command.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.99 2000/09/12 04:30:08 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.100 2000/09/12 04:33:18 momjian Exp $
*
* NOTES
* The PerformAddAttribute() code, like most of the relation
@@ -26,6 +26,7 @@
#include "catalog/indexing.h"
#include "catalog/pg_attrdef.h"
#include "catalog/pg_opclass.h"
+#include "catalog/pg_rewrite.h"
#include "commands/command.h"
#include "executor/spi.h"
#include "catalog/heap.h"
@@ -55,7 +56,8 @@
static bool needs_toast_table(Relation rel);
-static bool is_view(char *relname, char *command);
+static bool is_viewr(char *relname);
+static bool is_view(Relation rel);
@@ -1100,7 +1102,7 @@ AlterTableAddConstraint(char *relationName,
#endif
/* check to see if the table to be constrained is a view. */
- if (is_view(relationName, "ALTER TABLE"))
+ if (is_viewr(relationName))
elog(ERROR, "ALTER TABLE: Cannot add constraints to views.");
switch (nodeTag(newConstraint))
@@ -1250,7 +1252,7 @@ AlterTableAddConstraint(char *relationName,
}
/* check to see if the referenced table is a view. */
- if (is_view(fkconstraint->pktable_name, "ALTER TABLE"))
+ if (is_viewr(fkconstraint->pktable_name))
elog(ERROR, "ALTER TABLE: Cannot add constraints to views.");
/*
@@ -1698,11 +1700,11 @@ LockTableCommand(LockStmt *lockstmt)
Relation rel;
int aclresult;
- if (is_view(lockstmt->relname, "LOCK TABLE"))
- elog(ERROR, "LOCK TABLE: cannot lock a view");
-
rel = heap_openr(lockstmt->relname, NoLock);
+ if (is_view(rel))
+ elog(ERROR, "LOCK TABLE: cannot lock a view");
+
if (lockstmt->mode == AccessShareLock)
aclresult = pg_aclcheck(lockstmt->relname, GetUserId(), ACL_RD);
else
@@ -1719,26 +1721,63 @@ LockTableCommand(LockStmt *lockstmt)
static
bool
-is_view (char * relname, char *command)
+is_viewr(char *name)
{
- bool retval;
- char rulequery[41+NAMEDATALEN];
- void *qplan;
- char nulls[1]="";
-
- sprintf(rulequery, "select * from pg_views where viewname='%s'", relname);
- if (SPI_connect()!=SPI_OK_CONNECT)
- elog(ERROR, "%s: Unable to determine if %s is a view - SPI_connect failure..", command, relname);
- qplan=SPI_prepare(rulequery, 0, NULL);
- if (!qplan)
- elog(ERROR, "%s: Unable to determine if %s is a view - SPI_prepare failure.", command, relname);
- qplan=SPI_saveplan(qplan);
- if (SPI_execp(qplan, NULL, nulls, 1)!=SPI_OK_SELECT)
- elog(ERROR, "%s: Unable to determine if %s is a view - SPI_execp failure.", command, relname);
-
- retval = (SPI_processed != 0);
- if (SPI_finish() != SPI_OK_FINISH)
- elog(NOTICE, "SPI_finish() failed in %s", command);
+ Relation rel = heap_openr(name, NoLock);
+
+ bool retval = is_view(rel);
+
+ heap_close(rel, NoLock);
+
+ return retval;
+}
+
+static
+bool
+is_view (Relation rel)
+{
+ Relation RewriteRelation;
+ HeapScanDesc scanDesc;
+ ScanKeyData scanKeyData;
+ HeapTuple tuple;
+ Form_pg_rewrite data;
+
+
+ bool retval = 0;
+
+ /*
+ * Open the pg_rewrite relation.
+ */
+ RewriteRelation = heap_openr(RewriteRelationName, RowExclusiveLock);
+
+ /*
+ * Scan the RuleRelation ('pg_rewrite') for all the tuples that has
+ * the same ev_class as the relation being checked.
+ */
+ ScanKeyEntryInitialize(&scanKeyData,
+ 0,
+ Anum_pg_rewrite_ev_class,
+ F_OIDEQ,
+ ObjectIdGetDatum(rel->rd_id));
+ scanDesc = heap_beginscan(RewriteRelation,
+ 0, SnapshotNow, 1, &scanKeyData);
+
+ while (HeapTupleIsValid(tuple = heap_getnext(scanDesc, 0)))
+ {
+ if (tuple->t_data != NULL)
+ {
+ data = (Form_pg_rewrite) GETSTRUCT(tuple);
+ if (data->ev_type == '1')
+ {
+ retval = 1;
+ break;
+ }
+ }
+
+ }
+ heap_endscan(scanDesc);
+ heap_close(RewriteRelation, RowExclusiveLock);
+
return retval;
}
--
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