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Clean up handling of COLLATE clauses in index column definitions.

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Ensure that COLLATE at the top level of an index expression is treated the
same as a grammatically separate COLLATE.  Fix bogus reverse-parsing logic
in pg_get_indexdef.
This commit is contained in:
Tom Lane
2011-03-24 15:29:52 -04:00
parent 472671e133
commit 3bba9ce945
6 changed files with 94 additions and 70 deletions
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85
src/backend/commands/indexcmds.c
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@@ -837,49 +837,62 @@ ComputeIndexAttrs(IndexInfo *indexInfo,
attcollation = attform->attcollation;
ReleaseSysCache(atttuple);
}
else if (attribute->expr && IsA(attribute->expr, Var) &&
((Var *) attribute->expr)->varattno != InvalidAttrNumber)
{
/* Tricky tricky, he wrote (column) ... treat as simple attr */
Var *var = (Var *) attribute->expr;
indexInfo->ii_KeyAttrNumbers[attn] = var->varattno;
atttype = get_atttype(relId, var->varattno);
attcollation = var->varcollid;
}
else
{
/* Index expression */
Assert(attribute->expr != NULL);
indexInfo->ii_KeyAttrNumbers[attn] = 0; /* marks expression */
indexInfo->ii_Expressions = lappend(indexInfo->ii_Expressions,
attribute->expr);
atttype = exprType(attribute->expr);
attcollation = exprCollation(attribute->expr);
Node *expr = attribute->expr;
Assert(expr != NULL);
atttype = exprType(expr);
attcollation = exprCollation(expr);
/*
* We don't currently support generation of an actual query plan
* for an index expression, only simple scalar expressions; hence
* these restrictions.
* Strip any top-level COLLATE clause. This ensures that we treat
* "x COLLATE y" and "(x COLLATE y)" alike.
*/
if (contain_subplans(attribute->expr))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot use subquery in index expression")));
if (contain_agg_clause(attribute->expr))
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in index expression")));
while (IsA(expr, CollateExpr))
expr = (Node *) ((CollateExpr *) expr)->arg;
/*
* A expression using mutable functions is probably wrong, 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 (CheckMutability((Expr *) attribute->expr))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("functions in index expression must be marked IMMUTABLE")));
if (IsA(expr, Var) &&
((Var *) expr)->varattno != InvalidAttrNumber)
{
/*
* User wrote "(column)" or "(column COLLATE something)".
* Treat it like simple attribute anyway.
*/
indexInfo->ii_KeyAttrNumbers[attn] = ((Var *) expr)->varattno;
}
else
{
indexInfo->ii_KeyAttrNumbers[attn] = 0; /* marks expression */
indexInfo->ii_Expressions = lappend(indexInfo->ii_Expressions,
expr);
/*
* We don't currently support generation of an actual query
* plan for an index expression, only simple scalar
* expressions; hence these restrictions.
*/
if (contain_subplans(expr))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot use subquery in index expression")));
if (contain_agg_clause(expr))
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in index expression")));
/*
* A expression using mutable functions is probably wrong,
* 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 (CheckMutability((Expr *) expr))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("functions in index expression must be marked IMMUTABLE")));
}
}
/*