After reading the code and the patch, I think the patch is good. If the type is non-collatable, we do not add a CollateExpr node as a 'parent' node to the coerced node.
________________________________ 发件人: Tom Lane <[email protected]> 发送时间: 2021年4月13日 0:59 收件人: Yulin PEI <[email protected]> 抄送: [email protected] <[email protected]> 主题: Re: Core dump happens when execute sql CREATE VIEW v1(c1) AS (SELECT ('4' COLLATE "C")::INT FROM generate_series(1, 10)); Yulin PEI <[email protected]> writes: > I found it could cause a crash when executing sql statement: `CREATE VIEW > v1(c1) AS (SELECT ('4' COLLATE "C")::INT FROM generate_series(1, 10)); ` in > postgres 13.2 release. Nice catch. I don't think the code in DefineVirtualRelation is wrong: exprCollation shouldn't report any collation for an expression of a non-collatable type. Rather the problem is with an old kluge in coerce_type(), which will push a type coercion underneath a CollateExpr ... without any mind for the possibility that the coercion result isn't collatable. So the right fix is more or less the attached. regards, tom lane
