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Fix longstanding bug with VIEW using BETWEEN: OffsetVarNodes would get

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applied to the duplicated subtree twice.  Probably someday we should
fix the parser not to generate multiple links to the same subtree,
but for now a quick copyObject() is the path of least resistance.
This commit is contained in:
Tom Lane 2000-12-21 17:36:15 +00:00
parent 4408f04208
commit 0e952cdb90
1 changed files with 29 additions and 28 deletions
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57
src/backend/commands/view.c
View File

@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: view.c,v 1.50 2000/10/26 17:04:12 tgl Exp $
* $Id: view.c,v 1.51 2000/12/21 17:36:15 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -156,12 +156,12 @@ FormViewRetrieveRule(char *viewName, Query *viewParse)
static void
DefineViewRules(char *viewName, Query *viewParse)
{
RuleStmt *retrieve_rule = NULL;
RuleStmt *retrieve_rule;
#ifdef NOTYET
RuleStmt *replace_rule = NULL;
RuleStmt *append_rule = NULL;
RuleStmt *delete_rule = NULL;
RuleStmt *replace_rule;
RuleStmt *append_rule;
RuleStmt *delete_rule;
#endif
@ -198,16 +198,11 @@ DefineViewRules(char *viewName, Query *viewParse)
* Of course we must also increase the 'varnos' of all the Var nodes
* by 2...
*
* These extra RT entries are not actually used in the query, obviously.
* We add them so that views look the same as ON SELECT rules ---
* the rule rewriter assumes that ALL rules have OLD and NEW RTEs.
*
* NOTE: these are destructive changes. It would be difficult to
* make a complete copy of the parse tree and make the changes
* in the copy.
* These extra RT entries are not actually used in the query,
* except for run-time permission checking.
*---------------------------------------------------------------
*/
static void
static Query *
UpdateRangeTableOfViewParse(char *viewName, Query *viewParse)
{
List *new_rt;
@ -215,7 +210,17 @@ UpdateRangeTableOfViewParse(char *viewName, Query *viewParse)
*rt_entry2;
/*
* create the 2 new range table entries and form the new range
* Make a copy of the given parsetree. It's not so much that we
* don't want to scribble on our input, it's that the parser has
* a bad habit of outputting multiple links to the same subtree
* for constructs like BETWEEN, and we mustn't have OffsetVarNodes
* increment the varno of a Var node twice. copyObject will expand
* any multiply-referenced subtree into multiple copies.
*/
viewParse = (Query *) copyObject(viewParse);
/*
* Create the 2 new range table entries and form the new range
* table... OLD first, then NEW....
*/
rt_entry1 = addRangeTableEntry(NULL, viewName,
@ -230,16 +235,14 @@ UpdateRangeTableOfViewParse(char *viewName, Query *viewParse)
new_rt = lcons(rt_entry1, lcons(rt_entry2, viewParse->rtable));
/*
* Now the tricky part.... Update the range table in place... Be
* careful here, or hell breaks loooooooooooooOOOOOOOOOOOOOOOOOOSE!
*/
viewParse->rtable = new_rt;
/*
* now offset all var nodes by 2, and jointree RT indexes too.
* Now offset all var nodes by 2, and jointree RT indexes too.
*/
OffsetVarNodes((Node *) viewParse, 2, 0);
return viewParse;
}
/*-------------------------------------------------------------------
@ -257,15 +260,11 @@ UpdateRangeTableOfViewParse(char *viewName, Query *viewParse)
void
DefineView(char *viewName, Query *viewParse)
{
List *viewTlist;
viewTlist = viewParse->targetList;
/*
* Create the "view" relation NOTE: if it already exists, the xact
* will be aborted.
*/
DefineVirtualRelation(viewName, viewTlist);
DefineVirtualRelation(viewName, viewParse->targetList);
/*
* The relation we have just created is not visible to any other
@ -276,11 +275,13 @@ DefineView(char *viewName, Query *viewParse)
/*
* The range table of 'viewParse' does not contain entries for the
* "OLD" and "NEW" relations. So... add them! NOTE: we make the
* update in place! After this call 'viewParse' will never be what it
* used to be...
* "OLD" and "NEW" relations. So... add them!
*/
viewParse = UpdateRangeTableOfViewParse(viewName, viewParse);
/*
* Now create the rules associated with the view.
*/
UpdateRangeTableOfViewParse(viewName, viewParse);
DefineViewRules(viewName, viewParse);
}