Re: Use %u to print user mapping's umid and userid

From: Etsuro Fujita <fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp>
To: Ashutosh Bapat <ashutosh(dot)bapat(at)enterprisedb(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Use %u to print user mapping's umid and userid
Date: 2016-03-14 07:59:29
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On 2016/02/09 14:09, Ashutosh Bapat wrote:
> Sorry, I was wrong. For public user mapping userid is 0 (InvalidOid),
> which is returned as is in UserMapping object. I confused InvalidOid
> with -1.

I think the following umid handling in postgresGetForeignPlan has the
same issue:

* Build the fdw_private list that will be available to the executor.
* Items in the list must match order in enum FdwScanPrivateIndex.
fdw_private = list_make4(makeString(,

I don't think it's correct to use makeInteger for the foreignrel's umid.

You store the umid in the fdw_private list here and extract it from the
list in postgresBeginForeignScan, to get the user mapping. But we
really need that? We have a validated plan when getting called from
postgresBeginForeignScan, so if foreign join, we can simply pick any of
the plan's fs_relids and use it to identify which user to do the remote
access as, in the same way as for foreign tables.

Attached is a patch for that.

Best regards,
Etsuro Fujita

Attachment Content-Type Size
postgres-fdw-umid.patch application/x-patch 4.0 KB

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