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Disallow non-cachable functions in functional indexes and in index 

predicates.  Per suggestion from Hiroshi.
This commit is contained in:
Tom Lane 2001-07-17 21:53:01 +00:00
parent 84a3634411
commit 75586cb584
1 changed files with 24 additions and 2 deletions
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26
src/backend/commands/indexcmds.c
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@ -1,14 +1,14 @@
/*-------------------------------------------------------------------------
*
* indexcmds.c
* POSTGRES define, extend and remove index code.
* POSTGRES define and remove index code.
*
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/indexcmds.c,v 1.52 2001/07/16 05:06:57 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/indexcmds.c,v 1.53 2001/07/17 21:53:01 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -39,8 +39,10 @@
#include "parser/parse_type.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#define IsFuncIndex(ATTR_LIST) (((IndexElem*)lfirst(ATTR_LIST))->args != NIL)
/* non-export function prototypes */
@ -232,10 +234,21 @@ CheckPredicate(List *predList, List *rangeTable, Oid baseRelOid)
elog(ERROR,
"Partial-index predicates may refer only to the base relation");
/*
* We don't currently support generation of an actual query plan for a
* predicate, only simple scalar expressions; hence these restrictions.
*/
if (contain_subplans((Node *) predList))
elog(ERROR, "Cannot use subselect in index predicate");
if (contain_agg_clause((Node *) predList))
elog(ERROR, "Cannot use aggregate in index predicate");
/*
* A predicate using noncachable functions is probably wrong, for the
* same reasons that we don't allow a functional index to use one.
*/
if (contain_noncachable_functions((Node *) predList))
elog(ERROR, "Cannot use non-cachable function in index predicate");
}
@ -308,6 +321,15 @@ FuncIndexArgs(IndexInfo *indexInfo,
"Index function must be binary-compatible with table datatype");
}
/*
* Require that the function be marked cachable. Using a noncachable
* function for a functional index is highly questionable, since if you
* aren't going to get the same result for the same data every time,
* it's not clear what the index entries mean at all.
*/
if (!func_iscachable(funcid))
elog(ERROR, "DefineIndex: index function must be marked iscachable");
/* Process opclass, using func return type as default type */
classOidP[0] = GetAttrOpClass(funcIndex, rettype,