Re: pgsql: Make Vars be outer-join-aware.

Hi Tom,

On Tue, 31 Jan 2023 at 05:43, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> Make Vars be outer-join-aware.
>

Since this commit, my test setup is triggering asserts every few minutes.
The repro SQL itself doesn't make much sense, but it's the smallest I could
narrow it down to:


create table t1(a int);
create table t2(a int);
SELECT table_catalog AS c2
FROM public.t1
     INNER JOIN (t2
                 LEFT JOIN information_schema.column_udt_usage ON NULL)
        ON NULL;


Sample backtrace (can provide full backtrace if it helps):

Core was generated by `postgres: 8c1cd726c5@master@sqith: u76 postgres
127.0.0.1(55412) SELECT       '.
Program terminated with signal SIGABRT, Aborted.
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
#1  0x00007f4e32fbf859 in __GI_abort () at abort.c:79
#2  0x000055bc9fb256bf in ExceptionalCondition (
    conditionName=0x55bc9fcdaaf1 "phv->phnullingrels == NULL",
    fileName=0x55bc9fcda72f "setrefs.c", lineNumber=2208) at assert.c:66
#3  0x000055bc9f8147a4 in fix_scan_expr_mutator (node=0x55bca21c78b0,
    context=0x7fff72760960) at setrefs.c:2208
#4  0x000055bc9f768081 in expression_tree_mutator_impl (node=0x55bca21c9dc0,
    mutator=0x55bc9f8144a2 <fix_scan_expr_mutator>, context=0x7fff72760960)
    at nodeFuncs.c:3051
#5  0x000055bc9f81482c in fix_scan_expr_mutator (node=0x55bca21c9dc0,
    context=0x7fff72760960) at setrefs.c:2217
#6  0x000055bc9f76848c in expression_tree_mutator_impl (node=0x55bca21c9e10,
    mutator=0x55bc9f8144a2 <fix_scan_expr_mutator>, context=0x7fff72760960)
    at nodeFuncs.c:3137
#7  0x000055bc9f81482c in fix_scan_expr_mutator (node=0x55bca21c9e10,
    context=0x7fff72760960) at setrefs.c:2217
#8  0x000055bc9f814473 in fix_scan_expr (root=0x55bca217e358,
    node=0x55bca21c9e10, rtoffset=1, num_exec=0) at setrefs.c:2127


TRAP: failed Assert("phv->phnullingrels == NULL"), File: "setrefs.c",
Line: 2208, PID: 1045580


Thanks to SQLSmith / SQLReduce for help on this.

-
Robins Tharakan
Amazon Web Services