回复： [BUGS] BUG #13762: server will crash after superuser alter function and set client_encoding

Although its is in the category of "don't do that", but server crashed is dangerous. If I alter a function to "set work_mem = '4MB'", it should be no problem and reasonable.

Sorry, the correct statements which make server crash is:

1. alter function koi8r_to_utf8(integer, integer, cstring, internal, integer) set work_mem = '4MB';
2. set client_encoding = 'koi8';
3. select 1;

------------------ 原始邮件 ------------------
发件人: "Tom Lane";<tgl(at)sss(dot)pgh(dot)pa(dot)us>;
发送时间: 2015年11月9日(星期一) 晚上10:45
收件人: "笑见江湖"<funnyxj(at)qq(dot)com>;
抄送: "pgsql-bugs"<pgsql-bugs(at)postgresql(dot)org>;
主题: Re: [BUGS] BUG #13762: server will crash after superuser alter function and set client_encoding

funnyxj(at)qq(dot)com writes:
> When superuser execute the following statements, the server will crash, it
> may be a bug.

> 1. alter function koi8r_to_utf8(integer, integer, cstring, internal,
> integer) set work_mem = default ;

That would be in the category of "don't do that". Encoding conversion
functions are invoked using special code paths that don't support every
possible option for functions, so I'm not too surprised that this breaks
things (and I see no reason to expend effort to try to make it not be
broken).

FWIW, I can't reproduce a crash with the described case either, so
I think there's probably some additional condition required. But
it doesn't really matter. Mucking with the properties of built-in
functions isn't considered a supported thing to do.

regards, tom lane

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