Re: Getting sorted data from foreign server

On Fri, Oct 30, 2015 at 6:19 AM, Ashutosh Bapat
<ashutosh(dot)bapat(at)enterprisedb(dot)com> wrote:
> If there is a collate clause in the ORDER BY, the server crashes with
> assertion
> + Assert(loc_cxt.state == FDW_COLLATE_NONE ||
> + loc_cxt.state == FDW_COLLATE_SAFE);
>
>
> The assertion is fine as long as is_foreign_expr() tests only boolean
> expressions (appearing in quals). This patch uses the function to test an
> expression appearing in ORDER BY clause, which need not be boolean. Attached
> patch removed the assertion and instead makes the function return false,
> when the walker deems collation of the expression unsafe. The walker can not
> return false when it encounter unsafe expression since the subtree it's
> examining might be part of an expression which does not use the collation
> ultimately.

I've committed this version.

--
Robert Haas
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