From: Tom Lane <tgl@sss.pgh.pa.us>
To: David G. Johnston <david.g.johnston@gmail.com>
Cc: exe-dealer <exe-dealer@yandex.ru>
Cc: pgsql-bugs@lists.postgresql.org <pgsql-bugs@lists.postgresql.org>
Subject: Re: jsonb subscript operator returns null when key is fetched from table
Date: Mon, 12 Dec 2022 14:09:21 -0500
Message-ID: <2035559.1670872161@sss.pgh.pa.us> (raw)
In-Reply-To: <CAKFQuwaKHLG5cPPmeoE0uYu5MYrHkwxhH1LV9aE0QrcDk0GnpA@mail.gmail.com>
References: <205321670615953@mail.yandex.ru>
<CAKFQuwaKHLG5cPPmeoE0uYu5MYrHkwxhH1LV9aE0QrcDk0GnpA@mail.gmail.com>
"David G. Johnston" <david.g.johnston@gmail.com> writes:
> Someone more experienced than I will need to actually do the debugging work
> though; hoping this reply will be seen by one of them.
Meh. Somebody was cavalier about detoasting the subscript:
jbvp = getKeyJsonValueFromContainer(container,
VARDATA(path[i]),
VARSIZE(path[i]) - VARHDRSZ,
NULL);
Neither VARDATA nor VARSIZE are valid to apply to an arbitrary datum.
Apparently, nobody has ever tested this with a subscript value fetched
straight from disk :-(. The given example accidentally works with
a NOT MATERIALIZED CTE because the whole thing gets stepwise folded
to constants. Likewise, the expression with || accidentally works
because concatenation always yields a non-toasted result.
regards, tom lane
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Cc: tgl@sss.pgh.pa.us, david.g.johnston@gmail.com, exe-dealer@yandex.ru, pgsql-bugs@lists.postgresql.org
Subject: Re: jsonb subscript operator returns null when key is fetched from table
In-Reply-To: <2035559.1670872161@sss.pgh.pa.us>
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